package mention

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// A workspace with a file, a nested file and a directory, to mention.
func workspace(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	for _, p := range []string{"main.go", "internal/acp/acp.go"} {
		if err := os.MkdirAll(filepath.Dir(filepath.Join(dir, p)), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(dir, p), []byte("package x"), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return dir
}

// The text is kept as typed and each existing path becomes one attachment
// line, in order, once — the shape an ACP resource_link takes.
func TestExpandAttachesExistingPathsOnce(t *testing.T) {
	dir := workspace(t)
	in := "compare @main.go with @internal/acp/acp.go, then @main.go again; and @internal too"
	got, att := Expand(in, dir)

	want := in +
		"\n[attached file: " + filepath.Join(dir, "main.go") + "]" +
		"\n[attached file: " + filepath.Join(dir, "internal/acp/acp.go") + "]" +
		"\n[attached directory: " + filepath.Join(dir, "internal") + "]"
	if got != want {
		t.Errorf("Expand:\n got %q\nwant %q", got, want)
	}
	if len(att) != 3 || att[0].Mention != "main.go" || att[2].Dir != true || att[1].Dir {
		t.Errorf("attachments %+v", att)
	}
}

// What is NOT a mention: a path that does not exist (a name, a handle), an
// e-mail address (@ glued to a word), a lone @, and the input untouched when
// nothing matches.
func TestExpandLeavesNonPathsAlone(t *testing.T) {
	dir := workspace(t)
	for _, in := range []string{
		"ask @bob about it",
		"mail k33g@example.com",
		"a lone @ sign",
		"@does/not/exist.go",
		"",
	} {
		got, att := Expand(in, dir)
		if got != in || len(att) != 0 {
			t.Errorf("Expand(%q) = %q, %+v; want the input unchanged and no attachment", in, got, att)
		}
	}
}

// Absolute paths, ~ paths, and mentions wrapped in brackets or quotes or
// glued to punctuation all resolve to the same clean absolute path.
func TestExpandResolvesAbsoluteHomeAndPunctuated(t *testing.T) {
	dir := workspace(t)
	t.Setenv("HOME", dir)
	abs := filepath.Join(dir, "main.go")
	for _, in := range []string{
		"see @" + abs + ".",
		"see @~/main.go!",
		"see (@main.go)",
		"see \"@./main.go\"",
		"see @" + dir + "/internal/../main.go",
		"@main.go",
	} {
		_, att := Expand(in, dir)
		if len(att) != 1 || att[0].Path != abs {
			t.Errorf("Expand(%q) attachments = %+v, want one at %s", in, att, abs)
		}
	}
}

// A mention is resolved against cwd, not the process directory: the ACP
// front end passes the session's cwd, the terminal the directory mm runs in.
func TestExpandIsRelativeToCwd(t *testing.T) {
	dir := workspace(t)
	_, att := Expand("@acp.go", filepath.Join(dir, "internal", "acp"))
	if len(att) != 1 || !strings.HasSuffix(att[0].Path, filepath.Join("internal", "acp", "acp.go")) {
		t.Errorf("attachments %+v", att)
	}
	if _, att := Expand("@acp.go", dir); len(att) != 0 {
		t.Errorf("acp.go does not exist at the root, yet %+v", att)
	}
}