package com.mydreamjob.common.exception;

import com.mydreamjob.common.api.ApiResponse;
import com.mydreamjob.salarycalculator.SalaryPolicyVersionConflictException;
import com.mydreamjob.common.logging.RequestIdAccessor;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.validation.ConstraintViolationException;
import lombok.extern.slf4j.Slf4j;
import lombok.RequiredArgsConstructor;
import org.springframework.context.annotation.Import;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.core.AuthenticationException;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.method.annotation.MethodArgumentTypeMismatchException;
import org.springframework.web.servlet.resource.NoResourceFoundException;

import java.util.HashMap;
import java.util.Map;

/**
 * 全局异常处理器
 *
 * <p>R01-B/B2：业务错误码 → HTTP 状态的映射已收束到 {@link ErrorHttpStatusRegistry}，
 * 本类只负责调用它，不再持有任何映射表或条件链。</p>
 */
@Slf4j
@RestControllerAdvice
@RequiredArgsConstructor
@Import(ErrorHttpStatusRegistry.class)
public class GlobalExceptionHandler {

    private final RequestIdAccessor requestIdAccessor;
    private final ErrorHttpStatusRegistry errorHttpStatusRegistry;

    public record SalaryPolicyConflictDetails(String latestPolicyVersion,
                                             java.time.LocalDate policyEffectiveDate) {}

    @ExceptionHandler(SalaryPolicyVersionConflictException.class)
    public ResponseEntity<ApiResponse<SalaryPolicyConflictDetails>> handleSalaryPolicyConflict(
            SalaryPolicyVersionConflictException ex, HttpServletRequest request) {
        ErrorCode code = ErrorCode.SALARY_POLICY_VERSION_CONFLICT;
        ApiResponse<SalaryPolicyConflictDetails> body = ApiResponse.error(
                code.getCode(), code.getMessage(), getRequestId(request));
        body.setData(new SalaryPolicyConflictDetails(
                ex.getLatestPolicyVersion(), ex.getLatestPolicyEffectiveDate()));
        return ResponseEntity.status(errorHttpStatusRegistry.resolve(code.getCode())).body(body);
    }

    @ExceptionHandler(ConstraintViolationException.class)
    public ResponseEntity<ApiResponse<Void>> handleConstraintViolation(
            ConstraintViolationException ex, HttpServletRequest request) {
        log.warn("Constraint violation: path={}, message={}", request.getRequestURI(), ex.getMessage());
        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(ApiResponse.badRequest(ex.getMessage(), getRequestId(request)));
    }

    @ExceptionHandler(BusinessException.class)
    public ResponseEntity<ApiResponse<Void>> handleBusinessException(
            BusinessException e, HttpServletRequest request) {
        int errorCode = e.getErrorCode();
        log.warn("BusinessException: code={}, message={}, path={}",
                errorCode, e.getMessage(), request.getRequestURI());
        HttpStatus status = errorHttpStatusRegistry.resolve(errorCode);
        return ResponseEntity
                .status(status)
                .body(ApiResponse.error(errorCode, e.getMessage(), getRequestId(request)));
    }

    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<ApiResponse<Void>> handleValidationException(
            MethodArgumentNotValidException ex, HttpServletRequest request) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getAllErrors().forEach((error) -> {
            String fieldName = ((FieldError) error).getField();
            String errorMessage = error.getDefaultMessage();
            errors.put(fieldName, errorMessage);
        });
        log.warn("Validation failed: path={}, errors={}", request.getRequestURI(), errors);
        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(ApiResponse.badRequest("validation failed: " + errors, getRequestId(request)));
    }

    @ExceptionHandler(HttpMessageNotReadableException.class)
    public ResponseEntity<ApiResponse<Void>> handleMessageNotReadable(
            HttpMessageNotReadableException ex, HttpServletRequest request) {
        log.warn("Message not readable: path={}", request.getRequestURI(), ex);
        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(ApiResponse.badRequest("request body is invalid", getRequestId(request)));
    }

    @ExceptionHandler(MissingServletRequestParameterException.class)
    public ResponseEntity<ApiResponse<Void>> handleMissingParam(
            MissingServletRequestParameterException ex, HttpServletRequest request) {
        log.warn("Missing parameter: {} path={}", ex.getParameterName(), request.getRequestURI());
        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(ApiResponse.badRequest("missing parameter: " + ex.getParameterName(), getRequestId(request)));
    }

    @ExceptionHandler(MethodArgumentTypeMismatchException.class)
    public ResponseEntity<ApiResponse<Void>> handleTypeMismatch(
            MethodArgumentTypeMismatchException ex, HttpServletRequest request) {
        log.warn("Type mismatch: {} path={}", ex.getName(), request.getRequestURI());
        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(ApiResponse.error(ErrorCode.BAD_REQUEST.getCode(), "bad request", getRequestId(request)));
    }

    @ExceptionHandler(AuthenticationException.class)
    public ResponseEntity<ApiResponse<Void>> handleAuthentication(
            AuthenticationException ex, HttpServletRequest request) {
        log.warn("Authentication failed: path={}, message={}", request.getRequestURI(), ex.getMessage());
        return ResponseEntity
                .status(HttpStatus.UNAUTHORIZED)
                .body(ApiResponse.unauthorized(ex.getMessage(), getRequestId(request)));
    }

    @ExceptionHandler(AccessDeniedException.class)
    public ResponseEntity<ApiResponse<Void>> handleAccessDenied(
            AccessDeniedException ex, HttpServletRequest request) {
        log.warn("Access denied: path={}", request.getRequestURI());
        return ResponseEntity
                .status(HttpStatus.FORBIDDEN)
                .body(ApiResponse.forbidden("access denied", getRequestId(request)));
    }

    @ExceptionHandler(NoResourceFoundException.class)
    public ResponseEntity<ApiResponse<Void>> handleNoResourceFound(
            NoResourceFoundException ex, HttpServletRequest request) {
        // S03-C 整改：业务端口 /actuator/** 等不存在资源统一返回 404。
        // 只记录固定文案与归一化 requestId，不回显异常 message、资源路径或堆栈。
        log.warn("No resource found: requestId={}", getRequestId(request));
        return ResponseEntity
                .status(HttpStatus.NOT_FOUND)
                .body(ApiResponse.error(404, "not found", getRequestId(request)));
    }

    @ExceptionHandler(Exception.class)
    public ResponseEntity<ApiResponse<Void>> handleGenericException(
            Exception ex, HttpServletRequest request) {
        log.error("Unexpected error: path={}", request.getRequestURI(), ex);
        return ResponseEntity
                .status(HttpStatus.INTERNAL_SERVER_ERROR)
                .body(ApiResponse.internalError(getRequestId(request)));
    }

    private String getRequestId(HttpServletRequest request) {
        return requestIdAccessor.get(request);
    }
}