package services

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

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/zap"
)

func setupTestMetadataService(t *testing.T) *MetadataService {
	logger := zap.NewNop()
	return NewMetadataService(logger)
}

func TestMetadataService_NewMetadataService(t *testing.T) {
	service := setupTestMetadataService(t)
	assert.NotNil(t, service)
	assert.NotNil(t, service.logger)
}

func TestMetadataService_ValidateMetadata_Valid(t *testing.T) {
	service := setupTestMetadataService(t)

	metadata := &AudioMetadata{
		Title:  "Test Title",
		Artist: "Test Artist",
		Album:  "Test Album",
		Genre:  "Rock",
		Year:   2023,
		Track:  1,
	}

	err := service.ValidateMetadata(metadata)
	assert.NoError(t, err)
}

func TestMetadataService_ValidateMetadata_MissingTitle(t *testing.T) {
	service := setupTestMetadataService(t)

	metadata := &AudioMetadata{
		Title:  "",
		Artist: "Test Artist",
	}

	err := service.ValidateMetadata(metadata)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "title is required")
}

func TestMetadataService_ValidateMetadata_MissingArtist(t *testing.T) {
	service := setupTestMetadataService(t)

	metadata := &AudioMetadata{
		Title:  "Test Title",
		Artist: "",
	}

	err := service.ValidateMetadata(metadata)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "artist is required")
}

func TestMetadataService_ValidateMetadata_MissingBoth(t *testing.T) {
	service := setupTestMetadataService(t)

	metadata := &AudioMetadata{
		Title:  "",
		Artist: "",
	}

	err := service.ValidateMetadata(metadata)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "title is required")
}

func TestMetadataService_getDefaultMetadata_SimpleFilename(t *testing.T) {
	service := setupTestMetadataService(t)

	filePath := "/path/to/track.mp3"
	metadata := service.getDefaultMetadata(filePath)

	assert.NotNil(t, metadata)
	assert.Equal(t, "track", metadata.Title)
	assert.Equal(t, "Unknown", metadata.Artist)
	assert.Equal(t, ".mp3", metadata.Format)
	assert.Equal(t, "", metadata.Album)
	assert.Equal(t, "", metadata.Genre)
	assert.Equal(t, 0, metadata.Year)
	assert.Equal(t, 0, metadata.Track)
}

func TestMetadataService_getDefaultMetadata_WithExtension(t *testing.T) {
	service := setupTestMetadataService(t)

	testCases := []struct {
		name     string
		filePath string
		expected string
	}{
		{"MP3", "/path/to/song.mp3", ".mp3"},
		{"FLAC", "/path/to/song.flac", ".flac"},
		{"WAV", "/path/to/song.wav", ".wav"},
		{"M4A", "/path/to/song.m4a", ".m4a"},
		{"OGG", "/path/to/song.ogg", ".ogg"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			metadata := service.getDefaultMetadata(tc.filePath)
			assert.Equal(t, tc.expected, metadata.Format)
		})
	}
}

func TestMetadataService_getDefaultMetadata_ComplexFilename(t *testing.T) {
	service := setupTestMetadataService(t)

	filePath := "/path/to/Artist - Song Title (Remix).mp3"
	metadata := service.getDefaultMetadata(filePath)

	assert.NotNil(t, metadata)
	// The current implementation doesn't properly parse "Artist - Title" pattern
	// but it should still extract the filename
	assert.Contains(t, metadata.Title, "Artist")
}

func TestMetadataService_getDefaultMetadata_NoExtension(t *testing.T) {
	service := setupTestMetadataService(t)

	filePath := "/path/to/track"
	metadata := service.getDefaultMetadata(filePath)

	assert.NotNil(t, metadata)
	assert.Equal(t, "track", metadata.Title)
	assert.Equal(t, "", metadata.Format)
}

func TestMetadataService_ExtractMetadata_NonExistentFile(t *testing.T) {
	service := setupTestMetadataService(t)

	filePath := "/nonexistent/path/to/file.mp3"
	metadata, err := service.ExtractMetadata(filePath)

	assert.Error(t, err)
	assert.Nil(t, metadata)
	assert.Contains(t, err.Error(), "failed to open file")
}

func TestMetadataService_ExtractMetadata_InvalidFile(t *testing.T) {
	service := setupTestMetadataService(t)

	// Create a temporary file that's not a valid audio file
	tmpFile, err := os.CreateTemp("", "test_*.txt")
	require.NoError(t, err)
	defer os.Remove(tmpFile.Name())
	defer tmpFile.Close()

	_, err = tmpFile.WriteString("This is not an audio file")
	require.NoError(t, err)
	tmpFile.Close()

	// ExtractMetadata should handle invalid files gracefully
	metadata, err := service.ExtractMetadata(tmpFile.Name())

	// Should return default metadata instead of error
	assert.NoError(t, err)
	assert.NotNil(t, metadata)
	assert.Equal(t, filepath.Ext(tmpFile.Name()), metadata.Format)
}

func TestMetadataService_ExtractMetadata_EmptyFile(t *testing.T) {
	service := setupTestMetadataService(t)

	// Create an empty temporary file
	tmpFile, err := os.CreateTemp("", "test_*.mp3")
	require.NoError(t, err)
	defer os.Remove(tmpFile.Name())
	tmpFile.Close()

	// ExtractMetadata should handle empty files gracefully
	metadata, err := service.ExtractMetadata(tmpFile.Name())

	// Should return default metadata instead of error
	assert.NoError(t, err)
	assert.NotNil(t, metadata)
	assert.Equal(t, ".mp3", metadata.Format)
}

func TestMetadataService_AudioMetadata_Fields(t *testing.T) {
	metadata := &AudioMetadata{
		Title:    "Test Title",
		Artist:   "Test Artist",
		Album:    "Test Album",
		Genre:    "Rock",
		Year:     2023,
		Track:    1,
		Duration: 180.5,
		Bitrate:  320,
		Format:   ".mp3",
	}

	assert.Equal(t, "Test Title", metadata.Title)
	assert.Equal(t, "Test Artist", metadata.Artist)
	assert.Equal(t, "Test Album", metadata.Album)
	assert.Equal(t, "Rock", metadata.Genre)
	assert.Equal(t, 2023, metadata.Year)
	assert.Equal(t, 1, metadata.Track)
	assert.Equal(t, 180.5, metadata.Duration)
	assert.Equal(t, 320, metadata.Bitrate)
	assert.Equal(t, ".mp3", metadata.Format)
}

func TestMetadataService_getDefaultMetadata_PathVariations(t *testing.T) {
	service := setupTestMetadataService(t)

	testCases := []struct {
		name          string
		filePath      string
		expectedTitle string
	}{
		{"Unix path", "/home/user/music/song.mp3", "song"},
		{"Windows path", filepath.Join("C:", "Users", "Music", "song.mp3"), "song"},
		{"Relative path", "./music/song.mp3", "song"},
		{"Filename only", "song.mp3", "song"},
		{"Nested path", "/very/deep/nested/path/to/song.mp3", "song"},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			metadata := service.getDefaultMetadata(tc.filePath)
			// Use filepath.Base to get the expected filename regardless of OS
			expectedBase := filepath.Base(tc.filePath)
			expectedTitle := expectedBase[:len(expectedBase)-len(filepath.Ext(expectedBase))]
			assert.Equal(t, expectedTitle, metadata.Title)
		})
	}
}