package handlers_test

import (
	"context"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/go-chi/chi"
	"github.com/google/uuid"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/fx/fxtest"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
	"sneak.berlin/go/webhooker/internal/config"
	"sneak.berlin/go/webhooker/internal/database"
	"sneak.berlin/go/webhooker/internal/handlers"
	"sneak.berlin/go/webhooker/internal/logger"
	"sneak.berlin/go/webhooker/internal/session"
)

// statsReceive posts one event to an entrypoint through the real
// receiver.
func statsReceive(t *testing.T, h *handlers.Handlers, path string) {
	t.Helper()

	req := httptest.NewRequestWithContext(
		context.Background(), http.MethodPost, "/",
		strings.NewReader(`{"stats":true}`),
	)

	rctx := chi.NewRouteContext()
	rctx.URLParams.Add("uuid", path)

	req = req.WithContext(context.WithValue(
		req.Context(), chi.RouteCtxKey, rctx,
	))

	w := httptest.NewRecorder()
	h.HandleWebhook().ServeHTTP(w, req)

	require.Equal(t, http.StatusOK, w.Code)
}

// statsEntrypoint adds an entrypoint to a webhook and returns its path.
func statsEntrypoint(
	t *testing.T, db *database.Database, webhookID string, active bool,
) string {
	t.Helper()

	ep := &database.Entrypoint{
		WebhookID: webhookID,
		Path:      uuid.New().String(),
	}

	require.NoError(t, db.DB().Omit(clause.Associations).Create(ep).Error)
	require.NoError(t, db.DB().Model(ep).Update("active", active).Error)

	return ep.Path
}

// statsDelivery returns the id of an event's delivery to a target.
func statsDelivery(
	t *testing.T, webhookDB *gorm.DB, eventID, targetID string,
) string {
	t.Helper()

	var d database.Delivery

	require.NoError(t, webhookDB.Where(
		"event_id = ? AND target_id = ?", eventID, targetID,
	).First(&d).Error)

	return d.ID
}

// statsFinish settles a delivery as the delivery engine does: its
// final status and the time it finished, and for a failure one more on
// the webhook's failure total, in one transaction.
func statsFinish(
	t *testing.T,
	webhookDB *gorm.DB,
	deliveryID string,
	status database.DeliveryStatus,
	at time.Time,
) {
	t.Helper()

	require.NoError(t, webhookDB.Transaction(func(tx *gorm.DB) error {
		err := tx.Model(&database.Delivery{}).
			Where("id = ?", deliveryID).
			Updates(map[string]any{"status": status, "finished_at": at}).
			Error
		if err != nil || status != database.DeliveryStatusFailed {
			return err
		}

		return database.AddTotals(tx, database.Totals{Failures: 1})
	}))
}

// statsAge moves an event's arrival back to the given time.
func statsAge(
	t *testing.T, webhookDB *gorm.DB, eventID string, at time.Time,
) {
	t.Helper()

	require.NoError(t, webhookDB.Model(&database.Event{}).
		Where("id = ?", eventID).
		Update("created_at", at).Error)
}

// statsPrune runs the real retention reaper until it has removed one
// event from the webhook's database, then stops it.
func statsPrune(
	t *testing.T,
	db *database.Database,
	dbMgr *database.WebhookDBManager,
	log *logger.Logger,
	webhookDB *gorm.DB,
) {
	t.Helper()

	lc := fxtest.NewLifecycle(t)
	database.NewRetentionReaper(lc, database.RetentionReaperParams{
		Config: &config.Config{
			RetentionSweepInterval: 10 * time.Millisecond,
		},
		Database:  db,
		DBManager: dbMgr,
		Logger:    log,
	})

	lc.RequireStart()

	require.Eventually(t, func() bool {
		var totals database.Totals

		err := webhookDB.Take(&totals).Error

		return err == nil && totals.EventsRemoved == 1
	}, 10*time.Second, 10*time.Millisecond)

	lc.RequireStop()
}

// assertStatsTotals checks the lifetime events, deliveries and
// failures, and those within retention.
func assertStatsTotals(
	t *testing.T, totals database.Totals, lifetime, within [3]int64,
) {
	t.Helper()

	assert.Equal(t, lifetime, [3]int64{
		totals.Events, totals.Deliveries, totals.Failures,
	}, "lifetime events, deliveries, failures")
	assert.Equal(t, within, [3]int64{
		totals.EventsWithinRetention(),
		totals.DeliveriesWithinRetention(),
		totals.FailuresWithinRetention(),
	}, "events, deliveries, failures within retention")
}

// TestWebhookStats_EveryFigureAcrossRetentionPrune builds a webhook's
// history through the receiver and a replay, settles its deliveries as
// the delivery engine would, and checks every figure the statistics
// pane shows, before and after the real retention reaper removes the
// oldest event.
func TestWebhookStats_EveryFigureAcrossRetentionPrune(t *testing.T) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
		log   *logger.Logger
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr, &log)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	wh := &database.Webhook{
		UserID: deleteTestUserID, Name: "stats", RetentionDays: 1,
	}
	require.NoError(t, db.DB().Omit(clause.Associations).Create(wh).Error)

	path := statsEntrypoint(t, db, wh.ID, true)
	statsEntrypoint(t, db, wh.ID, false)

	first := seedConfiguredTarget(
		t, db, wh.ID, database.TargetTypeHTTP,
		`{"url":"`+replayTargetURL+`"}`,
	)
	second := seedTarget(t, db, wh.ID, database.TargetTypeLog)
	inactive := seedTarget(t, db, wh.ID, database.TargetTypeLog)
	require.NoError(t, db.DB().Model(inactive).
		Update("active", false).Error)

