package service

import (
	"context"
	"errors"
	"strings"
	"sync"
	"testing"

	"github.com/stretchr/testify/require"
)

func TestNotificationEmailPreviewEscapesHTMLAndSanitizesSubject(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	preview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{
		Event:   NotificationEmailEventBalanceLow,
		Locale:  "en-US,en;q=0.9",
		Subject: "Low balance for {{recipient_name}}\r\nInjected",
		HTML:    `<p>{{recipient_name}}</p><a href="{{recharge_url}}">Recharge</a>`,
		Variables: map[string]string{
			"recipient_name": `<script>alert("x")</script>`,
			"recharge_url":   `javascript:alert(1)`,
		},
	})
	require.NoError(t, err)
	require.NotContains(t, preview.Subject, "\r")
	require.NotContains(t, preview.Subject, "\n")
	require.Contains(t, preview.Subject, `Low balance for <script>alert("x")</script>Injected`)
	require.Contains(t, preview.HTML, `&lt;script&gt;alert(&#34;x&#34;)&lt;/script&gt;`)
	require.NotContains(t, preview.HTML, `javascript:alert(1)`)
	require.Contains(t, preview.HTML, `href=""`)
}

func TestNotificationEmailTemplateOverrideAndRestore(t *testing.T) {
	ctx := context.Background()
	repo := newNotificationEmailMemorySettingRepo()
	svc := NewNotificationEmailService(repo, nil)

	official, err := svc.GetTemplate(ctx, NotificationEmailEventBalanceRechargeSuccess, "en")
	require.NoError(t, err)
	require.False(t, official.IsCustom)

	updated, err := svc.UpdateTemplate(
		ctx,
		NotificationEmailEventBalanceRechargeSuccess,
		"zh-Hans",
		"充值完成：{{recharge_amount}}",
		"<p>{{recipient_name}} 已充值 {{recharge_amount}}</p>",
	)
	require.NoError(t, err)
	require.True(t, updated.IsCustom)
	require.Equal(t, "zh", updated.Locale)
	require.Equal(t, "充值完成：{{recharge_amount}}", updated.Subject)
	require.NotNil(t, updated.UpdatedAt)

	restored, err := svc.RestoreOfficialTemplate(ctx, NotificationEmailEventBalanceRechargeSuccess, "zh")
	require.NoError(t, err)
	require.False(t, restored.IsCustom)
	require.NotEqual(t, updated.Subject, restored.Subject)
	_, err = repo.GetValue(ctx, notificationEmailTemplateKey(NotificationEmailEventBalanceRechargeSuccess, "zh"))
	require.ErrorIs(t, err, ErrSettingNotFound)
}

func TestNotificationEmailTemplateRejectsUnsupportedPlaceholder(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	_, err := svc.UpdateTemplate(
		ctx,
		NotificationEmailEventSubscriptionPurchaseSuccess,
		"en",
		"Purchased {{not_allowed}}",
		"<p>{{subscription_group}}</p>",
	)
	require.Error(t, err)
	require.Contains(t, err.Error(), "unsupported placeholder")
}

func TestNotificationEmailAuthTemplatesAreListedAndPreviewable(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	infos := svc.ListEventInfos()
	events := make(map[string]NotificationEmailEventInfo, len(infos))
	for _, info := range infos {
		events[info.Event] = info
	}
	require.Contains(t, events, NotificationEmailEventAuthVerifyCode)
	require.Contains(t, events, NotificationEmailEventAuthPasswordReset)
	require.False(t, events[NotificationEmailEventAuthVerifyCode].Optional)
	require.False(t, events[NotificationEmailEventAuthPasswordReset].Optional)
	require.Contains(t, events[NotificationEmailEventAuthVerifyCode].Placeholders, "verification_code")
	require.Contains(t, events[NotificationEmailEventAuthPasswordReset].Placeholders, "reset_url")

	verifyPreview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{
		Event:  NotificationEmailEventAuthVerifyCode,
		Locale: "zh-CN",
		Variables: map[string]string{
			"verification_code":  "654321",
			"expires_in_minutes": "15",
		},
	})
	require.NoError(t, err)
	require.Contains(t, verifyPreview.Subject, "邮箱验证码")
	require.Contains(t, verifyPreview.HTML, "654321")

	resetPreview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{
		Event:  NotificationEmailEventAuthPasswordReset,
		Locale: "en",
		Variables: map[string]string{
			"reset_url":          "https://example.com/reset?token=abc",
			"expires_in_minutes": "30",
		},
	})
	require.NoError(t, err)
	require.Contains(t, resetPreview.Subject, "Password reset")
	require.Contains(t, resetPreview.HTML, "https://example.com/reset?token=abc")
}

