import { Request, Response, NextFunction } from 'express';
import { AppError } from './AppError';
import { ZodError } from 'zod';
import { TErrorSource } from '../interfaces/errors';
import { logger } from '../utils/logger';
import handleMongooseCastError from './handleMongooseCastError';
import handleMongooseDuplicateError from './handleMongooseDuplicateError';
import handleMongooseValidationError from './handleMongooseValidationError';
import handlePrismaCastError from './handlePrismaCastError';
import handlePrismaDuplicateError from './handlePrismaDuplicateError';
import handlePrismaValidationError from './handlePrismaValidationError';

export const globalErrorHandler = (err: unknown, _req: Request, res: Response, _next: NextFunction) => {
  let statusCode = 500;
  let message = 'Internal Server Error';
  let errorSources: TErrorSource[] = [
    {
      path: '',
      message: 'Something went wrong'
    }
  ];

  // Handle AppError
  if (err instanceof AppError) {
    statusCode = err.statusCode;
    message = err.message;
    errorSources = [
      {
        path: err.path,
        message: err.message
      }
    ];
  }
  // Handle Zod Validation Error
  else if (err instanceof ZodError) {
    statusCode = 400;
    message = 'Validation Error';
    errorSources = err.errors.map((issue) => ({
      path: issue.path.join('.'),
      message: issue.message
    }));
  }
  // Handle Mongoose CastError
  else if (err?.constructor?.name === 'CastError') {
    const simplified = handleMongooseCastError(err as any);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Mongoose ValidationError
  else if (err?.constructor?.name === 'ValidationError') {
    const simplified = handleMongooseValidationError(err as any);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Mongoose Duplicate Key Error (11000)
  else if ((err as any)?.code === 11000) {
    const simplified = handleMongooseDuplicateError(err);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Prisma Unique Constraint Error (P2002)
  else if ((err as any)?.code === 'P2002') {
    const simplified = handlePrismaDuplicateError(err);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Prisma Validation Error (P2000, P2001, etc.)
  else if ((err as any)?.code?.startsWith('P20')) {
    const simplified = handlePrismaValidationError(err);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Prisma Cast Error
  else if ((err as any)?.code === 'P2023') {
    const simplified = handlePrismaCastError(err);
    statusCode = simplified.statusCode;
    message = simplified.message;
    errorSources = simplified.errorSources;
  }
  // Handle Generic Error
  else if (err instanceof Error) {
    message = err.message;
    errorSources = [
      {
        path: '',
        message: err.message
      }
    ];
  }

  // Log all errors
  logger.error(`[${statusCode}] ${message}`, {
    errorSources,
    stack: (err as Error)?.stack,
  });

  res.status(statusCode).json({
    success: false,
    message,
    errorSources,
    stack: process.env.NODE_ENV === 'development' ? (err as Error)?.stack : undefined
  });
};