export type ErrorType =
  | "validation"
  | "not_found"
  | "permission_denied"
  | "unauthorized"
  | "conflict"
  | "business"
  | "database"
  | "bad_gateway"
  | "internal";

export interface ErrorDetails {
  [key: string]: unknown;
}

export abstract class ApplicationError extends Error {
  abstract readonly type: ErrorType;
  abstract readonly statusCode: number;
  readonly code: string;
  readonly details?: ErrorDetails;
  traceId?: string;

  constructor(message: string, code: string, details?: ErrorDetails) {
    super(message);
    this.name = this.constructor.name;
    this.code = code;
    this.details = details;
  }

  toJSON(): Record<string, unknown> {
    return {
      success: false,
      error: {
        code: this.code,
        message: this.message,
        details: this.details,
        traceId: this.traceId,
      },
    };
  }
}

export class ValidationError extends ApplicationError {
  readonly type = "validation" as const;
  readonly statusCode = 400;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_VALIDATION_ERROR", details);
  }
}

export class NotFoundError extends ApplicationError {
  readonly type = "not_found" as const;
  readonly statusCode = 404;
  constructor(resource: string, id: string) {
    super(`${resource} not found: ${id}`, "TEACHER_BFF_NOT_FOUND", {
      resource,
      id,
    });
  }
}

export class PermissionDeniedError extends ApplicationError {
  readonly type = "permission_denied" as const;
  readonly statusCode = 403;
  constructor(permission: string) {
    super(`Permission denied: ${permission}`, "TEACHER_BFF_PERMISSION_DENIED", {
      permission,
    });
  }
}

export class UnauthorizedError extends ApplicationError {
  readonly type = "unauthorized" as const;
  readonly statusCode = 401;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_UNAUTHORIZED", details);
  }
}

export class ConflictError extends ApplicationError {
  readonly type = "conflict" as const;
  readonly statusCode = 409;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_CONFLICT", details);
  }
}

export class BusinessError extends ApplicationError {
  readonly type = "business" as const;
  readonly statusCode = 422;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_BUSINESS_ERROR", details);
  }
}

export class DatabaseError extends ApplicationError {
  readonly type = "database" as const;
  readonly statusCode = 500;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_DATABASE_ERROR", details);
  }
}

export class BadGatewayError extends ApplicationError {
  readonly type = "bad_gateway" as const;
  readonly statusCode = 502;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_BAD_GATEWAY", details);
  }
}

export class InternalError extends ApplicationError {
  readonly type = "internal" as const;
  readonly statusCode = 500;
  constructor(message: string, details?: ErrorDetails) {
    super(message, "TEACHER_BFF_INTERNAL_ERROR", details);
  }
}