import axios, { AxiosError, AxiosInstance, InternalAxiosRequestConfig } from 'axios';
import AsyncStorage from '@react-native-async-storage/async-storage';
import {
  LoginRequest,
  SignupRequest,
  ForgotPasswordRequest,
  ResetPasswordRequest,
  AuthResponse,
  User,
  Resource,
  ResourceCategory,
  CommunitySpace,
  UserPreferences,
  ApiError,
} from './types';

// Storage keys
const TOKEN_KEY = 'auth_token';
const REFRESH_TOKEN_KEY = 'refresh_token';

// API base URL - update this for your environment
const API_BASE_URL = process.env.EXPO_PUBLIC_API_URL || 'https://api.morethanadiagnosis.org/api/v1';

// Create axios instance
const api: AxiosInstance = axios.create({
  baseURL: API_BASE_URL,
  timeout: 30000,
  headers: {
    'Content-Type': 'application/json',
  },
});

// Request interceptor - add auth token to requests
api.interceptors.request.use(
  async (config: InternalAxiosRequestConfig) => {
    const token = await AsyncStorage.getItem(TOKEN_KEY);
    if (token && config.headers) {
      config.headers.Authorization = `Bearer ${token}`;
    }
    return config;
  },
  (error) => {
    return Promise.reject(error);
  }
);

// Response interceptor - handle token refresh
api.interceptors.response.use(
  (response) => response,
  async (error: AxiosError<ApiError>) => {
    const originalRequest = error.config;

    // If 401 and we haven't tried to refresh yet
    if (error.response?.status === 401 && originalRequest && !originalRequest._retry) {
      originalRequest._retry = true;

      try {
        const refreshToken = await AsyncStorage.getItem(REFRESH_TOKEN_KEY);
        if (refreshToken) {
          const response = await axios.post<AuthResponse>(`${API_BASE_URL}/auth/refresh`, {
            refreshToken,
          });

          const { accessToken, refreshToken: newRefreshToken } = response.data;

          // Store new tokens
          await AsyncStorage.setItem(TOKEN_KEY, accessToken);
          await AsyncStorage.setItem(REFRESH_TOKEN_KEY, newRefreshToken);

          // Retry original request with new token
          if (originalRequest.headers) {
            originalRequest.headers.Authorization = `Bearer ${accessToken}`;
          }
          return api(originalRequest);
        }
      } catch (refreshError) {
        // Refresh failed - clear tokens and redirect to login
        await AsyncStorage.multiRemove([TOKEN_KEY, REFRESH_TOKEN_KEY]);
        // The auth store should handle navigation
      }
    }

    return Promise.reject(error);
  }
);

// Extend AxiosRequestConfig to include _retry property
declare module 'axios' {
  export interface InternalAxiosRequestConfig {
    _retry?: boolean;
  }
}

// ==========================================
// Authentication API
// ==========================================

export const authApi = {
  login: async (data: LoginRequest): Promise<AuthResponse> => {
    const response = await api.post<AuthResponse>('/auth/login', data);
    const { accessToken, refreshToken } = response.data;

    // Store tokens
    await AsyncStorage.setItem(TOKEN_KEY, accessToken);
    await AsyncStorage.setItem(REFRESH_TOKEN_KEY, refreshToken);

    return response.data;
  },

  signup: async (data: SignupRequest): Promise<AuthResponse> => {
    const response = await api.post<AuthResponse>('/auth/signup', data);
    const { accessToken, refreshToken } = response.data;

