package main

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"reflect"
	"sort"
	"strings"
	"syscall"
	"testing"
	"time"

	"github.com/google/shlex"
)

// =============================================================================
// Direct tests for shlex parsing (the Phase 1.1 improvement)
// =============================================================================

func TestShlexParsing_SingleQuotes(t *testing.T) {
	args, err := shlex.Split("echo 'hello world'")
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 2 {
		t.Fatalf("expected 2 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != "hello world" {
		t.Errorf("expected 'hello world', got '%s'", args[1])
	}
}

func TestShlexParsing_DoubleQuotes(t *testing.T) {
	args, err := shlex.Split(`echo "hello world"`)
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 2 {
		t.Fatalf("expected 2 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != "hello world" {
		t.Errorf("expected 'hello world', got '%s'", args[1])
	}
}

func TestShlexParsing_MixedQuotes(t *testing.T) {
	args, err := shlex.Split(`echo 'single' "double" unquoted`)
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 4 {
		t.Fatalf("expected 4 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != "single" {
		t.Errorf("expected 'single', got '%s'", args[1])
	}
	if args[2] != "double" {
		t.Errorf("expected 'double', got '%s'", args[2])
	}
	if args[3] != "unquoted" {
		t.Errorf("expected 'unquoted', got '%s'", args[3])
	}
}

func TestShlexParsing_EscapedSpaces(t *testing.T) {
	args, err := shlex.Split("echo file\\ with\\ spaces")
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 2 {
		t.Fatalf("expected 2 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != "file with spaces" {
		t.Errorf("expected 'file with spaces', got '%s'", args[1])
	}
}

func TestShlexParsing_NestedQuotes(t *testing.T) {
	args, err := shlex.Split(`echo "hello \"world\""`)
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 2 {
		t.Fatalf("expected 2 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != `hello "world"` {
		t.Errorf("expected 'hello \"world\"', got '%s'", args[1])
	}
}

func TestShlexParsing_MultipleSpaces(t *testing.T) {
	args, err := shlex.Split("echo   arg1   arg2")
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 3 {
		t.Fatalf("expected 3 args, got %d: %v", len(args), args)
	}
	if args[0] != "echo" {
		t.Errorf("expected 'echo', got '%s'", args[0])
	}
	if args[1] != "arg1" {
		t.Errorf("expected 'arg1', got '%s'", args[1])
	}
	if args[2] != "arg2" {
		t.Errorf("expected 'arg2', got '%s'", args[2])
	}
}

func TestShlexParsing_Empty(t *testing.T) {
	args, err := shlex.Split("")
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 0 {
		t.Fatalf("expected 0 args for empty string, got %d: %v", len(args), args)
	}
}

func TestShlexParsing_WhitespaceOnly(t *testing.T) {
	args, err := shlex.Split("   ")
	if err != nil {
		t.Fatalf("shlex.Split failed: %v", err)
	}
	if len(args) != 0 {
		t.Fatalf("expected 0 args for whitespace, got %d: %v", len(args), args)
	}
}

func TestShlexParsing_InvalidUnclosedQuote(t *testing.T) {
	_, err := shlex.Split("echo 'unclosed")
	if err == nil {
		t.Error("expected error for unclosed quote, got nil")
	}
}

func TestShlexParsing_InvalidUnclosedDoubleQuote(t *testing.T) {
	_, err := shlex.Split(`echo "unclosed`)
	if err == nil {
		t.Error("expected error for unclosed double quote, got nil")
	}
}

// =============================================================================
// Tests for execInput with controlled environment
// =============================================================================

func TestExecInput_CdNoArgs(t *testing.T) {
	// cd with no args now goes to home directory
	// Save current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	err := execInput("cd")
	if err != nil {
		t.Errorf("cd with no args should go to home, got error: %v", err)
	}

	// Verify we changed to home directory
	home := getHomeDir()
	newDir, _ := os.Getwd()
	if newDir != home {
		t.Errorf("expected to be in home dir %s, but in %s", home, newDir)
	}
}

func TestExecInput_EmptyInput(t *testing.T) {
	err := execInput("")
	if err != nil {
		t.Errorf("expected nil for empty input, got %v", err)
	}
}

func TestExecInput_WhitespaceInput(t *testing.T) {
	err := execInput("   ")
	if err != nil {
		t.Errorf("expected nil for whitespace input, got %v", err)
	}
}

func TestErrNoPath(t *testing.T) {
	if ErrNoPath.Error() != "path required" {
		t.Errorf("expected 'path required', got '%s'", ErrNoPath.Error())
	}
}

// =============================================================================
// Integration tests using subprocess (minimal, run sequentially)
// =============================================================================

func TestShell_EndToEnd(t *testing.T) {
	// Test basic shell interaction
	tests := []struct {
		name         string
		input        string
		expectOutput string
		expectError  bool
	}{
		{"echo simple", "echo hello\nquit\n", "hello", false},
		{"echo quoted", "echo 'hello world'\nquit\n", "hello world", false},
		{"pwd", "pwd\nquit\n", "", false}, // pwd output depends on current dir
		{"cd to home", "cd\npwd\nquit\n", "", false},
		{"cd with tilde", "cd ~\npwd\nquit\n", "", false},
		{"quit", "quit\n", "", false},
		{"exit", "exit\n", "", false},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			cmd := exec.Command("go", "run", ".")
			cmd.Stdin = strings.NewReader(tc.input)
			var stdout, stderr bytes.Buffer
			cmd.Stdout = &stdout
			cmd.Stderr = &stderr

			_ = cmd.Run()

			output := stdout.String()

			if tc.expectOutput != "" && !strings.Contains(output, tc.expectOutput) {
				t.Errorf("%s: expected output to contain '%s', got: %s", tc.name, tc.expectOutput, output)
			}

			if tc.expectError {
				combined := output + stderr.String()
				if !strings.Contains(combined, "path required") &&
					!strings.Contains(combined, "error") {
					t.Errorf("%s: expected error, got stdout: %s, stderr: %s", tc.name, output, stderr.String())
				}
			}
		})
	}
}

// =============================================================================
// Tests for Phase 1.2: Graceful Ctrl+D and Ctrl+C handling
// =============================================================================

func TestShell_EOF_ExitsGracefully(t *testing.T) {
	// Simulate EOF by sending empty input
	// Note: When using piped input, readline doesn't print prompts
	// So we just verify the shell exits cleanly
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	// Shell should exit cleanly on EOF
	if err != nil {
		t.Logf("Shell exited with: %v", err)
	}
	// When using piped input, readline doesn't print prompts
	// So we just check that it exited cleanly
	_ = stdout.String()
}

func TestShell_EOF_AfterCommand(t *testing.T) {
	// Test that EOF after a command works
	// Note: When using piped input, readline doesn't print prompts
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("echo test\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("Shell exited with: %v", err)
	}

	output := stdout.String()
	// Should contain the echo output
	if !strings.Contains(output, "test") {
		t.Errorf("expected 'test' in output, got: %s", output)
	}
	// Note: With piped input, readline doesn't print prompts
	// In a real TTY, the prompt would be shown
}

func TestShell_SIGINT_HandlerSetup(t *testing.T) {
	// This test verifies that the shell doesn't panic when receiving signals
	// We can't easily test SIGINT handling from a test, but we can verify
	// the shell runs without crashing
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("echo test\nquit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("Shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	if !strings.Contains(output, "test") {
		t.Errorf("expected 'test' in output, got: %s", output)
	}
}

// =============================================================================
// Tests for Phase 1.3: cd to home, ~ expansion, cd -
// =============================================================================

func TestExecInput_CdToHomeWithTilde(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	// Test cd ~
	err := execInput("cd ~")
	if err != nil {
		t.Errorf("cd ~ failed: %v", err)
	}

	home := getHomeDir()
	newDir, _ := os.Getwd()
	if newDir != home {
		t.Errorf("expected to be in home dir %s, but in %s", home, newDir)
	}
}

func TestExecInput_CdWithTildePath(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	// Test cd ~/ (this should go to home)
	// But we can't easily test this without knowing the home structure
	// So let's just test that tilde expansion doesn't cause errors
	err := execInput("cd ~")
	if err != nil {
		t.Errorf("cd ~ failed: %v", err)
	}
}

func TestExecInput_CdDash(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	// First, cd to a temp dir
	tmpDir := t.TempDir()
	err := execInput("cd " + tmpDir)
	if err != nil {
		t.Fatalf("cd to tmpDir failed: %v", err)
	}

	// Now cd - should go back
	err = execInput("cd -")
	if err != nil {
		t.Fatalf("cd - failed: %v", err)
	}

	// Verify we're back in origDir
	newDir, _ := os.Getwd()
	if newDir != origDir {
		t.Errorf("cd -: expected to be in %s, but in %s", origDir, newDir)
	}
}

func TestExecInput_CdDashNoPrevious(t *testing.T) {
	// Reset previousDir for this test
	origPrevDir := previousDir
	defer func() { previousDir = origPrevDir }()
	previousDir = ""

	// cd - with no previous directory should return an error
	err := execInput("cd -")
	if err == nil {
		t.Error("cd - with no previous directory: expected error, got nil")
	}
	if !strings.Contains(err.Error(), "no previous directory") {
		t.Errorf("expected 'no previous directory' error, got: %v", err)
	}
}

