package tools

import (
	"encoding/json"
	"fmt"
	"sync"
	"time"

	"git.x2erp.com/qdy/go-svc-mcp/internal/mcp"
)

// 数据库字典表结构
type FieldDictionary struct {
	TableNameCN  string `json:"table_name_cn"`
	TableNameEN  string `json:"table_name_en"`
	FieldNameCN  string `json:"field_name_cn"`
	FieldNameEN  string `json:"field_name_en"`
	FieldType    string `json:"field_type"`
	StandardName string `json:"standard_name"`
	Description  string `json:"description"`
	Category     string `json:"category"`
	IsCalculated bool   `json:"is_calculated"`
	Aliases      string `json:"aliases"`
}

// 缓存结构，添加过期时间和最后访问时间
type fieldDictionaryCache struct {
	data           []FieldDictionary
	expireTime     time.Time     // 缓存过期时间
	lastAccessTime time.Time     // 最后访问时间
	expireDuration time.Duration // 过期时长
	mutex          sync.RWMutex  // 读写锁
}

// 全局缓存实例
var cache *fieldDictionaryCache

// 初始化缓存
func initCache() {
	if cache == nil {
		cache = &fieldDictionaryCache{
			expireDuration: 20 * time.Minute, // 20分钟过期
			data:           make([]FieldDictionary, 0),
		}
	}
}

// 获取缓存数据（会更新最后访问时间）
func getCache() ([]FieldDictionary, bool) {
	initCache()

	cache.mutex.RLock()
	defer cache.mutex.RUnlock()

	// 检查缓存是否有效
	if len(cache.data) == 0 {
		return nil, false
	}

	// 检查是否过期（20分钟没有被访问）
	if time.Since(cache.lastAccessTime) > cache.expireDuration {
		return nil, false
	}

	// 检查是否到达过期时间
	if time.Now().After(cache.expireTime) {
		return nil, false
	}

	return cache.data, true
}

// 设置缓存数据
func setCache(data []FieldDictionary) {
	initCache()

	cache.mutex.Lock()
	defer cache.mutex.Unlock()

	cache.data = data
	cache.lastAccessTime = time.Now()
	cache.expireTime = time.Now().Add(cache.expireDuration)
}

// 清除缓存
func clearCache() {
	initCache()

	cache.mutex.Lock()
	defer cache.mutex.Unlock()

	cache.data = make([]FieldDictionary, 0)
	cache.lastAccessTime = time.Time{}
	cache.expireTime = time.Time{}
}

// 更新最后访问时间
func updateLastAccessTime() {
	initCache()

	cache.mutex.Lock()
	defer cache.mutex.Unlock()

	cache.lastAccessTime = time.Now()
}

// 从数据库读取字段字典的方法
func getFieldDictionaryFromDB() ([]FieldDictionary, error) {
	// TODO: 你来实现这个数据库查询
	// 这里返回示例数据用于测试

	// 示例查询SQL（根据你的实际表结构调整）：
	/*
		SELECT
			table_name_cn,
			table_name_en,
			field_name_cn,
			field_name_en,
			field_type,
			standard_name,
			description,
			category,
			is_calculated,
			aliases
		FROM system_field_dictionary
		WHERE tenant_id = ? AND is_active = true
		ORDER BY category, table_name_cn, field_name_cn
	*/

	return []FieldDictionary{
		// 销售相关字段
		{
			TableNameCN:  "销售订单",
			TableNameEN:  "sales_order",
			FieldNameCN:  "销售数量",
			FieldNameEN:  "sales_quantity",
			FieldType:    "decimal(10,2)",
			StandardName: "销售数量",
			Description:  "销售订单中的商品数量",
			Category:     "销售",
			IsCalculated: false,
			Aliases:      "销量,销售数",
		},
		{
			TableNameCN:  "销售订单",
			TableNameEN:  "sales_order",
			FieldNameCN:  "结算单价",
			FieldNameEN:  "settlement_price",
			FieldType:    "decimal(10,2)",
			StandardName: "结算单价",
			Description:  "销售结算时的单价",
			Category:     "销售",
			IsCalculated: false,
			Aliases:      "单价,销售单价",
		},
		{
			TableNameCN:  "销售订单",
			TableNameEN:  "sales_order",
			FieldNameCN:  "销售金额",
			FieldNameEN:  "sales_amount",
			FieldType:    "decimal(10,2)",
			StandardName: "销售金额",
			Description:  "销售总金额（计算字段：销售数量 × 结算单价）",
			Category:     "销售",
			IsCalculated: true,
			Aliases:      "销售额,销售总额",
		},
		// 采购相关字段
		{
			TableNameCN:  "采购订单",
			TableNameEN:  "purchase_order",
			FieldNameCN:  "采购数量",
			FieldNameEN:  "purchase_quantity",
			FieldType:    "decimal(10,2)",
			StandardName: "采购数量",
			Description:  "采购订单中的商品数量",
			Category:     "采购",
			IsCalculated: false,
			Aliases:      "进货数量,采购数",
		},
		{
			TableNameCN:  "采购订单",
			TableNameEN:  "purchase_order",
			FieldNameCN:  "采购单价",
			FieldNameEN:  "purchase_price",
			FieldType:    "decimal(10,2)",
			StandardName: "采购单价",
			Description:  "采购商品单价",
			Category:     "采购",
			IsCalculated: false,
			Aliases:      "进价,采购价",
		},
		// 库存相关字段
		{
			TableNameCN:  "库存表",
			TableNameEN:  "inventory",
			FieldNameCN:  "库存数量",
			FieldNameEN:  "inventory_quantity",
			FieldType:    "decimal(10,2)",
			StandardName: "库存数量",
			Description:  "当前库存数量",
			Category:     "库存",
			IsCalculated: false,
			Aliases:      "库存,现存量",
		},
	}, nil
}

