package dbs

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

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

func init() {
	mcp.Register("get_oracle_data", "通过表名称获取Oracle表数据：只能接收表名称和分页查询参数分页参数数据获取数据不能超过10条",
		map[string]interface{}{
			"type": "object",
			"properties": map[string]interface{}{
				"table_name": map[string]interface{}{
					"type":        "string",
					"description": "表名称（支持大小写敏感）",
				},
				"schema": map[string]interface{}{
					"type":        "string",
					"description": "模式名称（默认为当前用户）",
					"default":     "",
				},
				"page": map[string]interface{}{
					"type":        "integer",
					"description": "页码（从1开始）",
					"default":     1,
					"minimum":     1,
				},
				"page_size": map[string]interface{}{
					"type":        "integer",
					"description": "每页记录数（最大10条）",
					"default":     10,
					"minimum":     1,
					"maximum":     10,
				},
				"order_by": map[string]interface{}{
					"type":        "string",
					"description": "排序字段（例如：column1 ASC, column2 DESC）",
					"default":     "",
				},
				"where_clause": map[string]interface{}{
					"type":        "string",
					"description": "WHERE条件（例如：status = 'ACTIVE'）",
					"default":     "",
				},
				"database_key": map[string]interface{}{
					"type":        "string",
					"description": "数据库配置键名（如：business），可选，默认使用主数据库",
					"enum":        []string{"warehouse", "business"},
					"default":     "warehouse",
				},
			},
			"required": []string{"table_name"},
		},
		func(input json.RawMessage, deps *mcp.ToolDependencies) (interface{}, error) {
			var params struct {
				TableName   string `json:"table_name"`
				Schema      string `json:"schema"`
				Page        int    `json:"page"`
				PageSize    int    `json:"page_size"`
				OrderBy     string `json:"order_by"`
				WhereClause string `json:"where_clause"`
				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.Page == 0 {
				params.Page = 1
			}
			if params.PageSize == 0 {
				params.PageSize = 10
			}

			// 确保每页记录数不超过10条
			if params.PageSize > 10 {
				params.PageSize = 10
			}

			// 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，确保是Oracle
			dbType := dbFactory.GetDBType()
			if dbType != "oracle" {
				return nil, fmt.Errorf("当前数据库类型为 %s，此工具仅支持Oracle数据库", dbType)
			}

			// 清理表名和模式名
			tableName := strings.TrimSpace(params.TableName)
			schema := strings.TrimSpace(params.Schema)

			if tableName == "" {
				return nil, fmt.Errorf("表名称不能为空")
			}

			// 验证表是否存在
			tableExists := false
			var tableExistsQuery string
			if schema == "" {
				tableExistsQuery = `SELECT COUNT(*) as table_count FROM user_tables WHERE table_name = UPPER(:1)`
			} else {
				tableExistsQuery = `SELECT COUNT(*) as table_count FROM all_tables WHERE table_name = UPPER(:1) AND owner = UPPER(:2)`
			}

			var tableCheckResults []map[string]interface{}

			if schema == "" {
				tableCheckResults, err = dbFactory.QuerySliceMapWithParams(tableExistsQuery, tableName)
			} else {
				tableCheckResults, err = dbFactory.QuerySliceMapWithParams(tableExistsQuery, tableName, schema)
			}

			if err != nil {
				return nil, fmt.Errorf("检查表是否存在失败: %v", err)
			}

			if len(tableCheckResults) > 0 {
				if count, ok := tableCheckResults[0]["table_count"].(int64); ok && count > 0 {
					tableExists = true
				}
			}

			if !tableExists {
				return nil, fmt.Errorf("表 '%s' 不存在", tableName)
			}

			// 构建带模式前缀的表名
			fullTableName := tableName
			if schema != "" {
				fullTableName = fmt.Sprintf("%s.%s", schema, tableName)
			}

			// 构建WHERE子句
			whereClause := ""
			if params.WhereClause != "" {
				whereClause = fmt.Sprintf("WHERE %s", params.WhereClause)
			}

			// 构建ORDER BY子句
			orderByClause := ""
			if params.OrderBy != "" {
				orderByClause = fmt.Sprintf("ORDER BY %s", params.OrderBy)
			}