// =============================================================================
// Tests for Phase 2.1: Dynamic Prompt
// =============================================================================

func TestGetPrompt_Format(t *testing.T) {
	prompt := getPrompt()

	// Should contain username@hostname:path $ pattern
	if !strings.Contains(prompt, "@") {
		t.Errorf("expected @ in prompt, got: %s", prompt)
	}
	if !strings.Contains(prompt, ":") {
		t.Errorf("expected : in prompt, got: %s", prompt)
	}
	if !strings.Contains(prompt, "$") {
		t.Errorf("expected $ in prompt, got: %s", prompt)
	}
}

func TestGetPrompt_IncludesHome(t *testing.T) {
	// Save and restore current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	// Change to home directory
	os.Chdir(getHomeDir())

	prompt := getPrompt()
	// When in home, should show ~
	if !strings.Contains(prompt, "~") {
		t.Errorf("expected ~ in prompt when in home dir, got: %s", prompt)
	}
}

// =============================================================================
// Tests for Phase 2.2: Exit Status Code
// =============================================================================

func TestExecInput_ExitWithStatusCode(t *testing.T) {
	// We can't easily test os.Exit from a unit test
	// So we just verify the function doesn't panic with a status code
	// The actual exit behavior is tested in integration tests

	// This test just documents the expected behavior
	// Actual testing requires subprocess
	_ = true // Placeholder - integration tests handle this
}

func TestShell_ExitWithStatusCode(t *testing.T) {
	// Test exit with custom status code
	// Note: We build the binary first because 'go run' doesn't preserve exit codes properly
	tests := []struct {
		input    string
		expected int
	}{
		{"exit\n", 0},
		{"exit 0\n", 0},
		{"exit 1\n", 1},
		{"exit 42\n", 42},
		{"quit\n", 0},
		{"quit 0\n", 0},
		{"quit 5\n", 5},
	}

	// Build the binary once
	build := exec.Command("go", "build", "-o", "gosh_test", ".")
	if err := build.Run(); err != nil {
		t.Fatalf("failed to build: %v", err)
	}
	defer os.Remove("gosh_test")

	for _, tc := range tests {
		t.Run(tc.input, func(t *testing.T) {
			cmd := exec.Command("./gosh_test")
			cmd.Stdin = strings.NewReader(tc.input)

			err := cmd.Run()
			if err == nil && tc.expected != 0 {
				t.Errorf("expected non-zero exit code %d, got 0", tc.expected)
			}
			if err != nil {
				// Check the exit code
				if exitErr, ok := err.(*exec.ExitError); ok {
					actualCode := exitErr.ExitCode()
					if actualCode != tc.expected {
						t.Errorf("expected exit code %d, got %d", tc.expected, actualCode)
					}
				} else {
					// Not an ExitError, might be another error
					t.Logf("got error: %v", err)
				}
			}
		})
	}
}

// =============================================================================
// Tests for Phase 2.3: Environment Variable Expansion
// =============================================================================

func TestShell_EnvExpansion_Home(t *testing.T) {
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("echo $HOME\nexit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	home := getHomeDir()
	if !strings.Contains(output, home) {
		t.Errorf("expected home dir %s in output, got: %s", home, output)
	}
}

func TestShell_EnvExpansion_Path(t *testing.T) {
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("echo $PATH\nexit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	// PATH should contain : (path separator)
	if !strings.Contains(output, ":") {
		t.Errorf("expected PATH with : separator in output, got: %s", output)
	}
}

func TestShell_EnvExpansion_Braces(t *testing.T) {
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("echo ${HOME}\nexit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	home := getHomeDir()
	if !strings.Contains(output, home) {
		t.Errorf("expected home dir %s in output with ${HOME}, got: %s", home, output)
	}
}

func TestShell_EnvExpansion_CdWithVar(t *testing.T) {
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("cd $HOME\npwd\nexit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	home := getHomeDir()
	if !strings.Contains(output, home) {
		t.Errorf("expected home dir %s in pwd output, got: %s", home, output)
	}
}

func TestShell_TildeExpansion_Ls(t *testing.T) {
	cmd := exec.Command("go", "run", ".")
	cmd.Stdin = strings.NewReader("ls ~\nexit\n")
	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	err := cmd.Run()
	if err != nil {
		t.Logf("shell exited with: %v, stderr: %s", err, stderr.String())
	}

	output := stdout.String()
	// Should contain files from home directory
	// We can't predict exact files, but it should have some output
	if strings.TrimSpace(output) == "" {
		t.Errorf("expected output from ls ~, got empty")
	}
}

// =============================================================================
// Tests for Phase 2.5, 2.6, 2.7: set/export commands, help
// =============================================================================

func TestExecInput_SetEnvVar(t *testing.T) {
	// Save original value
	orig := os.Getenv("GOSH_TEST_VAR")
	defer os.Setenv("GOSH_TEST_VAR", orig)

	// Set a new variable
	err := execInput("set GOSH_TEST_VAR=test_value")
	if err != nil {
		t.Errorf("set failed: %v", err)
	}

	// Verify it was set
	val := os.Getenv("GOSH_TEST_VAR")
	if val != "test_value" {
		t.Errorf("expected 'test_value', got '%s'", val)
	}
}

func TestExecInput_ExportEnvVar(t *testing.T) {
	// Save original value
	orig := os.Getenv("GOSH_TEST_VAR2")
	defer os.Setenv("GOSH_TEST_VAR2", orig)

	// Export a new variable
	err := execInput("export GOSH_TEST_VAR2=exported_value")
	if err != nil {
		t.Errorf("export failed: %v", err)
	}

	// Verify it was set
	val := os.Getenv("GOSH_TEST_VAR2")
	if val != "exported_value" {
		t.Errorf("expected 'exported_value', got '%s'", val)
	}
}

func TestExecInput_SetNoArgs(t *testing.T) {
	// set without arguments shows the variables, quoted for the shell
	t.Setenv("GOSH_SHOWN", "a b")
	got := runIn(t, "set > out")
	if !strings.Contains(got, "GOSH_SHOWN='a b'\n") {
		t.Errorf("set: GOSH_SHOWN missing in %q", got)
	}
}

func TestExecInput_ExportNoArgs(t *testing.T) {
	err := execInput("export")
	if err == nil {
		t.Error("expected error for export with no args, got nil")
	}
	if !strings.Contains(err.Error(), "usage: export VAR=value") {
		t.Errorf("expected usage error, got: %v", err)
	}
}

func TestVersionInfo(t *testing.T) {
	origVersion, origCommit, origBranch := version, commit, branch
	defer func() { version, commit, branch = origVersion, origCommit, origBranch }()

	version, commit, branch = "1.2.3", "abc1234", "main"
	if got := versionInfo(); got != "1.2.3 (branch: main, commit: abc1234)" {
		t.Errorf("versionInfo() = %q", got)
	}

	branch = ""
	if got := versionInfo(); got != "1.2.3 (commit: abc1234)" {
		t.Errorf("versionInfo() without branch = %q", got)
	}
}

func TestExecInput_Help(t *testing.T) {
	// Just verify help doesn't return an error
	// We can't easily capture stdout in a unit test without a pipe
	// but we can verify it doesn't crash
	err := execInput("help")
	if err != nil {
		t.Errorf("help failed: %v", err)
	}
	// If we get here without panicking, help command works
}

// =============================================================================
// Tests for Command Completion (Phase 3: Tab Completion)
// =============================================================================

func TestFilePathCompleter_CurrentDirectory(t *testing.T) {
	// Save and restore current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	// Create a temp directory with known files
	tmpDir := t.TempDir()
	os.Chdir(tmpDir)

	// Create test files and directories
	os.Create("file_a.txt")
	os.Create("file_b.txt")
	os.Create("file_c.txt")
	os.Mkdir("dir_a", 0755)
	os.Mkdir("dir_b", 0755)

	// Test completion for "ls file_"
	// Extract the prefix (last word after space)
	line := "ls file_"
	prefix := "file_"
	matches := completeFilePath(line, prefix)
	if len(matches) == 0 {
		t.Error("expected matches for 'ls file_', got none")
	}

	// All matches should contain "file_"
	for _, m := range matches {
		if !strings.Contains(m, "file_") {
			t.Errorf("match %s doesn't contain 'file_'", m)
		}
	}
}

func TestFilePathCompleter_AbsolutePath(t *testing.T) {
	// Create a temp directory with known structure
	tmpDir := t.TempDir()
	os.Mkdir(filepath.Join(tmpDir, "testdir"), 0755)
	os.Create(filepath.Join(tmpDir, "testdir", "file1.txt"))
	os.Create(filepath.Join(tmpDir, "testdir", "file2.txt"))

	// Test completion for absolute path
	line := "ls " + tmpDir + "/te"
	prefix := tmpDir + "/te"
	matches := completeFilePath(line, prefix)
	if len(matches) == 0 {
		t.Error("expected matches for absolute path, got none")
	}

	// All matches should contain "testdir"
	found := false
	for _, m := range matches {
		if strings.Contains(m, "testdir") {
			found = true
			break
		}
	}
	if !found {
		t.Errorf("expected match containing 'testdir', got: %v", matches)
	}
}

func TestFilePathCompleter_TildeExpansion(t *testing.T) {
	// Save and restore current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	home := getHomeDir()
	if home == "" {
		t.Skip("skipping: HOME directory not available")
	}

