package services

import (
	"context"
	"github.com/google/uuid"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/zap"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"veza-backend-api/internal/models"
)

func setupTestAnalyticsService(t *testing.T) (*AnalyticsService, *gorm.DB, func()) {
	// Setup in-memory SQLite database
	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
	require.NoError(t, err)

	// Enable foreign keys for SQLite
	db.Exec("PRAGMA foreign_keys = ON")

	// Auto-migrate
	err = db.AutoMigrate(&models.User{}, &models.Track{}, &models.TrackPlay{})
	require.NoError(t, err)

	// Create test user
	user := &models.User{
		Username:     "testuser",
		Email:        "test@example.com",
		PasswordHash: "hash",
		Slug:         "testuser",
		IsActive:     true,
	}
	err = db.Create(user).Error
	require.NoError(t, err)

	// Create test track
	track := &models.Track{
		UserID:   user.ID,
		Title:    "Test Track",
		FilePath: "/test/track.mp3",
		FileSize: 5 * 1024 * 1024,
		Format:   "MP3",
		Duration: 180, // 3 minutes
		IsPublic: true,
		Status:   models.TrackStatusCompleted,
	}
	err = db.Create(track).Error
	require.NoError(t, err)

	// Setup logger
	logger := zap.NewNop()

	// Setup test service
	service := NewAnalyticsService(db, logger)

	// Cleanup function
	cleanup := func() {
		// Database will be closed automatically
	}

	return service, db, cleanup
}

func TestAnalyticsService_RecordPlay(t *testing.T) {
	service, db, cleanup := setupTestAnalyticsService(t)
	defer cleanup()

	ctx := context.Background()

	// Get track ID
	var track models.Track
	err := db.First(&track).Error
	require.NoError(t, err)

	// Get user ID
	var user models.User
	err = db.First(&user).Error
	require.NoError(t, err)

	t.Run("Record play with user", func(t *testing.T) {
		userID := user.ID
		err := service.RecordPlay(ctx, track.ID, &userID, 120, "Chrome", "192.168.1.1")
		assert.NoError(t, err)

		// Verify play was recorded
		var count int64
		db.Model(&models.TrackPlay{}).Where("track_id = ? AND user_id = ?", track.ID, userID).Count(&count)
		assert.Equal(t, int64(1), count)
	})

	t.Run("Record play without user (anonymous)", func(t *testing.T) {
		err := service.RecordPlay(ctx, track.ID, nil, 60, "Firefox", "10.0.0.1")
		assert.NoError(t, err)

		// Verify play was recorded
		var count int64
		db.Model(&models.TrackPlay{}).Where("track_id = ? AND user_id IS NULL", track.ID).Count(&count)
		assert.Equal(t, int64(1), count)
	})

	t.Run("Record play with invalid track ID", func(t *testing.T) {
		userID := user.ID
		err := service.RecordPlay(ctx, uuid.New(), &userID, 120, "Chrome", "192.168.1.1")
		assert.Error(t, err)
		assert.Contains(t, err.Error(), "track not found")
	})
}

func TestAnalyticsService_GetTrackStats(t *testing.T) {
	service, db, cleanup := setupTestAnalyticsService(t)
	defer cleanup()

	ctx := context.Background()

	// Get track ID
	var track models.Track
	err := db.First(&track).Error
	require.NoError(t, err)

	// Get user ID
	var user models.User
	err = db.First(&user).Error
	require.NoError(t, err)

	// Create multiple plays
	userID := user.ID
	plays := []models.TrackPlay{
		{TrackID: track.ID, UserID: &userID, Duration: 120, PlayedAt: time.Now()},
		{TrackID: track.ID, UserID: &userID, Duration: 150, PlayedAt: time.Now()},
		{TrackID: track.ID, UserID: nil, Duration: 100, PlayedAt: time.Now()},
		{TrackID: track.ID, UserID: nil, Duration: 180, PlayedAt: time.Now()}, // Completed
	}

	for _, play := range plays {
		err = db.Create(&play).Error
		require.NoError(t, err)
	}

	t.Run("Get track stats", func(t *testing.T) {
		stats, err := service.GetTrackStats(ctx, track.ID)
		assert.NoError(t, err)
		assert.NotNil(t, stats)
		assert.Equal(t, int64(4), stats.TotalPlays)
		assert.Equal(t, int64(1), stats.UniqueListeners) // Only one user (anonymous plays don't count)
		assert.Greater(t, stats.AverageDuration, 0.0)
		assert.Greater(t, stats.CompletionRate, 0.0) // At least one play completed 90%+
	})

