package project

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

func TestDiscoverFindsRepositoryRootFromNestedDirectory(t *testing.T) {
	root := writeProjectRoot(t, false)
	nested := filepath.Join(root, "tools", "tht", "internal")
	if err := os.MkdirAll(nested, 0o755); err != nil {
		t.Fatal(err)
	}

	got, err := Discover(nested)
	if err != nil {
		t.Fatal(err)
	}
	want := resolvedPath(t, root)
	if got.Path != want {
		t.Fatalf("Discover() root = %q, want %q", got.Path, want)
	}
	if got.IsWorktree {
		t.Fatal("Discover() marked a main checkout as a worktree")
	}
}

func TestDiscoverRecognizesLinkedGitWorktree(t *testing.T) {
	root := writeProjectRoot(t, true)

	got, err := Discover(root)
	if err != nil {
		t.Fatal(err)
	}
	want := resolvedPath(t, root)
	if got.Path != want {
		t.Fatalf("Discover() root = %q, want %q", got.Path, want)
	}
	if !got.IsWorktree {
		t.Fatal("Discover() did not mark a linked checkout as a worktree")
	}
}

func TestDiscoverResolvesSymlinkForRootIdentity(t *testing.T) {
	root := writeProjectRoot(t, false)
	alias := filepath.Join(t.TempDir(), "checkout")
	if err := os.Symlink(root, alias); err != nil {
		t.Fatal(err)
	}

	got, err := Discover(filepath.Join(alias, "frontend"))
	if err != nil {
		t.Fatal(err)
	}
	want := resolvedPath(t, root)
	if got.Path != want {
		t.Fatalf("Discover() root = %q, want canonical %q", got.Path, want)
	}
}

func TestDiscoverRejectsDirectoriesThatAreNotThothIIProjects(t *testing.T) {
	_, err := Discover(t.TempDir())
	if err == nil {
		t.Fatal("Discover() error = nil, want root discovery failure")
	}
}

func writeProjectRoot(t *testing.T, linkedWorktree bool) string {
	t.Helper()
	root := t.TempDir()
	for _, directory := range []string{"backend", "frontend", "harness", "tools", "deploy"} {
		if err := os.MkdirAll(filepath.Join(root, directory), 0o755); err != nil {
			t.Fatal(err)
		}
	}
	if err := os.WriteFile(filepath.Join(root, "compose.yaml"), []byte("services: {}\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	gitPath := filepath.Join(root, ".git")
	if linkedWorktree {
		if err := os.WriteFile(gitPath, []byte("gitdir: /tmp/thothii-worktree.git\n"), 0o600); err != nil {
			t.Fatal(err)
		}
		return root
	}
	if err := os.Mkdir(gitPath, 0o755); err != nil {
		t.Fatal(err)
	}
	return root
}

func resolvedPath(t *testing.T, path string) string {
	t.Helper()
	resolved, err := filepath.EvalSymlinks(path)
	if err != nil {
		t.Fatal(err)
	}
	return resolved
}