	// Create a test file in home if possible
	// (we can't always write to home, so we'll just test the completer logic)
	matches := completeFilePath("ls ~/", "~/")
	// Just verify it doesn't panic - actual matches depend on home directory contents
	_ = matches
}

func TestFilePathCompleter_DirectoriesWithTrailingSlash(t *testing.T) {
	// Save and restore current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	tmpDir := t.TempDir()
	os.Chdir(tmpDir)

	// Create a subdirectory
	os.Mkdir("subdir", 0755)
	os.Create("subdir/file.txt")

	// Test completion when the prefix already has a trailing slash
	matches := completeFilePath("ls subdir/", "subdir/")
	if len(matches) == 0 {
		t.Error("expected matches for 'ls subdir/', got none")
	}

	// Matches should include the file in the subdirectory
	found := false
	for _, m := range matches {
		if strings.Contains(m, "file.txt") {
			found = true
			break
		}
	}
	if !found {
		t.Errorf("expected match containing 'file.txt', got: %v", matches)
	}
}

func TestFilePathCompleter_NoMatches(t *testing.T) {
	// Save and restore current directory
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	tmpDir := t.TempDir()
	os.Chdir(tmpDir)

	// Test completion for a prefix that won't match anything
	matches := completeFilePath("ls xyz_nonexistent_", "xyz_nonexistent_")
	if len(matches) != 0 {
		t.Errorf("expected no matches for non-existent prefix, got: %v", matches)
	}
}

// completeLine runs the completer on line (cursor at the end) and returns the
// candidates as strings together with the reported length.
func completeLine(line string) ([]string, int) {
	cands, length := newShellCompleter().Do([]rune(line), len([]rune(line)))
	var out []string
	for _, c := range cands {
		out = append(out, string(c))
	}
	sort.Strings(out)
	return out, length
}

func TestShellCompleter_Do(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	tmpDir := t.TempDir()
	os.Chdir(tmpDir)
	os.Create("main.go")
	os.Create("my file.txt")
	os.Create(".hidden")
	os.Mkdir("subdir", 0755)
	os.Create("subdir/inner.txt")

	// Controlled PATH with one executable, one non-executable and a
	// duplicate of a builtin
	binDir := t.TempDir()
	os.WriteFile(filepath.Join(binDir, "gitty"), nil, 0755)
	os.WriteFile(filepath.Join(binDir, "girl"), nil, 0644)
	os.WriteFile(filepath.Join(binDir, "echo"), nil, 0755)
	os.Mkdir(filepath.Join(binDir, "gidir"), 0755)
	t.Setenv("PATH", binDir)

	tests := []struct {
		line   string
		want   []string
		length int
	}{
		{"c", []string{"d ", "ontinue "}, 1},
		{"e", []string{"cho ", "xit ", "xport "}, 1},
		{"gi", []string{"tty "}, 2},
		{"  gi", []string{"tty "}, 2},
		{"ls gi", nil, 2},
		{"ls ma", []string{"in.go"}, 2},
		{"ls su", []string{"bdir/"}, 2},
		{"ls subdir/", []string{"inner.txt"}, 0},
		{"ls subdir/in", []string{"ner.txt"}, 2},
		{"ls my", []string{`\ file.txt`}, 2},
		{`ls my\ f`, []string{"ile.txt"}, 4},
		{`ls "my f`, []string{"ile.txt"}, 4},
		{"ls ./ma", []string{"in.go"}, 2},
		{"ls .h", []string{"idden"}, 2},
		{"ls ", []string{"main.go", `my\ file.txt`, "subdir/"}, 0},
		{"ls " + tmpDir + "/ma", []string{"in.go"}, 2},
		{"ls xyz", nil, 3},
		{"ls ~", []string{"/"}, 1},
		// Commands are completed after |, ;, && and ||, files after redirections
		{"ls | gi", []string{"tty "}, 2},
		{"ls|gi", []string{"tty "}, 2},
		{"true; gi", []string{"tty "}, 2},
		{"true && gi", []string{"tty "}, 2},
		{"false || gi", []string{"tty "}, 2},
		{"ls > ma", []string{"in.go"}, 2},
		{"ls 2>ma", []string{"in.go"}, 2},
		{"cat <ma", []string{"in.go"}, 2},
	}
	for _, tt := range tests {
		got, length := completeLine(tt.line)
		if !reflect.DeepEqual(got, tt.want) || length != tt.length {
			t.Errorf("Do(%q) = %q, %d; want %q, %d", tt.line, got, length, tt.want, tt.length)
		}
	}
}

// =============================================================================
// Security fixes: history file, quoting/expansion, escape sequences, SIGINT
// =============================================================================

// TestMain keeps the integration tests (which run the shell as a subprocess)
// from writing into the user's real history file.
func TestMain(m *testing.M) {
	dir, err := os.MkdirTemp("", "gosh-test-")
	if err != nil {
		panic(err)
	}
	os.Setenv("GOSH_HISTFILE", filepath.Join(dir, "history"))
	// Never read the system's startup files; tests that read the user's
	// files set $HOME themselves
	sysConfDir = filepath.Join(dir, "etc")
	// Command substitution runs gosh, not the test binary
	subshellPath = filepath.Join(dir, "gosh")
	if out, err := exec.Command("go", "build", "-o", subshellPath, ".").CombinedOutput(); err != nil {
		panic(fmt.Sprintf("building gosh: %v\n%s", err, out))
	}
	code := m.Run()
	os.RemoveAll(dir)
	os.Exit(code)
}

// buildShell builds the shell into a temporary directory and returns its path
func buildShell(t *testing.T) string {
	t.Helper()
	bin := filepath.Join(t.TempDir(), "gosh")
	if out, err := exec.Command("go", "build", "-o", bin, ".").CombinedOutput(); err != nil {
		t.Fatalf("failed to build: %v\n%s", err, out)
	}
	return bin
}

func TestSplitWords(t *testing.T) {
	t.Setenv("GOSH_A", "a b")
	t.Setenv("GOSH_EMPTY", "")
	t.Setenv("GOSH_TILDE", "~/x")
	os.Unsetenv("GOSH_UNSET")
	home := getHomeDir()

	tests := []struct {
		input string
		want  []string
	}{
		{`echo hello world`, []string{"echo", "hello", "world"}},
		{`echo 'hello world'`, []string{"echo", "hello world"}},
		{`echo "hello \"world\""`, []string{"echo", `hello "world"`}},
		{`echo file\ with\ spaces`, []string{"echo", "file with spaces"}},
		{`echo '' ""`, []string{"echo", "", ""}},
		{`echo a # comment`, []string{"echo", "a"}},
		{`echo a#b`, []string{"echo", "a#b"}},
		// No expansion inside single quotes
		{`echo '$GOSH_A'`, []string{"echo", "$GOSH_A"}},
		{`grep 'foo$'`, []string{"grep", "foo$"}},
		{`echo '$GOSH_UNSET/out'`, []string{"echo", "$GOSH_UNSET/out"}},
		// Expansion outside of and inside double quotes, never word splitting
		{`echo $GOSH_A`, []string{"echo", "a b"}},
		{`echo "${GOSH_A}c"`, []string{"echo", "a bc"}},
		{`echo x${GOSH_A}y`, []string{"echo", "xa by"}},
		// Escaped and lone dollar signs stay literal
		{`echo \$GOSH_A "\$GOSH_A"`, []string{"echo", "$GOSH_A", "$GOSH_A"}},
		{`echo $ 5$ $%`, []string{"echo", "$", "5$", "$%"}},
		// Backslash in double quotes only escapes $ " \ and `
		{`echo "a\nb\\c"`, []string{"echo", `a\nb\c`}},
		// Defaults
		{`echo ${GOSH_UNSET:-def} ${GOSH_EMPTY:-def} ${GOSH_A:-def}`, []string{"echo", "def", "def", "a b"}},
		{`echo ${GOSH_UNSET:-}x`, []string{"echo", "x"}},
		// Unquoted empty expansions vanish, quoted ones are kept
		{`echo $GOSH_EMPTY x`, []string{"echo", "x"}},
		{`echo "$GOSH_EMPTY" x`, []string{"echo", "", "x"}},
		// Tilde only at the start of an unquoted word, not from variables
		{`ls ~ ~/x a~ '~' "~/x" \~`, []string{"ls", home, filepath.Join(home) + "/x", "a~", "~", "~/x", "~"}},
		{`ls ~root`, []string{"ls", "~root"}},
		{`ls $GOSH_TILDE`, []string{"ls", "~/x"}},
	}
	for _, tc := range tests {
		t.Run(tc.input, func(t *testing.T) {
			got, err := splitWords(tc.input)
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			if !reflect.DeepEqual(got, tc.want) {
				t.Errorf("got %q, want %q", got, tc.want)
			}
		})
	}
}

func TestSplitWords_Errors(t *testing.T) {
	os.Unsetenv("GOSH_UNSET")
	tests := []struct {
		input   string
		wantErr string
	}{
		{`rm -rf $GOSH_UNSET/out`, "GOSH_UNSET: unbound variable"},
		{`rm -rf "${GOSH_UNSET}/out"`, "GOSH_UNSET: unbound variable"},
		{`echo 'unclosed`, "unterminated ' quote"},
		{`echo "unclosed`, `unterminated " quote`},
		{`echo foo\`, "unexpected end of input"},
		{`echo ${GOSH_UNSET`, "missing }"},
		{`echo ${}`, "bad substitution"},
		{`echo ${1x}`, "bad substitution"},
	}
	for _, tc := range tests {
		t.Run(tc.input, func(t *testing.T) {
			got, err := splitWords(tc.input)
			if err == nil {
				t.Fatalf("expected error, got %q", got)
			}
			if !strings.Contains(err.Error(), tc.wantErr) {
				t.Errorf("expected error containing %q, got %q", tc.wantErr, err)
			}
		})
	}
}

func TestExecInput_UnsetVariableDoesNotRun(t *testing.T) {
	os.Unsetenv("GOSH_UNSET")
	marker := filepath.Join(t.TempDir(), "marker")

