package index

import (
	"fmt"

	"github.com/iancoleman/orderedmap"
	"go.mongodb.org/mongo-driver/bson"
	"git.pyer.club/kingecg/godocdb/storage"
)

// IndexType 表示索引类型
type IndexType string

const (
	SingleField IndexType = "single"
	Composite   IndexType = "composite"
)

// IndexMetadata 索引元数据
type IndexMetadata struct {
	Name      string
	Type      IndexType
	KeyFields []string
}

// IndexStore 管理索引的存储和查询
type IndexStore struct {
	storage *storage.LevelDBStorage
}

// NewIndexStore 创建新的索引存储实例
func NewIndexStore(path string) (*IndexStore, error) {
	storage, err := storage.NewLevelDBStorage(path)
	if err != nil {
		return nil, err
	}
	return &IndexStore{storage: storage}, nil
}

// CreateIndex 创建索引
func (is *IndexStore) CreateIndex(indexName string, indexType IndexType, keyFields []string) error {
	// 存储索引元数据
	metadata := IndexMetadata{
		Name:      indexName,
		Type:      indexType,
		KeyFields: keyFields,
	}

	data, err := bson.Marshal(metadata)
	if err != nil {
		return fmt.Errorf("failed to marshal index metadata: %v", err)
	}

	key := []byte(fmt.Sprintf("indexes:metadata:%s", indexName))
	if err := is.storage.Put(key, data); err != nil {
		return err
	}

	// 初始化索引存储结构
	indexKey := fmt.Sprintf("indexes:data:%s", indexName)
	index := orderedmap.New()
	indexData, _ := bson.Marshal(index)
	return is.storage.Put([]byte(indexKey), indexData)
}

// DropIndex 删除索引
func (is *IndexStore) DropIndex(indexName string) error {
	// 删除元数据
	metadataKey := []byte(fmt.Sprintf("indexes:metadata:%s", indexName))
	if err := is.storage.Delete(metadataKey); err != nil {
		return err
	}

	// 删除索引数据
	indexKey := []byte(fmt.Sprintf("indexes:data:%s", indexName))
	return is.storage.Delete(indexKey)
}

// GetIndexMetadata 获取索引元数据
func (is *IndexStore) GetIndexMetadata(indexName string) (*IndexMetadata, error) {
	key := []byte(fmt.Sprintf("indexes:metadata:%s", indexName))
	rawData, err := is.storage.Get(key)
	if err != nil {
		return nil, fmt.Errorf("index not found: %v", err)
	}

	var metadata IndexMetadata
	if err := bson.Unmarshal(rawData, &metadata); err != nil {
		return nil, err
	}

	return &metadata, nil
}