import {
  CanActivate,
  ExecutionContext,
  Injectable,
  UnauthorizedException,
} from "@nestjs/common";
import { JwtService } from "@nestjs/jwt";
import { Request } from "express";
import { RoleEnum } from "src/Types&Enums/role.enum";

const GLOBAL_GUARD_ROLES = new Set<string>([
  RoleEnum.USER,
  RoleEnum.FIELD_EXPERT,
  RoleEnum.REGISTRAR,
]);

@Injectable()
export class GlobalGuard implements CanActivate {
  constructor(private readonly jwtService: JwtService) {}

  async canActivate(context: ExecutionContext): Promise<boolean> {
    const request = context.switchToHttp().getRequest();

    const token = this.extractTokenFromHeader(request);
    if (!token) {
      throw new UnauthorizedException("Missing Bearer token");
    }

    try {
      const payload = await this.jwtService.verifyAsync(token, {
        secret: `${process.env.JWT_SECRET}`,
      });

      if (!payload?.role || !GLOBAL_GUARD_ROLES.has(String(payload.role))) {
        throw new UnauthorizedException(
          `Role "${payload?.role ?? "unknown"}" is not allowed on user-panel APIs. Use /user/login for USER, or /actor/login for experts.`,
        );
      }

      request.user = payload;
      request.identity = request.user;
    } catch (error) {
      if (error instanceof UnauthorizedException) {
        throw error;
      }
      throw new UnauthorizedException("Invalid or expired token");
    }
    return true;
  }

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