func TestNotificationEmailAdditionalEventsAreListedAndPreviewable(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	infos := svc.ListEventInfos()
	events := make(map[string]NotificationEmailEventInfo, len(infos))
	for _, info := range infos {
		events[info.Event] = info
	}

	checks := []struct {
		event       string
		placeholder string
	}{
		{NotificationEmailEventNotificationEmailVerifyCode, "verification_code"},
		{NotificationEmailEventAccountQuotaAlert, "account_name"},
		{NotificationEmailEventContentModerationViolation, "moderation_category"},
		{NotificationEmailEventContentModerationDisabled, "violation_count"},
		{NotificationEmailEventOpsAlert, "rule_name"},
		{NotificationEmailEventOpsScheduledReport, "report_html"},
	}

	for _, check := range checks {
		info, ok := events[check.event]
		require.Truef(t, ok, "expected %s to be listed", check.event)
		require.False(t, info.Optional)
		require.Contains(t, info.Placeholders, check.placeholder)

		preview, err := svc.PreviewTemplate(ctx, NotificationEmailPreviewInput{Event: check.event, Locale: "zh"})
		require.NoError(t, err)
		require.NotEmpty(t, preview.Subject)
		require.NotEmpty(t, preview.HTML)
	}
}

func TestNotificationEmailRawHTMLVariablesAreTrustedOnlyForHTMLPlaceholders(t *testing.T) {
	require.True(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsScheduledReport, "report_html"))
	require.False(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsScheduledReport, "recipient_name"))
	require.False(t, notificationEmailRawHTMLAllowed(NotificationEmailEventOpsAlert, "report_html"))

	preview, err := renderNotificationEmail(
		NotificationEmailEventOpsScheduledReport,
		"Report for {{recipient_name}}",
		`<section>{{report_html}}</section><p>{{recipient_name}}</p>`,
		map[string]string{
			"recipient_name": `<script>alert("x")</script>`,
			"report_html":    `<p>escaped report</p>`,
		},
		map[string]string{
			"report_html": `<table><tr><td>trusted report</td></tr></table>`,
		},
	)
	require.NoError(t, err)
	require.Contains(t, preview.HTML, `<table><tr><td>trusted report</td></tr></table>`)
	require.NotContains(t, preview.HTML, `escaped report`)
	require.Contains(t, preview.HTML, `&lt;script&gt;alert(&#34;x&#34;)&lt;/script&gt;`)
	require.Contains(t, preview.Subject, `<script>alert("x")</script>`)

	preview, err = renderNotificationEmail(
		NotificationEmailEventOpsScheduledReport,
		"Recipient {{recipient_name}}",
		`<p>{{recipient_name}}</p>`,
		map[string]string{"recipient_name": `<em>escaped</em>`},
		map[string]string{"recipient_name": `<strong>raw</strong>`},
	)
	require.NoError(t, err)
	require.Contains(t, preview.HTML, `&lt;em&gt;escaped&lt;/em&gt;`)
	require.NotContains(t, preview.HTML, `<strong>raw</strong>`)
}

func TestNotificationEmailFallbackClassification(t *testing.T) {
	templateErr := notificationEmailTemplateErr(errors.New("bad template"))
	configErr := notificationEmailConfigErr(errors.New("missing email service"))
	deliveryErr := notificationEmailDeliveryErr(errors.New("smtp timeout"))

	require.True(t, shouldFallbackNotificationEmail(templateErr))
	require.True(t, shouldFallbackNotificationEmail(configErr))
	require.False(t, shouldFallbackNotificationEmail(deliveryErr))
	require.True(t, isNotificationEmailDeliveryError(deliveryErr))
	require.False(t, isNotificationEmailDeliveryError(templateErr))
	require.False(t, shouldFallbackNotificationEmail(nil))
}

func TestEmailQueueTasksPreserveLocaleHints(t *testing.T) {
	queue := &EmailQueueService{taskChan: make(chan EmailTask, 2)}
	require.NoError(t, queue.EnqueueVerifyCode("user@example.com", "Sub2API", "zh-CN"))
	require.NoError(t, queue.EnqueuePasswordReset("user@example.com", "Sub2API", "https://example.com/reset", "en-US"))

	verifyTask := <-queue.taskChan
	require.Equal(t, TaskTypeVerifyCode, verifyTask.TaskType)
	require.Equal(t, "zh-CN", verifyTask.Locale)

	resetTask := <-queue.taskChan
	require.Equal(t, TaskTypePasswordReset, resetTask.TaskType)
	require.Equal(t, "en-US", resetTask.Locale)
}

