package barkfile

import (
	"context"
	"os"
	"path/filepath"
	"testing"
	"time"
)

func TestWatchDeliversInitialAndChangedConfiguration(t *testing.T) {
	path := filepath.Join(t.TempDir(), "Barkfile")
	writeWatchConfig(t, path, ":5432")
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	changes, err := Watch(ctx, path, WatchOptions{PollInterval: 10 * time.Millisecond})
	if err != nil {
		t.Fatal(err)
	}
	if change := nextChange(t, changes); change.Err != nil || change.Config.Listen != ":5432" {
		t.Fatalf("initial change = %#v", change)
	}

	writeWatchConfig(t, path, ":6543")
	if change := nextChange(t, changes); change.Err != nil || change.Config.Listen != ":6543" {
		t.Fatalf("changed configuration = %#v", change)
	}
}

func TestWatchReportsInvalidRevisionAndRecovers(t *testing.T) {
	path := filepath.Join(t.TempDir(), "Barkfile")
	writeWatchConfig(t, path, ":5432")
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	changes, err := Watch(ctx, path, WatchOptions{PollInterval: 10 * time.Millisecond})
	if err != nil {
		t.Fatal(err)
	}
	_ = nextChange(t, changes)
	if err := os.WriteFile(path, []byte("pawsql {\n listen :5432\n}"), 0o600); err != nil {
		t.Fatal(err)
	}
	if change := nextChange(t, changes); change.Err == nil {
		t.Fatal("invalid revision did not report an error")
	}

	writeWatchConfig(t, path, ":7654")
	if change := nextChange(t, changes); change.Err != nil || change.Config.Listen != ":7654" {
		t.Fatalf("recovered configuration = %#v", change)
	}
}

func nextChange(t *testing.T, changes <-chan Change) Change {
	t.Helper()
	select {
	case change, open := <-changes:
		if !open {
			t.Fatal("watch channel closed before delivering a change")
		}
		return change
	case <-time.After(time.Second):
		t.Fatal("timed out waiting for Barkfile change")
		return Change{}
	}
}

func writeWatchConfig(t *testing.T, path, listen string) {
	t.Helper()
	contents := "pawsql {\n listen " + listen + "\n tls {\n  cert cert.pem\n  key key.pem\n }\n database app {\n  upstream 127.0.0.1:5432\n }\n}\n"
	if err := os.WriteFile(path, []byte(contents), 0o600); err != nil {
		t.Fatal(err)
	}
}