package config

import (
	"log"
	"path/filepath"

	"github.com/fsnotify/fsnotify"
)

// WatchConfig watches the config file for changes and triggers the callback
func WatchConfig(path string, onChange func(*Config)) error {
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		return err
	}

	absPath, err := filepath.Abs(path)
	if err != nil {
		return err
	}
	configDir := filepath.Dir(absPath)

	go func() {
		defer watcher.Close()
		for {
			select {
			case event, ok := <-watcher.Events:
				if !ok {
					return
				}
				// Many editors trigger Write or Rename when saving
				if event.Has(fsnotify.Write) || event.Has(fsnotify.Create) {
					if filepath.Base(event.Name) == filepath.Base(absPath) {
						log.Printf("Config file changed: %s", event.Name)
						newCfg, err := LoadConfig(absPath)
						if err != nil {
							log.Printf("Failed to reload config: %v", err)
							continue
						}
						onChange(newCfg)
					}
				}
			case err, ok := <-watcher.Errors:
				if !ok {
					return
				}
				log.Printf("Watcher error: %v", err)
			}
		}
	}()

	// Watch the directory instead of the file to handle cases where 
	// editors use atomic saves (create new file, delete old, rename new)
	return watcher.Add(configDir)
}