func TestOpsScheduledReportDeliverySourceIDIncludesReportIdentity(t *testing.T) {
	report := &opsScheduledReport{Name: "日报", ReportType: "daily_summary", Schedule: "0 9 * * *"}
	sourceID := opsScheduledReportDeliverySourceID(report)
	require.Contains(t, sourceID, "daily_summary")
	require.Contains(t, sourceID, "日报")
	require.Contains(t, sourceID, "0 9 * * *")
	require.NotEqual(t, sourceID, opsScheduledReportDeliverySourceID(&opsScheduledReport{Name: "周报", ReportType: "weekly_summary", Schedule: "0 9 * * 1"}))
	require.Equal(t, "scheduled_report", opsScheduledReportDeliverySourceID(nil))
}

func TestNotificationEmailUnsubscribeOnlyAllowsOptionalEvents(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	token, err := svc.createUnsubscribeToken(ctx, "User@Example.com", NotificationEmailEventBalanceLow)
	require.NoError(t, err)
	result, err := svc.Unsubscribe(ctx, token)
	require.NoError(t, err)
	require.True(t, result.Done)
	require.Equal(t, NotificationEmailEventBalanceLow, result.Event)
	unsubscribed, err := svc.IsUnsubscribed(ctx, "user@example.com", NotificationEmailEventBalanceLow)
	require.NoError(t, err)
	require.True(t, unsubscribed)

	transactionalToken, err := svc.createUnsubscribeToken(ctx, "user@example.com", NotificationEmailEventBalanceRechargeSuccess)
	require.NoError(t, err)
	_, err = svc.Unsubscribe(ctx, transactionalToken)
	require.Error(t, err)
	require.Contains(t, err.Error(), "transactional")

	authToken, err := svc.createUnsubscribeToken(ctx, "user@example.com", NotificationEmailEventAuthVerifyCode)
	require.NoError(t, err)
	_, err = svc.Unsubscribe(ctx, authToken)
	require.Error(t, err)
	require.Contains(t, err.Error(), "transactional")
}

func TestNotificationEmailLocaleMemoryNormalizesAcceptLanguage(t *testing.T) {
	ctx := context.Background()
	svc := NewNotificationEmailService(newNotificationEmailMemorySettingRepo(), nil)

	svc.RememberRecipientLocale(ctx, 42, "User@Example.com", "zh-CN,zh;q=0.9,en;q=0.8")
	require.Equal(t, "zh", svc.ResolveRecipientLocale(ctx, 42, "user@example.com"))
	require.Equal(t, "zh", svc.ResolveRecipientLocale(ctx, 0, "user@example.com"))
}

type notificationEmailMemorySettingRepo struct {
	mu     sync.RWMutex
	values map[string]string
}

func newNotificationEmailMemorySettingRepo() *notificationEmailMemorySettingRepo {
	return &notificationEmailMemorySettingRepo{values: make(map[string]string)}
}

func (r *notificationEmailMemorySettingRepo) Get(_ context.Context, key string) (*Setting, error) {
	r.mu.RLock()
	defer r.mu.RUnlock()
	value, ok := r.values[key]
	if !ok {
		return nil, ErrSettingNotFound
	}
	return &Setting{Key: key, Value: value}, nil
}

func (r *notificationEmailMemorySettingRepo) GetValue(ctx context.Context, key string) (string, error) {
	setting, err := r.Get(ctx, key)
	if err != nil {
		return "", err
	}
	return setting.Value, nil
}

func (r *notificationEmailMemorySettingRepo) Set(_ context.Context, key, value string) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.values[key] = value
	return nil
}

func (r *notificationEmailMemorySettingRepo) GetMultiple(_ context.Context, keys []string) (map[string]string, error) {
	r.mu.RLock()
	defer r.mu.RUnlock()
	out := make(map[string]string, len(keys))
	for _, key := range keys {
		if value, ok := r.values[key]; ok {
			out[key] = value
		}
	}
	return out, nil
}

func (r *notificationEmailMemorySettingRepo) SetMultiple(_ context.Context, settings map[string]string) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	for key, value := range settings {
		r.values[key] = value
	}
	return nil
}

func (r *notificationEmailMemorySettingRepo) GetAll(_ context.Context) (map[string]string, error) {
	r.mu.RLock()
	defer r.mu.RUnlock()
	out := make(map[string]string, len(r.values))
	for key, value := range r.values {
		out[key] = value
	}
	return out, nil
}

func (r *notificationEmailMemorySettingRepo) Delete(_ context.Context, key string) error {
	r.mu.Lock()
	defer r.mu.Unlock()
	if _, ok := r.values[key]; !ok {
		return ErrSettingNotFound
	}
	delete(r.values, key)
	return nil
}

func TestNotificationEmailMemorySettingRepoSatisfiesInterface(t *testing.T) {
	var _ SettingRepository = (*notificationEmailMemorySettingRepo)(nil)
	require.False(t, strings.Contains(notificationEmailPreferenceKey(NotificationEmailEventBalanceLow, "User@Example.com"), "User@Example.com"))
}