package dbs

import (
	"encoding/json"
	"fmt"
	"regexp"
	"strings"
	"time"

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

func init() {
	mcp.Register("get_common_query", "通用数据库查询工具，支持参数化查询和结果列自定义",
		map[string]interface{}{
			"type": "object",
			"properties": map[string]interface{}{
				"query_sql": map[string]interface{}{
					"type":        "string",
					"description": "基础SQL查询语句（可包含WHERE、ORDER BY，或使用where_clause和order_by参数）",
				},
				"where_clause": map[string]interface{}{
					"type":        "string",
					"description": "WHERE条件语句（可选，如果query_sql中已包含则不需要）",
					"default":     "",
				},
				"order_by": map[string]interface{}{
					"type":        "string",
					"description": "ORDER BY排序语句（可选，如果query_sql中已包含则不需要）",
					"default":     "",
				},
				"params": map[string]interface{}{
					"type":        "object",
					"description": "查询参数键值对，用于参数化查询（例如 {\"status\": \"ACTIVE\", \"min_age\": 18}）",
					"default":     map[string]interface{}{},
				},
				"columns_config": map[string]interface{}{
					"type":        "array",
					"description": "执行查询返回的列配置信息，定义字段显示名称和宽度",
					"items": map[string]interface{}{
						"type": "object",
						"properties": map[string]interface{}{
							"field_name": map[string]interface{}{
								"type":        "string",
								"description": "查询返回的字段名称",
							},
							"display_name": map[string]interface{}{
								"type":        "string",
								"description": "字段显示名称（中文）",
								"default":     "",
							},
							"width": map[string]interface{}{
								"type":        "integer",
								"description": "前端显示宽度（像素）",
								"default":     100,
							},
							"align": map[string]interface{}{
								"type":        "string",
								"description": "对齐方式（left/center/right）",
								"default":     "left",
							},
						},
						"required": []string{"field_name"},
					},
					"default": []interface{}{},
				},
				"page": map[string]interface{}{
					"type":        "integer",
					"description": "页码（从1开始，0表示不分页）",
					"default":     0,
					"minimum":     0,
				},
				"page_size": map[string]interface{}{
					"type":        "integer",
					"description": "每页记录数（最大100条）",
					"default":     10,
					"minimum":     1,
					"maximum":     100,
				},
				"schema": map[string]interface{}{
					"type":        "string",
					"description": "数据库模式/名称（可选，部分数据库需要）",
					"default":     "",
				},
				"include_total_count": map[string]interface{}{
					"type":        "boolean",
					"description": "是否包含总记录数",
					"default":     true,
				},
				"database_key": map[string]interface{}{
					"type":        "string",
					"description": "数据库配置键名：warehouse（仓库数据库）或 business（业务数据库），可选，默认使用主数据库",
					"enum":        []string{"warehouse", "business"},
					"default":     "",
				},
			},
			"required": []string{"query_sql"},
		},
		func(input json.RawMessage, deps *mcp.ToolDependencies) (interface{}, error) {
			var params struct {
				QuerySQL          string                   `json:"query_sql"`
				WhereClause       string                   `json:"where_clause"`
				OrderBy           string                   `json:"order_by"`
				Params            map[string]interface{}   `json:"params"`
				ColumnsConfig     []map[string]interface{} `json:"columns_config"`
				Page              int                      `json:"page"`
				PageSize          int                      `json:"page_size"`
				Schema            string                   `json:"schema"`
				IncludeTotalCount bool                     `json:"include_total_count"`
				DatabaseKey       string                   `json:"database_key"`
			}

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

			// 设置默认值
			if params.PageSize == 0 {
				params.PageSize = 10
			}
			if params.PageSize > 100 {
				params.PageSize = 100
			}

			// 获取数据库工厂
			dbFactory, err := GetDBFactory(params.DatabaseKey, deps)
			if err != nil {
				return nil, err
			}

			// 获取数据库类型
			dbType := dbFactory.GetDBType()

