package com.vincent.rsf.server.manager.utils;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author chen.lin
 * @time 2026-02-02
 * Areas 字段自定义 TypeHandler
 * 处理数据库和 Java 对象之间的转换
 * 支持两种格式：
 * 1. [1, 2, 3] - 纯ID数组（向后兼容）
 * 2. [{"id": 1, "sort": 1}, {"id": 2, "sort": 2}] - 对象数组（新格式）
 *
 */
@MappedTypes({List.class})
@MappedJdbcTypes(JdbcType.VARCHAR)
public class AreasTypeHandler extends BaseTypeHandler<List<Map<String, Object>>> {

    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
    private static final TypeReference<List<Object>> LIST_TYPE_REF = new TypeReference<List<Object>>() {};

    /**
     * 解析 JSON 字符串为 List<Map<String, Object>>
     */
    private List<Map<String, Object>> parse(String json) {
        if (json == null || json.trim().isEmpty()) {
            return new ArrayList<>();
        }
        
        try {
            // 先解析为 List<Object>
            List<Object> rawList = OBJECT_MAPPER.readValue(json, LIST_TYPE_REF);
            
            if (rawList == null || rawList.isEmpty()) {
                return new ArrayList<>();
            }
            
            List<Map<String, Object>> result = new ArrayList<>();
            
            // 遍历所有元素并转换
            for (int i = 0; i < rawList.size(); i++) {
                Object item = rawList.get(i);
                
                if (item instanceof Map) {
                    // 已经是对象数组格式 [{"id": 1, "sort": 1}]
                    @SuppressWarnings("unchecked")
                    Map<String, Object> map = (Map<String, Object>) item;
                    result.add(map);
                } else if (item instanceof Number) {
                    // 纯ID数组格式 [1, 2, 3]，转换为对象数组
                    Map<String, Object> area = new HashMap<>();
                    area.put("id", ((Number) item).intValue());
                    area.put("sort", i + 1);
                    result.add(area);
                }
                // 忽略其他类型
            }
            
            return result;
        } catch (Exception e) {
            throw new RuntimeException("Failed to parse areas JSON: " + json, e);
        }
    }

    /**
     * 将 List<Map<String, Object>> 转换为 JSON 字符串
     */
    private String toJson(List<Map<String, Object>> obj) {
        if (obj == null) {
            return null;
        }
        try {
            return OBJECT_MAPPER.writeValueAsString(obj);
        } catch (Exception e) {
            throw new RuntimeException("Failed to serialize areas to JSON", e);
        }
    }

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, List<Map<String, Object>> parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, toJson(parameter));
    }

    @Override
    public List<Map<String, Object>> getNullableResult(ResultSet rs, String columnName) throws SQLException {
        String json = rs.getString(columnName);
        return parse(json);
    }

    @Override
    public List<Map<String, Object>> getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        String json = rs.getString(columnIndex);
        return parse(json);
    }

    @Override
    public List<Map<String, Object>> getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        String json = cs.getString(columnIndex);
        return parse(json);
    }
}