package com.talentcard.server.common;

import java.util.stream.Collectors;

import jakarta.validation.ConstraintViolationException;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.validation.BindException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@RestControllerAdvice
public class GlobalExceptionHandler {

	private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);

	@ExceptionHandler(BusinessException.class)
	public ResponseEntity<ApiResponse<Void>> handleBusinessException(BusinessException exception) {
		HttpStatus status = HttpStatus.valueOf(exception.errorCode().code());
		return ResponseEntity.status(status)
				.body(ApiResponse.failure(exception.errorCode().code(), exception.getMessage()));
	}

	@ExceptionHandler(MethodArgumentNotValidException.class)
	public ResponseEntity<ApiResponse<Void>> handleMethodArgumentNotValid(MethodArgumentNotValidException exception) {
		String message = exception.getBindingResult().getFieldErrors().stream()
				.map(error -> error.getField() + " " + error.getDefaultMessage())
				.collect(Collectors.joining("; "));
		return badRequest(message);
	}

	@ExceptionHandler(BindException.class)
	public ResponseEntity<ApiResponse<Void>> handleBindException(BindException exception) {
		String message = exception.getBindingResult().getFieldErrors().stream()
				.map(error -> error.getField() + " " + error.getDefaultMessage())
				.collect(Collectors.joining("; "));
		return badRequest(message);
	}

	@ExceptionHandler(ConstraintViolationException.class)
	public ResponseEntity<ApiResponse<Void>> handleConstraintViolation(ConstraintViolationException exception) {
		String message = exception.getConstraintViolations().stream()
				.map(violation -> violation.getPropertyPath() + " " + violation.getMessage())
				.collect(Collectors.joining("; "));
		return badRequest(message);
	}

	@ExceptionHandler(HttpMessageNotReadableException.class)
	public ResponseEntity<ApiResponse<Void>> handleUnreadableMessage(HttpMessageNotReadableException exception) {
		return badRequest("请求内容格式不正确");
	}

	/**
	 * 权限拦截器用 {@link ResponseStatusException} 表达 403；不显式处理会被下面的兜底分支包成 500，
	 * 前端只看到「服务器内部错误」，看不出是权限问题。这里原样透出状态码和原因。
	 */
	@ExceptionHandler(ResponseStatusException.class)
	public ResponseEntity<ApiResponse<Void>> handleResponseStatus(ResponseStatusException exception) {
		int status = exception.getStatusCode().value();
		String reason = exception.getReason() == null || exception.getReason().isBlank()
				? "请求被拒绝" : exception.getReason();
		return ResponseEntity.status(status).body(ApiResponse.failure(status, reason));
	}

	/**
	 * 唯一键冲突（例如同一微信换绑并发、卡号/证件号重复）以前会掉进下面的兜底分支，前端只看到
	 * 「服务器内部错误」，用户除了反复重试没有别的办法。这里按约束名给出可读提示，返回 409。
	 */
	@ExceptionHandler(DuplicateKeyException.class)
	public ResponseEntity<ApiResponse<Void>> handleDuplicateKey(DuplicateKeyException exception) {
		Throwable cause = exception.getMostSpecificCause();
		log.warn("Duplicate key conflict: {}", cause == null ? exception.getMessage() : cause.getMessage());
		return ResponseEntity.status(HttpStatus.CONFLICT)
				.body(ApiResponse.failure(HttpStatus.CONFLICT.value(), duplicateKeyMessage(exception)));
	}

	private String duplicateKeyMessage(DuplicateKeyException exception) {
		Throwable cause = exception.getMostSpecificCause();
		String detail = cause == null ? "" : String.valueOf(cause.getMessage());
		if (detail.contains("uk_openid")) return "该微信已绑定到其它账号，请稍后重试或联系管理员处理";
		if (detail.contains("uk_mobile")) return "该手机号已存在账号，请改用原手机号登录或联系管理员";
		// 先判 id_card：'uk_id_card_no' 里也含 'card_no'，顺序反了会把它当成卡号。
		if (detail.contains("id_card")) return "该证件号已存在账号，请核对后重试";
		if (detail.contains("card_no")) return "该人才卡号已被使用，请核对后重试";
		return "数据已存在，请核对后重试";
	}

	@ExceptionHandler(Exception.class)
	public ResponseEntity<ApiResponse<Void>> handleException(Exception exception) {
		log.error("Unhandled request exception", exception);
		return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
				.body(ApiResponse.failure(ErrorCode.INTERNAL_ERROR.code(), ErrorCode.INTERNAL_ERROR.message()));
	}

	private ResponseEntity<ApiResponse<Void>> badRequest(String message) {
		return ResponseEntity.status(HttpStatus.BAD_REQUEST)
				.body(ApiResponse.failure(ErrorCode.BAD_REQUEST.code(), message));
	}
}