/**
 * TouchBistro API Client
 * Handles authentication, pagination, error handling, and rate limiting
 */

import type { TouchBistroConfig, PaginatedResponse, PaginationParams } from './types.js';

export class TouchBistroAPIError extends Error {
  constructor(
    message: string,
    public statusCode?: number,
    public responseBody?: unknown
  ) {
    super(message);
    this.name = 'TouchBistroAPIError';
  }
}

export class TouchBistroAPIClient {
  private apiKey: string;
  private baseUrl: string;
  private venueId?: string;

  constructor(config: TouchBistroConfig) {
    this.apiKey = config.apiKey;
    this.baseUrl = config.baseUrl || 'https://api.touchbistro.com/v1';
    this.venueId = config.venueId;
  }

  /**
   * Make an authenticated request to the TouchBistro API
   */
  private async request<T>(
    endpoint: string,
    options: RequestInit = {}
  ): Promise<T> {
    const url = `${this.baseUrl}${endpoint}`;
    
    const headers: HeadersInit = {
      'Authorization': `Bearer ${this.apiKey}`,
      'Content-Type': 'application/json',
      'Accept': 'application/json',
      ...options.headers,
    };

    if (this.venueId) {
      headers['X-Venue-ID'] = this.venueId;
    }

    try {
      const response = await fetch(url, {
        ...options,
        headers,
      });

      // Handle rate limiting
      if (response.status === 429) {
        const retryAfter = response.headers.get('Retry-After');
        throw new TouchBistroAPIError(
          `Rate limited. Retry after ${retryAfter} seconds`,
          429,
          { retryAfter }
        );
      }

      // Parse response body
      const contentType = response.headers.get('content-type');
      let data: unknown;
      
      if (contentType?.includes('application/json')) {
        data = await response.json();
      } else {
        data = await response.text();
      }

      // Handle errors
      if (!response.ok) {
        throw new TouchBistroAPIError(
          `TouchBistro API error: ${response.statusText}`,
          response.status,
          data
        );
      }

      return data as T;
    } catch (error) {
      if (error instanceof TouchBistroAPIError) {
        throw error;
      }
      
      if (error instanceof Error) {
        throw new TouchBistroAPIError(
          `Network error: ${error.message}`,
          undefined,
          error
        );
      }
      
      throw new TouchBistroAPIError('Unknown error occurred');
    }
  }

  /**
   * GET request
   */
  async get<T>(endpoint: string, params?: Record<string, unknown>): Promise<T> {
    const queryString = params 
      ? '?' + new URLSearchParams(
          Object.entries(params)
            .filter(([_, v]) => v !== undefined && v !== null)
            .map(([k, v]) => [k, String(v)])
        ).toString()
      : '';
    
    return this.request<T>(`${endpoint}${queryString}`, {
      method: 'GET',
    });
  }

  /**
   * POST request
   */
  async post<T>(endpoint: string, body?: unknown): Promise<T> {
    return this.request<T>(endpoint, {
      method: 'POST',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  /**
   * PUT request
   */
  async put<T>(endpoint: string, body?: unknown): Promise<T> {
    return this.request<T>(endpoint, {
      method: 'PUT',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  /**
   * PATCH request
   */
  async patch<T>(endpoint: string, body?: unknown): Promise<T> {
    return this.request<T>(endpoint, {
      method: 'PATCH',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  /**
   * DELETE request
   */
  async delete<T>(endpoint: string): Promise<T> {
    return this.request<T>(endpoint, {
      method: 'DELETE',
    });
  }

  /**
   * Paginated GET request - automatically handles pagination
   */
  async getPaginated<T>(
    endpoint: string,
    params: PaginationParams & Record<string, unknown> = {}
  ): Promise<PaginatedResponse<T>> {
    const { page = 1, limit = 50, ...otherParams } = params;
    
    const response = await this.get<{
      data: T[];
      pagination?: {
        total?: number;
        page?: number;
        limit?: number;
        hasMore?: boolean;
        nextPage?: string;
      };
    }>(endpoint, {
      page,
      limit,
      ...otherParams,
    });

    // Normalize pagination response
    return {
      data: response.data || [],
      pagination: {
        total: response.pagination?.total || response.data?.length || 0,
        page: response.pagination?.page || page,
        limit: response.pagination?.limit || limit,
        hasMore: response.pagination?.hasMore || false,
      },
    };
  }

  /**
   * Fetch all pages automatically
   */
  async getAllPages<T>(
    endpoint: string,
    params: Record<string, unknown> = {},
    maxPages = 10
  ): Promise<T[]> {
    const allData: T[] = [];
    let page = 1;
    let hasMore = true;

    while (hasMore && page <= maxPages) {
      const response = await this.getPaginated<T>(endpoint, {
        ...params,
        page,
        limit: 100,
      });

      allData.push(...response.data);
      hasMore = response.pagination.hasMore;
      page++;
    }

    return allData;
  }

  /**
   * Health check
   */
  async healthCheck(): Promise<{ status: string; timestamp: string }> {
    try {
      return await this.get('/health');
    } catch (error) {
      return {
        status: 'error',
        timestamp: new Date().toISOString(),
      };
    }
  }
}