import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { JwtService } from '@nestjs/jwt';
import { ConfigService } from '@nestjs/config';
import { Request } from 'express';
import { IS_PUBLIC_KEY } from '../decorators/public.decorator';
import { AuthenticatedUser } from '../decorators/current-user.decorator';

@Injectable()
export class JwtAuthGuard implements CanActivate {
  constructor(
    private readonly reflector: Reflector,
    private readonly jwtService: JwtService,
    private readonly config: ConfigService,
  ) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const isPublic = this.reflector.getAllAndOverride<boolean>(IS_PUBLIC_KEY, [
      context.getHandler(),
      context.getClass(),
    ]);
    if (isPublic) return true;

    const request = context.switchToHttp().getRequest<Request>();
    const token = this.extractToken(request);
    if (!token) {
      throw new UnauthorizedException('Missing access token');
    }

    try {
      const payload = await this.jwtService.verifyAsync<AuthenticatedUser>(
        token,
        { secret: this.config.get<string>('jwt.secret') },
      );
      (request as Request & { user: AuthenticatedUser }).user = payload;
      return true;
    } catch {
      throw new UnauthorizedException('Invalid or expired token');
    }
  }

  private extractToken(request: Request): string | undefined {
    const authHeader = request.headers.authorization;
    if (authHeader?.toLowerCase().startsWith('bearer ')) {
      return authHeader.slice(7).trim();
    }
    const cookieToken = (request as Request & {
      cookies?: Record<string, string>;
    }).cookies?.access_token;
    return cookieToken;
  }
}