package files

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"testing"
	"time"
)

func TestInstanceDataRemoverDeletesExistingDirectory(t *testing.T) {
	root := t.TempDir()
	target := filepath.Join(root, "profile")
	if err := os.MkdirAll(filepath.Join(target, "Default"), 0o700); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(target, "Local State"), []byte("state"), 0o600); err != nil {
		t.Fatal(err)
	}
	remover := NewInstanceDataRemover()
	if err := remover.RemoveInstanceData(context.Background(), target); err != nil {
		t.Fatal(err)
	}
	if _, err := os.Lstat(target); !errors.Is(err, os.ErrNotExist) {
		t.Fatalf("target still exists or could not be inspected: %v", err)
	}
}

func TestInstanceDataRemoverRejectsUnsafePathsBeforeDeletion(t *testing.T) {
	called := false
	remover := newInstanceDataRemover(func(string) (os.FileInfo, error) {
		return nil, os.ErrNotExist
	}, func(string) error {
		called = true
		return nil
	})
	for _, path := range []string{"", "relative-profile", filepath.VolumeName(t.TempDir()) + string(filepath.Separator)} {
		if err := remover.RemoveInstanceData(context.Background(), path); !errors.Is(err, ErrUnsafeInstanceDataDirectory) {
			t.Fatalf("path %q error = %v", path, err)
		}
	}
	if called {
		t.Fatal("unsafe path reached removal")
	}
}

func TestInstanceDataRemoverRejectsFilesAndLinks(t *testing.T) {
	file := filepath.Join(t.TempDir(), "not-a-directory")
	if err := os.WriteFile(file, []byte("data"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := NewInstanceDataRemover().RemoveInstanceData(context.Background(), file); !errors.Is(err, ErrInstanceDataNotDirectory) {
		t.Fatalf("file error = %v", err)
	}

	linkInfo := fakeFileInfo{mode: os.ModeSymlink | 0o777}
	remover := newInstanceDataRemover(func(string) (os.FileInfo, error) {
		return linkInfo, nil
	}, func(string) error {
		t.Fatal("link reached removal")
		return nil
	})
	if err := remover.RemoveInstanceData(context.Background(), t.TempDir()); !errors.Is(err, ErrUnsafeInstanceDataDirectory) {
		t.Fatalf("link error = %v", err)
	}
}

func TestInstanceDataRemoverHonorsCanceledContext(t *testing.T) {
	target := filepath.Join(t.TempDir(), "profile")
	if err := os.Mkdir(target, 0o700); err != nil {
		t.Fatal(err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := NewInstanceDataRemover().RemoveInstanceData(ctx, target); !errors.Is(err, context.Canceled) {
		t.Fatalf("error = %v", err)
	}
	if _, err := os.Lstat(target); err != nil {
		t.Fatalf("canceled deletion changed target: %v", err)
	}
}

func TestInstanceDataPreparerCreatesAndVerifiesWritableDirectory(t *testing.T) {
	target := filepath.Join(t.TempDir(), "new-profile")
	if err := NewInstanceDataPreparer().PrepareInstanceDataDir(context.Background(), target); err != nil {
		t.Fatal(err)
	}
	info, err := os.Stat(target)
	if err != nil || !info.IsDir() {
		t.Fatalf("prepared directory = %#v, error = %v", info, err)
	}
	probes, err := filepath.Glob(filepath.Join(target, ".chub-write-*"))
	if err != nil || len(probes) != 0 {
		t.Fatalf("write probes = %#v, error = %v", probes, err)
	}
}

func TestInstanceDataPreparerRejectsUnavailableDirectoryBeforeBrowserLaunch(t *testing.T) {
	target := filepath.Join(t.TempDir(), "profile")
	preparer := newInstanceDataPreparer(os.MkdirAll, os.Lstat, func(string, string) (*os.File, error) {
		return nil, errors.New("denied")
	}, os.Remove)
	if err := preparer.PrepareInstanceDataDir(context.Background(), target); !errors.Is(err, ErrInstanceDataDirectoryUnavailable) {
		t.Fatalf("unwritable directory error = %v", err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := NewInstanceDataPreparer().PrepareInstanceDataDir(ctx, filepath.Join(t.TempDir(), "canceled")); !errors.Is(err, context.Canceled) {
		t.Fatalf("canceled preparation error = %v", err)
	}
}

type fakeFileInfo struct {
	mode os.FileMode
	sys  any
}

func (f fakeFileInfo) Name() string       { return "fake" }
func (f fakeFileInfo) Size() int64        { return 0 }
func (f fakeFileInfo) Mode() os.FileMode  { return f.mode }
func (f fakeFileInfo) ModTime() time.Time { return time.Time{} }
func (f fakeFileInfo) IsDir() bool        { return f.mode.IsDir() }
func (f fakeFileInfo) Sys() any           { return f.sys }