// 加载字段字典（带缓存）
func loadFieldDictionary(refresh bool) ([]FieldDictionary, error) {
	// 如果强制刷新，先清除缓存
	if refresh {
		clearCache()
	}

	// 尝试从缓存获取
	if data, ok := getCache(); ok {
		return data, nil
	}

	// 从数据库加载
	dict, err := getFieldDictionaryFromDB()
	if err != nil {
		return nil, fmt.Errorf("加载字段字典失败: %v", err)
	}

	// 设置缓存
	setCache(dict)

	return dict, nil
}

// 查找字段匹配
func findFieldMatch(fieldCN string, dictionary []FieldDictionary) (bool, *FieldDictionary, []string) {
	// 精确匹配
	for _, dict := range dictionary {
		if dict.FieldNameCN == fieldCN {
			return true, &dict, nil
		}
	}

	// 别名匹配
	var matchedDict *FieldDictionary
	for _, dict := range dictionary {
		if dict.Aliases != "" {
			// 简单的别名匹配（实际使用时你可能需要解析逗号分隔的字符串）
			if dict.Aliases == fieldCN {
				matchedDict = &dict
				break
			}
		}
	}

	if matchedDict != nil {
		return true, matchedDict, nil
	}

	// 收集所有字段名作为建议
	var suggestions []string
	for _, dict := range dictionary {
		suggestions = append(suggestions, dict.FieldNameCN)
	}

	return false, nil, suggestions
}

func init() {
	mcp.Register("field_matcher", "根据中文字段名称匹配数据库字段信息，返回英文字段名、表名、类型等详细信息",
		map[string]interface{}{
			"type": "object",
			"properties": map[string]interface{}{
				"fields": map[string]interface{}{
					"type": "array",
					"items": map[string]interface{}{
						"type": "string",
					},
					"description": "要匹配的中文字段名称数组",
					"minItems":    1,
				},
				"refresh_cache": map[string]interface{}{
					"type":        "boolean",
					"description": "是否刷新字段字典缓存",
					"default":     false,
				},
			},
			"required": []string{"fields"},
		},
		func(input json.RawMessage, deps *mcp.ToolDependencies) (interface{}, error) {
			var params struct {
				Fields       []string `json:"fields"`
				RefreshCache bool     `json:"refresh_cache"`
			}

			if len(input) > 0 {
				if err := json.Unmarshal(input, &params); err != nil {
					return nil, err
				}
			}

			if len(params.Fields) == 0 {
				return nil, fmt.Errorf("fields 参数不能为空")
			}

			// 加载字段字典（带缓存）
			startTime := time.Now()
			dictionary, err := loadFieldDictionary(params.RefreshCache)
			if err != nil {
				return nil, err
			}
			loadTime := time.Since(startTime)

			// 更新缓存最后访问时间
			updateLastAccessTime()

			// 处理每个字段的匹配结果
			matches := make([]map[string]interface{}, 0, len(params.Fields))
			foundCount := 0

			for _, fieldCN := range params.Fields {
				isFound, fieldInfo, suggestions := findFieldMatch(fieldCN, dictionary)

				matchResult := map[string]interface{}{
					"input_field_cn": fieldCN,
					"is_found":       isFound,
				}

				if isFound && fieldInfo != nil {
					foundCount++
					matchResult["match_info"] = map[string]interface{}{
						"table_name_cn": fieldInfo.TableNameCN,
						"table_name_en": fieldInfo.TableNameEN,
						"field_name_en": fieldInfo.FieldNameEN,
						"field_type":    fieldInfo.FieldType,
						"standard_name": fieldInfo.StandardName,
						"description":   fieldInfo.Description,
						"category":      fieldInfo.Category,
						"is_calculated": fieldInfo.IsCalculated,
					}
				} else {
					matchResult["suggestions"] = suggestions
					matchResult["note"] = "未找到匹配字段，请尝试其他名称或拆解字段"
				}

				matches = append(matches, matchResult)
			}

			// 获取缓存信息
			cacheData, cacheValid := getCache()
			cacheInfo := map[string]interface{}{
				"is_valid":     cacheValid,
				"total_fields": len(cacheData),
			}

			if cacheValid {
				cacheInfo["last_access_time"] = cache.lastAccessTime.Format(time.RFC3339)
				cacheInfo["expire_time"] = cache.expireTime.Format(time.RFC3339)
				cacheInfo["will_expire_in"] = time.Until(cache.expireTime).String()
			}

			// 按照示例的返回格式
			return map[string]interface{}{
				"tenant_id":    deps.ReqCtx.TenantID,
				"user_id":      deps.ReqCtx.UserID,
				"input_fields": params.Fields,
				"matches":      matches,
				"summary": map[string]interface{}{
					"total_fields":    len(params.Fields),
					"found_count":     foundCount,
					"not_found_count": len(params.Fields) - foundCount,
					"success_rate":    fmt.Sprintf("%.1f%%", float64(foundCount)/float64(len(params.Fields))*100),
				},
				"cache_info": cacheInfo,
				"load_time":  loadTime.String(),
				"timestamp":  time.Now().Format(time.RFC3339),
				"suggestion": "如果未找到匹配字段，请尝试将复合字段拆解为ERP常用基本字段再次查询",
			}, nil
		},
	)
}