	// Without the fix this would have run "touch /marker"-like commands
	err := execInput("touch $GOSH_UNSET" + marker)
	if err == nil || !strings.Contains(err.Error(), "unbound variable") {
		t.Fatalf("expected unbound variable error, got %v", err)
	}
	if _, err := os.Stat(marker); err == nil {
		t.Errorf("command was executed despite unset variable")
	}
}

func TestExecInput_SingleQuotedDollarIsLiteral(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("GOSH_X", "expanded")

	if err := execInput("touch '" + dir + "/$GOSH_X'"); err != nil {
		t.Fatalf("touch failed: %v", err)
	}
	if _, err := os.Stat(filepath.Join(dir, "$GOSH_X")); err != nil {
		t.Errorf("expected literal file name $GOSH_X: %v", err)
	}
}

func TestSanitize(t *testing.T) {
	tests := []struct{ in, want string }{
		{"plain/path äöü", "plain/path äöü"},
		{"evil\x1b]0;title\x07", `evil\x1b]0;title\x07`},
		{"a\nb\tc", `a\x0ab\x09c`},
		{"bad\xffutf8", `bad\xffutf8`},
		{"bidi\u202eoverride", `bidi\u202eoverride`},
	}
	for _, tc := range tests {
		if got := sanitize(tc.in); got != tc.want {
			t.Errorf("sanitize(%q) = %q, want %q", tc.in, got, tc.want)
		}
	}
}

func TestGetPrompt_EscapesControlCharacters(t *testing.T) {
	t.Setenv("NO_COLOR", "1")
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	dir := filepath.Join(t.TempDir(), "evil\x1b[2J\x1b]52;c;cHduZWQ=\x07")
	if err := os.Mkdir(dir, 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.Chdir(dir); err != nil {
		t.Fatal(err)
	}

	prompt := getPrompt()
	if strings.ContainsAny(prompt, "\x1b\x07") {
		t.Errorf("prompt contains control characters: %q", prompt)
	}
	if !strings.Contains(prompt, `evil\x1b[2J`) {
		t.Errorf("expected escaped directory name in prompt, got %q", prompt)
	}
}

func TestBuildPrompt_Color(t *testing.T) {
	got := buildPrompt("flow", "host", "~/src", false, 0, &defaultColors)
	want := "\x1b[1;32mflow@host\x1b[0m:\x1b[1;34m~/src\x1b[0m $ "
	if got != want {
		t.Errorf("buildPrompt() = %q, want %q", got, want)
	}

	got = buildPrompt("root", "host", "/", true, 0, &defaultColors)
	if !strings.HasPrefix(got, "\x1b[1;31mroot@host") {
		t.Errorf("expected red user for root, got %q", got)
	}

	got = buildPrompt("flow", "host", "~/src", false, 0, nil)
	if got != "flow@host:~/src $ " {
		t.Errorf("buildPrompt() without color = %q", got)
	}

	colors := promptColors{user: "38;5;208", path: ""}
	got = buildPrompt("flow", "host", "~/src", false, 0, &colors)
	if got != "\x1b[38;5;208mflow@host\x1b[0m:~/src $ " {
		t.Errorf("buildPrompt() with custom colors = %q", got)
	}
}

func TestParseColors(t *testing.T) {
	tests := []struct {
		spec string
		want promptColors
	}{
		{"", defaultColors},
		{"user=1;33", promptColors{user: "1;33", root: "1;31", path: "1;34", error: "1;31"}},
		{"user=33:root=41;97:path=38;5;208", promptColors{user: "33", root: "41;97", path: "38;5;208", error: "1;31"}},
		{"error=33", promptColors{user: "1;32", root: "1;31", path: "1;34", error: "33"}},
		{"path=", promptColors{user: "1;32", root: "1;31", path: "", error: "1;31"}},
		{"path=0m\x1b[2J", defaultColors}, // escape sequences are rejected
		{"path=red", defaultColors},       // only numeric codes
		{"foo=1:user", defaultColors},     // unknown key, missing value
		{"user=35::path=36", promptColors{user: "35", root: "1;31", path: "36", error: "1;31"}},
	}
	for _, tc := range tests {
		if got := parseColors(tc.spec); got != tc.want {
			t.Errorf("parseColors(%q) = %+v, want %+v", tc.spec, got, tc.want)
		}
	}
}

func TestBuildPrompt_Status(t *testing.T) {
	if got := buildPrompt("flow", "host", "~", false, 0, nil); got != "flow@host:~ $ " {
		t.Errorf("status 0: %q", got)
	}
	if got := buildPrompt("flow", "host", "~", false, 127, nil); got != "flow@host:~ [127] $ " {
		t.Errorf("status 127 without color: %q", got)
	}
	got := buildPrompt("flow", "host", "~", false, 1, &defaultColors)
	want := "\x1b[1;32mflow@host\x1b[0m:\x1b[1;34m~\x1b[0m \x1b[1;31m[1]\x1b[0m $ "
	if got != want {
		t.Errorf("status 1 with color = %q, want %q", got, want)
	}
	colors := defaultColors
	colors.error = ""
	if got := buildPrompt("flow", "host", "~", false, 2, &colors); !strings.HasSuffix(got, " [2] $ ") {
		t.Errorf("status without error color = %q", got)
	}
}

func TestBuildPrompt_ColorEscapesControlCharacters(t *testing.T) {
	got := buildPrompt("flow", "host", "evil\x1b[2J\x07", false, 0, &defaultColors)
	if strings.Contains(got, "\x1b[2J") || strings.Contains(got, "\x07") {
		t.Errorf("prompt contains control characters from path: %q", got)
	}
	if !strings.Contains(got, `evil\x1b[2J\x07`) {
		t.Errorf("expected escaped path in prompt, got %q", got)
	}
}

func TestUseColor_NoColor(t *testing.T) {
	t.Setenv("NO_COLOR", "1")
	if useColor() {
		t.Error("expected no color when NO_COLOR is set")
	}
}

func TestFilePathCompleter_SkipsControlCharacters(t *testing.T) {
	dir := t.TempDir()
	for _, name := range []string{"good", "go\x1b[31mred"} {
		if err := os.WriteFile(filepath.Join(dir, name), nil, 0644); err != nil {
			t.Fatal(err)
		}
	}

	matches := completeFilePath("", dir+"/go")
	if !reflect.DeepEqual(matches, []string{"good"}) {
		t.Errorf("expected only [good], got %q", matches)
	}
}

func TestHistoryFile(t *testing.T) {
	t.Setenv("GOSH_HISTFILE", "/custom/history")
	if got := historyFile(); got != "/custom/history" {
		t.Errorf("expected $GOSH_HISTFILE, got %q", got)
	}

	os.Unsetenv("GOSH_HISTFILE")
	t.Setenv("XDG_STATE_HOME", "/state")
	if got := historyFile(); got != "/state/gosh/history" {
		t.Errorf("expected /state/gosh/history, got %q", got)
	}

	t.Setenv("XDG_STATE_HOME", "")
	want := filepath.Join(getHomeDir(), ".local", "state", "gosh", "history")
	if got := historyFile(); got != want {
		t.Errorf("expected %q, got %q", want, got)
	}

	// Never relative to the current directory
	if !filepath.IsAbs(historyFile()) {
		t.Errorf("history file must be an absolute path, got %q", historyFile())
	}
}

func TestPrepareHistoryFile_Permissions(t *testing.T) {
	dir := filepath.Join(t.TempDir(), "state", "gosh")
	path := filepath.Join(dir, "history")

	if err := prepareHistoryFile(path); err != nil {
		t.Fatalf("prepareHistoryFile failed: %v", err)
	}
	if info, _ := os.Stat(dir); info.Mode().Perm() != 0700 {
		t.Errorf("expected directory mode 0700, got %o", info.Mode().Perm())
	}
	if info, _ := os.Stat(path); info.Mode().Perm() != 0600 {
		t.Errorf("expected file mode 0600, got %o", info.Mode().Perm())
	}

