// index_manager.go
package sqldef

import (
	"fmt"
	"strings"
)

// IndexManager 索引管理器
type IndexManager struct {
	ddlExecutor DDLExecutor
}

// IndexDefinition 索引定义
type IndexDefinition struct {
	TableName string
	IndexName string
	Columns   []string
	IsUnique  bool
	IsPrimary bool
}

// NewIndexManager 创建索引管理器
func NewIndexManager(executor DDLExecutor) *IndexManager {
	return &IndexManager{
		ddlExecutor: executor,
	}
}

// CreateIndex 创建索引
func (im *IndexManager) CreateIndex(idx *IndexDefinition) error {
	var indexType string
	if idx.IsPrimary {
		indexType = "PRIMARY KEY"
	} else if idx.IsUnique {
		indexType = "UNIQUE INDEX"
	} else {
		indexType = "INDEX"
	}

	columns := strings.Join(idx.Columns, ", ")
	sql := fmt.Sprintf("CREATE %s %s ON %s (%s)",
		indexType, idx.IndexName, idx.TableName, columns)

	return im.ddlExecutor.ExecuteDDL(sql)
}

// DropIndex 删除索引
func (im *IndexManager) DropIndex(tableName, indexName string) error {
	sql := fmt.Sprintf("DROP INDEX %s ON %s", indexName, tableName)
	return im.ddlExecutor.ExecuteDDL(sql)
}

// TableManager 添加索引相关方法
func (tm *TableManager) SetIndexManager(im *IndexManager) {
	// 可以在这里关联索引管理器
}

// CreateIndexesFromDDL 从DDL语句中解析并创建索引
func (tm *TableManager) CreateIndexesFromDDL() error {
	// 获取所有表
	tables := tm.GetRegisteredTables()

	for _, tableName := range tables {
		ddl, exists := tm.GetTableDDL(tableName)
		if !exists {
			continue
		}

		// 解析DDL中的索引信息
		indexes := parseIndexesFromDDL(ddl)

		// 创建索引
		for _, index := range indexes {
			if err := tm.ddlExecutor.ExecuteDDL(index); err != nil {
				return fmt.Errorf("创建索引失败: %w", err)
			}
		}
	}

	return nil
}

// parseIndexesFromDDL 从DDL语句中解析索引
func parseIndexesFromDDL(ddl string) []string {
	var indexes []string
	lines := strings.Split(ddl, "\n")

	for _, line := range lines {
		line = strings.TrimSpace(line)
		if strings.Contains(line, "INDEX") || strings.Contains(line, "PRIMARY KEY") {
			// 移除末尾的逗号
			line = strings.TrimSuffix(line, ",")
			indexes = append(indexes, line)
		}
	}

	return indexes
}