/**
 * Education Service
 * API client for courses, lessons, quizzes, and gamification
 */

import axios from 'axios';
import type {
  CourseListItem,
  CourseDetail,
  CourseCategory,
  CourseModule,
  LessonDetail,
  UserEnrollment,
  EnrollmentWithCourse,
  CourseFilters,
  PaginatedResponse,
  ApiResponse,
  Quiz,
  QuizAttempt,
  QuizResult,
  GamificationProfile,
  LevelProgress,
  StreakStats,
  Achievement,
  LeaderboardEntry,
  UserLeaderboardPosition,
  GamificationSummary,
} from '../types/education.types';

const API_BASE_URL = import.meta.env?.VITE_API_URL || '/api/v1';

const api = axios.create({
  baseURL: API_BASE_URL,
  headers: {
    'Content-Type': 'application/json',
  },
});

// Add auth token to requests
api.interceptors.request.use((config) => {
  const token = localStorage.getItem('auth_token');
  if (token) {
    config.headers.Authorization = `Bearer ${token}`;
  }
  return config;
});

// ============================================================================
// Categories
// ============================================================================

export async function getCategories(): Promise<CourseCategory[]> {
  const response = await api.get<ApiResponse<CourseCategory[]>>('/education/categories');
  return response.data.data;
}

export async function createCategory(data: {
  name: string;
  slug: string;
  description?: string;
  icon?: string;
}): Promise<CourseCategory> {
  const response = await api.post<ApiResponse<CourseCategory>>('/education/categories', data);
  return response.data.data;
}

// ============================================================================
// Courses
// ============================================================================

export async function getCourses(
  filters?: CourseFilters
): Promise<PaginatedResponse<CourseListItem>> {
  const response = await api.get<ApiResponse<PaginatedResponse<CourseListItem>>>(
    '/education/courses',
    { params: filters }
  );
  return response.data.data;
}

export async function getPopularCourses(limit = 6): Promise<CourseListItem[]> {
  const response = await api.get<ApiResponse<CourseListItem[]>>('/education/courses/popular', {
    params: { limit },
  });
  return response.data.data;
}

export async function getNewCourses(limit = 6): Promise<CourseListItem[]> {
  const response = await api.get<ApiResponse<CourseListItem[]>>('/education/courses/new', {
    params: { limit },
  });
  return response.data.data;
}

export async function getCourseById(courseId: string): Promise<CourseDetail> {
  const response = await api.get<ApiResponse<CourseDetail>>(`/education/courses/${courseId}`);
  return response.data.data;
}

export async function getCourseBySlug(slug: string): Promise<CourseDetail> {
  const response = await api.get<ApiResponse<CourseDetail>>(`/education/courses/slug/${slug}`);
  return response.data.data;
}

export async function getCourseModules(courseId: string): Promise<CourseModule[]> {
  const response = await api.get<ApiResponse<CourseModule[]>>(
    `/education/courses/${courseId}/modules`
  );
  return response.data.data;
}

export async function getCourseStats(courseId: string): Promise<{
  totalEnrollments: number;
  completionRate: number;
  avgRating: number;
}> {
  const response = await api.get<
    ApiResponse<{ totalEnrollments: number; completionRate: number; avgRating: number }>
  >(`/education/courses/${courseId}/stats`);
  return response.data.data;
}

// ============================================================================
// Lessons
// ============================================================================

export async function getModuleLessons(
  moduleId: string
): Promise<{ id: string; title: string; contentType: string; durationMinutes: number }[]> {
  const response = await api.get<
    ApiResponse<{ id: string; title: string; contentType: string; durationMinutes: number }[]>
  >(`/education/modules/${moduleId}/lessons`);
  return response.data.data;
}

export async function getLessonById(lessonId: string): Promise<LessonDetail> {
  const response = await api.get<ApiResponse<LessonDetail>>(`/education/lessons/${lessonId}`);
  return response.data.data;
}

export async function updateLessonProgress(
  lessonId: string,
  data: {
    videoWatchedSeconds?: number;
    videoCompleted?: boolean;
    userNotes?: string;
  }
): Promise<{ progressId: string; isCompleted: boolean }> {
  const response = await api.post<ApiResponse<{ progressId: string; isCompleted: boolean }>>(
    `/education/lessons/${lessonId}/progress`,
    data
  );
  return response.data.data;
}

export async function markLessonComplete(
  lessonId: string
): Promise<{ progressId: string; xpAwarded: number }> {
  const response = await api.post<ApiResponse<{ progressId: string; xpAwarded: number }>>(
    `/education/lessons/${lessonId}/complete`
  );
  return response.data.data;
}

