package data

import (
	"os"
	"path/filepath"
	"sync"
	"testing"
	"time"

	"kra/internal/config"
)

func TestConfigWatcherStopWaitsForDebouncedReload(t *testing.T) {
	root := t.TempDir()
	configPath := filepath.Join(root, "config.yaml")
	config := []byte("data:\n  database:\n    driver: sqlite\n    path: " + filepath.ToSlash(root) + "\nadmin: {}\n")
	if err := os.WriteFile(configPath, config, 0o600); err != nil {
		t.Fatal(err)
	}
	runtime := config.NewStore(&config.Config{Data: &config.Data{}, Admin: &config.Admin{ConfigPath: configPath}})
	started := make(chan struct{})
	release := make(chan struct{})
	var startOnce sync.Once
	stopListener := runtime.Subscribe(func(*config.Data, *config.Admin) {
		startOnce.Do(func() { close(started) })
		<-release
	})
	defer stopListener()
	data := &Data{runtime: runtime}
	stop := data.watchConfig()

	// A write event schedules the 100ms debounce reload.
	if err := os.WriteFile(configPath, config, 0o600); err != nil {
		t.Fatal(err)
	}
	select {
	case <-started:
	case <-time.After(3 * time.Second):
		stop()
		t.Fatal("debounced reload did not start")
	}

	stopped := make(chan struct{})
	go func() {
		stop()
		close(stopped)
	}()
	select {
	case <-stopped:
		t.Fatal("watcher stop returned before reload callback finished")
	case <-time.After(100 * time.Millisecond):
	}
	close(release)
	select {
	case <-stopped:
	case <-time.After(time.Second):
		t.Fatal("watcher stop did not wait for callback completion")
	}
}