package notifications_test

import (
	"context"
	"encoding/json"
	"io"
	"log/slog"
	"os"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/stretchr/testify/require"

	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
	"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
)

func testPool(t *testing.T) *pgxpool.Pool {
	t.Helper()
	if testing.Short() {
		t.Skip("skipping integration test in -short mode")
	}
	dsn := os.Getenv("MINSTREL_TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
	}
	if err := db.Migrate(dsn, slog.New(slog.NewTextHandler(io.Discard, nil))); err != nil {
		t.Fatalf("migrate: %v", err)
	}
	pool, err := pgxpool.New(context.Background(), dsn)
	if err != nil {
		t.Fatalf("pool: %v", err)
	}
	t.Cleanup(pool.Close)
	dbtest.ResetDB(t, pool)
	return pool
}

func mkUser(t *testing.T, q *dbq.Queries, name string, admin bool) pgtype.UUID {
	t.Helper()
	u, err := q.CreateUser(context.Background(), dbq.CreateUserParams{
		Username:     dbtest.TestUserPrefix + name,
		PasswordHash: "x",
		ApiTokenHash: "tok-" + name, // unique per user
		IsAdmin:      admin,
	})
	require.NoError(t, err)
	return u.ID
}

func rowsFor(t *testing.T, q *dbq.Queries, user pgtype.UUID) []dbq.ListNotificationsRow {
	t.Helper()
	rows, err := q.ListNotifications(context.Background(), dbq.ListNotificationsParams{UserID: user, PageLimit: 100})
	require.NoError(t, err)
	return rows
}

func count(t *testing.T, payload []byte) int64 {
	t.Helper()
	var p struct {
		Count int64 `json:"count"`
	}
	require.NoError(t, json.Unmarshal(payload, &p))
	return p.Count
}

func TestNotify_WritesARowAndNudgesOnlyThatUser(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	alice := mkUser(t, q, "alice", false)
	bob := mkUser(t, q, "bob", false)

	bus := eventbus.New()
	events, unsub := bus.Subscribe(8)
	defer unsub()

	n := notifications.New(pool, bus, nil)
	require.NoError(t, n.Notify(ctx, notifications.KindRequestApproved,
		notifications.ToUser(alice), map[string]any{"request_id": "r1", "title": "WWW"}))

	rows := rowsFor(t, q, alice)
	require.Len(t, rows, 1)
	require.Equal(t, "request_approved", rows[0].Kind)
	require.False(t, rows[0].ReadAt.Valid)
	require.JSONEq(t, `{"request_id":"r1","title":"WWW"}`, string(rows[0].Payload))
	require.Empty(t, rowsFor(t, q, bob))

	select {
	case e := <-events:
		require.Equal(t, notifications.EventCreated, e.Kind)
		require.Equal(t, uuid.UUID(alice.Bytes).String(), e.UserID)
		require.Empty(t, e.Data, "the nudge carries no content; the client fetches")
	case <-time.After(time.Second):
		t.Fatal("no nudge published")
	}
}

func TestNotify_AdminKindReachesAdminsOnly_AndNeverTheExcepted(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	requester := mkUser(t, q, "admin-requester", true)
	other := mkUser(t, q, "admin-other", true)
	plain := mkUser(t, q, "plain", false)

	n := notifications.New(pool, nil, nil)
	// A plain user named directly must still get nothing: the kind is admin-only.
	to := notifications.ToAdmins(requester)
	to.Users = []pgtype.UUID{plain}
	require.NoError(t, n.Notify(ctx, notifications.KindRequestPending, to, nil))

	require.Empty(t, rowsFor(t, q, requester), "the admin who filed it needs no notice")
	require.Len(t, rowsFor(t, q, other), 1)
	require.Empty(t, rowsFor(t, q, plain))
}

func TestNotify_CoalescedCountAddsUpWhileUnread_AndStartsAfreshOnceRead(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	admin := mkUser(t, q, "admin", true)
	n := notifications.New(pool, nil, nil)
	to := notifications.ToUser(admin)

	require.NoError(t, n.Notify(ctx, notifications.KindTracksMissing, to, map[string]any{"count": 3}))
	require.NoError(t, n.Notify(ctx, notifications.KindTracksMissing, to, map[string]any{"count": 4}))
	rows := rowsFor(t, q, admin)
	require.Len(t, rows, 1, "a burst is one notification")
	require.Equal(t, int64(7), count(t, rows[0].Payload))