// ============================================================================
// Enrollments
// ============================================================================

export async function getMyEnrollments(): Promise<EnrollmentWithCourse[]> {
  const response = await api.get<ApiResponse<EnrollmentWithCourse[]>>('/education/my/enrollments');
  return response.data.data;
}

export async function getMyLearningStats(): Promise<{
  totalEnrollments: number;
  completedCourses: number;
  inProgressCourses: number;
  totalLessonsCompleted: number;
  totalTimeSpent: number;
}> {
  const response = await api.get<
    ApiResponse<{
      totalEnrollments: number;
      completedCourses: number;
      inProgressCourses: number;
      totalLessonsCompleted: number;
      totalTimeSpent: number;
    }>
  >('/education/my/stats');
  return response.data.data;
}

export async function enrollInCourse(courseId: string): Promise<UserEnrollment> {
  const response = await api.post<ApiResponse<UserEnrollment>>(
    `/education/courses/${courseId}/enroll`
  );
  return response.data.data;
}

export async function getEnrollmentStatus(courseId: string): Promise<UserEnrollment | null> {
  try {
    const response = await api.get<ApiResponse<UserEnrollment>>(
      `/education/courses/${courseId}/enrollment`
    );
    return response.data.data;
  } catch {
    return null;
  }
}

// ============================================================================
// Quizzes
// ============================================================================

export async function getQuizByLessonId(lessonId: string): Promise<Quiz | null> {
  try {
    const response = await api.get<ApiResponse<Quiz>>(`/education/lessons/${lessonId}/quiz`);
    return response.data.data;
  } catch {
    return null;
  }
}

export async function getQuizById(quizId: string): Promise<Quiz> {
  const response = await api.get<ApiResponse<Quiz>>(`/education/quizzes/${quizId}`);
  return response.data.data;
}

export async function getCourseQuizzes(courseId: string): Promise<Quiz[]> {
  const response = await api.get<ApiResponse<Quiz[]>>(`/education/courses/${courseId}/quizzes`);
  return response.data.data;
}

export async function startQuizAttempt(
  quizId: string,
  enrollmentId?: string
): Promise<{ attemptId: string; quiz: Quiz; startedAt: string; expiresAt?: string }> {
  const response = await api.post<
    ApiResponse<{ attemptId: string; quiz: Quiz; startedAt: string; expiresAt?: string }>
  >(`/education/quizzes/${quizId}/start`, { enrollmentId });
  return response.data.data;
}

export async function submitQuizAttempt(
  attemptId: string,
  answers: { questionId: string; answer: string | string[] }[]
): Promise<QuizResult> {
  const response = await api.post<ApiResponse<QuizResult>>(
    `/education/quizzes/attempts/${attemptId}/submit`,
    { answers }
  );
  return response.data.data;
}

export async function getQuizResults(attemptId: string): Promise<QuizResult> {
  const response = await api.get<ApiResponse<QuizResult>>(
    `/education/quizzes/attempts/${attemptId}/results`
  );
  return response.data.data;
}

export async function getUserQuizAttempts(quizId: string): Promise<QuizAttempt[]> {
  const response = await api.get<ApiResponse<QuizAttempt[]>>(
    `/education/quizzes/${quizId}/my-attempts`
  );
  return response.data.data;
}

export async function getQuizStatistics(quizId: string): Promise<{
  totalAttempts: number;
  passRate: number;
  averageScore: number;
}> {
  const response = await api.get<
    ApiResponse<{ totalAttempts: number; passRate: number; averageScore: number }>
  >(`/education/quizzes/${quizId}/stats`);
  return response.data.data;
}

export async function getUserQuizStats(): Promise<{
  totalAttempts: number;
  quizzesPassed: number;
  averageScore: number;
  bestScore: number;
}> {
  const response = await api.get<
    ApiResponse<{
      totalAttempts: number;
      quizzesPassed: number;
      averageScore: number;
      bestScore: number;
    }>
  >('/education/my/quiz-stats');
  return response.data.data;
}

