import { HttpException } from '@nestjs/common';
import { Prisma } from '../../generated/prisma/client';
import { AppError } from './app-error';
import type { ErrorCode } from './error-catalog';

export function classifyError(error: unknown): AppError {
  if (error instanceof AppError) return error;
  if (error instanceof Prisma.PrismaClientKnownRequestError) {
    const codes: Record<string, ErrorCode> = {
      P2002: 'RECORD_CONFLICT',
      P2003: 'REFERENCE_INVALID',
      P2004: 'DATA_CONSTRAINT',
      P2025: 'RECORD_NOT_FOUND',
      P2024: 'DATABASE_BUSY',
      P2028: 'DATABASE_BUSY',
      P2034: 'TRANSACTION_CONFLICT',
    };
    return new AppError(codes[error.code] ?? 'INTERNAL_FAILURE', error.code);
  }
  if (error instanceof Prisma.PrismaClientInitializationError)
    return new AppError('DATABASE_BUSY');
  if (error instanceof HttpException) {
    const codes: Record<number, ErrorCode> = {
      400: 'REQUEST_MALFORMED',
      401: 'AUTH_REQUIRED',
      403: 'ACCESS_DENIED',
      404: 'ROUTE_NOT_FOUND',
      413: 'REQUEST_TOO_LARGE',
      429: 'RATE_LIMITED',
      503: 'DATABASE_BUSY',
    };
    return new AppError(codes[error.getStatus()] ?? 'INTERNAL_FAILURE');
  }
  // Express parser errors are not Nest HttpExceptions.
  if (typeof error === 'object' && error !== null && 'type' in error) {
    if (error.type === 'entity.too.large')
      return new AppError('REQUEST_TOO_LARGE');
    if (error.type === 'entity.parse.failed')
      return new AppError('REQUEST_MALFORMED');
  }
  return new AppError('INTERNAL_FAILURE');
}