package document

import (
	"fmt"
	"os"
	"sync"
	"strings"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/bson"
	"git.pyer.club/kingecg/godocdb/index"
	"git.pyer.club/kingecg/godocdb/storage"
)

// DocumentStore 管理带命名空间的文档存储
type DocumentStore struct {
	storage    *storage.LevelDBStorage
	indexStore *index.IndexStore // 添加索引存储依赖
	mu         sync.RWMutex     // 保护并发访问
}

// NewDocumentStore 创建新的文档存储实例
func NewDocumentStore(path string) (*DocumentStore, error) {
	// 确保目录存在
	if err := os.MkdirAll(path, 0755); err != nil {
		return nil, fmt.Errorf("failed to create storage directory: %v", err)
	}

	storage, err := storage.NewLevelDBStorage(path)
	if err != nil {
		return nil, fmt.Errorf("failed to create LevelDB storage: %v", err)
	}

	// 创建关联的索引存储
	is, err := index.NewIndexStore(path)
	if err != nil {
		storage.Close()
		return nil, fmt.Errorf("failed to create index store: %v", err)
	}

	return &DocumentStore{
		storage:    storage,
		indexStore: is,
	}, nil
}

// StoreDocument 带collection标识的文档存储
func (ds *DocumentStore) StoreDocument(collection string, id string, doc interface{}) error {
	// 类型断言
	docMap, ok := doc.(map[string]interface{})
	if !ok {
		return fmt.Errorf("document must be a map[string]interface{}")
	}

	// 自动生成文档ID
	if id == "" {
		// 使用文档自带的_id字段
		if docID, exists := docMap["_id"].(primitive.ObjectID); exists {
			id = docID.Hex()
		} else {
			// 自动生成新ID
			newID := primitive.NewObjectID()
			docMap["_id"] = newID
			id = newID.Hex()
		}
	}

	// 序列化文档
	data, err := bson.Marshal(docMap)
	if err != nil {
		return fmt.Errorf("failed to marshal document: %v", err)
	}

	// 存储文档到LevelDB
	key := []byte(fmt.Sprintf("documents:%s:%s", collection, id))
	if err := ds.storage.Put(key, data); err != nil {
		return err
	}

	// 获取相关索引
	relatedIndexes, err := getRelatedIndexes(docMap, collection, ds.indexStore)
	if err != nil {
		return err
	}

	// 更新所有相关索引
	for _, indexName := range relatedIndexes {
		metadata, err := ds.indexStore.GetIndexMetadata(indexName)
		if err != nil {
			continue
		}

		for _, field := range metadata.KeyFields {
			fieldValue, exists := extractFieldValue(docMap, field)
			if !exists {
				continue
			}

			// 更新索引并处理错误
			if err := ds.indexStore.UpdateIndex(collection, indexName, fieldValue, id); err != nil {
				// 如果是唯一索引冲突，返回错误
				if strings.Contains(err.Error(), "duplicate key error") {
					return fmt.Errorf("unique index constraint violated for %s.%s", collection, field)
				}
			}
		}
	}

	// 创建默认索引（如果不存在）
	if _, err := ds.indexStore.GetIndexMetadata("default_index"); err != nil {
		// 如果索引不存在，创建默认索引
		if errCreate := ds.indexStore.CreateIndex("default_index", index.NonUnique, []string{"_id"}, nil); errCreate != nil {
			return errCreate
		}
	}

	return nil
}

// GetDocument 带collection标识的文档获取
func (ds *DocumentStore) GetDocument(collection string, id string, doc interface{}) error {
	// 在文档键中加入collection标识
	key := []byte(fmt.Sprintf("documents:%s:%s", collection, id))

	// 从LevelDB获取数据
	rawData, err := ds.storage.Get(key)
	if err != nil {
		return fmt.Errorf("document not found: %v", err)
	}

	// 反序列化BSON数据
	if err := bson.Unmarshal(rawData, doc); err != nil {
		return err
	}

	return nil
}

// GetRelatedIndexes 获取文档关联的索引
func getRelatedIndexes(doc map[string]interface{}, coll string, is *index.IndexStore) ([]string, error) {
	// 获取所有索引元数据
	metadataList, err := is.GetAllIndexMetadata(coll)
	if err != nil {
		return nil, err
	}

	var related []string
	for _, md := range metadataList {
		// 检查文档是否包含索引字段
		for _, field := range md.KeyFields {
			if _, exists := doc[field]; exists {
				related = append(related, md.Name)
				break
			}
		}
	}

	// 如果没有匹配的索引，尝试获取默认索引
	if len(related) == 0 {
		_, err := is.GetIndexMetadata("default_index")
		if err == nil {
			related = append(related, "default_index")
		} else {
			return nil, fmt.Errorf("no suitable index found for collection %s", coll)
		}
	}
	
	return related, nil
}

// ExtractFieldValue 提取文档字段值
func extractFieldValue(doc map[string]interface{}, field string) (interface{}, bool) {
	value, exists := doc[field]
	return value, exists
}

// DeleteDocument 删除文档并更新索引
func (ds *DocumentStore) DeleteDocument(collection string, id string) error {
	ds.mu.Lock()
	defer ds.mu.Unlock()

	// 构建文档键
	key := []byte(fmt.Sprintf("documents:%s:%s", collection, id))

	// 获取文档内容以获取相关索引
	rawData, err := ds.storage.Get(key)
	if err != nil {
		return fmt.Errorf("document not found: %v", err)
	}

	// 解析文档
	var docMap map[string]interface{}
	if err := bson.Unmarshal(rawData, &docMap); err != nil {
		return fmt.Errorf("failed to unmarshal document: %v", err)
	}

	// 获取相关索引
	relatedIndexes, err := getRelatedIndexes(docMap, collection, ds.indexStore)
	if err != nil {
		return err
	}

	// 删除相关索引条目
	for _, indexName := range relatedIndexes {
		metadata, err := ds.indexStore.GetIndexMetadata(indexName)
		if err != nil {
			continue
		}

		for _, field := range metadata.KeyFields {
			fieldValue, exists := extractFieldValue(docMap, field)
			if !exists {
				continue
			}

			// 从索引中删除
			_ = ds.indexStore.DeleteIndex(collection, indexName, fieldValue, id)
		}
	}

	// 最后删除文档
	return ds.storage.Delete(key)
}