package config

import (
	"fmt"
	"path/filepath"
	"sync"
	"testing"
)

func TestSetConfigValueConcurrentUpdatesPreserveEveryKey(t *testing.T) {
	home := t.TempDir()
	isolateConfigHome(t, home)
	t.Setenv("USERPROFILE", home)
	t.Setenv("APPDATA", home)
	t.Setenv("XDG_CONFIG_HOME", filepath.Join(home, ".config"))

	const updates = 24
	start := make(chan struct{})
	errs := make(chan error, updates)
	var wg sync.WaitGroup
	for i := 0; i < updates; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			<-start
			key := fmt.Sprintf("cor06-option-%02d", i)
			value := fmt.Sprintf("value-%02d", i)
			if err := SetConfigValue(key, []string{value}, true); err != nil {
				errs <- err
			}
		}(i)
	}
	close(start)
	wg.Wait()
	close(errs)
	for err := range errs {
		t.Fatal(err)
	}

	configPath := GetConfigPath()
	parsed, err := ParseConfig(configPath)
	if err != nil {
		t.Fatal(err)
	}
	for i := 0; i < updates; i++ {
		key := fmt.Sprintf("cor06-option-%02d", i)
		want := fmt.Sprintf("value-%02d", i)
		if got := parsed[key]; len(got) != 1 || got[0] != want {
			t.Errorf("%s = %v, want [%s]", key, got, want)
		}
	}

	temps, err := filepath.Glob(filepath.Join(filepath.Dir(configPath), ".mpv.conf.tmp-*"))
	if err != nil {
		t.Fatal(err)
	}
	if len(temps) != 0 {
		t.Fatalf("temporary files remain after concurrent updates: %v", temps)
	}
}