package main

import (
	"os"
	"reflect"
	"strings"
	"testing"
)

func TestExpandBraces(t *testing.T) {
	tests := []struct {
		word string
		want []string
	}{
		{"a{b,c}d", []string{"abd", "acd"}},
		{"{a,b}{1,2}", []string{"a1", "a2", "b1", "b2"}},
		{"x{a,{b,c}}y", []string{"xay", "xby", "xcy"}},
		{"file{,.bak}", []string{"file", "file.bak"}},
		{"{1..5}", []string{"1", "2", "3", "4", "5"}},
		{"{3..1}", []string{"3", "2", "1"}},
		{"{1..10..3}", []string{"1", "4", "7", "10"}},
		{"{10..1..-4}", []string{"10", "6", "2"}},
		{"{01..10..4}", []string{"01", "05", "09"}},
		{"{8..010..1}", []string{"008", "009", "010"}},
		{"{-2..2}", []string{"-2", "-1", "0", "1", "2"}},
		{"{-01..1}", []string{"-01", "000", "001"}},
		{"{a..e}", []string{"a", "b", "c", "d", "e"}},
		{"{C..A}", []string{"C", "B", "A"}},
		{"*.{go,md}", []string{"*.go", "*.md"}},
		{`{"a b",c}`, []string{`"a b"`, "c"}},
		{`{a\,b,c}`, []string{`a\,b`, "c"}},
		{"{$HOME,~}/x", []string{"$HOME/x", "~/x"}},
		// Not expanded: quoted, escaped, no comma, ${...}, invalid sequences
		{`"{a,b}"`, []string{`"{a,b}"`}},
		{`'{a,b}'`, []string{`'{a,b}'`}},
		{`\{a,b\}`, []string{`\{a,b\}`}},
		{"{a}", []string{"{a}"}},
		{"{}", []string{"{}"}},
		{"{a,b", []string{"{a,b"}},
		{"a,b}", []string{"a,b}"}},
		{"${HOME}", []string{"${HOME}"}},
		{"${X:-a,b}", []string{"${X:-a,b}"}},
		{"{a..1}", []string{"{a..1}"}},
		{"{1..2..x}", []string{"{1..2..x}"}},
		{"{ab..cd}", []string{"{ab..cd}"}},
		// An invalid brace before a valid one
		{"{a}{b,c}", []string{"{a}b", "{a}c"}},
	}
	for _, tc := range tests {
		got, err := expandBraces(tc.word)
		if err != nil {
			t.Errorf("expandBraces(%q) returned error: %v", tc.word, err)
			continue
		}
		if !reflect.DeepEqual(got, tc.want) {
			t.Errorf("expandBraces(%q) = %q, want %q", tc.word, got, tc.want)
		}
	}

	if _, err := expandBraces("{1..1000000}"); err == nil {
		t.Error("expected an error for a too large sequence")
	}
	if _, err := expandBraces("{1..11}{1..100}{1..100}"); err == nil {
		t.Error("expected an error for too many words")
	}
}

func TestExpandBraceWords(t *testing.T) {
	tests := []struct {
		input, want string
	}{
		{"echo a{b,c} d", "echo ab ac d"},
		{"echo {1..3}|wc -w", "echo 1 2 3|wc -w"},
		{"echo a > {f}", "echo a > {f}"},
		{"echo {a,b} 2>&1", "echo a b 2>&1"},
		{"echo x # {a,b}", "echo x # {a,b}"},
		{`echo "{a,b} c" {d,e}`, `echo "{a,b} c" d e`},
	}
	for _, tc := range tests {
		got, err := expandBraceWords(tc.input)
		if err != nil || got != tc.want {
			t.Errorf("expandBraceWords(%q) = %q, %v; want %q", tc.input, got, err, tc.want)
		}
	}

	for _, input := range []string{"echo a > {f,g}", "cat < x{1..2}", "echo a 2>> {a,b}"} {
		if _, err := expandBraceWords(input); err == nil || !strings.Contains(err.Error(), "ambiguous redirect") {
			t.Errorf("expandBraceWords(%q): %v, want ambiguous redirect", input, err)
		}
	}
}

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

	if err := execInput("mkdir -p d/{x,y}/{1..2} && touch d/x/1/f{a,b}.txt"); err != nil {
		t.Fatal(err)
	}
	for _, path := range []string{"d/x/1", "d/x/2", "d/y/1", "d/y/2", "d/x/1/fa.txt", "d/x/1/fb.txt"} {
		if _, err := os.Stat(path); err != nil {
			t.Errorf("%s was not created", path)
		}
	}

	// Brace expansion comes before wildcards and variables
	t.Setenv("GOSH_BRACE", "v")
	execInput("echo d/x/1/*.{txt,go} {${GOSH_BRACE},w}1 > out")
	if got, _ := os.ReadFile("out"); string(got) != "d/x/1/fa.txt d/x/1/fb.txt d/x/1/*.go v1 w1\n" {
		t.Errorf("out = %q", got)
	}

	if err := execInput("echo a > {f,g}"); err == nil || lastStatus != 1 {
		t.Errorf("ambiguous redirect: %v, $? = %d", err, lastStatus)
	}
}