package shared

import (
	"encoding/json"
	"os"
	"sync"
)

type TorrentStorage struct {
	torrents map[string]*Torrent
	mu       sync.RWMutex
	order    []string
	filename string // Added to store the filename for persistence
}

func loadTorrentsFromJSON(filename string) (map[string]*Torrent, error) {
	data, err := os.ReadFile(filename)
	if err != nil {
		return nil, err
	}
	torrents := make(map[string]*Torrent)
	if err := json.Unmarshal(data, &torrents); err != nil {
		return nil, err
	}
	return torrents, nil
}

func NewTorrentStorage(filename string) *TorrentStorage {
	// Open the JSON file and read the data
	torrents, err := loadTorrentsFromJSON(filename)
	if err != nil {
		torrents = make(map[string]*Torrent)
	}
	order := make([]string, 0, len(torrents))
	for id := range torrents {
		order = append(order, id)
	}
	// Create a new TorrentStorage
	return &TorrentStorage{
		torrents: torrents,
		order:    order,
		filename: filename,
	}
}

func (ts *TorrentStorage) Add(torrent *Torrent) {
	ts.mu.Lock()
	defer ts.mu.Unlock()
	ts.torrents[torrent.Hash] = torrent
	ts.order = append(ts.order, torrent.Hash)
	ts.saveToFile()
}

func (ts *TorrentStorage) AddOrUpdate(torrent *Torrent) {
	ts.mu.Lock()
	defer ts.mu.Unlock()
	if _, exists := ts.torrents[torrent.Hash]; !exists {
		ts.order = append(ts.order, torrent.Hash)
	}
	ts.torrents[torrent.Hash] = torrent
	ts.saveToFile()
}

func (ts *TorrentStorage) Update(torrent *Torrent) {
	ts.mu.Lock()
	defer ts.mu.Unlock()
	ts.torrents[torrent.Hash] = torrent
	ts.saveToFile()
}

func (ts *TorrentStorage) Delete(hash string) {
	ts.mu.Lock()
	defer ts.mu.Unlock()
	torrent, exists := ts.torrents[hash]
	if !exists {
		return
	}
	delete(ts.torrents, hash)
	for i, id := range ts.order {
		if id == hash {
			ts.order = append(ts.order[:i], ts.order[i+1:]...)
			break
		}
	}
	// Delete the torrent folder
	if torrent.ContentPath != "" {
		err := os.RemoveAll(torrent.ContentPath)
		if err != nil {
			return
		}
	}
	ts.saveToFile()
}

func (ts *TorrentStorage) Save() error {
	ts.mu.RLock()
	defer ts.mu.RUnlock()
	return ts.saveToFile()
}

// saveToFile is a helper function to write the current state to the JSON file
func (ts *TorrentStorage) saveToFile() error {
	data, err := json.MarshalIndent(ts.torrents, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(ts.filename, data, 0644)
}