	t.Run("Get track stats with invalid track ID", func(t *testing.T) {
		stats, err := service.GetTrackStats(ctx, uuid.New())
		assert.Error(t, err)
		assert.Nil(t, stats)
		assert.Contains(t, err.Error(), "track not found")
	})

	t.Run("Get track stats with no plays", func(t *testing.T) {
		// Create a new track without plays
		newTrack := &models.Track{
			UserID:   user.ID,
			Title:    "New Track",
			FilePath: "/test/new.mp3",
			FileSize: 5 * 1024 * 1024,
			Format:   "MP3",
			Duration: 180,
			IsPublic: true,
			Status:   models.TrackStatusCompleted,
		}
		err = db.Create(newTrack).Error
		require.NoError(t, err)

		stats, err := service.GetTrackStats(ctx, newTrack.ID)
		assert.NoError(t, err)
		assert.NotNil(t, stats)
		assert.Equal(t, int64(0), stats.TotalPlays)
		assert.Equal(t, int64(0), stats.UniqueListeners)
		assert.Equal(t, 0.0, stats.AverageDuration)
		assert.Equal(t, 0.0, stats.CompletionRate)
	})
}

func TestAnalyticsService_GetPlaysOverTime(t *testing.T) {
	service, db, cleanup := setupTestAnalyticsService(t)
	defer cleanup()

	ctx := context.Background()

	// Get track ID
	var track models.Track
	err := db.First(&track).Error
	require.NoError(t, err)

	// Create plays at different times
	now := time.Now()
	plays := []models.TrackPlay{
		{TrackID: track.ID, Duration: 120, PlayedAt: now.Add(-24 * time.Hour)},
		{TrackID: track.ID, Duration: 150, PlayedAt: now.Add(-12 * time.Hour)},
		{TrackID: track.ID, Duration: 100, PlayedAt: now},
	}

	for _, play := range plays {
		err = db.Create(&play).Error
		require.NoError(t, err)
	}

	t.Run("Get plays over time", func(t *testing.T) {
		startDate := now.Add(-48 * time.Hour)
		endDate := now.Add(1 * time.Hour)
		points, err := service.GetPlaysOverTime(ctx, track.ID, startDate, endDate, "day")
		assert.NoError(t, err)
		assert.NotNil(t, points)
		assert.Greater(t, len(points), 0)
	})

	t.Run("Get plays over time with invalid track ID", func(t *testing.T) {
		startDate := time.Now().Add(-48 * time.Hour)
		endDate := time.Now()
		points, err := service.GetPlaysOverTime(ctx, uuid.New(), startDate, endDate, "day")
		assert.Error(t, err)
		assert.Nil(t, points)
		assert.Contains(t, err.Error(), "track not found")
	})
}

func TestAnalyticsService_GetTopTracks(t *testing.T) {
	service, db, cleanup := setupTestAnalyticsService(t)
	defer cleanup()

	ctx := context.Background()

	// Get user ID
	var user models.User
	err := db.First(&user).Error
	require.NoError(t, err)

	// Create multiple tracks
	tracks := []models.Track{
		{UserID: user.ID, Title: "Track 1", FilePath: "/test/1.mp3", FileSize: 5 * 1024 * 1024, Format: "MP3", Duration: 180, IsPublic: true, Status: models.TrackStatusCompleted},
		{UserID: user.ID, Title: "Track 2", FilePath: "/test/2.mp3", FileSize: 5 * 1024 * 1024, Format: "MP3", Duration: 180, IsPublic: true, Status: models.TrackStatusCompleted},
		{UserID: user.ID, Title: "Track 3", FilePath: "/test/3.mp3", FileSize: 5 * 1024 * 1024, Format: "MP3", Duration: 180, IsPublic: true, Status: models.TrackStatusCompleted},
	}

	for i := range tracks {
		err = db.Create(&tracks[i]).Error
		require.NoError(t, err)
	}

