/**
 * Reports Service - API client for Django Reports System
 * Provides abstraction layer between frontend and Django backend
 */

import { supabase } from '@/integrations/supabase/client';
import { handleError } from '@/lib/errorHandler';
import { logger } from '@/lib/logger';
import type {
  Report,
  SubmitReportData,
  LegacySubmitReportData,
  ReportFilters,
  PaginatedReports,
  ReportStats,
  UpdateReportStatusData,
  ServiceResponse,
} from './types';
import { mapSubmitReportToBackend } from './mappers';

/**
 * Reports Service Class
 * Handles all communication with Django Reports API endpoints
 */
class ReportsService {
  private baseUrl: string;

  constructor() {
    // Use environment variable or fallback to relative path
    this.baseUrl = import.meta.env.VITE_DJANGO_API_URL || '/api/v1';
    logger.log('[ReportsService] Initialized with base URL:', this.baseUrl);
  }

  /**
   * Get authentication token from current Supabase session
   * @returns JWT token for Django API authentication
   * @throws Error if no active session
   */
  private async getAuthToken(): Promise<string> {
    const { data: { session }, error } = await supabase.auth.getSession();
    
    if (error) {
      logger.error('[ReportsService] Failed to get session', { error });
      throw new Error('Failed to retrieve authentication session');
    }
    
    if (!session?.access_token) {
      logger.error('[ReportsService] No active session');
      throw new Error('Authentication required. Please sign in.');
    }
    
    return session.access_token;
  }

  /**
   * Make authenticated request to Django API
   * @param endpoint - API endpoint path (e.g., '/reports/')
   * @param options - Fetch options
   * @returns Parsed JSON response
   * @throws Error with details from Django API
   */
  private async request<T>(
    endpoint: string,
    options: RequestInit = {}
  ): Promise<T> {
    const token = await this.getAuthToken();
    const url = `${this.baseUrl}${endpoint}`;

    logger.log('[ReportsService] Making request', { 
      method: options.method || 'GET',
      url,
      hasBody: !!options.body 
    });

    const response = await fetch(url, {
      ...options,
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${token}`,
        ...options.headers,
      },
    });

    // Handle non-JSON responses (e.g., 204 No Content)
    if (response.status === 204) {
      return undefined as T;
    }

    const data = await response.json();

    if (!response.ok) {
      // Django returns errors in { detail: "message" } format
      const errorMessage = data.detail || data.message || 'Request failed';
      logger.error('[ReportsService] Request failed', {
        status: response.status,
        error: errorMessage,
        url,
      });
      throw new Error(errorMessage);
    }

    logger.log('[ReportsService] Request successful', { 
      status: response.status,
      url 
    });

    return data;
  }

  /**
   * Submit a new report
   * @param data - Report submission data (supports legacy Supabase format)
   * @returns Created report
   */
  async submitReport(
    data: SubmitReportData | LegacySubmitReportData
  ): Promise<ServiceResponse<Report>> {
    try {
      // Handle both new format and legacy Supabase format
      const payload = 'reported_entity_type' in data 
        ? mapSubmitReportToBackend(data)
        : data;

      const report = await this.request<Report>('/reports/', {
        method: 'POST',
        body: JSON.stringify(payload),
      });

      return { success: true, data: report };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'Submit report',
        metadata: { 
          entityType: 'entity_type' in data ? data.entity_type : data.reported_entity_type,
          reportType: data.report_type,
        },
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to submit report',
      };
    }
  }

  /**
   * List reports with optional filters and pagination
   * @param filters - Optional filters (status, type, entity)
   * @param page - Page number (1-indexed)
   * @param pageSize - Number of items per page
   * @returns Paginated list of reports
   */
  async listReports(
    filters: ReportFilters = {},
    page: number = 1,
    pageSize: number = 50
  ): Promise<ServiceResponse<PaginatedReports>> {
    try {
      const params = new URLSearchParams({
        page: page.toString(),
        page_size: pageSize.toString(),
      });

      // Add optional filters
      if (filters.status) params.append('status', filters.status);
      if (filters.report_type) params.append('report_type', filters.report_type);
      if (filters.entity_type) params.append('entity_type', filters.entity_type);
      if (filters.entity_id) params.append('entity_id', filters.entity_id);

      const data = await this.request<PaginatedReports>(
        `/reports/?${params.toString()}`
      );

      return { success: true, data };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'List reports',
        metadata: { filters, page, pageSize },
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to list reports',
      };
    }
  }

  /**
   * Get a single report by ID
   * @param id - Report UUID
   * @returns Report details
   */
  async getReport(id: string): Promise<ServiceResponse<Report>> {
    try {
      const report = await this.request<Report>(`/reports/${id}/`);
      return { success: true, data: report };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'Get report',
        metadata: { reportId: id },
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get report',
      };
    }
  }

  /**
   * Update report status (moderators only)
   * @param id - Report UUID
   * @param status - New status
   * @param resolutionNotes - Optional resolution notes
   * @returns Updated report
   */
  async updateReportStatus(
    id: string,
    status: string,
    resolutionNotes?: string
  ): Promise<ServiceResponse<Report>> {
    try {
      const payload: UpdateReportStatusData = {
        status: status as any,
        resolution_notes: resolutionNotes,
      };

      const report = await this.request<Report>(`/reports/${id}/`, {
        method: 'PATCH',
        body: JSON.stringify(payload),
      });

      return { success: true, data: report };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'Update report status',
        metadata: { reportId: id, newStatus: status },
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to update report',
      };
    }
  }

  /**
   * Delete a report (moderators only)
   * @param id - Report UUID
   * @returns Success status
   */
  async deleteReport(id: string): Promise<ServiceResponse<void>> {
    try {
      await this.request<void>(`/reports/${id}/`, {
        method: 'DELETE',
      });

      return { success: true };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'Delete report',
        metadata: { reportId: id },
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to delete report',
      };
    }
  }

  /**
   * Get report statistics (moderators only)
   * @returns Report statistics
   */
  async getStatistics(): Promise<ServiceResponse<ReportStats>> {
    try {
      const stats = await this.request<ReportStats>('/reports/stats/');
      return { success: true, data: stats };
    } catch (error) {
      const errorId = handleError(error, {
        action: 'Get report statistics',
      });

      return {
        success: false,
        error: error instanceof Error ? error.message : 'Failed to get statistics',
      };
    }
  }

  /**
   * Get base URL for debugging/testing
   * @returns Current base URL
   */
  getBaseUrl(): string {
    return this.baseUrl;
  }
}

// Export singleton instance
export const reportsService = new ReportsService();

// Export class for testing
export { ReportsService };