package com.emergencyrepair.system.log;

import com.emergencyrepair.common.audit.CurrentUserContext;
import com.emergencyrepair.system.entity.SysErrorLog;
import com.emergencyrepair.system.mapper.SysErrorLogMapper;
import lombok.RequiredArgsConstructor;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.time.LocalDateTime;
import java.util.List;

/**
 * Persists unhandled server exceptions so administrators can inspect runtime bugs.
 */
@Component
@RequiredArgsConstructor
public class ErrorLogRecorder {
    private static final int MAX_MESSAGE_LENGTH = 2000;
    private static final int MAX_STACK_LENGTH = 60000;

    private final SysErrorLogMapper errorLogMapper;
    private final JdbcTemplate jdbcTemplate;

    public void record(Exception exception, HttpServletRequest request) {
        if (exception == null) {
            return;
        }
        try {
            String username = CurrentUserContext.get();
            Long userId = resolveUserId(username);
            SysErrorLog log = new SysErrorLog();
            log.setUserId(userId);
            log.setUserName(username);
            log.setNickName(resolveNickName(userId));
            log.setModule(resolveModule(request));
            log.setRequestMethod(request == null ? null : limit(request.getMethod(), 10));
            log.setRequestUri(request == null ? null : limit(request.getRequestURI(), 500));
            log.setExceptionType(limit(exception.getClass().getName(), 300));
            log.setMessage(limit(resolveMessage(exception), MAX_MESSAGE_LENGTH));
            log.setStackTrace(limit(stackTrace(exception), MAX_STACK_LENGTH));
            log.setErrorTime(LocalDateTime.now());
            errorLogMapper.insert(log);
        } catch (Exception ignored) {
            // Error logging must never interfere with the original error response.
        }
    }

    private Long resolveUserId(String username) {
        if (!StringUtils.hasText(username)) {
            return null;
        }
        List<Long> ids = jdbcTemplate.query(
                "SELECT USER_ID FROM CSICZB_ZB.SYS_USER WHERE USER_NAME = ? AND (DEL_FLAG = '0' OR DEL_FLAG IS NULL)",
                new Object[]{username}, (rs, rowNum) -> rs.getLong(1));
        return ids.isEmpty() ? null : ids.get(0);
    }

    private String resolveNickName(Long userId) {
        if (userId == null) {
            return null;
        }
        List<String> names = jdbcTemplate.query(
                "SELECT NICK_NAME FROM CSICZB_ZB.SYS_USER WHERE USER_ID = ?",
                new Object[]{userId}, (rs, rowNum) -> rs.getString(1));
        return names.isEmpty() ? null : names.get(0);
    }

    private String resolveMessage(Exception exception) {
        String message = exception.getMessage();
        return StringUtils.hasText(message) ? message : exception.getClass().getSimpleName();
    }

    private String stackTrace(Exception exception) {
        StringWriter writer = new StringWriter();
        exception.printStackTrace(new PrintWriter(writer));
        return writer.toString();
    }

    private String resolveModule(HttpServletRequest request) {
        if (request == null || !StringUtils.hasText(request.getRequestURI())) {
            return "其他";
        }
        String uri = request.getRequestURI();
        if (uri.startsWith("/api/faults") || uri.startsWith("/api/fault")) return "故障管理";
        if (uri.startsWith("/api/work-orders") || uri.startsWith("/api/completion")) return "完工管理";
        if (uri.startsWith("/api/acceptances")) return "完工验收";
        if (uri.startsWith("/api/reports")) return "统计报表";
        if (uri.startsWith("/api/system/users")) return "用户管理";
        if (uri.startsWith("/api/system/roles")) return "角色管理";
        if (uri.startsWith("/api/system/menu")) return "菜单管理";
        if (uri.startsWith("/api/system/contractors")) return "承修单位管理";
        if (uri.startsWith("/api/system")) return "系统管理";
        return "其他";
    }

    private String limit(String value, int maxLength) {
        if (value == null || value.length() <= maxLength) {
            return value;
        }
        return value.substring(0, maxLength);
    }
}