package app

import (
	"context"
	"io"
	"log/slog"
	"net"
	"os"
	"path/filepath"
	"testing"
	"time"

	"galaxy/mail/internal/config"

	"github.com/alicebob/miniredis/v2"
	"github.com/stretchr/testify/require"
)

func TestNewRuntimeStartsWithStubMode(t *testing.T) {
	redisServer := miniredis.RunT(t)
	templateDir := writeStage6Templates(t)

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Templates.Dir = templateDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	runtime, err := NewRuntime(context.Background(), cfg, testLogger())
	require.NoError(t, err)
	require.NoError(t, runtime.Close())
}

func TestNewRuntimeRejectsInvalidRedisConfig(t *testing.T) {
	redisServer := miniredis.RunT(t)
	templateDir := writeStage6Templates(t)

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Redis.Conn.Password = ""
	cfg.Templates.Dir = templateDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	_, err := NewRuntime(context.Background(), cfg, testLogger())
	require.Error(t, err)
	require.Contains(t, err.Error(), "redis password")
}

func TestNewRuntimeRejectsUnavailableRedis(t *testing.T) {
	templateDir := writeStage6Templates(t)

	cfg := runtimeBaseConfig(t, "127.0.0.1:6399")
	cfg.Redis.Conn.OperationTimeout = 100 * time.Millisecond
	cfg.Templates.Dir = templateDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	_, err := NewRuntime(context.Background(), cfg, testLogger())
	require.Error(t, err)
	require.Contains(t, err.Error(), "ping redis")
}

func TestNewRuntimeRejectsMissingTemplateDirectory(t *testing.T) {
	redisServer := miniredis.RunT(t)

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Templates.Dir = filepath.Join(t.TempDir(), "missing")
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	_, err := NewRuntime(context.Background(), cfg, testLogger())
	require.Error(t, err)
	require.Contains(t, err.Error(), "template catalog")
}

func TestNewRuntimeRejectsMissingRequiredTemplateFile(t *testing.T) {
	redisServer := miniredis.RunT(t)
	rootDir := t.TempDir()
	require.NoError(t, os.MkdirAll(filepath.Join(rootDir, "auth.login_code", "en"), 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(rootDir, "auth.login_code", "en", "subject.tmpl"), []byte("Subject"), 0o644))

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Templates.Dir = rootDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	_, err := NewRuntime(context.Background(), cfg, testLogger())
	require.Error(t, err)
	require.Contains(t, err.Error(), "text.tmpl")
}

func TestNewRuntimeRejectsBrokenTemplateCatalog(t *testing.T) {
	redisServer := miniredis.RunT(t)
	rootDir := t.TempDir()
	require.NoError(t, os.MkdirAll(filepath.Join(rootDir, "auth.login_code", "en"), 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(rootDir, "auth.login_code", "en", "subject.tmpl"), []byte("Your login code"), 0o644))
	require.NoError(t, os.WriteFile(filepath.Join(rootDir, "auth.login_code", "en", "text.tmpl"), []byte("Code: {{.code}}"), 0o644))
	require.NoError(t, os.MkdirAll(filepath.Join(rootDir, "game.turn.ready", "en"), 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(rootDir, "game.turn.ready", "en", "subject.tmpl"), []byte("{{if .turn_number}"), 0o644))
	require.NoError(t, os.WriteFile(filepath.Join(rootDir, "game.turn.ready", "en", "text.tmpl"), []byte("Turn ready"), 0o644))

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Templates.Dir = rootDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)

	_, err := NewRuntime(context.Background(), cfg, testLogger())
	require.Error(t, err)
	require.Contains(t, err.Error(), "template parse failed")
}

func TestRuntimeRunStopsOnContextCancellation(t *testing.T) {
	redisServer := miniredis.RunT(t)
	templateDir := writeStage6Templates(t)

	truncateRuntimeMail(t)
	cfg := runtimeBaseConfig(t, redisServer.Addr())
	cfg.Templates.Dir = templateDir
	cfg.InternalHTTP.Addr = mustFreeAddr(t)
	cfg.ShutdownTimeout = time.Second

	runtime, err := NewRuntime(context.Background(), cfg, testLogger())
	require.NoError(t, err)
	defer func() {
		require.NoError(t, runtime.Close())
	}()

	runCtx, cancel := context.WithCancel(context.Background())
	done := make(chan error, 1)
	go func() {
		done <- runtime.Run(runCtx)
	}()

	time.Sleep(100 * time.Millisecond)
	cancel()

	require.Eventually(t, func() bool {
		select {
		case err := <-done:
			return err == nil
		default:
			return false
		}
	}, 5*time.Second, 10*time.Millisecond)
}

func writeStage6Templates(t *testing.T) string {
	t.Helper()

	rootDir := t.TempDir()
	templateDir := filepath.Join(rootDir, "auth.login_code", "en")
	require.NoError(t, os.MkdirAll(templateDir, 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(templateDir, "subject.tmpl"), []byte("Your login code"), 0o644))
	require.NoError(t, os.WriteFile(filepath.Join(templateDir, "text.tmpl"), []byte("Code: {{.code}}"), 0o644))

	return rootDir
}

func testLogger() *slog.Logger {
	return slog.New(slog.NewJSONHandler(io.Discard, nil))
}

func mustFreeAddr(t *testing.T) string {
	t.Helper()

	listener, err := net.Listen("tcp", "127.0.0.1:0")
	require.NoError(t, err)
	defer func() {
		require.NoError(t, listener.Close())
	}()

	return listener.Addr().String()
}

var _ = config.SMTPModeStub // keep config import even when no test uses it directly