			// 构建完整SQL
			finalSQL := params.QuerySQL
			if params.WhereClause != "" {
				// 检查query_sql是否已包含WHERE关键字
				if strings.Contains(strings.ToUpper(finalSQL), "WHERE") {
					finalSQL += " AND " + params.WhereClause
				} else {
					finalSQL += " WHERE " + params.WhereClause
				}
			}
			if params.OrderBy != "" {
				finalSQL += " ORDER BY " + params.OrderBy
			}

			// 根据数据库类型处理参数绑定
			processedSQL, queryParams, err := processParameters(finalSQL, params.Params, dbType)
			if err != nil {
				return nil, fmt.Errorf("参数处理失败: %v", err)
			}

			// 执行查询
			results, err := dbFactory.QuerySliceMapWithParams(processedSQL, queryParams...)
			if err != nil {
				return nil, fmt.Errorf("查询执行失败: %v", err)
			}

			// 处理列配置
			columnsMeta := processColumnsMetadata(results, params.ColumnsConfig)

			// 计算总记录数（如果需要）
			totalCount := int64(0)
			if params.IncludeTotalCount && params.Page > 0 {
				countSQL, countParams, err := buildCountSQL(finalSQL, params.Params, dbType)
				if err != nil {
					return nil, fmt.Errorf("构建计数SQL失败: %v", err)
				}
				countResults, err := dbFactory.QuerySliceMapWithParams(countSQL, countParams...)
				if err == nil && len(countResults) > 0 {
					if count, ok := countResults[0]["total_count"].(int64); ok {
						totalCount = count
					}
				}
			}

			// 应用分页（如果启用）
			var pagedResults []map[string]interface{}
			if params.Page > 0 && params.PageSize > 0 {
				offset := (params.Page - 1) * params.PageSize
				if offset < len(results) {
					end := offset + params.PageSize
					if end > len(results) {
						end = len(results)
					}
					pagedResults = results[offset:end]
				}
			} else {
				pagedResults = results
			}

			// 构建响应
			response := map[string]interface{}{
				"tenant_id":           deps.ReqCtx.TenantID,
				"user_id":             deps.ReqCtx.UserID,
				"database_type":       dbType,
				"database_name":       dbFactory.GetDatabaseName(),
				"schema":              params.Schema,
				"original_sql":        params.QuerySQL,
				"processed_sql":       processedSQL,
				"parameters":          params.Params,
				"columns_metadata":    columnsMeta,
				"data":                pagedResults,
				"data_count":          len(pagedResults),
				"total_count":         totalCount,
				"page":                params.Page,
				"page_size":           params.PageSize,
				"include_total_count": params.IncludeTotalCount,
				"timestamp":           time.Now().Format(time.RFC3339),
			}

			// 如果启用了分页，添加分页信息
			if params.Page > 0 {
				totalPages := 0
				if totalCount > 0 {
					totalPages = int((totalCount + int64(params.PageSize) - 1) / int64(params.PageSize))
				}
				response["total_pages"] = totalPages
				response["has_more"] = int64(params.Page*params.PageSize) < totalCount
			}

			return response, nil
		},
	)
}

// processParameters 处理SQL参数绑定，根据数据库类型转换命名参数
func processParameters(sql string, params map[string]interface{}, dbType string) (string, []interface{}, error) {
	if len(params) == 0 {
		return sql, []interface{}{}, nil
	}

	// 根据数据库类型选择参数处理器
	switch dbType {
	case "mysql", "doris":
		return processMySQLParameters(sql, params)
	case "postgresql":
		return processPostgreSQLParameters(sql, params)
	case "oracle":
		return processOracleParameters(sql, params)
	case "sqlserver":
		return processSQLServerParameters(sql, params)
	default:
		return sql, []interface{}{}, fmt.Errorf("不支持的数据库类型: %s", dbType)
	}
}

// parseNamedParameters 解析命名参数，返回替换后的SQL和有序参数值
func parseNamedParameters(sql string, params map[string]interface{}, placeholderFunc func(int) string) (string, []interface{}, error) {
	// 正则匹配 :paramName 格式的参数
	re := regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
	matches := re.FindAllStringSubmatch(sql, -1)
	if len(matches) == 0 {
		return sql, []interface{}{}, nil
	}

