import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from "@nestjs/common";
import { JwtService } from "@nestjs/jwt";
import { Request } from "express";

/**
 * Verifies Bearer JWT for platform settings routes. Does not restrict by role;
 * pair with {@link RolesGuard} on handlers.
 */
@Injectable()
export class SettingsJwtGuard implements CanActivate {
  constructor(private readonly jwtService: JwtService) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const request = context.switchToHttp().getRequest<Request>();
    const token = this.extractTokenFromHeader(request);
    if (!token) {
      throw new UnauthorizedException("Token not found");
    }

    try {
      const payload = await this.jwtService.verifyAsync(token, {
        secret: `${process.env.JWT_SECRET}`,
      });
      (request as any).user = payload;
      (request as any).identity = payload;
      return true;
    } catch {
      throw new UnauthorizedException("Invalid token");
    }
  }

  private extractTokenFromHeader(request: Request): string | undefined {
    const [type, token] = request.headers.authorization?.split(" ") ?? [];
    return type === "Bearer" ? token : undefined;
  }
}