	// Create plays for tracks (Track 1: 5 plays, Track 2: 3 plays, Track 3: 1 play)
	for i := 0; i < 5; i++ {
		play := models.TrackPlay{TrackID: tracks[0].ID, Duration: 120, PlayedAt: time.Now()}
		db.Create(&play)
	}
	for i := 0; i < 3; i++ {
		play := models.TrackPlay{TrackID: tracks[1].ID, Duration: 150, PlayedAt: time.Now()}
		db.Create(&play)
	}
	play := models.TrackPlay{TrackID: tracks[2].ID, Duration: 100, PlayedAt: time.Now()}
	db.Create(&play)

	t.Run("Get top tracks", func(t *testing.T) {
		topTracks, err := service.GetTopTracks(ctx, 10, nil, nil)
		assert.NoError(t, err)
		assert.NotNil(t, topTracks)
		assert.GreaterOrEqual(t, len(topTracks), 3)

		// Verify ordering (most plays first)
		if len(topTracks) >= 3 {
			assert.Equal(t, int64(5), topTracks[0].TotalPlays) // Track 1
			assert.Equal(t, int64(3), topTracks[1].TotalPlays) // Track 2
			assert.Equal(t, int64(1), topTracks[2].TotalPlays) // Track 3
		}
	})

	t.Run("Get top tracks with limit", func(t *testing.T) {
		topTracks, err := service.GetTopTracks(ctx, 2, nil, nil)
		assert.NoError(t, err)
		assert.NotNil(t, topTracks)
		assert.LessOrEqual(t, len(topTracks), 2)
	})

	t.Run("Get top tracks with date filter", func(t *testing.T) {
		startDate := time.Now().Add(-24 * time.Hour)
		endDate := time.Now().Add(1 * time.Hour)
		topTracks, err := service.GetTopTracks(ctx, 10, &startDate, &endDate)
		assert.NoError(t, err)
		assert.NotNil(t, topTracks)
	})
}

func TestAnalyticsService_GetUserStats(t *testing.T) {
	service, db, cleanup := setupTestAnalyticsService(t)
	defer cleanup()

	ctx := context.Background()

	// Get user ID
	var user models.User
	err := db.First(&user).Error
	require.NoError(t, err)

	// Get track ID
	var track models.Track
	err = db.First(&track).Error
	require.NoError(t, err)

	// Create another track
	anotherTrack := &models.Track{
		UserID:   user.ID,
		Title:    "Another Track",
		FilePath: "/test/another.mp3",
		FileSize: 5 * 1024 * 1024,
		Format:   "MP3",
		Duration: 180,
		IsPublic: true,
		Status:   models.TrackStatusCompleted,
	}
	err = db.Create(anotherTrack).Error
	require.NoError(t, err)

	// Create plays for the user
	userID := user.ID
	plays := []models.TrackPlay{
		{TrackID: track.ID, UserID: &userID, Duration: 120, PlayedAt: time.Now()},
		{TrackID: track.ID, UserID: &userID, Duration: 150, PlayedAt: time.Now()},
		{TrackID: anotherTrack.ID, UserID: &userID, Duration: 100, PlayedAt: time.Now()},
	}

	for _, play := range plays {
		err = db.Create(&play).Error
		require.NoError(t, err)
	}

	t.Run("Get user stats", func(t *testing.T) {
		stats, err := service.GetUserStats(ctx, user.ID)
		assert.NoError(t, err)
		assert.NotNil(t, stats)
		assert.Equal(t, int64(3), stats.TotalPlays)
		assert.Equal(t, int64(2), stats.UniqueTracks)
		assert.Greater(t, stats.TotalDuration, int64(0))
		assert.Greater(t, stats.AverageDuration, 0.0)
	})

	t.Run("Get user stats with invalid user ID", func(t *testing.T) {
		stats, err := service.GetUserStats(ctx, uuid.New())
		assert.Error(t, err)
		assert.Nil(t, stats)
		assert.Contains(t, err.Error(), "user not found")
	})

	t.Run("Get user stats with no plays", func(t *testing.T) {
		// Create a new user without plays
		newUser := &models.User{
			Username:     "newuser",
			Email:        "new@example.com",
			PasswordHash: "hash",
			Slug:         "newuser",
			IsActive:     true,
		}
		err = db.Create(newUser).Error
		require.NoError(t, err)

		stats, err := service.GetUserStats(ctx, newUser.ID)
		assert.NoError(t, err)
		assert.NotNil(t, stats)
		assert.Equal(t, int64(0), stats.TotalPlays)
		assert.Equal(t, int64(0), stats.UniqueTracks)
		assert.Equal(t, int64(0), stats.TotalDuration)
		assert.Equal(t, 0.0, stats.AverageDuration)
	})
}