// ============================================================================
// Gamification
// ============================================================================

export async function getGamificationProfile(): Promise<GamificationProfile & { levelProgress: LevelProgress }> {
  const response = await api.get<ApiResponse<GamificationProfile & { levelProgress: LevelProgress }>>(
    '/education/gamification/profile'
  );
  return response.data.data;
}

export async function getPublicProfile(userId: string): Promise<{
  userId: string;
  totalXp: number;
  currentLevel: number;
  currentStreakDays: number;
  totalCoursesCompleted: number;
  levelProgress: { currentLevel: number; progressPercentage: number };
}> {
  const response = await api.get<
    ApiResponse<{
      userId: string;
      totalXp: number;
      currentLevel: number;
      currentStreakDays: number;
      totalCoursesCompleted: number;
      levelProgress: { currentLevel: number; progressPercentage: number };
    }>
  >(`/education/gamification/profile/${userId}`);
  return response.data.data;
}

export async function getLevelProgress(): Promise<LevelProgress> {
  const response = await api.get<ApiResponse<LevelProgress>>(
    '/education/gamification/level-progress'
  );
  return response.data.data;
}

export async function getStreakStats(): Promise<StreakStats> {
  const response = await api.get<ApiResponse<StreakStats>>('/education/gamification/streak');
  return response.data.data;
}

export async function recordDailyActivity(): Promise<{
  currentStreak: number;
  longestStreak: number;
  streakMaintained: boolean;
  xpBonusApplied: boolean;
}> {
  const response = await api.post<
    ApiResponse<{
      currentStreak: number;
      longestStreak: number;
      streakMaintained: boolean;
      xpBonusApplied: boolean;
    }>
  >('/education/gamification/daily-activity');
  return response.data.data;
}

export async function getMyAchievements(): Promise<Achievement[]> {
  const response = await api.get<ApiResponse<Achievement[]>>(
    '/education/gamification/achievements'
  );
  return response.data.data;
}

export async function getUserAchievements(userId: string): Promise<Achievement[]> {
  const response = await api.get<ApiResponse<Achievement[]>>(
    `/education/gamification/achievements/${userId}`
  );
  return response.data.data;
}

export async function getLeaderboard(
  period: 'all_time' | 'month' | 'week' = 'all_time',
  limit = 100
): Promise<LeaderboardEntry[]> {
  const response = await api.get<ApiResponse<LeaderboardEntry[]>>(
    '/education/gamification/leaderboard',
    { params: { period, limit } }
  );
  return response.data.data;
}

export async function getMyLeaderboardPosition(
  period: 'all_time' | 'month' | 'week' = 'all_time'
): Promise<UserLeaderboardPosition> {
  const response = await api.get<ApiResponse<UserLeaderboardPosition>>(
    '/education/gamification/leaderboard/my-position',
    { params: { period } }
  );
  return response.data.data;
}

export async function getNearbyUsers(
  period: 'all_time' | 'month' | 'week' = 'all_time',
  radius = 5
): Promise<LeaderboardEntry[]> {
  const response = await api.get<ApiResponse<LeaderboardEntry[]>>(
    '/education/gamification/leaderboard/nearby',
    { params: { period, radius } }
  );
  return response.data.data;
}

export async function getGamificationSummary(): Promise<GamificationSummary> {
  const response = await api.get<ApiResponse<GamificationSummary>>(
    '/education/gamification/summary'
  );
  return response.data.data;
}

// ============================================================================
// Admin/Instructor Operations
// ============================================================================

export async function createCourse(data: {
  title: string;
  slug: string;
  description?: string;
  shortDescription?: string;
  categoryId?: string;
  difficultyLevel: 'beginner' | 'intermediate' | 'advanced';
  isFree: boolean;
  priceUsd?: number;
  thumbnailUrl?: string;
  learningObjectives?: string[];
  requirements?: string[];
  tags?: string[];
}): Promise<CourseDetail> {
  const response = await api.post<ApiResponse<CourseDetail>>('/education/courses', data);
  return response.data.data;
}

export async function updateCourse(
  courseId: string,
  data: Partial<{
    title: string;
    description: string;
    shortDescription: string;
    categoryId: string;
    difficultyLevel: 'beginner' | 'intermediate' | 'advanced';
    isFree: boolean;
    priceUsd: number;
    thumbnailUrl: string;
    learningObjectives: string[];
    requirements: string[];
    tags: string[];
  }>
): Promise<CourseDetail> {
  const response = await api.patch<ApiResponse<CourseDetail>>(
    `/education/courses/${courseId}`,
    data
  );
  return response.data.data;
}

