package filestore

import (
	"context"
	"fmt"
	"io"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"github.com/google/uuid"
	"github.com/minio/minio-go/v7"
	minioUtil "fwh-toolbox-server/utils/minio"
	"go.uber.org/zap"
)

const AIFileBucket = "fwh-toolbox-ai-file"
const AIFileExpireDays = 7

// FileRecord 文件记录
type FileRecord struct {
	Key       string `json:"key"`       // MinIO object key
	FileName  string `json:"fileName"`  // 原始文件名
	Path      string `json:"path"`      // Agent 请求的路径
	Size      int64  `json:"size"`      // 文件大小
	CreatedAt int64  `json:"createdAt"` // 创建时间戳
}

// FileStore 会话级别的虚拟文件系统
type FileStore struct {
	prefix string // "upload" 或 "download"，用于区分文件来源
	mu     sync.RWMutex
	files  map[string]*FileRecord // path → FileRecord（同路径覆盖更新）
}

// NewFileStore 创建文件存储
// prefix: "upload" 或 "download"，对应 MinIO 中的子目录前缀
func NewFileStore(prefix string) *FileStore {
	return &FileStore{
		prefix: prefix,
		files:  make(map[string]*FileRecord),
	}
}

// WriteFile 将内容上传到 MinIO，返回文件记录
// objectKey 格式: {prefix}/{userId}/{sessionId}/{uuid}_{fileName}
func (fs *FileStore) WriteFile(userId, sessionId, path, content string) (*FileRecord, error) {
	fileName := filepath.Base(path)
	uniqueId := uuid.New().String()[:8]
	objectKey := fmt.Sprintf("%s/%s/%s/%s_%s", fs.prefix, userId, sessionId, uniqueId, fileName)

	// 上传到 MinIO（带7天过期）
	reader := strings.NewReader(content)
	ctx := context.Background()

	_, err := minioUtil.Client.PutObject(ctx, AIFileBucket, objectKey, reader, int64(len(content)), minio.PutObjectOptions{
		ContentType: DetectContentType(fileName),
		Expires:     time.Now().Add(AIFileExpireDays * 24 * time.Hour),
	})
	if err != nil {
		return nil, fmt.Errorf("上传文件到MinIO失败: %w", err)
	}

	record := &FileRecord{
		Key:       objectKey,
		FileName:  fileName,
		Path:      path,
		Size:      int64(len(content)),
		CreatedAt: time.Now().Unix(),
	}

	// 存入内存映射（同路径覆盖）
	fs.mu.Lock()
	fs.files[path] = record
	fs.mu.Unlock()

	zap.L().Info("[FileStore] 文件已保存到MinIO",
		zap.String("prefix", fs.prefix),
		zap.String("path", path),
		zap.String("key", objectKey),
		zap.String("fileName", fileName),
	)

	return record, nil
}

// WriteBytes 将字节内容上传到 MinIO（支持二进制文件）
// objectKey 格式: {prefix}/{userId}/{timestamp}_{uuid}_{fileName}
func (fs *FileStore) WriteBytes(userId, fileName string, data []byte, contentType string) (*FileRecord, error) {
	uniqueId := uuid.New().String()[:8]
	timestamp := time.Now().Unix()
	objectKey := fmt.Sprintf("%s/%s/%d_%s_%s", fs.prefix, userId, timestamp, uniqueId, fileName)

	// 虚拟路径（供 Agent readTextFile 使用）
	virtualPath := fmt.Sprintf("/uploads/%s", fileName)

	reader := strings.NewReader(string(data))
	ctx := context.Background()

	if contentType == "" {
		contentType = DetectContentType(fileName)
	}

	_, err := minioUtil.Client.PutObject(ctx, AIFileBucket, objectKey, reader, int64(len(data)), minio.PutObjectOptions{
		ContentType: contentType,
		Expires:     time.Now().Add(AIFileExpireDays * 24 * time.Hour),
	})
	if err != nil {
		return nil, fmt.Errorf("上传文件到MinIO失败: %w", err)
	}

	record := &FileRecord{
		Key:       objectKey,
		FileName:  fileName,
		Path:      virtualPath,
		Size:      int64(len(data)),
		CreatedAt: time.Now().Unix(),
	}

	// 存入内存映射
	fs.mu.Lock()
	fs.files[virtualPath] = record
	fs.mu.Unlock()

	zap.L().Info("[FileStore] 文件已保存到MinIO",
		zap.String("prefix", fs.prefix),
		zap.String("path", virtualPath),
		zap.String("key", objectKey),
		zap.String("fileName", fileName),
	)

	return record, nil
}

// ReadFile 从 MinIO 读取文件内容
func (fs *FileStore) ReadFile(path string) (string, error) {
	fs.mu.RLock()
	record, ok := fs.files[path]
	fs.mu.RUnlock()

	if !ok {
		return "", fmt.Errorf("文件不存在: %s", path)
	}

	ctx := context.Background()
	obj, err := minioUtil.Client.GetObject(ctx, AIFileBucket, record.Key, minio.GetObjectOptions{})
	if err != nil {
		return "", fmt.Errorf("从MinIO读取文件失败: %w", err)
	}
	defer obj.Close()

	data, err := io.ReadAll(obj)
	if err != nil {
		return "", fmt.Errorf("读取文件内容失败: %w", err)
	}

	return string(data), nil
}

// HasFile 检查路径是否有文件记录
func (fs *FileStore) HasFile(path string) bool {
	fs.mu.RLock()
	defer fs.mu.RUnlock()
	_, ok := fs.files[path]
	return ok
}

// GetFiles 获取所有文件记录
func (fs *FileStore) GetFiles() []FileRecord {
	fs.mu.RLock()
	defer fs.mu.RUnlock()

	result := make([]FileRecord, 0, len(fs.files))
	for _, record := range fs.files {
		result = append(result, *record)
	}
	return result
}

// GetFileByKey 按 MinIO key 查找文件记录
func (fs *FileStore) GetFileByKey(key string) *FileRecord {
	fs.mu.RLock()
	defer fs.mu.RUnlock()

	for _, record := range fs.files {
		if record.Key == key {
			return record
		}
	}
	return nil
}

// Clear 清除所有文件记录（不删除 MinIO 文件）
func (fs *FileStore) Clear() {
	fs.mu.Lock()
	fs.files = make(map[string]*FileRecord)
	fs.mu.Unlock()
}

// DetectContentType 根据文件扩展名推断 Content-Type
func DetectContentType(fileName string) string {
	ext := strings.ToLower(filepath.Ext(fileName))
	switch ext {
	case ".txt":
		return "text/plain; charset=utf-8"
	case ".json":
		return "application/json"
	case ".html", ".htm":
		return "text/html"
	case ".css":
		return "text/css"
	case ".js":
		return "application/javascript"
	case ".ts":
		return "application/typescript"
	case ".go":
		return "text/x-go"
	case ".py":
		return "text/x-python"
	case ".md":
		return "text/markdown"
	case ".csv":
		return "text/csv"
	case ".xml":
		return "application/xml"
	case ".yaml", ".yml":
		return "text/yaml"
	case ".sh":
		return "text/x-shellscript"
	case ".vue":
		return "text/x-vue"
	case ".sql":
		return "text/x-sql"
	case ".log":
		return "text/plain; charset=utf-8"
	default:
		return "application/octet-stream"
	}
}