	// Three events, each delivered to the two active targets.
	for range 3 {
		statsReceive(t, h, path)
	}

	webhookDB, err := dbMgr.GetDB(wh.ID)
	require.NoError(t, err)

	events := listEvents(t, webhookDB)
	require.Len(t, events, 3)

	oldest, middle, newest := events[0], events[1], events[2]
	now := time.Now()

	// The oldest is past the webhook's one day of retention.
	statsAge(t, webhookDB, oldest.ID, now.Add(-50*time.Hour))
	statsAge(t, webhookDB, middle.ID, now.Add(-6*time.Hour))

	oldestFailure := statsDelivery(t, webhookDB, oldest.ID, first.ID)
	statsFinish(t, webhookDB, oldestFailure,
		database.DeliveryStatusFailed, now.Add(-49*time.Hour))
	statsFinish(t, webhookDB,
		statsDelivery(t, webhookDB, oldest.ID, second.ID),
		database.DeliveryStatusDelivered, now.Add(-49*time.Hour))
	statsFinish(t, webhookDB,
		statsDelivery(t, webhookDB, middle.ID, first.ID),
		database.DeliveryStatusFailed, now.Add(-5*time.Hour))
	statsFinish(t, webhookDB,
		statsDelivery(t, webhookDB, middle.ID, second.ID),
		database.DeliveryStatusFailed, now.Add(-time.Minute))
	statsFinish(t, webhookDB,
		statsDelivery(t, webhookDB, newest.ID, first.ID),
		database.DeliveryStatusDelivered, now.Add(-2*time.Minute))

	// A replay adds a delivery, still pending, to the oldest event.
	require.Equal(t, http.StatusSeeOther,
		postReplay(t, h, sess, wh.ID, oldestFailure).Code)

	stats := h.WebhookStatsForTest(wh.ID)
	require.NotNil(t, stats)

	assert.Equal(t, 2, stats.Entrypoints)
	assert.Equal(t, 1, stats.ActiveEntrypoints)
	assert.Equal(t, 3, stats.Targets)
	assert.Equal(t, 2, stats.ActiveTargets)
	assertStatsTotals(t, stats.Totals, [3]int64{3, 7, 3}, [3]int64{3, 7, 3})
	assert.Equal(t, int64(2), stats.InProgress)
	require.NotNil(t, stats.LastEventAt)
	assert.True(t, newest.CreatedAt.Equal(*stats.LastEventAt))
	assert.Equal(t, handlers.RecentWindow{
		Events: 1, Delivered: 1, Failed: 1,
	}, stats.Last10Minutes)
	assert.Equal(t, handlers.RecentWindow{
		Events: 2, Delivered: 1, Failed: 2,
	}, stats.Last24Hours)
	assert.Equal(t, "50.0%", stats.Last10Minutes.FailurePercent())
	assert.Equal(t, "66.7%", stats.Last24Hours.FailurePercent())

	// Retention removes the oldest event with its three deliveries,
	// one of them failed and one the pending replay.
	statsPrune(t, db, dbMgr, log, webhookDB)

	after := h.WebhookStatsForTest(wh.ID)
	require.NotNil(t, after)

	assertStatsTotals(t, after.Totals, [3]int64{3, 7, 3}, [3]int64{2, 4, 2})
	assert.Equal(t, int64(1), after.InProgress)
	assert.Equal(t, stats.LastEventAt, after.LastEventAt)
	assert.Equal(t, stats.Last10Minutes, after.Last10Minutes)
	assert.Equal(t, stats.Last24Hours, after.Last24Hours)

	body := renderSourceDetailPage(t, h, sess, wh.ID)
	assert.Contains(t, body, "Statistics")
	assert.Contains(t, body, "Within retention (1 day)")
	assert.Contains(t, body, "50.0%")
	assert.Contains(t, body, "66.7%")
}

// TestWebhookStats_WebhookWithNoEvents covers a webhook whose event
// database has never been opened: every count is zero, the
// percentages are a dash, and showing the page does not create the
// database.
func TestWebhookStats_WebhookWithNoEvents(t *testing.T) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)

	assert.Equal(t, &handlers.WebhookStats{}, h.WebhookStatsForTest(wh.ID))
	assert.Equal(t, "—", handlers.RecentWindow{}.FailurePercent())

	body := renderSourceDetailPage(t, h, sess, wh.ID)
	assert.Contains(t, body, "Statistics")
	assert.False(t, dbMgr.DBExists(wh.ID))
}

// TestRecentWindow_FailurePercent pins the percentage: failed
// deliveries out of all that finished in the window.
func TestRecentWindow_FailurePercent(t *testing.T) {
	t.Parallel()

	tests := []struct {
		window handlers.RecentWindow
		want   string
	}{
		{handlers.RecentWindow{}, "—"},
		{handlers.RecentWindow{Events: 4}, "—"},
		{handlers.RecentWindow{Delivered: 3, Failed: 1}, "25.0%"},
		{handlers.RecentWindow{Failed: 2}, "100.0%"},
		{handlers.RecentWindow{Delivered: 2}, "0.0%"},
	}

	for _, tt := range tests {
		assert.Equal(t, tt.want, tt.window.FailurePercent(), tt.window)
	}
}