package torrent

import (
	"context"
	"crypto/sha1"
	"encoding/hex"
	"fmt"
	"os"
	"sync"
	"time"
)

type StubClient struct {
	logPath  string
	savePath string
	mu       sync.RWMutex
	logMu    sync.Mutex
	torrents map[string]*TorrentInfo
}

func NewStubClient(logPath, savePath string) *StubClient {
	return &StubClient{
		logPath:  logPath,
		savePath: savePath,
		torrents: make(map[string]*TorrentInfo),
	}
}

func (c *StubClient) log(format string, args ...any) {
	if c.logPath == "" {
		return
	}
	c.logMu.Lock()
	defer c.logMu.Unlock()

	f, err := os.OpenFile(c.logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return
	}
	defer f.Close()

	timestamp := time.Now().Format(time.RFC3339)
	msg := fmt.Sprintf(format, args...)
	fmt.Fprintf(f, "[%s] %s\n", timestamp, msg)
}

func (c *StubClient) Connect(ctx context.Context) error {
	c.log("CONNECT")
	return nil
}

func (c *StubClient) Disconnect(ctx context.Context) error {
	c.log("DISCONNECT")
	return nil
}

func (c *StubClient) ListTorrents(ctx context.Context) ([]TorrentInfo, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	c.log("LIST_TORRENTS count=%d", len(c.torrents))

	result := make([]TorrentInfo, 0, len(c.torrents))
	for _, t := range c.torrents {
		result = append(result, *t)
	}
	return result, nil
}

func (c *StubClient) GetTorrent(ctx context.Context, hash string) (*TorrentInfo, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	c.log("GET_TORRENT hash=%s", hash)

	t, ok := c.torrents[hash]
	if !ok {
		return nil, ErrTorrentNotFound
	}
	return t, nil
}

func (c *StubClient) AddTorrentURL(ctx context.Context, url string, savePath *string) error {
	path := c.savePath
	if savePath != nil {
		path = *savePath
	}

	hash := generateHashFromURL(url)
	name := "Torrent-" + hash[:8]

	c.mu.Lock()
	c.torrents[hash] = &TorrentInfo{
		Hash:          hash,
		Name:          name,
		Size:          500 * 1024 * 1024,
		Progress:      0,
		DownloadSpeed: 0,
		UploadSpeed:   0,
		State:         StateQueued,
		SavePath:      path,
	}
	c.mu.Unlock()

	c.log("ADD_TORRENT_URL url=%s hash=%s save_path=%s", url, hash, path)
	return nil
}

func (c *StubClient) AddTorrentFile(ctx context.Context, data []byte, savePath *string) error {
	path := c.savePath
	if savePath != nil {
		path = *savePath
	}

	hash := generateHashFromData(data)
	name := "Torrent-" + hash[:8]

	c.mu.Lock()
	c.torrents[hash] = &TorrentInfo{
		Hash:          hash,
		Name:          name,
		Size:          uint64(len(data) * 100),
		Progress:      0,
		DownloadSpeed: 0,
		UploadSpeed:   0,
		State:         StateQueued,
		SavePath:      path,
	}
	c.mu.Unlock()

	c.log("ADD_TORRENT_FILE size=%d hash=%s save_path=%s", len(data), hash, path)
	return nil
}

func (c *StubClient) RemoveTorrent(ctx context.Context, hash string, deleteFiles bool) error {
	c.mu.Lock()
	delete(c.torrents, hash)
	c.mu.Unlock()

	c.log("REMOVE_TORRENT hash=%s delete_files=%t", hash, deleteFiles)
	return nil
}

func (c *StubClient) PauseTorrent(ctx context.Context, hash string) error {
	c.mu.Lock()
	if t, ok := c.torrents[hash]; ok {
		t.State = StatePaused
		t.DownloadSpeed = 0
	}
	c.mu.Unlock()

	c.log("PAUSE_TORRENT hash=%s", hash)
	return nil
}

func (c *StubClient) ResumeTorrent(ctx context.Context, hash string) error {
	c.mu.Lock()
	if t, ok := c.torrents[hash]; ok {
		if t.Progress < 1.0 {
			t.State = StateDownloading
		} else {
			t.State = StateSeeding
		}
	}
	c.mu.Unlock()

	c.log("RESUME_TORRENT hash=%s", hash)
	return nil
}

func (c *StubClient) SetTorrentState(hash string, state TorrentState, progress float64) {
	c.mu.Lock()
	defer c.mu.Unlock()

	if t, ok := c.torrents[hash]; ok {
		t.State = state
		t.Progress = progress
		if state == StateSeeding {
			t.Progress = 1.0
		}
	}
}

func (c *StubClient) SetTorrentName(hash, name string) {
	c.mu.Lock()
	defer c.mu.Unlock()

	if t, ok := c.torrents[hash]; ok {
		t.Name = name
	}
}

func (c *StubClient) AddTorrentDirect(info TorrentInfo) {
	c.mu.Lock()
	defer c.mu.Unlock()
	c.torrents[info.Hash] = &info
}

func (c *StubClient) Clear() {
	c.mu.Lock()
	defer c.mu.Unlock()
	c.torrents = make(map[string]*TorrentInfo)
}

func (c *StubClient) GetAllTorrents() map[string]*TorrentInfo {
	c.mu.RLock()
	defer c.mu.RUnlock()

	result := make(map[string]*TorrentInfo, len(c.torrents))
	for k, v := range c.torrents {
		copy := *v
		result[k] = &copy
	}
	return result
}

func generateHashFromURL(url string) string {
	h := sha1.New()
	h.Write([]byte(url))
	return hex.EncodeToString(h.Sum(nil))
}

func generateHashFromData(data []byte) string {
	h := sha1.New()
	h.Write(data)
	return hex.EncodeToString(h.Sum(nil))
}