package engine

import (
	"context"
	"fmt"
	"gosvc/logger"
	"strings"
	"time"

	"robotfs/utils"
)

func (f *FileSystemManager) RenameDirectory(ctx context.Context, oldPath, newPath utils.FullPath, isDir bool) error {
	f.Lock()
	defer f.Unlock()

	if err := f.canRename(oldPath, newPath, isDir); err != nil {
		return err
	}

	oldEntry, err := f.FindEntry(ctx, oldPath)
	if err != nil {
		return fmt.Errorf("%s not found: %v", oldPath, err)
	}

	moveErr := f.moveEntry(ctx, oldPath, oldEntry, newPath)
	if moveErr != nil {
		return fmt.Errorf("%s move error: %v", oldPath, moveErr)
	}

	if err := utils.Move(f.root, string(oldPath), string(newPath)); err != nil {
		return fmt.Errorf("move file data failed: %v", err)
	}

	return nil
}

func (f *FileSystemManager) canRename(source, target utils.FullPath, isDir bool) error {
	if string(source) == "/" {
		return fmt.Errorf("mv: cannot move root directory")
	}

	if isDir && strings.HasPrefix(string(target), string(source)) {
		return fmt.Errorf("mv: can not move directory to a subdirectory if itself")
	}

	return nil
}

func (f *FileSystemManager) moveEntry(ctx context.Context, oldPath utils.FullPath, entry *utils.Entry, newPath utils.FullPath) error {
	if err := f.moveSelfEntry(ctx, oldPath, entry, newPath, func() error {
		if entry.IsDir {
			if err := f.moveFolderSubEntries(ctx, oldPath, newPath); err != nil {
				return err
			}
		}
		return nil
	}); err != nil {
		return fmt.Errorf("fail to move %s => %s: %v", oldPath, newPath, err)
	}

	return nil
}

func (f *FileSystemManager) moveFolderSubEntries(ctx context.Context, oldPath utils.FullPath, newPath utils.FullPath) error {
	logger.Info("moving folder %s => %s", oldPath, newPath)

	lastFileName := ""
	includeLastFile := false
	for {
		entries := make([]*utils.Entry, 0, 1000)
		lastFileName, err := f.doListDirectoryEntries(ctx, oldPath, lastFileName, includeLastFile, 1000, func(entry *utils.Entry) bool {
			entries = append(entries, entry)
			return true
		})
		if err != nil {
			return err
		}

		if len(entries) == 0 {
			break
		}

		for _, item := range entries {
			itemOldPath := oldPath.Child(item.FullPath.Name())
			itemNewPath := newPath.Child(item.FullPath.Name())
			err := f.moveEntry(ctx, itemOldPath, item, itemNewPath)
			if err != nil {
				return err
			}
		}

		if lastFileName == "" || len(entries) < 1000 {
			break
		}
	}

	return nil
}

func (f *FileSystemManager) moveSelfEntry(ctx context.Context, oldPath utils.FullPath, entry *utils.Entry, newPath utils.FullPath, moveFolderSubEntries func() error) error {
	logger.Info("moving entry %s => %s", oldPath, newPath)

	if oldPath == newPath {
		logger.Info("skip moving entry %s => %s", oldPath, newPath)
		return nil
	}

	newEntry := &utils.Entry{
		FullPath:             newPath,
		IsDir:                entry.IsDir,
		Size:                 entry.Size,
		CreateTime:           time.Now().Unix(),
		S3Key:                entry.S3Key,
		ContentType:          entry.ContentType,
		Etag:                 entry.Etag,
		VersionID:            entry.VersionID,
		LastModificationTime: time.Now().Unix(),
		Extended:             entry.Extended,
	}

	if createErr := f.meta.InsertEntry(ctx, newEntry); createErr != nil {
		return createErr
	}

	if moveFolderSubEntries != nil {
		if moveChildrenErr := moveFolderSubEntries(); moveChildrenErr != nil {
			return moveChildrenErr
		}
	}

	deleteErr := f.meta.DeleteEntry(ctx, oldPath)
	if deleteErr != nil {
		return deleteErr
	}

	return nil
}