	// Existing files and directories with too open permissions are fixed
	os.Chmod(dir, 0755)
	os.Chmod(path, 0644)
	if err := prepareHistoryFile(path); err != nil {
		t.Fatalf("prepareHistoryFile failed: %v", err)
	}
	if info, _ := os.Stat(dir); info.Mode().Perm() != 0700 {
		t.Errorf("expected directory mode 0700, got %o", info.Mode().Perm())
	}
	if info, _ := os.Stat(path); info.Mode().Perm() != 0600 {
		t.Errorf("expected file mode 0600, got %o", info.Mode().Perm())
	}
}

func TestShell_History(t *testing.T) {
	bin := buildShell(t)
	histFile := filepath.Join(t.TempDir(), "gosh", "history")
	workDir := t.TempDir()

	cmd := exec.Command(bin, "-i", "--norc")
	cmd.Dir = workDir
	cmd.Env = append(os.Environ(), "GOSH_HISTFILE="+histFile)
	cmd.Stdin = strings.NewReader("echo first\n set SECRET=hunter2\nexit\n")
	if out, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("shell failed: %v\n%s", err, out)
	}

	data, err := os.ReadFile(histFile)
	if err != nil {
		t.Fatalf("history file not written: %v", err)
	}
	history := string(data)
	if strings.Count(history, "echo first") != 1 {
		t.Errorf("expected 'echo first' exactly once in history, got %q", history)
	}
	if strings.Contains(history, "hunter2") {
		t.Errorf("line starting with a space must not be saved, got %q", history)
	}
	if info, _ := os.Stat(histFile); info.Mode().Perm() != 0600 {
		t.Errorf("expected history mode 0600, got %o", info.Mode().Perm())
	}

	// Nothing may be written into the working directory
	if entries, _ := os.ReadDir(workDir); len(entries) != 0 {
		t.Errorf("shell wrote files into the working directory: %v", entries)
	}
}

func TestShell_SIGINTKillsOnlyChild(t *testing.T) {
	bin := buildShell(t)

	cmd := exec.Command(bin, "-i", "--norc")
	// Own process group, so that we can signal it like the terminal does
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	stdin, err := cmd.StdinPipe()
	if err != nil {
		t.Fatal(err)
	}
	var stdout bytes.Buffer
	cmd.Stdout = &stdout
	if err := cmd.Start(); err != nil {
		t.Fatal(err)
	}

	start := time.Now()
	io.WriteString(stdin, "sleep 10\n")
	time.Sleep(500 * time.Millisecond)
	// Ctrl+C: SIGINT to the whole foreground process group
	syscall.Kill(-cmd.Process.Pid, syscall.SIGINT)
	io.WriteString(stdin, "echo still alive\nexit\n")
	stdin.Close()

	if err := cmd.Wait(); err != nil {
		t.Errorf("shell did not exit cleanly: %v", err)
	}
	if !strings.Contains(stdout.String(), "still alive") {
		t.Errorf("shell was killed by SIGINT, output: %q", stdout.String())
	}
	if elapsed := time.Since(start); elapsed > 5*time.Second {
		t.Errorf("child was not interrupted (took %v)", elapsed)
	}
}

func TestExecInput_PassesStdin(t *testing.T) {
	r, w, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}
	origStdin := os.Stdin
	os.Stdin = r
	defer func() {
		os.Stdin = origStdin
		r.Close()
	}()

	if _, err := w.WriteString("hello\n"); err != nil {
		t.Fatal(err)
	}
	w.Close()

	out := filepath.Join(t.TempDir(), "out")
	t.Setenv("GOSH_TEST_OUT", out)
	if err := execInput(`sh -c 'read x; printf %s "$x" > "$GOSH_TEST_OUT"'`); err != nil {
		t.Fatal(err)
	}
	got, err := os.ReadFile(out)
	if err != nil {
		t.Fatal(err)
	}
	if string(got) != "hello" {
		t.Errorf("command read %q from stdin, want %q", got, "hello")
	}
}

func TestExitStatus(t *testing.T) {
	tests := []struct {
		input string
		want  int
	}{
		{"true", 0},
		{"false", 1},
		{`sh -c "exit 42"`, 42},
		{`sh -c "kill -TERM \$\$"`, 128 + 15},
		{"gosh-no-such-command", 127},
		{"cd /gosh-no-such-dir", 127},
	}
	for _, tc := range tests {
		if got := exitStatus(execInput(tc.input)); got != tc.want {
			t.Errorf("exitStatus(execInput(%q)) = %d, want %d", tc.input, got, tc.want)
		}
	}
	if got := exitStatus(errors.New("other")); got != 1 {
		t.Errorf("exitStatus(other error) = %d, want 1", got)
	}
}

func TestRunScript(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)

	dir := t.TempDir()
	script := "#!/usr/bin/gosh\n" +
		"# comment\n" +
		"\n" +
		"cd " + dir + "\n" +
		"  # indented comment\n" +
		"touch first\n" +
		"false\n" +
		"touch second" // no trailing newline
	if got := runScript(strings.NewReader(script), ""); got != 0 {
		t.Errorf("runScript() = %d, want 0", got)
	}
	for _, name := range []string{"first", "second"} {
		if _, err := os.Stat(filepath.Join(dir, name)); err != nil {
			t.Errorf("expected %s to be created: %v", name, err)
		}
	}

	// The status of the last command is returned
	if got := runScript(strings.NewReader("true\nsh -c 'exit 3'\n"), ""); got != 3 {
		t.Errorf("runScript() = %d, want 3", got)
	}
}

func TestRun_Options(t *testing.T) {
	tests := []struct {
		args []string
		want int
	}{
		{[]string{"-c", "true"}, 0},
		{[]string{"-c", "false"}, 1},
		{[]string{"-l", "--noprofile", "-c", "sh -c 'exit 5'"}, 5},
		{[]string{"-c"}, 2},
		{[]string{"-z"}, 2},
		{[]string{"/gosh/no/such/script"}, 127},
	}
	for _, tc := range tests {
		if got := run(tc.args); got != tc.want {
			t.Errorf("run(%q) = %d, want %d", tc.args, got, tc.want)
		}
	}
}

func TestReadLine_DoesNotReadAhead(t *testing.T) {
	r := strings.NewReader("first\nsecond\n")
	line, err := readLine(r)
	if line != "first" || err != nil {
		t.Fatalf("readLine() = %q, %v", line, err)
	}
	if r.Len() != len("second\n") {
		t.Errorf("readLine() consumed more than one line, %d bytes left", r.Len())
	}
}

// treeString formats a syntax tree for the tests: simple commands in
// brackets, background commands with a trailing &.
func treeString(l *listNode) string {
	var parts []string
	for _, e := range l.items {
		s := pipelineString(e.andOr.first)
		for _, r := range e.andOr.rest {
			s += " " + r.op + " " + pipelineString(r.pipeline)
		}
		if e.background {
			s += " &"
		}
		parts = append(parts, s)
	}
	return strings.Join(parts, "; ")
}

func pipelineString(pl *pipelineNode) string {
	s := ""
	if pl.negate {
		s = "! "
	}
	switch n := pl.cmd.(type) {
	case *simpleNode:
		s += "[" + n.text + "]"
	case *ifNode:
		s += "if"
		for i := range n.conds {
			if i > 0 {
				s += " elif"
			}
			s += " " + treeString(n.conds[i]) + " then " + treeString(n.bodies[i])
		}
		if n.elseBody != nil {
			s += " else " + treeString(n.elseBody)
		}
		s += " fi"
	case *forNode:
		s += "for " + n.name
		if n.hasIn {
			s += " in (" + n.words + ")"
		}
		s += " do " + treeString(n.body) + " done"
	case *whileNode:
		if n.until {
			s += "until "
		} else {
			s += "while "
		}
		s += treeString(n.cond) + " do " + treeString(n.body) + " done"
	case *caseNode:
		s += "case " + n.word + " in"
		for _, c := range n.clauses {
			s += " (" + strings.Join(c.patterns, "|") + ") " + treeString(c.body) + " ;;"
		}
		s += " esac"
	case *groupNode:
		s += "{ " + treeString(n.body) + " }"
	case *subshellNode:
		s += "(" + n.text + ")"
	case *redirNode:
		s += pipelineString(&pipelineNode{cmd: n.cmd}) + " <" + n.redirs + ">"
	case *pipeNode:
		var elems []string
		for _, e := range n.elems {
			elems = append(elems, "<"+e.text+">")
		}
		s += strings.Join(elems, " | ")
	case *funcDefNode:
		s += n.def.name + "() " + pipelineString(&pipelineNode{cmd: n.def.body})
	}
	return s
}

