package database_test

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

	"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/globals"
	"sneak.berlin/go/webhooker/internal/logger"
)

// retentionTestEnv bundles the pieces a retention test drives.
type retentionTestEnv struct {
	reaper *database.RetentionReaper
	mainDB *database.Database
	mgr    *database.WebhookDBManager
}

func setupRetentionTest(t *testing.T) *retentionTestEnv {
	t.Helper()

	lc := fxtest.NewLifecycle(t)

	g := &globals.Globals{
		Appname: testAppname,
		Version: testVersion,
	}

	l, err := logger.New(lc, logger.LoggerParams{Globals: g})
	require.NoError(t, err)

	cfg := &config.Config{
		DataDir:     t.TempDir(),
		Environment: "dev",
	}

	mainDB, err := database.New(lc, database.DatabaseParams{
		Config: cfg,
		Logger: l,
	})
	require.NoError(t, err)

	mgr, err := database.NewWebhookDBManager(
		lc,
		database.WebhookDBManagerParams{Config: cfg, Logger: l},
	)
	require.NoError(t, err)

	ctx := context.Background()
	require.NoError(t, lc.Start(ctx))
	t.Cleanup(func() { require.NoError(t, lc.Stop(ctx)) })

	return &retentionTestEnv{
		reaper: database.NewTestRetentionReaper(mainDB, mgr),
		mainDB: mainDB,
		mgr:    mgr,
	}
}

// createWebhook inserts a webhook row into the main database with the
// given retention policy and returns its ID.
func createWebhook(
	t *testing.T,
	db *gorm.DB,
	retentionDays int,
) string {
	t.Helper()

	wh := &database.Webhook{
		UserID:        uuid.New().String(),
		Name:          testWebhookName,
		RetentionDays: retentionDays,
	}
	require.NoError(
		t,
		db.Omit(clause.Associations).Create(wh).Error,
	)

	// Webhook.BeforeSave rewrites a non-positive RetentionDays to the
	// retain-forever sentinel, and the column's GORM default would
	// otherwise substitute 30. Force the requested value with a
	// column-level update so tests can plant legacy rows that predate
	// the sentinel and still carry a literal 0 or negative value.
	require.NoError(
		t,
		db.Model(wh).
			Update("retention_days", retentionDays).Error,
	)

	return wh.ID
}

// createWebhookNormally inserts a webhook through the ordinary Create
// path, with no column-level forcing, so Webhook.BeforeSave applies
// exactly as it does in production. Passing 0 therefore yields a row
// holding the RetentionForeverDays sentinel.
func createWebhookNormally(
	t *testing.T,
	db *gorm.DB,
	retentionDays int,
) string {
	t.Helper()

	wh := &database.Webhook{
		UserID:        uuid.New().String(),
		Name:          testWebhookName,
		RetentionDays: retentionDays,
	}
	require.NoError(
		t,
		db.Omit(clause.Associations).Create(wh).Error,
	)

	return wh.ID
}

// eventChain is the set of row IDs seeded for a single event.
type eventChain struct {
	eventID    string
	deliveryID string
	resultID   string
}

// seedEventChain creates an event with one delivery and one delivery
// result, all stamped with createdAt, and returns their IDs.
func seedEventChain(
	t *testing.T,
	db *gorm.DB,
	webhookID string,
	createdAt time.Time,
) eventChain {
	t.Helper()

	event := &database.Event{
		WebhookID:    webhookID,
		EntrypointID: uuid.New().String(),
		Method:       http.MethodPost,
		Body:         `{"seed": true}`,
		ContentType:  testContentType,
	}
	event.CreatedAt = createdAt
	require.NoError(t, db.Create(event).Error)

	delivery := &database.Delivery{
		EventID:  event.ID,
		TargetID: uuid.New().String(),
		Status:   database.DeliveryStatusDelivered,
	}
	delivery.CreatedAt = createdAt
	require.NoError(t, db.Create(delivery).Error)

	result := &database.DeliveryResult{
		DeliveryID: delivery.ID,
		AttemptNum: 1,
		Success:    true,
		StatusCode: 200,
		Duration:   10,
	}
	result.CreatedAt = createdAt
	require.NoError(t, db.Create(result).Error)

	return eventChain{
		eventID:    event.ID,
		deliveryID: delivery.ID,
		resultID:   result.ID,
	}
}

