package com.dsh.guns.modular.system.audit;

import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.lang.reflect.Field;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/** 从数据库字段备注自动解析审计展示名；每个实体只查询一次并缓存。 */
@Component
public class AuditColumnCommentResolver {
    @Resource private JdbcTemplate jdbcTemplate;
    private final Map<Class<?>, Map<String, String>> cache = new ConcurrentHashMap<Class<?>, Map<String, String>>();

    public Map<String, String> resolve(Class<?> entityType) {
        if (entityType == null) return Collections.emptyMap();
        Map<String, String> cached = cache.get(entityType);
        if (cached != null) return cached;
        Map<String, String> labels = load(entityType);
        cache.put(entityType, labels);
        return labels;
    }

    private Map<String, String> load(Class<?> entityType) {
        TableName tableName = entityType.getAnnotation(TableName.class);
        if (tableName == null || tableName.value().trim().isEmpty()) return Collections.emptyMap();
        try {
            List<Map<String, Object>> columns = jdbcTemplate.queryForList(
                    "SELECT COLUMN_NAME, COLUMN_COMMENT FROM information_schema.COLUMNS "
                            + "WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ?", tableName.value());
            Map<String, String> comments = new LinkedHashMap<String, String>();
            for (Map<String, Object> column : columns) {
                Object name = column.get("COLUMN_NAME");
                Object comment = column.get("COLUMN_COMMENT");
                if (name != null && comment != null && !String.valueOf(comment).trim().isEmpty()) {
                    comments.put(String.valueOf(name), concise(String.valueOf(comment)));
                }
            }
            Map<String, String> result = new LinkedHashMap<String, String>();
            for (Class<?> type = entityType; type != null && type != Object.class; type = type.getSuperclass()) {
                for (Field field : type.getDeclaredFields()) {
                    TableField tableField = field.getAnnotation(TableField.class);
                    String column = tableField == null || tableField.value().trim().isEmpty() ? field.getName() : tableField.value();
                    String comment = comments.get(column);
                    if (comment != null) result.put(field.getName(), comment);
                }
            }
            return result;
        } catch (Exception ignored) {
            return Collections.emptyMap();
        }
    }

    private String concise(String comment) {
        int bracket = comment.indexOf('（');
        int asciiBracket = comment.indexOf('(');
        int cut = bracket >= 0 ? bracket : asciiBracket;
        return cut > 0 ? comment.substring(0, cut).trim() : comment;
    }
}