export async function deleteCourse(courseId: string): Promise<void> {
  await api.delete(`/education/courses/${courseId}`);
}

export async function publishCourse(courseId: string): Promise<CourseDetail> {
  const response = await api.post<ApiResponse<CourseDetail>>(
    `/education/courses/${courseId}/publish`
  );
  return response.data.data;
}

export async function createModule(
  courseId: string,
  data: {
    title: string;
    description?: string;
    sortOrder?: number;
  }
): Promise<CourseModule> {
  const response = await api.post<ApiResponse<CourseModule>>(
    `/education/courses/${courseId}/modules`,
    data
  );
  return response.data.data;
}

export async function deleteModule(moduleId: string): Promise<void> {
  await api.delete(`/education/modules/${moduleId}`);
}

export async function createLesson(
  moduleId: string,
  data: {
    title: string;
    description?: string;
    contentType: 'video' | 'text' | 'quiz' | 'exercise';
    durationMinutes?: number;
    sortOrder?: number;
    isFree?: boolean;
    videoUrl?: string;
    contentHtml?: string;
    contentMarkdown?: string;
  }
): Promise<LessonDetail> {
  const response = await api.post<ApiResponse<LessonDetail>>(
    `/education/modules/${moduleId}/lessons`,
    data
  );
  return response.data.data;
}

export async function deleteLesson(lessonId: string): Promise<void> {
  await api.delete(`/education/lessons/${lessonId}`);
}

export async function createQuiz(data: {
  courseId: string;
  lessonId?: string;
  title: string;
  description?: string;
  passingScore?: number;
  maxAttempts?: number;
  timeLimitMinutes?: number;
  shuffleQuestions?: boolean;
  showCorrectAnswers?: boolean;
}): Promise<Quiz> {
  const response = await api.post<ApiResponse<Quiz>>('/education/quizzes', data);
  return response.data.data;
}

export async function deleteQuiz(quizId: string): Promise<void> {
  await api.delete(`/education/quizzes/${quizId}`);
}

export async function createQuizQuestion(
  quizId: string,
  data: {
    questionType: 'multiple_choice' | 'multiple_answer' | 'true_false' | 'short_answer';
    questionText: string;
    explanation?: string;
    options?: { text: string; isCorrect: boolean }[];
    points?: number;
    sortOrder?: number;
  }
): Promise<{ id: string }> {
  const response = await api.post<ApiResponse<{ id: string }>>(
    `/education/quizzes/${quizId}/questions`,
    data
  );
  return response.data.data;
}

export async function deleteQuizQuestion(questionId: string): Promise<void> {
  await api.delete(`/education/questions/${questionId}`);
}

// Export service object for convenience
export const educationService = {
  // Categories
  getCategories,
  createCategory,
  // Courses
  getCourses,
  getPopularCourses,
  getNewCourses,
  getCourseById,
  getCourseBySlug,
  getCourseModules,
  getCourseStats,
  createCourse,
  updateCourse,
  deleteCourse,
  publishCourse,
  // Modules
  createModule,
  deleteModule,
  // Lessons
  getModuleLessons,
  getLessonById,
  updateLessonProgress,
  markLessonComplete,
  createLesson,
  deleteLesson,
  // Enrollments
  getMyEnrollments,
  getMyLearningStats,
  enrollInCourse,
  getEnrollmentStatus,
  // Quizzes
  getQuizByLessonId,
  getQuizById,
  getCourseQuizzes,
  startQuizAttempt,
  submitQuizAttempt,
  getQuizResults,
  getUserQuizAttempts,
  getQuizStatistics,
  getUserQuizStats,
  createQuiz,
  deleteQuiz,
  createQuizQuestion,
  deleteQuizQuestion,
  // Gamification
  getGamificationProfile,
  getPublicProfile,
  getLevelProgress,
  getStreakStats,
  recordDailyActivity,
  getMyAchievements,
  getUserAchievements,
  getLeaderboard,
  getMyLeaderboardPosition,
  getNearbyUsers,
  getGamificationSummary,
};

export default educationService;