	// 确定参数名到索引的映射（按第一次出现的顺序）
	paramIndex := make(map[string]int)
	var paramOrder []string
	for _, match := range matches {
		paramName := match[1]
		if _, exists := paramIndex[paramName]; !exists {
			paramIndex[paramName] = len(paramOrder)
			paramOrder = append(paramOrder, paramName)
		}
	}

	// 构建参数值列表（按索引顺序）
	paramValues := make([]interface{}, len(paramOrder))
	for i, paramName := range paramOrder {
		value, exists := params[paramName]
		if !exists {
			return "", nil, fmt.Errorf("参数 '%s' 未提供", paramName)
		}
		paramValues[i] = value
	}

	// 替换占位符
	replacedSQL := re.ReplaceAllStringFunc(sql, func(match string) string {
		paramName := match[1:]
		index := paramIndex[paramName]
		return placeholderFunc(index + 1) // 通常占位符从1开始
	})

	return replacedSQL, paramValues, nil
}

// processColumnsMetadata 处理列元数据，合并查询结果和列配置
func processColumnsMetadata(results []map[string]interface{}, columnsConfig []map[string]interface{}) []map[string]interface{} {
	if len(results) == 0 {
		return []map[string]interface{}{}
	}

	// 从第一条结果中提取列名
	var columns []map[string]interface{}
	if len(results) > 0 {
		for fieldName := range results[0] {
			columnMeta := map[string]interface{}{
				"field_name":   fieldName,
				"display_name": fieldName,
				"width":        100,
				"align":        "left",
			}

			// 查找列配置
			for _, config := range columnsConfig {
				if configFieldName, ok := config["field_name"].(string); ok && configFieldName == fieldName {
					if displayName, ok := config["display_name"].(string); ok && displayName != "" {
						columnMeta["display_name"] = displayName
					}
					if width, ok := config["width"].(float64); ok && width > 0 {
						columnMeta["width"] = int(width)
					}
					if align, ok := config["align"].(string); ok && align != "" {
						columnMeta["align"] = align
					}
					break
				}
			}
			columns = append(columns, columnMeta)
		}
	}
	return columns
}

// buildCountSQL 构建计数SQL
func buildCountSQL(originalSQL string, params map[string]interface{}, dbType string) (string, []interface{}, error) {
	// 移除ORDER BY子句
	countSQL := regexp.MustCompile(`(?i)\s+ORDER BY\s+.*$`).ReplaceAllString(originalSQL, "")

	// 构建COUNT查询
	countSQL = fmt.Sprintf("SELECT COUNT(*) as total_count FROM (%s) as count_query", countSQL)

	// 处理参数
	return processParameters(countSQL, params, dbType)
}

// processMySQLParameters 处理MySQL/Doris数据库参数绑定
func processMySQLParameters(sql string, params map[string]interface{}) (string, []interface{}, error) {
	if len(params) == 0 {
		return sql, []interface{}{}, nil
	}

	// 正则匹配 :paramName 格式的参数
	re := regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
	matches := re.FindAllStringSubmatch(sql, -1)
	if len(matches) == 0 {
		return sql, []interface{}{}, nil
	}

	// 按出现顺序收集参数值（允许重复）
	var paramValues []interface{}
	replacedSQL := re.ReplaceAllStringFunc(sql, func(match string) string {
		paramName := match[1:]
		value, exists := params[paramName]
		if !exists {
			// 如果参数未提供，保留原占位符（后续会报错）
			return match
		}
		paramValues = append(paramValues, value)
		return "?"
	})

	// 检查是否有参数未提供
	if len(paramValues) != len(matches) {
		// 找出未提供的参数名
		for _, match := range matches {
			paramName := match[1]
			if _, exists := params[paramName]; !exists {
				return "", nil, fmt.Errorf("参数 '%s' 未提供", paramName)
			}
		}
	}

	return replacedSQL, paramValues, nil
}

// processPostgreSQLParameters 处理PostgreSQL数据库参数绑定
func processPostgreSQLParameters(sql string, params map[string]interface{}) (string, []interface{}, error) {
	if len(params) == 0 {
		return sql, []interface{}{}, nil
	}

