package config

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
)

func TestConfigCASAndMetadataIsolation(t *testing.T) {
	store := NewStore(filepath.Join(t.TempDir(), "config.yaml"), "")
	m, err := NewManager(context.Background(), store)
	if err != nil {
		t.Fatal(err)
	}
	a, _ := m.Load(nil)
	b, _ := m.Load(nil)
	if a.Revision == "" {
		t.Fatal("missing revision")
	}
	if err = m.SaveLastAgentModelHash(nil, "model-new"); err != nil {
		t.Fatal(err)
	}
	a.CLIHTTPSListenAddr = "127.0.0.1:39099"
	first, err := m.Save(nil, a)
	if err != nil {
		t.Fatal(err)
	}
	if first.LastAgentModelHash != "model-new" {
		t.Fatal("UI overwrote backend metadata")
	}
	b.HomeMetrics.RefreshIntervalSeconds = 11
	if _, err = m.Save(nil, b); !errors.Is(err, ErrConfigConflict) {
		t.Fatalf("stale save accepted: %v", err)
	}
	current, _ := m.Load(nil)
	if current.CLIHTTPSListenAddr != "127.0.0.1:39099" {
		t.Fatal("CLI port lost")
	}
	data, _ := os.ReadFile(store.Path())
	if strings.Contains(string(data), "revision:") {
		t.Fatal("revision persisted in YAML")
	}
	if current.Revision == a.Revision {
		t.Fatal("revision did not change")
	}
}

func TestConcurrentSavesHaveExactlyOneWinner(t *testing.T) {
	store := NewStore(filepath.Join(t.TempDir(), "config.yaml"), "")
	m, err := NewManager(context.Background(), store)
	if err != nil {
		t.Fatal(err)
	}
	a, _ := m.Load(nil)
	b := cloneConfig(a)
	a.HomeMetrics.RefreshIntervalSeconds = 11
	b.HomeMetrics.RefreshIntervalSeconds = 12
	var wg sync.WaitGroup
	results := make(chan error, 2)
	for _, cfg := range []Config{a, b} {
		wg.Add(1)
		go func(c Config) { defer wg.Done(); _, err := m.Save(nil, c); results <- err }(cfg)
	}
	wg.Wait()
	close(results)
	success, conflict := 0, 0
	for err := range results {
		if err == nil {
			success++
		} else if errors.Is(err, ErrConfigConflict) {
			conflict++
		} else {
			t.Fatal(err)
		}
	}
	if success != 1 || conflict != 1 {
		t.Fatalf("success=%d conflict=%d", success, conflict)
	}
}