			// 计算分页偏移量
			offset := (params.Page - 1) * params.PageSize

			// Oracle分页查询（使用ROWNUM）
			// 先获取总记录数
			countQuery := fmt.Sprintf("SELECT COUNT(*) as total_count FROM %s %s", fullTableName, whereClause)
			countResults, err := dbFactory.QuerySliceMap(countQuery)
			if err != nil {
				return nil, fmt.Errorf("查询总记录数失败: %v", err)
			}

			totalCount := int64(0)
			if len(countResults) > 0 {
				if count, ok := countResults[0]["total_count"].(int64); ok {
					totalCount = count
				}
			}

			// 计算总页数
			totalPages := 0
			if totalCount > 0 {
				totalPages = int((totalCount + int64(params.PageSize) - 1) / int64(params.PageSize))
			}

			// 如果请求的页码大于总页数，返回空结果
			if params.Page > totalPages && totalPages > 0 {
				return map[string]interface{}{
					"tenant_id":       deps.ReqCtx.TenantID,
					"user_id":         deps.ReqCtx.UserID,
					"database_type":   dbType,
					"database_name":   dbFactory.GetDatabaseName(),
					"schema":          schema,
					"table_name":      tableName,
					"full_table_name": fullTableName,
					"page":            params.Page,
					"page_size":       params.PageSize,
					"total_count":     totalCount,
					"total_pages":     totalPages,
					"where_clause":    params.WhereClause,
					"order_by":        params.OrderBy,
					"data":            []map[string]interface{}{},
					"data_count":      0,
					"has_more":        false,
					"timestamp":       time.Now().Format(time.RFC3339),
				}, nil
			}

			// 构建数据查询（Oracle分页查询）
			dataQuery := ""
			if whereClause == "" && orderByClause == "" {
				// 简单查询，使用ROWNUM分页
				dataQuery = fmt.Sprintf(`
					SELECT * FROM (
						SELECT t.*, ROWNUM rn FROM %s t
						WHERE ROWNUM <= %d
					) WHERE rn > %d`,
					fullTableName, offset+params.PageSize, offset)
			} else {
				// 复杂查询，需要子查询
				if orderByClause == "" {
					// 有WHERE条件但没有ORDER BY
					dataQuery = fmt.Sprintf(`
						SELECT * FROM (
							SELECT t.*, ROWNUM rn FROM %s t
							%s
							AND ROWNUM <= %d
						) WHERE rn > %d`,
						fullTableName, whereClause, offset+params.PageSize, offset)
				} else {
					// 有WHERE条件和ORDER BY
					dataQuery = fmt.Sprintf(`
						SELECT * FROM (
							SELECT inner.*, ROWNUM rn FROM (
								SELECT * FROM %s
								%s
								%s
							) inner
							WHERE ROWNUM <= %d
						) WHERE rn > %d`,
						fullTableName, whereClause, orderByClause, offset+params.PageSize, offset)
				}
			}

			// 执行数据查询
			dataResults, err := dbFactory.QuerySliceMap(dataQuery)
			if err != nil {
				return nil, fmt.Errorf("查询表数据失败: %v", err)
			}

			// 移除Oracle分页添加的rn字段
			for i := range dataResults {
				delete(dataResults[i], "rn")
			}

			// 检查是否有更多数据
			hasMore := (int64(offset+params.PageSize) < totalCount)

			return map[string]interface{}{
				"tenant_id":       deps.ReqCtx.TenantID,
				"user_id":         deps.ReqCtx.UserID,
				"database_type":   dbType,
				"database_name":   dbFactory.GetDatabaseName(),
				"schema":          schema,
				"table_name":      tableName,
				"full_table_name": fullTableName,
				"page":            params.Page,
				"page_size":       params.PageSize,
				"total_count":     totalCount,
				"total_pages":     totalPages,
				"where_clause":    params.WhereClause,
				"order_by":        params.OrderBy,
				"data":            dataResults,
				"data_count":      len(dataResults),
				"has_more":        hasMore,
				"timestamp":       time.Now().Format(time.RFC3339),
				"note":            "数据获取限制：最多返回10条记录",
			}, nil
		},
	)
}