func TestParse_Lists(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{"", ""},
		{"   ", ""},
		{"# only a comment", ""},
		{"ls", "[ls]"},
		{"a; b", "[a]; [b]"},
		{"a;", "[a]"},
		{"a\nb\n", "[a]; [b]"},
		{"a && b || c", "[a] && [b] || [c]"},
		{"a &&\n  b", "[a] && [b]"},
		{"a | b|c", "[a | b|c]"},
		{"a |\n b", "[a |\n b]"},
		{`echo "a;b" 'c&&d' e\;f`, `[echo "a;b" 'c&&d' e\;f]`},
		{`echo "x\"; y"`, `[echo "x\"; y"]`},
		{"echo ${X:-a;b}; c", "[echo ${X:-a;b}]; [c]"},
		{"echo a # b; c", "[echo a]"},
		{"echo a#b; c", "[echo a#b]; [c]"},
		{"a & b", "[a] &; [b]"},
		{"a&", "[a] &"},
		{"a 2>&1 &", "[a 2>&1] &"},
		{"a &> f &", "[a &> f] &"},
		{"a >&2 && b", "[a >&2] && [b]"},
		{`echo "a & b" \&`, `[echo "a & b" \&]`},
		{"echo $(a; b && c | d) \"$(e || f)\" & g", `[echo $(a; b && c | d) "$(e || f)"] &; [g]`},
		{"! false", "! [false]"},
		{"echo a \\\n b", "[echo a  b]"},
		// Reserved words are only special as the first word of a command
		{"echo if then fi do done", "[echo if then fi do done]"},
	}
	for _, tc := range tests {
		tree, err := parse(tc.input)
		if err != nil {
			t.Errorf("parse(%q) returned error: %v", tc.input, err)
			continue
		}
		if got := treeString(tree); got != tc.want {
			t.Errorf("parse(%q) = %s, want %s", tc.input, got, tc.want)
		}
	}
}

func TestParse_ControlStructures(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{"if a; then b; fi", "if [a] then [b] fi"},
		{"if a\nthen\n  b\n  c\nfi", "if [a] then [b]; [c] fi"},
		{"if a; then b; elif c; then d; else e; fi", "if [a] then [b] elif [c] then [d] else [e] fi"},
		{"if a && ! b; then c; fi; echo x", "if [a] && ! [b] then [c] fi; [echo x]"},
		{"for x in a b c; do echo $x; done", "for x in (a b c) do [echo $x] done"},
		{"for x in *.go {1..3}\ndo\n  echo $x\ndone", "for x in (*.go {1..3}) do [echo $x] done"},
		{"for x; do echo; done", "for x do [echo] done"},
		{"for x in; do echo; done", "for x in () do [echo] done"},
		{"while a; do b; done", "while [a] do [b] done"},
		{"until a; do b; done", "until [a] do [b] done"},
		{"while a; do if b; then break; fi; done", "while [a] do if [b] then [break] fi done"},
		{"for i in 1 2; do for j in 3 4; do echo $i$j; done; done", "for i in (1 2) do for j in (3 4) do [echo $i$j] done done"},
		{"if a; then if b; then c; fi fi", "if [a] then if [b] then [c] fi fi"},
		// Compound commands in pipelines, with redirections, in the background
		{"for x in a; do b; done | cat", "<for x in a; do b; done> | <cat>"},
		{"a | while b; do c; done | d", "<a> | <while b; do c; done> | <d>"},
		{"if a; then b; fi > out 2>&1", "if [a] then [b] fi <> out 2>&1>"},
		{"while read l; do b; done < in", "while [read l] do [b] done << in>"},
		{"{ a; b; } 2> err", "{ [a]; [b] } <2> err>"},
		{"for x in a; do b; done &", "for x in (a) do [b] done &"},
		{"a && b &", "[a] && [b] &"},
		// Subshells
		{"(a; b)", "(a; b)"},
		{"( a ) | b", "<( a )> | <b>"},
		{"(a) > f", "(a) <> f>"},
		{"(a; (b)) && c", "(a; (b)) && [c]"},
		// case, groups and functions
		{"case $x in a|b) c;; (d) e; f;; esac", "case $x in (a|b) [c] ;; (d) [e]; [f] ;; esac"},
		{"case x in\n  a)\n    b\n    ;;\nesac", "case x in (a) [b] ;; esac"},
		{"{ a; }", "{ [a] }"},
		{"f() { a; }", "f() { [a] }"},
		{"f ( ) { a; }", "f() { [a] }"},
		{"function f { a; }", "f() { [a] }"},
		{"f() (a)", "f() (a)"},
	}
	for _, tc := range tests {
		tree, err := parse(tc.input)
		if err != nil {
			t.Errorf("parse(%q) returned error: %v", tc.input, err)
			continue
		}
		if got := treeString(tree); got != tc.want {
			t.Errorf("parse(%q) = %s, want %s", tc.input, got, tc.want)
		}
	}
}

func TestParse_Incomplete(t *testing.T) {
	for _, input := range []string{
		"if a", "if a; then", "if a; then b", "if a; then b; else", "if a; then b; elif c",
		"for x", "for x in a b", "for x in a; do", "for x in a; do b",
		"while a", "while a; do b", "until a; do",
		"(a", "(a; b", "{ a;", "case x in", "case x in a) b;;", "f() {", "f()",
		"cat <<EOF", "cat <<EOF\nbody", "cat <<'EOF'\nbody\nEO",
		"a &&", "a ||", "a |", "echo 'open", `echo "open`, "echo $(a", "echo a \\",
	} {
		if _, err := parse(input); !errors.Is(err, errIncomplete) {
			t.Errorf("parse(%q) = %v, want incomplete", input, err)
		}
	}
}

func TestParse_SyntaxErrors(t *testing.T) {
	for _, input := range []string{
		"; a", "a ;; b", "&& a", "a && ; b", "a || && b", "& a", "a & && b", "a & & b",
		"fi", "then", "done", "if a; then fi", "if ; then a; fi", "while a; do done",
		"if a; then b; done", "for 1x in a; do b; done", "for x in a do b; done; x",
		"a | | b", "| a",
		"()", "a (", "a )", "echo (a)", ")", "(a) b", "if a; then b; fi c", "{ a; } b",
		"case x in a b) c;; esac", "case x in ) a;; esac", "cat <<", "cat << ;",
		"f() { a; } | b",
	} {
		_, err := parse(input)
		if err == nil || errors.Is(err, errIncomplete) {
			t.Errorf("parse(%q) = %v, want syntax error", input, err)
		}
	}
	for input, want := range map[string]string{
		"f() { a; } | b":     "function definitions in pipelines are not supported",
		"f() { a; } > out":   "redirections of function definitions are not supported",
		"if a; then b; fi c": "syntax error near unexpected token `c'",
	} {
		if _, err := parse(input); err == nil || err.Error() != want {
			t.Errorf("parse(%q) = %v, want %q", input, err, want)
		}
	}
}

func TestExecInput_Lists(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("D", dir)
	tests := []struct {
		input   string
		created []string
		missing []string
		status  int
	}{
		{"touch $D/a; touch $D/b", []string{"a", "b"}, nil, 0},
		{"false; touch $D/c", []string{"c"}, nil, 0},
		{"true && touch $D/d", []string{"d"}, nil, 0},
		{"false && touch $D/e", nil, []string{"e"}, 1},
		{"false || touch $D/f", []string{"f"}, nil, 0},
		{"true || touch $D/g", nil, []string{"g"}, 0},
		{"false && touch $D/h || touch $D/i", []string{"i"}, []string{"h"}, 0},
		{"true && false || touch $D/j", []string{"j"}, nil, 0},
		{"gosh-no-such-command || touch $D/k", []string{"k"}, nil, 0},
		{"true && sh -c 'exit 4'", nil, nil, 4},
	}
	for _, tc := range tests {
		execInput(tc.input)
		if lastStatus != tc.status {
			t.Errorf("%q: $? = %d, want %d", tc.input, lastStatus, tc.status)
		}
		for _, name := range tc.created {
			if _, err := os.Stat(filepath.Join(dir, name)); err != nil {
				t.Errorf("%q: expected %s to be created", tc.input, name)
			}
		}
		for _, name := range tc.missing {
			if _, err := os.Stat(filepath.Join(dir, name)); err == nil {
				t.Errorf("%q: %s must not be created", tc.input, name)
			}
		}
	}
}

func TestExecInput_ExpandsPerCommand(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	out := filepath.Join(dir, "out")
	t.Setenv("GOSH_TEST_OUT", out)
	os.Unsetenv("GOSH_TEST_LIST")
	defer os.Unsetenv("GOSH_TEST_LIST")

	// The variable is set by the first command and used by the second one
	err := execInput(`set GOSH_TEST_LIST=hello && sh -c 'printf %s "$GOSH_TEST_LIST" > "$GOSH_TEST_OUT"'`)
	if err != nil {
		t.Fatal(err)
	}
	if got, _ := os.ReadFile(out); string(got) != "hello" {
		t.Errorf("got %q, want %q", got, "hello")
	}
}

func TestExpandVar_LastStatus(t *testing.T) {
	execInput("sh -c 'exit 3'")
	for _, input := range []string{"$?", "${?}"} {
		words, err := splitWords("echo " + input)
		if err != nil {
			t.Fatal(err)
		}
		if words[1] != "3" {
			t.Errorf("%s = %q, want %q", input, words[1], "3")
		}
	}
	execInput("true")
	if words, _ := splitWords("echo $?"); words[1] != "0" {
		t.Errorf("$? = %q after true, want 0", words[1])
	}
}

func TestExecInput_CommandNotFound(t *testing.T) {
	err := execInput("gosh-no-such-command")
	if err == nil || err.Error() != "gosh-no-such-command: command not found" {
		t.Errorf("got %v, want command not found", err)
	}
	if lastStatus != 127 {
		t.Errorf("$? = %d, want 127", lastStatus)
	}
}

