import * as plugins from '../../plugins.js';
import type { IRouteConfig } from '../../proxies/smart-proxy/models/route-types.js';
import { DomainMatcher, PathMatcher } from '../../core/routing/matchers/index.js';

/**
 * Interface for router result with additional metadata
 */
export interface RouterResult {
  route: IRouteConfig;
  pathMatch?: string;
  pathParams?: Record<string, string>;
  pathRemainder?: string;
}


/**
 * Logger interface for HttpRouter
 */
export interface ILogger {
  debug?: (message: string, data?: any) => void;
  info: (message: string, data?: any) => void;
  warn: (message: string, data?: any) => void;
  error: (message: string, data?: any) => void;
}

/**
 * Unified HTTP Router for reverse proxy requests
 * 
 * Domain matching patterns:
 * - Exact matches: "example.com"
 * - Wildcard subdomains: "*.example.com" (matches any subdomain of example.com)
 * - TLD wildcards: "example.*" (matches example.com, example.org, etc.)
 * - Complex wildcards: "*.lossless*" (matches any subdomain of any lossless domain)
 * - Default fallback: "*" (matches any unmatched domain)
 * 
 * Path pattern matching:
 * - Exact path: "/api/users"
 * - Wildcard paths: "/api/*" 
 * - Path parameters: "/users/:id/profile"
 */
export class HttpRouter {
  // Store routes sorted by priority
  private routes: IRouteConfig[] = [];
  // Default route to use when no match is found (optional)
  private defaultRoute?: IRouteConfig;
  // Logger interface
  private logger: ILogger;

  constructor(
    routes?: IRouteConfig[],
    logger?: ILogger
  ) {
    this.logger = logger || {
      error: console.error.bind(console),
      warn: console.warn.bind(console),
      info: console.info.bind(console),
      debug: console.debug?.bind(console)
    };
    
    if (routes) {
      this.setRoutes(routes);
    }
  }

  /**
   * Sets a new set of routes
   * @param routes Array of route configurations
   */
  public setRoutes(routes: IRouteConfig[]): void {
    this.routes = [...routes];

    // Sort routes by priority (higher priority first)
    this.routes.sort((a, b) => {
      const priorityA = a.priority ?? 0;
      const priorityB = b.priority ?? 0;
      return priorityB - priorityA;
    });

    // Find default route if any (route with "*" as domain)
    this.defaultRoute = this.routes.find(route => {
      const domains = Array.isArray(route.match.domains) 
        ? route.match.domains 
        : route.match.domains ? [route.match.domains] : [];
      return domains.includes('*');
    });

    const uniqueDomains = this.getHostnames();
    this.logger.info(`HttpRouter initialized with ${this.routes.length} routes (${uniqueDomains.length} unique hosts)`);
  }

  /**
   * Routes a request based on hostname and path
   * @param req The incoming HTTP request
   * @returns The matching route or undefined if no match found
   */
  public routeReq(req: plugins.http.IncomingMessage): IRouteConfig | undefined {
    const result = this.routeReqWithDetails(req);
    return result ? result.route : undefined;
  }

  /**
   * Routes a request with detailed matching information
   * @param req The incoming HTTP request
   * @returns Detailed routing result including matched route and path information
   */
  public routeReqWithDetails(req: plugins.http.IncomingMessage): RouterResult | undefined {
    // Extract and validate host header
    const originalHost = req.headers.host;
    if (!originalHost) {
      this.logger.error('No host header found in request');
      return this.defaultRoute ? { route: this.defaultRoute } : undefined;
    }
    
    // Parse URL for path matching
    const parsedUrl = plugins.url.parse(req.url || '/');
    const urlPath = parsedUrl.pathname || '/';
    
    // Extract hostname without port
    const hostWithoutPort = originalHost.split(':')[0].toLowerCase();
    
    // Find matching route
    const matchingRoute = this.findMatchingRoute(hostWithoutPort, urlPath);
    
    if (matchingRoute) {
      return matchingRoute;
    }
    
    // Fall back to default route if available
    if (this.defaultRoute) {
      this.logger.warn(`No specific route found for host: ${hostWithoutPort}, using default`);
      return { route: this.defaultRoute };
    }
    
    this.logger.error(`No route found for host: ${hostWithoutPort}`);
    return undefined;
  }

  /**
   * Find the best matching route for a given hostname and path
   */
  private findMatchingRoute(hostname: string, path: string): RouterResult | undefined {
    // Try each route in priority order
    for (const route of this.routes) {
      // Skip disabled routes
      if (route.enabled === false) {
        continue;
      }

      // Check domain match
      if (route.match.domains) {
        const domains = Array.isArray(route.match.domains) 
          ? route.match.domains 
          : [route.match.domains];
        
        // Check if any domain pattern matches
        const domainMatches = domains.some(domain => 
          DomainMatcher.match(domain, hostname)
        );
        
        if (!domainMatches) {
          continue;
        }
      }

      // Check path match if specified
      if (route.match.path) {
        const pathResult = PathMatcher.match(route.match.path, path);
        if (pathResult.matches) {
          return {
            route,
            pathMatch: path,
            pathParams: pathResult.params,
            pathRemainder: pathResult.pathRemainder
          };
        }
      } else {
        // No path specified, so domain match is sufficient
        return { route };
      }
    }
    
    return undefined;
  }

  /**
   * Gets all currently active route configurations
   * @returns Array of all active routes
   */
  public getRoutes(): IRouteConfig[] {
    return [...this.routes];
  }

  /**
   * Gets all hostnames that this router is configured to handle
   * @returns Array of unique hostnames
   */
  public getHostnames(): string[] {
    const hostnames = new Set<string>();
    for (const route of this.routes) {
      if (!route.match.domains) continue;
      
      const domains = Array.isArray(route.match.domains) 
        ? route.match.domains 
        : [route.match.domains];
      
      for (const domain of domains) {
        if (domain !== '*') {
          hostnames.add(domain.toLowerCase());
        }
      }
    }
    return Array.from(hostnames);
  }

  /**
   * Adds a single new route configuration
   * @param route The route configuration to add
   */
  public addRoute(route: IRouteConfig): void {
    this.routes.push(route);
    
    // Re-sort routes by priority
    this.routes.sort((a, b) => {
      const priorityA = a.priority ?? 0;
      const priorityB = b.priority ?? 0;
      return priorityB - priorityA;
    });
  }

  /**
   * Removes routes by domain pattern
   * @param domain The domain pattern to remove routes for
   * @returns Boolean indicating whether any routes were removed
   */
  public removeRoutesByDomain(domain: string): boolean {
    const initialCount = this.routes.length;
    
    // Filter out routes that match the domain
    this.routes = this.routes.filter(route => {
      if (!route.match.domains) return true;
      
      const domains = Array.isArray(route.match.domains) 
        ? route.match.domains 
        : [route.match.domains];
      
      return !domains.includes(domain);
    });
    
    return this.routes.length !== initialCount;
  }

  /**
   * Remove a specific route by reference
   * @param route The route to remove
   * @returns Boolean indicating if the route was found and removed
   */
  public removeRoute(route: IRouteConfig): boolean {
    const index = this.routes.indexOf(route);
    if (index !== -1) {
      this.routes.splice(index, 1);
      return true;
    }
    return false;
  }

}