package analytics

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"veza-backend-api/internal/services"
	"veza-backend-api/internal/types"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/mock"
	"go.uber.org/zap"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

// MockAnalyticsService implements AnalyticsServiceInterface for testing
type MockAnalyticsService struct {
	mock.Mock
}

func (m *MockAnalyticsService) GetTrackStats(ctx context.Context, trackID uuid.UUID) (*types.TrackStats, error) {
	args := m.Called(ctx, trackID)
	if args.Get(0) == nil {
		return nil, args.Error(1)
	}
	return args.Get(0).(*types.TrackStats), args.Error(1)
}

func (m *MockAnalyticsService) GetPlaysOverTime(ctx context.Context, trackID uuid.UUID, startDate, endDate time.Time, interval string) ([]services.PlayTimePoint, error) {
	args := m.Called(ctx, trackID, startDate, endDate, interval)
	if args.Get(0) == nil {
		return nil, args.Error(1)
	}
	return args.Get(0).([]services.PlayTimePoint), args.Error(1)
}

func (m *MockAnalyticsService) GetDB() *gorm.DB {
	args := m.Called()
	return args.Get(0).(*gorm.DB)
}

// setupTestDB creates an in-memory SQLite DB with tracks table for ownership checks
func setupTestDB(trackID, creatorID uuid.UUID) *gorm.DB {
	db, _ := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
	db.Exec("CREATE TABLE tracks (id TEXT PRIMARY KEY, creator_id TEXT)")
	db.Exec("INSERT INTO tracks (id, creator_id) VALUES (?, ?)", trackID.String(), creatorID.String())
	return db
}

// MockAnalyticsJobWorker mocks JobWorker for analytics
type MockAnalyticsJobWorker struct {
	mock.Mock
}

func (m *MockAnalyticsJobWorker) EnqueueAnalyticsJob(eventName string, userID *uuid.UUID, payload map[string]interface{}) {
	m.Called(eventName, userID, payload)
}

func setupTestRouter(mockService *MockAnalyticsService, mockJobWorker *MockAnalyticsJobWorker) *gin.Engine {
	gin.SetMode(gin.TestMode)
	router := gin.New()

	logger := zap.NewNop()
	handler := NewHandlerWithInterface(mockService, logger)
	if mockJobWorker != nil {
		handler.SetJobWorker(mockJobWorker)
	}

	api := router.Group("/api/v1/analytics")
	api.Use(func(c *gin.Context) {
		userIDStr := c.GetHeader("X-User-ID")
		if userIDStr != "" {
			uid, err := uuid.Parse(userIDStr)
			if err == nil {
				c.Set("user_id", uid)
			}
		}
		c.Next()
	})
	{
		api.GET("", handler.GetAnalytics)
		api.GET("/tracks/:id", handler.GetTrackAnalyticsDashboard)
		api.POST("/events", handler.RecordEvent)
	}

	return router
}

func TestHandler_RecordEvent_Success(t *testing.T) {
	mockService := new(MockAnalyticsService)
	mockJobWorker := new(MockAnalyticsJobWorker)
	router := setupTestRouter(mockService, mockJobWorker)

	userID := uuid.New()
	reqBody := RecordEventRequest{
		EventName: "track_liked",
		Payload:   map[string]interface{}{"track_id": uuid.New().String()},
	}

	mockJobWorker.On("EnqueueAnalyticsJob", "track_liked", &userID, reqBody.Payload).Return()

	body, _ := json.Marshal(reqBody)

	req, _ := http.NewRequest("POST", "/api/v1/analytics/events", bytes.NewBuffer(body))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-User-ID", userID.String())
	w := httptest.NewRecorder()
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusOK, w.Code)
	mockJobWorker.AssertExpectations(t)
}

func TestHandler_RecordEvent_NoJobWorker(t *testing.T) {
	mockService := new(MockAnalyticsService)
	router := setupTestRouter(mockService, nil)

	userID := uuid.New()
	reqBody := RecordEventRequest{
		EventName: "track_liked",
		Payload:   map[string]interface{}{"track_id": uuid.New().String()},
	}

	body, _ := json.Marshal(reqBody)

	req, _ := http.NewRequest("POST", "/api/v1/analytics/events", bytes.NewBuffer(body))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-User-ID", userID.String())
	w := httptest.NewRecorder()
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusInternalServerError, w.Code)
}

func TestHandler_GetTrackAnalyticsDashboard_Success(t *testing.T) {
	mockService := new(MockAnalyticsService)
	mockJobWorker := new(MockAnalyticsJobWorker)
	router := setupTestRouter(mockService, mockJobWorker)

	trackID := uuid.New()
	creatorID := uuid.New()
	expectedStats := &types.TrackStats{
		TotalPlays:      100,
		UniqueListeners: 50,
		AverageDuration: 120,
		CompletionRate:  0.8,
	}
	expectedPoints := []services.PlayTimePoint{
		{Date: time.Now(), Count: 10},
	}

	testDB := setupTestDB(trackID, creatorID)
	mockService.On("GetDB").Return(testDB)
	mockService.On("GetTrackStats", mock.Anything, trackID).Return(expectedStats, nil)
	mockService.On("GetPlaysOverTime", mock.Anything, trackID, mock.Anything, mock.Anything, "day").Return(expectedPoints, nil)

	req, _ := http.NewRequest("GET", "/api/v1/analytics/tracks/"+trackID.String(), nil)
	req.Header.Set("X-User-ID", creatorID.String()) // SECURITY: Must be track creator
	w := httptest.NewRecorder()
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusOK, w.Code)
	mockService.AssertExpectations(t)
}

func TestHandler_GetTrackAnalyticsDashboard_IDOR_Blocked(t *testing.T) {
	mockService := new(MockAnalyticsService)
	router := setupTestRouter(mockService, nil)

	trackID := uuid.New()
	creatorID := uuid.New()
	attackerID := uuid.New()

	testDB := setupTestDB(trackID, creatorID)
	mockService.On("GetDB").Return(testDB)

	req, _ := http.NewRequest("GET", "/api/v1/analytics/tracks/"+trackID.String(), nil)
	req.Header.Set("X-User-ID", attackerID.String()) // Different user — should be blocked
	w := httptest.NewRecorder()
	router.ServeHTTP(w, req)

	assert.Equal(t, http.StatusForbidden, w.Code) // IDOR blocked
}