package main

import (
	"os"
	"testing"
)

func TestSubstEnd(t *testing.T) {
	tests := []struct {
		s    string
		want int
	}{
		{"$(echo a)", 8},
		{"$(echo a) b", 8},
		{"$(echo $(date))x", 14},
		{`$(echo ")")`, 10},
		{`$(echo ')')`, 10},
		{`$(echo \))`, 9},
		{`$(echo "$(echo ")")")`, 20},
		{"$(echo (a))", 10},
		{"$(echo a", -1},
		{`$(echo ")`, -1},
	}
	for _, tc := range tests {
		if got := substEnd(tc.s, 0); got != tc.want {
			t.Errorf("substEnd(%q) = %d, want %d", tc.s, got, tc.want)
		}
	}
}

func TestExpandAliasesAndBraces_SkipSubstitution(t *testing.T) {
	withAliases(t, map[string]string{"ll": "ls -l"})
	if got := expandAliases("echo $(ll; ll) && ll"); got != "echo $(ll; ll) && ls -l" {
		t.Errorf("expandAliases = %q", got)
	}
	got, err := expandBraceWords("echo $(echo {a,b}) {c,d}")
	if err != nil || got != "echo $(echo {a,b}) c d" {
		t.Errorf("expandBraceWords = %q, %v", got, err)
	}
}

func TestExecInput_CommandSubstitution(t *testing.T) {
	origDir, _ := os.Getwd()
	defer os.Chdir(origDir)
	dir := t.TempDir()
	os.Chdir(dir)
	os.WriteFile("a.go", nil, 0644)
	os.WriteFile("b.go", nil, 0644)

	tests := []struct {
		input string
		want  string
	}{
		{"echo $(echo hello) > out", "hello\n"},
		// Unquoted, the output is split into words
		{"printf '[%s]' $(printf 'a b\\nc\\n\\n') > out", "[a][b][c]"},
		{"printf '[%s]' x$(echo a b)y > out", "[xa][by]"},
		// Quoted, it is a single word, only trailing newlines are removed
		{`printf '[%s]' "$(printf 'a  b\nc\n\n')" > out`, "[a  b\nc]"},
		{`printf '[%s]' "$(true)" > out`, "[]"},
		{"printf '[%s]' $(true) x > out", "[x]"},
		// Nested, with quotes and operators inside
		{"echo $(echo $(echo nested)) > out", "nested\n"},
		{`echo "$(echo "a;b|c")" > out`, "a;b|c\n"},
		{"echo $(echo a | tr a-z A-Z) > out", "A\n"},
		// Wildcards in the output are not expanded, in the command they are
		{`echo $(echo "*") > out`, "*\n"},
		{"echo $(echo *.go) > out", "a.go b.go\n"},
		// Quoted or escaped, $( is literal
		{`echo '$(echo a)' \$(echo b) > out`, "$(echo a) $(echo b)\n"},
		// The subshell does not change the shell
		{"echo $(cd /; pwd) > out; pwd >> out", "/\n" + dir + "\n"},
		{"set GOSH_SUBST=$(echo value); echo $GOSH_SUBST > out", "value\n"},
	}
	for _, tc := range tests {
		if err := execInput(tc.input); err != nil {
			t.Errorf("%q: %v", tc.input, err)
		}
		if got, _ := os.ReadFile("out"); string(got) != tc.want {
			t.Errorf("%q: out = %q, want %q", tc.input, got, tc.want)
		}
	}
	os.Unsetenv("GOSH_SUBST")

	// A command that consists only of a substitution has its status
	execInput("$(sh -c 'exit 3')")
	if lastStatus != 3 {
		t.Errorf("$? = %d after $(exit 3), want 3", lastStatus)
	}
	// Otherwise the status of the command counts
	execInput("echo $(false) > out")
	if lastStatus != 0 {
		t.Errorf("$? = %d after echo $(false), want 0", lastStatus)
	}

	for input, wantErr := range map[string]string{
		"echo $(echo a":   "syntax error: unexpected end of input",
		"echo $((1 + 2))": "invalid input: arithmetic expansion $((...)) is not supported",
	} {
		if err := execInput(input); err == nil || err.Error() != wantErr {
			t.Errorf("%q: error %v, want %q", input, err, wantErr)
		}
	}
}