func TestTokenize_Operators(t *testing.T) {
	tests := []struct {
		input string
		want  []token
	}{
		{"a | b", []token{{word: "a"}, {op: "|"}, {word: "b"}}},
		{"a|b", []token{{word: "a"}, {op: "|"}, {word: "b"}}},
		{"a > f", []token{{word: "a"}, {op: ">", fd: 1}, {word: "f"}}},
		{"a >>f", []token{{word: "a"}, {op: ">>", fd: 1}, {word: "f"}}},
		{"a < f", []token{{word: "a"}, {op: "<", fd: 0}, {word: "f"}}},
		{"a 2>f", []token{{word: "a"}, {op: ">", fd: 2}, {word: "f"}}},
		{"a 2>>f", []token{{word: "a"}, {op: ">>", fd: 2}, {word: "f"}}},
		{"a 2>&1", []token{{word: "a"}, {op: ">&", fd: 2, dup: 1}}},
		{"a >&2", []token{{word: "a"}, {op: ">&", fd: 1, dup: 2}}},
		{"a 0<&2", []token{{word: "a"}, {op: "<&", fd: 0, dup: 2}}},
		{"a &>f", []token{{word: "a"}, {op: "&>", fd: 1}, {word: "f"}}},
		{"a &>>f", []token{{word: "a"}, {op: "&>>", fd: 1}, {word: "f"}}},
		// Only a word of unquoted digits is a file descriptor
		{"a x2>f", []token{{word: "a"}, {word: "x2"}, {op: ">", fd: 1}, {word: "f"}}},
		{`a "2">f`, []token{{word: "a"}, {word: "2"}, {op: ">", fd: 1}, {word: "f"}}},
		{"a 2 >f", []token{{word: "a"}, {word: "2"}, {op: ">", fd: 1}, {word: "f"}}},
		// Quoted and escaped operators are words
		{`echo "a|b" 'c>d' e\<f`, []token{{word: "echo"}, {word: "a|b"}, {word: "c>d"}, {word: "e<f"}}},
		// A lone & is a word
		{"a & b", []token{{word: "a"}, {word: "&"}, {word: "b"}}},
		{"cat ~|x", []token{{word: "cat"}, {word: getHomeDir()}, {op: "|"}, {word: "x"}}},
	}
	for _, tc := range tests {
		got, err := tokenize(tc.input)
		if err != nil {
			t.Errorf("tokenize(%q) returned error: %v", tc.input, err)
			continue
		}
		// Patterns are tested in TestTokenize_Patterns
		for i := range got {
			got[i].pattern, got[i].glob, got[i].assign = "", false, false
		}
		if !reflect.DeepEqual(got, tc.want) {
			t.Errorf("tokenize(%q) = %+v, want %+v", tc.input, got, tc.want)
		}
	}
}

func TestExecInput_SyntaxErrors(t *testing.T) {
	for _, input := range []string{"echo a |", "| echo a", "echo a | | b", "echo a >", "echo a > | b", "echo a >&", "echo a 2>&x", "; a"} {
		err := execInput(input)
		if err == nil || !strings.Contains(err.Error(), "syntax error") {
			t.Errorf("execInput(%q) = %v, want syntax error", input, err)
		}
		if lastStatus != 2 {
			t.Errorf("execInput(%q): $? = %d, want 2", input, lastStatus)
		}
	}
}

func TestExecInput_PipesAndRedirections(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	os.Chdir(dir)

	read := func(name string) string {
		data, err := os.ReadFile(filepath.Join(dir, name))
		if err != nil {
			t.Errorf("reading %s: %v", name, err)
		}
		return string(data)
	}

	tests := []struct {
		input  string
		file   string
		want   string
		status int
	}{
		{`printf 'b\na\nc\n' | sort | head -n 2 > out`, "out", "a\nb\n", 0},
		{"echo one > f1; echo two >> f1", "f1", "one\ntwo\n", 0},
		{"echo one > f2; echo two > f2", "f2", "two\n", 0},
		{"tr a-z A-Z < f1 > f3", "f3", "ONE\nTWO\n", 0},
		{"sh -c 'echo out; echo err >&2' > f4 2>&1", "f4", "out\nerr\n", 0},
		{"sh -c 'echo out; echo err >&2' &> f5", "f5", "out\nerr\n", 0},
		{"sh -c 'echo err >&2' 2> f6", "f6", "err\n", 0},
		// 2>&1 before >file sends stderr to the old stdout (the pipe)
		{"sh -c 'echo out; echo err >&2' 2>&1 > /dev/null | cat > f7", "f7", "err\n", 0},
		{"sh -c 'echo err >&2' 2>&1 | tr a-z A-Z > f8", "f8", "ERR\n", 0},
		// Builtins write to redirections and pipes
		{"pwd > f9", "f9", dir + "\n", 0},
		{"pwd | cat > f10", "f10", dir + "\n", 0},
		{"help | head -n 1 > f11", "f11", "gosh - Go Shell\n", 0},
		// Errors of builtins go to the redirected stderr
		{"cd /gosh/no/such/dir 2> f12", "f12", "gosh: chdir /gosh/no/such/dir: no such file or directory\n", 1},
		// The status of a pipeline is the one of the last command
		{"false | true > f13", "f13", "", 0},
		{"true | false > f14", "f14", "", 1},
		// A redirection without a command creates the file
		{"> f15", "f15", "", 0},
		// SIGPIPE ends the writer when the reader exits
		{"yes | head -n 1 > f16", "f16", "y\n", 0},
		// A command that is not found does not stop the pipeline
		{"gosh-no-such-command | echo after > f17", "f17", "after\n", 0},
		{"echo before | gosh-no-such-command 2> f18", "f18", "", 127},
	}
	for _, tc := range tests {
		execInput(tc.input)
		if lastStatus != tc.status {
			t.Errorf("%q: $? = %d, want %d", tc.input, lastStatus, tc.status)
		}
		if got := read(tc.file); got != tc.want {
			t.Errorf("%q: %s = %q, want %q", tc.input, tc.file, got, tc.want)
		}
	}
}

func TestExecInput_RedirectionErrors(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	os.Chdir(t.TempDir())

	tests := []struct {
		input   string
		wantErr string
	}{
		{"cat < gosh-no-such-file", "gosh-no-such-file: no such file or directory"},
		{"echo a > gosh-no-such-dir/f", "gosh-no-such-dir/f: no such file or directory"},
		{"echo a 3> f", "3: bad file descriptor"},
		{"echo a 2>&5", "5: bad file descriptor"},
		{"echo a | cd /", "cd: cannot be used in a pipeline"},
		{"echo a | exit 3", "exit: cannot be used in a pipeline"},
	}
	for _, tc := range tests {
		err := execInput(tc.input)
		if err == nil || err.Error() != tc.wantErr {
			t.Errorf("execInput(%q) = %v, want %q", tc.input, err, tc.wantErr)
		}
		if lastStatus != 1 {
			t.Errorf("execInput(%q): $? = %d, want 1", tc.input, lastStatus)
		}
	}
	// The command is not run if a redirection fails
	if _, err := os.Stat("f"); err == nil {
		t.Error("file f must not be created for a bad file descriptor")
	}
}

func TestTokenize_Patterns(t *testing.T) {
	t.Setenv("GOSH_GLOB", "*.go")
	tests := []struct {
		input   string
		pattern string
		glob    bool
	}{
		{"*.go", "*.go", true},
		{"a?c", "a?c", true},
		{"[ab].go", "[ab].go", true},
		{"[!a].go", "[^a].go", true},
		{"plain", "plain", false},
		// Quoted, escaped and expanded characters are literal
		{`"*.go"`, `\*.go`, false},
		{`'*'.go`, `\*.go`, false},
		{`\*.go`, `\*.go`, false},
		{`"x"*`, `x*`, true},
		{"$GOSH_GLOB", `\*.go`, false},
		{`'['!a].go`, `\[!a].go`, false},
	}
	for _, tc := range tests {
		tokens, err := tokenize(tc.input)
		if err != nil || len(tokens) != 1 {
			t.Errorf("tokenize(%q) = %+v, %v", tc.input, tokens, err)
			continue
		}
		if tokens[0].pattern != tc.pattern || tokens[0].glob != tc.glob {
			t.Errorf("tokenize(%q): pattern %q, glob %v; want %q, %v",
				tc.input, tokens[0].pattern, tokens[0].glob, tc.pattern, tc.glob)
		}
	}
}

func TestExpandGlob(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	os.Chdir(dir)
	for _, d := range []string{"sub/deep", "other"} {
		os.MkdirAll(d, 0755)
	}
	for _, f := range []string{"a.go", "b.go", "c.txt", ".hidden.go", "with space.go", "[x].go", "sub/s1.go", "sub/deep/d.go", "other/o.go"} {
		os.WriteFile(f, nil, 0644)
	}

	tests := []struct {
		pattern string
		want    []string
	}{
		{"*.go", []string{"[x].go", "a.go", "b.go", "with space.go"}},
		{".*.go", []string{".hidden.go"}},
		{"?.go", []string{"a.go", "b.go"}},
		{"[ab].go", []string{"a.go", "b.go"}},
		{"[^a].go", []string{"b.go"}},
		{"*/*.go", []string{"other/o.go", "sub/s1.go"}},
		{"*/", []string{"other/", "sub/"}},
		{"sub/*/*.go", []string{"sub/deep/d.go"}},
		{"./c*", []string{"./c.txt"}},
		{dir + "/c*", []string{dir + "/c.txt"}},
		{`\[x\].go`, []string{"[x].go"}},
		{"*.xyz", nil},
		{"[", nil},
	}
	for _, tc := range tests {
		if got := expandGlob(tc.pattern); !reflect.DeepEqual(got, tc.want) {
			t.Errorf("expandGlob(%q) = %q, want %q", tc.pattern, got, tc.want)
		}
	}
}

