package main

import (
	"bufio"
	"log/slog"
	"os"
	"time"
)

type watcher struct {
	path     string
	interval time.Duration
	store    *PermanentWhitelist
	lastMod  time.Time
}

func newPermanentWhitelistWatcher(path string, interval time.Duration, store *PermanentWhitelist) *watcher {
	w := &watcher{
		path:     path,
		interval: interval,
		store:    store,
	}
	w.reload()
	return w
}

func (w *watcher) start() {
	go func() {
		ticker := time.NewTicker(w.interval)
		defer ticker.Stop()
		for range ticker.C {
			w.reload()
		}
	}()
}

func (w *watcher) reload() {
	info, err := os.Stat(w.path)
	if err != nil {
		return
	}
	if info.ModTime().Equal(w.lastMod) {
		return
	}
	w.lastMod = info.ModTime()
	entries := make(map[string]struct{})
	f, err := os.Open(w.path)
	if err != nil {
		slog.Error("failed to open whitelist file", "error", err)
		return
	}
	defer f.Close()
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		line := scanner.Text()
		if line == "" || line[0] == '#' {
			continue
		}
		entries[line] = struct{}{}
	}
	w.store.mu.Lock()
	w.store.entries = entries
	w.store.mu.Unlock()
	slog.Info("reloaded permanent whitelist", "count", len(entries))
}