// countByID returns how many rows of model match the given id,
// counting even hard-deletable rows via Unscoped.
func countByID(
	t *testing.T,
	db *gorm.DB,
	model any,
	id string,
) int64 {
	t.Helper()

	var n int64

	require.NoError(
		t,
		db.Unscoped().Model(model).
			Where("id = ?", id).Count(&n).Error,
	)

	return n
}

func assertChainGone(
	t *testing.T,
	db *gorm.DB,
	chain eventChain,
) {
	t.Helper()

	assert.Zero(
		t,
		countByID(t, db, &database.Event{}, chain.eventID),
		"expired event should be removed",
	)
	assert.Zero(
		t,
		countByID(t, db, &database.Delivery{}, chain.deliveryID),
		"expired delivery should be removed",
	)
	assert.Zero(
		t,
		countByID(
			t, db, &database.DeliveryResult{}, chain.resultID,
		),
		"expired delivery result should be removed",
	)
}

func assertChainPresent(
	t *testing.T,
	db *gorm.DB,
	chain eventChain,
) {
	t.Helper()

	assert.Equal(
		t,
		int64(1),
		countByID(t, db, &database.Event{}, chain.eventID),
		"recent event should be retained",
	)
	assert.Equal(
		t,
		int64(1),
		countByID(t, db, &database.Delivery{}, chain.deliveryID),
		"recent delivery should be retained",
	)
	assert.Equal(
		t,
		int64(1),
		countByID(
			t, db, &database.DeliveryResult{}, chain.resultID,
		),
		"recent delivery result should be retained",
	)
}

func TestRetentionReaper_ReapsExpiredKeepsRecent(t *testing.T) {
	t.Parallel()

	env := setupRetentionTest(t)

	const retentionDays = 30

	webhookID := createWebhook(
		t, env.mainDB.DB(), retentionDays,
	)

	db, err := env.mgr.GetDB(webhookID)
	require.NoError(t, err)

	now := time.Now()
	old := seedEventChain(
		t, db, webhookID,
		now.Add(-40*24*time.Hour),
	)
	recent := seedEventChain(
		t, db, webhookID,
		now.Add(-1*24*time.Hour),
	)

	env.reaper.ExportSweep(context.Background())

	assertChainGone(t, db, old)
	assertChainPresent(t, db, recent)
}

// TestRetentionReaper_SkipsSentinelReapsFiniteInSameSweep covers the
// end-to-end retain-forever path: a webhook created the normal way with
// a requested retention of 0 lands on the RetentionForeverDays
// sentinel, and the reaper leaves its ancient events alone while still
// reaping a finite-retention webhook in the very same sweep.
func TestRetentionReaper_SkipsSentinelReapsFiniteInSameSweep(
	t *testing.T,
) {
	t.Parallel()

	env := setupRetentionTest(t)

	foreverID := createWebhookNormally(t, env.mainDB.DB(), 0)

	var stored database.Webhook

	require.NoError(
		t,
		env.mainDB.DB().Where("id = ?", foreverID).
			First(&stored).Error,
	)
	require.Equal(
		t,
		database.RetentionForeverDays,
		stored.RetentionDays,
		"a requested retention of 0 must persist as the sentinel",
	)

	finiteID := createWebhookNormally(t, env.mainDB.DB(), 30)

	foreverDB, err := env.mgr.GetDB(foreverID)
	require.NoError(t, err)

	finiteDB, err := env.mgr.GetDB(finiteID)
	require.NoError(t, err)

	ancient := time.Now().Add(-365 * 24 * time.Hour)
	kept := seedEventChain(t, foreverDB, foreverID, ancient)
	doomed := seedEventChain(t, finiteDB, finiteID, ancient)

	env.reaper.ExportSweep(context.Background())

	assertChainPresent(t, foreverDB, kept)
	assertChainGone(t, finiteDB, doomed)
}

func TestRetentionReaper_RetainsForeverWhenNonPositive(t *testing.T) {
	t.Parallel()

	env := setupRetentionTest(t)

	// A legacy row written before the sentinel existed still carries a
	// literal 0; the <= 0 guard must keep honouring it.
	webhookID := createWebhook(t, env.mainDB.DB(), 0)

	db, err := env.mgr.GetDB(webhookID)
	require.NoError(t, err)

	ancient := seedEventChain(
		t, db, webhookID,
		time.Now().Add(-365*24*time.Hour),
	)

	env.reaper.ExportSweep(context.Background())

	assertChainPresent(t, db, ancient)
}