	// 正则匹配 :paramName 格式的参数
	re := regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
	matches := re.FindAllStringSubmatch(sql, -1)
	if len(matches) == 0 {
		return sql, []interface{}{}, nil
	}

	// 确定参数名到索引的映射（按第一次出现的顺序）
	paramIndex := make(map[string]int)
	var paramOrder []string
	for _, match := range matches {
		paramName := match[1]
		if _, exists := paramIndex[paramName]; !exists {
			paramIndex[paramName] = len(paramOrder)
			paramOrder = append(paramOrder, paramName)
		}
	}

	// 构建参数值列表（按索引顺序）
	paramValues := make([]interface{}, len(paramOrder))
	for i, paramName := range paramOrder {
		value, exists := params[paramName]
		if !exists {
			return "", nil, fmt.Errorf("参数 '%s' 未提供", paramName)
		}
		paramValues[i] = value
	}

	// 替换占位符为 $1, $2, ...
	replacedSQL := re.ReplaceAllStringFunc(sql, func(match string) string {
		paramName := match[1:]
		index := paramIndex[paramName]
		return fmt.Sprintf("$%d", index+1)
	})

	return replacedSQL, paramValues, nil
}

// processOracleParameters 处理Oracle数据库参数绑定
func processOracleParameters(sql string, params map[string]interface{}) (string, []interface{}, error) {
	if len(params) == 0 {
		return sql, []interface{}{}, nil
	}

	// 正则匹配 :paramName 格式的参数
	re := regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
	matches := re.FindAllStringSubmatch(sql, -1)
	if len(matches) == 0 {
		return sql, []interface{}{}, nil
	}

	// 确定参数名到索引的映射（按第一次出现的顺序）
	paramIndex := make(map[string]int)
	var paramOrder []string
	for _, match := range matches {
		paramName := match[1]
		if _, exists := paramIndex[paramName]; !exists {
			paramIndex[paramName] = len(paramOrder)
			paramOrder = append(paramOrder, paramName)
		}
	}

	// 构建参数值列表（按索引顺序）
	paramValues := make([]interface{}, len(paramOrder))
	for i, paramName := range paramOrder {
		value, exists := params[paramName]
		if !exists {
			return "", nil, fmt.Errorf("参数 '%s' 未提供", paramName)
		}
		paramValues[i] = value
	}

	// 替换占位符为 :1, :2, ...（Oracle支持数字占位符）
	replacedSQL := re.ReplaceAllStringFunc(sql, func(match string) string {
		paramName := match[1:]
		index := paramIndex[paramName]
		return fmt.Sprintf(":%d", index+1)
	})

	return replacedSQL, paramValues, nil
}

// processSQLServerParameters 处理SQL Server数据库参数绑定
func processSQLServerParameters(sql string, params map[string]interface{}) (string, []interface{}, error) {
	if len(params) == 0 {
		return sql, []interface{}{}, nil
	}

	// 正则匹配 :paramName 格式的参数
	re := regexp.MustCompile(`:([a-zA-Z_][a-zA-Z0-9_]*)`)
	matches := re.FindAllStringSubmatch(sql, -1)
	if len(matches) == 0 {
		return sql, []interface{}{}, nil
	}

	// 确定参数名到索引的映射（按第一次出现的顺序）
	paramIndex := make(map[string]int)
	var paramOrder []string
	for _, match := range matches {
		paramName := match[1]
		if _, exists := paramIndex[paramName]; !exists {
			paramIndex[paramName] = len(paramOrder)
			paramOrder = append(paramOrder, paramName)
		}
	}

	// 构建参数值列表（按索引顺序）
	paramValues := make([]interface{}, len(paramOrder))
	for i, paramName := range paramOrder {
		value, exists := params[paramName]
		if !exists {
			return "", nil, fmt.Errorf("参数 '%s' 未提供", paramName)
		}
		paramValues[i] = value
	}

	// 替换占位符为 @p1, @p2, ...（SQL Server支持命名参数）
	replacedSQL := re.ReplaceAllStringFunc(sql, func(match string) string {
		paramName := match[1:]
		index := paramIndex[paramName]
		return fmt.Sprintf("@p%d", index+1)
	})

	return replacedSQL, paramValues, nil
}