    // Store tokens
    await AsyncStorage.setItem(TOKEN_KEY, accessToken);
    await AsyncStorage.setItem(REFRESH_TOKEN_KEY, refreshToken);

    return response.data;
  },

  forgotPassword: async (data: ForgotPasswordRequest): Promise<{ message: string }> => {
    const response = await api.post<{ message: string }>('/auth/forgot-password', data);
    return response.data;
  },

  resetPassword: async (data: ResetPasswordRequest): Promise<{ message: string }> => {
    const response = await api.post<{ message: string }>('/auth/reset-password', data);
    return response.data;
  },

  logout: async (): Promise<void> => {
    try {
      await api.post('/auth/logout');
    } catch {
      // Ignore errors on logout
    } finally {
      await AsyncStorage.multiRemove([TOKEN_KEY, REFRESH_TOKEN_KEY]);
    }
  },

  refreshToken: async (): Promise<AuthResponse> => {
    const refreshToken = await AsyncStorage.getItem(REFRESH_TOKEN_KEY);
    if (!refreshToken) {
      throw new Error('No refresh token available');
    }

    const response = await api.post<AuthResponse>('/auth/refresh', { refreshToken });
    const { accessToken, refreshToken: newRefreshToken } = response.data;

    await AsyncStorage.setItem(TOKEN_KEY, accessToken);
    await AsyncStorage.setItem(REFRESH_TOKEN_KEY, newRefreshToken);

    return response.data;
  },

  getStoredToken: async (): Promise<string | null> => {
    return AsyncStorage.getItem(TOKEN_KEY);
  },
};

// ==========================================
// User API
// ==========================================

export const userApi = {
  getMe: async (): Promise<User> => {
    const response = await api.get<User>('/user/me');
    return response.data;
  },

  updateMe: async (data: Partial<User>): Promise<User> => {
    const response = await api.put<User>('/user/me', data);
    return response.data;
  },

  getPreferences: async (): Promise<UserPreferences> => {
    const response = await api.get<UserPreferences>('/user/preferences');
    return response.data;
  },

  updatePreferences: async (data: Partial<UserPreferences>): Promise<UserPreferences> => {
    const response = await api.put<UserPreferences>('/user/preferences', data);
    return response.data;
  },
};

// ==========================================
// Resources API
// ==========================================

export const resourcesApi = {
  getCategories: async (): Promise<ResourceCategory[]> => {
    const response = await api.get<ResourceCategory[]>('/resources/categories');
    return response.data;
  },

  getAll: async (): Promise<Resource[]> => {
    const response = await api.get<Resource[]>('/resources');
    return response.data;
  },

  getById: async (id: string): Promise<Resource> => {
    const response = await api.get<Resource>(`/resources/${id}`);
    return response.data;
  },

  getByCategory: async (categoryId: string): Promise<Resource[]> => {
    const response = await api.get<Resource[]>(`/resources/category/${categoryId}`);
    return response.data;
  },
};

// ==========================================
// Community API
// ==========================================

export const communityApi = {
  getSpaces: async (): Promise<CommunitySpace[]> => {
    const response = await api.get<CommunitySpace[]>('/community');
    return response.data;
  },

  getSpaceById: async (id: string): Promise<CommunitySpace> => {
    const response = await api.get<CommunitySpace>(`/community/${id}`);
    return response.data;
  },

  joinSpace: async (id: string): Promise<{ message: string }> => {
    const response = await api.post<{ message: string }>(`/community/${id}/join`);
    return response.data;
  },

  leaveSpace: async (id: string): Promise<{ message: string }> => {
    const response = await api.post<{ message: string }>(`/community/${id}/leave`);
    return response.data;
  },
};

// ==========================================
// Helper functions
// ==========================================

export const handleApiError = (error: unknown): string => {
  if (axios.isAxiosError(error)) {
    const axiosError = error as AxiosError<ApiError>;

    // Network error
    if (!axiosError.response) {
      return 'Network error. Please check your connection.';
    }

    // API error response
    const apiError = axiosError.response.data;
    if (apiError?.message) {
      return apiError.message;
    }

    // HTTP status errors
    switch (axiosError.response.status) {
      case 400:
        return 'Invalid request. Please check your input.';
      case 401:
        return 'Invalid credentials. Please try again.';
      case 403:
        return 'You do not have permission to perform this action.';
      case 404:
        return 'Resource not found.';
      case 422:
        return 'Validation error. Please check your input.';
      case 500:
        return 'Server error. Please try again later.';
      default:
        return 'An unexpected error occurred.';
    }
  }

  if (error instanceof Error) {
    return error.message;
  }

  return 'An unexpected error occurred.';
};

export default api;