From c53c54a5d97aa03437c3251e697f8028eb66c373 Mon Sep 17 00:00:00 2001
From: Sky Johnson <skylearj@gmail.com>
Date: Tue, 1 Jul 2025 21:14:16 -0500
Subject: [PATCH] refactor DirectoryWatcher to Watcher

---
 watchers/watcher.go | 236 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 236 insertions(+)
 create mode 100644 watchers/watcher.go

diff --git a/watchers/watcher.go b/watchers/watcher.go
new file mode 100644
index 0000000..a6ff037
--- /dev/null
+++ b/watchers/watcher.go
@@ -0,0 +1,236 @@
+package watchers
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"Moonshark/logger"
+)
+
+const (
+	defaultDebounceTime = 300 * time.Millisecond
+	defaultPollInterval = 1 * time.Second
+)
+
+type FileChange struct {
+	Path      string
+	IsNew     bool
+	IsDeleted bool
+}
+
+type FileInfo struct {
+	ModTime time.Time
+}
+
+// Watcher is now self-contained and manages its own polling
+type Watcher struct {
+	dir          string
+	files        map[string]FileInfo
+	filesMu      sync.RWMutex
+	callback     func([]FileChange) error
+	debounceTime time.Duration
+	pollInterval time.Duration
+	recursive    bool
+
+	// Self-management
+	done          chan struct{}
+	debounceTimer *time.Timer
+	debouncing    bool
+	debounceMu    sync.Mutex
+	wg            sync.WaitGroup
+}
+
+type WatcherConfig struct {
+	Dir          string
+	Callback     func([]FileChange) error
+	DebounceTime time.Duration
+	PollInterval time.Duration
+	Recursive    bool
+}
+
+func NewWatcher(config WatcherConfig) (*Watcher, error) {
+	if config.DebounceTime == 0 {
+		config.DebounceTime = defaultDebounceTime
+	}
+	if config.PollInterval == 0 {
+		config.PollInterval = defaultPollInterval
+	}
+
+	w := &Watcher{
+		dir:          config.Dir,
+		files:        make(map[string]FileInfo),
+		callback:     config.Callback,
+		debounceTime: config.DebounceTime,
+		pollInterval: config.PollInterval,
+		recursive:    config.Recursive,
+		done:         make(chan struct{}),
+	}
+
+	if err := w.scanDirectory(); err != nil {
+		return nil, err
+	}
+
+	w.wg.Add(1)
+	go w.watchLoop()
+
+	return w, nil
+}
+
+func (w *Watcher) Close() {
+	close(w.done)
+	w.wg.Wait()
+
+	w.debounceMu.Lock()
+	if w.debounceTimer != nil {
+		w.debounceTimer.Stop()
+	}
+	w.debounceMu.Unlock()
+}
+
+func (w *Watcher) GetDir() string {
+	return w.dir
+}
+
+// watchLoop is the main polling loop for this watcher
+func (w *Watcher) watchLoop() {
+	defer w.wg.Done()
+	ticker := time.NewTicker(w.pollInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			w.checkAndNotify()
+		case <-w.done:
+			return
+		}
+	}
+}
+
+// checkAndNotify combines change detection and notification
+func (w *Watcher) checkAndNotify() {
+	changed, changedFiles := w.detectChanges()
+	if changed {
+		w.notifyChange(changedFiles)
+	}
+}
+
+// detectChanges scans directory and returns changes
+func (w *Watcher) detectChanges() (bool, []FileChange) {
+	newFiles := make(map[string]FileInfo)
+	var changedFiles []FileChange
+	changed := false
+
+	err := filepath.Walk(w.dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return nil
+		}
+
+		if !w.recursive && info.IsDir() && path != w.dir {
+			return filepath.SkipDir
+		}
+
+		currentInfo := FileInfo{ModTime: info.ModTime()}
+		newFiles[path] = currentInfo
+
+		w.filesMu.RLock()
+		prevInfo, exists := w.files[path]
+		w.filesMu.RUnlock()
+
+		if !exists {
+			changed = true
+			changedFiles = append(changedFiles, FileChange{Path: path, IsNew: true})
+			w.logDebug("File added: %s", path)
+		} else if currentInfo.ModTime != prevInfo.ModTime {
+			changed = true
+			changedFiles = append(changedFiles, FileChange{Path: path})
+			w.logDebug("File changed: %s", path)
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		w.logError("Error scanning directory: %v", err)
+		return false, nil
+	}
+
+	// Check for deletions
+	w.filesMu.RLock()
+	for path := range w.files {
+		if _, exists := newFiles[path]; !exists {
+			changed = true
+			changedFiles = append(changedFiles, FileChange{Path: path, IsDeleted: true})
+			w.logDebug("File deleted: %s", path)
+		}
+	}
+	w.filesMu.RUnlock()
+
+	if changed {
+		w.filesMu.Lock()
+		w.files = newFiles
+		w.filesMu.Unlock()
+	}
+
+	return changed, changedFiles
+}
+
+func (w *Watcher) scanDirectory() error {
+	w.filesMu.Lock()
+	defer w.filesMu.Unlock()
+
+	w.files = make(map[string]FileInfo)
+
+	return filepath.Walk(w.dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return nil
+		}
+
+		if !w.recursive && info.IsDir() && path != w.dir {
+			return filepath.SkipDir
+		}
+
+		w.files[path] = FileInfo{ModTime: info.ModTime()}
+		return nil
+	})
+}
+
+func (w *Watcher) notifyChange(changedFiles []FileChange) {
+	w.debounceMu.Lock()
+	defer w.debounceMu.Unlock()
+
+	if w.debouncing && w.debounceTimer != nil {
+		w.debounceTimer.Stop()
+	}
+	w.debouncing = true
+
+	// Copy to avoid race conditions
+	filesCopy := make([]FileChange, len(changedFiles))
+	copy(filesCopy, changedFiles)
+
+	w.debounceTimer = time.AfterFunc(w.debounceTime, func() {
+		var err error
+		if w.callback != nil {
+			err = w.callback(filesCopy)
+		}
+
+		if err != nil {
+			w.logError("Callback error: %v", err)
+		}
+
+		w.debounceMu.Lock()
+		w.debouncing = false
+		w.debounceMu.Unlock()
+	})
+}
+
+func (w *Watcher) logDebug(format string, args ...any) {
+	logger.Debugf("[Watcher] [%s] %s", w.dir, fmt.Sprintf(format, args...))
+}
+
+func (w *Watcher) logError(format string, args ...any) {
+	logger.Errorf("[Watcher] [%s] %s", w.dir, fmt.Sprintf(format, args...))
+}