import * as SecureStore from 'expo-secure-store';
import type { AuthResponse, ChatResponse, Patient, ApiResponse, ApiError } from '@/types';

const API_BASE_URL = 'https://eluxnetworks.net/function/well-api/api';
const CLIENT_ID = 'MA_001';

class ApiService {
  private async getToken(): Promise<string | null> {
    try {
      return await SecureStore.getItemAsync('accessToken');
    } catch {
      return null;
    }
  }

  private async getUserName(): Promise<string | null> {
    try {
      return await SecureStore.getItemAsync('userName');
    } catch {
      return null;
    }
  }

  private generateNonce(): string {
    return Math.floor(Math.random() * 1000000).toString();
  }

  private async makeRequest<T>(params: Record<string, string>): Promise<ApiResponse<T>> {
    try {
      const formData = new URLSearchParams();
      Object.entries(params).forEach(([key, value]) => {
        formData.append(key, value);
      });

      const response = await fetch(API_BASE_URL, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: formData.toString(),
      });

      const data = await response.json();

      if (data.status === '200 OK' || data.ok === true) {
        return { data: data as T, ok: true };
      }

      return {
        ok: false,
        error: {
          message: data.message || data.error || 'Request failed',
          status: response.status,
        },
      };
    } catch (error) {
      const apiError: ApiError = {
        message: error instanceof Error ? error.message : 'Network error',
        code: 'NETWORK_ERROR',
      };
      return { ok: false, error: apiError };
    }
  }

  // Authentication
  async login(username: string, password: string): Promise<ApiResponse<AuthResponse>> {
    const response = await this.makeRequest<AuthResponse>({
      function: 'credentials',
      user_name: username,
      ps: password,
      clientId: CLIENT_ID,
      nonce: this.generateNonce(),
    });

    if (response.ok && response.data) {
      // Save credentials to SecureStore
      await SecureStore.setItemAsync('accessToken', response.data.access_token);
      await SecureStore.setItemAsync('userId', response.data.user_id.toString());
      await SecureStore.setItemAsync('userName', username);
      await SecureStore.setItemAsync('privileges', response.data.privileges);
      await SecureStore.setItemAsync('maxRole', response.data.max_role.toString());
    }

    return response;
  }

  async logout(): Promise<void> {
    await SecureStore.deleteItemAsync('accessToken');
    await SecureStore.deleteItemAsync('userId');
    await SecureStore.deleteItemAsync('userName');
    await SecureStore.deleteItemAsync('privileges');
    await SecureStore.deleteItemAsync('maxRole');
  }

  async isAuthenticated(): Promise<boolean> {
    const token = await this.getToken();
    return !!token;
  }

  // Get stored user info
  async getStoredUser() {
    try {
      const userId = await SecureStore.getItemAsync('userId');
      const userName = await SecureStore.getItemAsync('userName');
      const privileges = await SecureStore.getItemAsync('privileges');
      const maxRole = await SecureStore.getItemAsync('maxRole');

      if (!userId || !userName) return null;

      return {
        user_id: parseInt(userId, 10),
        user_name: userName,
        privileges: privileges || '',
        max_role: parseInt(maxRole || '0', 10),
      };
    } catch {
      return null;
    }
  }

  // Patients
  async getPatients(): Promise<ApiResponse<{ patients: Patient[] }>> {
    const token = await this.getToken();
    if (!token) {
      return { ok: false, error: { message: 'Not authenticated', code: 'UNAUTHORIZED' } };
    }

    // Note: Using mock data since get_patients API structure is not fully documented
    // Replace with actual API call when available
    const mockPatients: Patient[] = [
      {
        id: 1,
        name: 'Julia Smith',
        status: 'online',
        relationship: 'Mother',
        last_activity: '2 min ago',
        health_data: {
          heart_rate: 72,
          steps: 3450,
          sleep_hours: 7.5,
        },
      },
      {
        id: 2,
        name: 'Robert Johnson',
        status: 'offline',
        relationship: 'Father',
        last_activity: '1 hour ago',
        health_data: {
          heart_rate: 68,
          steps: 2100,
          sleep_hours: 6.8,
        },
      },
    ];

    return { data: { patients: mockPatients }, ok: true };
  }

  async getPatient(id: number): Promise<ApiResponse<Patient>> {
    const response = await this.getPatients();
    if (!response.ok || !response.data) {
      return { ok: false, error: response.error };
    }

    const patient = response.data.patients.find((p) => p.id === id);
    if (!patient) {
      return { ok: false, error: { message: 'Patient not found', code: 'NOT_FOUND' } };
    }

    return { data: patient, ok: true };
  }

  // AI Chat
  async sendMessage(question: string, deploymentId: string = '21'): Promise<ApiResponse<ChatResponse>> {
    const token = await this.getToken();
    const userName = await this.getUserName();

    if (!token || !userName) {
      return { ok: false, error: { message: 'Not authenticated', code: 'UNAUTHORIZED' } };
    }

    return this.makeRequest<ChatResponse>({
      function: 'voice_ask',
      clientId: CLIENT_ID,
      user_name: userName,
      token: token,
      question: question,
      deployment_id: deploymentId,
    });
  }
}

export const api = new ApiService();