func TestExecInput_Wildcards(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	os.Chdir(dir)
	for _, f := range []string{"a.go", "b.go", "c.txt"} {
		os.WriteFile(f, []byte(f+"\n"), 0644)
	}

	tests := []struct {
		input string
		want  string
	}{
		{"echo *.go > out", "a.go b.go\n"},
		{"cat *.go > out", "a.go\nb.go\n"},
		// No match: the word is passed on unchanged, like in sh
		{"echo *.xyz > out", "*.xyz\n"},
		{`echo "*.go" '?.go' \*.go > out`, "*.go ?.go *.go\n"},
		// A redirection to a pattern with a single match uses that file
		{"echo hi > *.txt; cat c.txt > out", "hi\n"},
	}
	for _, tc := range tests {
		if err := execInput(tc.input); err != nil {
			t.Errorf("execInput(%q) returned error: %v", tc.input, err)
		}
		if got, _ := os.ReadFile("out"); string(got) != tc.want {
			t.Errorf("%q: got %q, want %q", tc.input, got, tc.want)
		}
	}

	err := execInput("echo hi > *.go")
	if err == nil || err.Error() != "*.go: ambiguous redirect" {
		t.Errorf("expected ambiguous redirect error, got %v", err)
	}
}

func TestStartupFiles(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	sys := sysConfDir

	tests := []struct {
		login, interactive bool
		want               []string
	}{
		{false, false, nil},
		{true, false, []string{sys + "/profile", home + "/.gosh_profile"}},
		{false, true, []string{sys + "/goshrc", home + "/.goshrc"}},
		{true, true, []string{sys + "/profile", home + "/.gosh_profile", sys + "/goshrc", home + "/.goshrc"}},
	}
	for _, tc := range tests {
		if got := startupFiles(tc.login, tc.interactive); !reflect.DeepEqual(got, tc.want) {
			t.Errorf("startupFiles(%v, %v) = %q, want %q", tc.login, tc.interactive, got, tc.want)
		}
	}
}

func TestRun_LoginReadsProfile(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	os.Unsetenv("GOSH_TEST_PROFILE")
	defer os.Unsetenv("GOSH_TEST_PROFILE")
	os.WriteFile(filepath.Join(home, ".gosh_profile"), []byte("export GOSH_TEST_PROFILE=yes\n"), 0644)
	// .goshrc is only read by interactive shells
	os.WriteFile(filepath.Join(home, ".goshrc"), []byte("exit 99\n"), 0644)

	check := `sh -c 'test "$GOSH_TEST_PROFILE" = yes'`
	if got := run([]string{"-c", check}); got != 1 {
		t.Errorf("non-login shell: status %d, want 1 (profile must not be read)", got)
	}
	if got := run([]string{"-l", "--noprofile", "-c", check}); got != 1 {
		t.Errorf("--noprofile: status %d, want 1 (profile must not be read)", got)
	}
	if got := run([]string{"-l", "-c", check}); got != 0 {
		t.Errorf("login shell: status %d, want 0 (profile must be read)", got)
	}
}

func TestShell_InteractiveReadsRC(t *testing.T) {
	bin := buildShell(t)
	home := t.TempDir()
	os.WriteFile(filepath.Join(home, ".goshrc"), []byte("export GOSH_TEST_RC=from-rc\n"), 0644)
	os.WriteFile(filepath.Join(home, ".gosh_profile"), []byte("export GOSH_TEST_PROFILE=from-profile\n"), 0644)

	tests := []struct {
		args []string
		want string
	}{
		{[]string{"-i"}, "from-rc -\n"},
		{[]string{"-i", "--norc"}, "- -\n"},
		{[]string{"-i", "-l"}, "from-rc from-profile\n"},
		{[]string{"-i", "-l", "--norc", "--noprofile"}, "- -\n"},
	}
	for _, tc := range tests {
		cmd := exec.Command(bin, tc.args...)
		cmd.Env = append(os.Environ(), "HOME="+home)
		cmd.Stdin = strings.NewReader("echo ${GOSH_TEST_RC:--} ${GOSH_TEST_PROFILE:--}\nexit\n")
		out, err := cmd.Output()
		if err != nil {
			t.Fatalf("%v: %v", tc.args, err)
		}
		if !strings.HasSuffix(string(out), tc.want) {
			t.Errorf("%v: output %q, want suffix %q", tc.args, out, tc.want)
		}
	}
}

func TestExecInput_Source(t *testing.T) {
	dir := t.TempDir()
	os.Unsetenv("GOSH_TEST_SOURCE")
	defer os.Unsetenv("GOSH_TEST_SOURCE")

	file := filepath.Join(dir, "vars")
	os.WriteFile(file, []byte("# comment\nexport GOSH_TEST_SOURCE=hello\nsh -c 'exit 4'\n"), 0644)

	for _, cmd := range []string{"source", "."} {
		os.Unsetenv("GOSH_TEST_SOURCE")
		execInput(cmd + " " + file)
		if os.Getenv("GOSH_TEST_SOURCE") != "hello" {
			t.Errorf("%s: variable was not set in the current shell", cmd)
		}
		if lastStatus != 4 {
			t.Errorf("%s: $? = %d, want 4 (status of the last command)", cmd, lastStatus)
		}
	}

	err := execInput("source " + filepath.Join(dir, "missing"))
	if err == nil || !strings.Contains(err.Error(), "source: "+dir+"/missing: no such file or directory") {
		t.Errorf("unexpected error for missing file: %v", err)
	}
	if lastStatus != 1 {
		t.Errorf("$? = %d for missing file, want 1", lastStatus)
	}

	// A file that sources itself is stopped
	loop := filepath.Join(dir, "loop")
	os.WriteFile(loop, []byte("source "+loop+"\n"), 0644)
	if err := execInput("source " + loop); err == nil {
		t.Error("expected an error for a file that sources itself")
	}
}

func TestGetHomeDir_UsesHOME(t *testing.T) {
	t.Setenv("HOME", "/gosh/test/home")
	if got := getHomeDir(); got != "/gosh/test/home" {
		t.Errorf("getHomeDir() = %q, want $HOME", got)
	}
	if words, _ := splitWords("echo ~/x"); words[1] != "/gosh/test/home/x" {
		t.Errorf("~/x = %q, want it based on $HOME", words[1])
	}

	// Without $HOME the user database is used
	t.Setenv("HOME", "")
	if got := getHomeDir(); got == "" {
		t.Error("getHomeDir() is empty without $HOME")
	}
}

func TestExecInput_Background(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	os.Chdir(dir)

	// The shell does not wait for a background job, wait does
	start := time.Now()
	if err := execInput("sh -c 'sleep 0.3; echo done > out' &"); err != nil {
		t.Fatal(err)
	}
	if lastStatus != 0 {
		t.Errorf("$? = %d after starting a background job, want 0", lastStatus)
	}
	if time.Since(start) > 200*time.Millisecond {
		t.Error("the shell waited for the background job")
	}
	if _, err := os.Stat("out"); err == nil {
		t.Error("background job finished too early")
	}
	if err := execInput("wait"); err != nil {
		t.Fatal(err)
	}
	if got, _ := os.ReadFile("out"); string(got) != "done\n" {
		t.Errorf("out = %q after wait", got)
	}
	if len(jobTable) != 0 {
		t.Errorf("job table not empty after wait: %d jobs", len(jobTable))
	}

	// wait %n returns the status of the job
	execInput("sh -c 'exit 3' &")
	execInput("wait %1")
	if lastStatus != 3 {
		t.Errorf("$? = %d after wait %%1, want 3", lastStatus)
	}

	// Without job control, background jobs read from /dev/null
	execInput("cat > stdin.txt &")
	execInput("wait")
	if got, err := os.ReadFile("stdin.txt"); err != nil || len(got) != 0 {
		t.Errorf("background job read %q, %v from stdin", got, err)
	}

	// jobs lists running jobs, also into a redirection
	execInput("sleep 0.3 &")
	execInput("jobs > jobs.txt")
	if got, _ := os.ReadFile("jobs.txt"); !strings.Contains(string(got), "Running                 sleep 0.3 &") {
		t.Errorf("jobs output = %q", got)
	}
	execInput("wait")

	// Builtins that change the shell cannot run in the background
	if err := execInput("cd / &"); err != nil {
		t.Fatal(err)
	}
	execInput("wait %1")
	if wd, _ := os.Getwd(); wd != dir {
		t.Errorf("cd in the background changed the directory to %s", wd)
	}

	// fg and bg need job control
	for _, cmd := range []string{"fg", "bg"} {
		if err := execInput(cmd); err == nil || err.Error() != cmd+": no job control" {
			t.Errorf("%s without job control: %v", cmd, err)
		}
	}
	if err := execInput("wait %9"); err == nil || err.Error() != "wait: %9: no such job" {
		t.Errorf("wait %%9: %v", err)
	}
}