	_, err := q.MarkNotificationRead(ctx, dbq.MarkNotificationReadParams{ID: rows[0].ID, UserID: admin})
	require.NoError(t, err)
	require.NoError(t, n.Notify(ctx, notifications.KindTracksMissing, to, map[string]any{"count": 2}))

	rows = rowsFor(t, q, admin)
	require.Len(t, rows, 2, "after it is read, the next event is new news")
	require.Equal(t, int64(2), count(t, rows[0].Payload))
	require.False(t, rows[0].ReadAt.Valid)
	require.True(t, rows[1].ReadAt.Valid)
}

func TestNotify_CoalescedTotalReplacesWhenEventsStateTheWhole(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	admin := mkUser(t, q, "admin", true)
	n := notifications.New(pool, nil, nil)

	// duplicates_found states the pending total each time; it must not sum.
	require.NoError(t, n.Notify(ctx, notifications.KindDuplicatesFound, notifications.ToUser(admin), map[string]any{"count": 5}))
	require.NoError(t, n.Notify(ctx, notifications.KindDuplicatesFound, notifications.ToUser(admin), map[string]any{"count": 3}))
	rows := rowsFor(t, q, admin)
	require.Len(t, rows, 1)
	require.Equal(t, int64(3), count(t, rows[0].Payload))
}

func TestNotify_RequestKindsNeverCoalesce(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	alice := mkUser(t, q, "alice", false)
	n := notifications.New(pool, nil, nil)
	for _, id := range []string{"r1", "r2"} {
		require.NoError(t, n.Notify(ctx, notifications.KindRequestCompleted, notifications.ToUser(alice), map[string]any{"request_id": id}))
	}
	require.Len(t, rowsFor(t, q, alice), 2)
}

func TestNotify_InboxOffStoresNothing_AndDefaultsApplyWithoutAPref(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	muted := mkUser(t, q, "muted", false)
	fresh := mkUser(t, q, "fresh", false)
	require.NoError(t, q.UpsertNotificationPref(ctx, dbq.UpsertNotificationPrefParams{
		UserID: muted, Kind: "request_rejected", Inbox: false, Phone: true, Email: true,
	}))

	n := notifications.New(pool, nil, nil)
	to := notifications.Recipients{Users: []pgtype.UUID{muted, fresh}}
	require.NoError(t, n.Notify(ctx, notifications.KindRequestRejected, to, nil))

	require.Empty(t, rowsFor(t, q, muted), "inbox off is off, whatever phone and email say")
	require.Len(t, rowsFor(t, q, fresh), 1)
}

func TestMarkRead_ScopedToTheOwner_AndIdempotent(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	alice := mkUser(t, q, "alice", false)
	mallory := mkUser(t, q, "mallory", false)
	n := notifications.New(pool, nil, nil)
	require.NoError(t, n.Notify(ctx, notifications.KindRequestApproved, notifications.ToUser(alice), nil))
	id := rowsFor(t, q, alice)[0].ID

	got, err := q.MarkNotificationRead(ctx, dbq.MarkNotificationReadParams{ID: id, UserID: mallory})
	require.NoError(t, err)
	require.Zero(t, got, "another user's id matches nothing")
	require.False(t, rowsFor(t, q, alice)[0].ReadAt.Valid)

	for i := 0; i < 2; i++ {
		got, err = q.MarkNotificationRead(ctx, dbq.MarkNotificationReadParams{ID: id, UserID: alice})
		require.NoError(t, err)
		require.Equal(t, int64(1), got, "a repeat still matches, so it is not mistaken for 'not yours'")
	}
	unread, err := q.CountUnreadNotifications(ctx, alice)
	require.NoError(t, err)
	require.Zero(t, unread)
}

// Every kind the code knows must pass both CHECKs in the real schema. This is
// rule 36's guard: a kind added in Go without the migration fails here, not in
// production at INSERT time.
func TestEveryKindPassesTheSchemaChecks(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	user := mkUser(t, q, "kinds", true)
	for _, k := range notifications.Kinds() {
		_, err := q.InsertNotification(ctx, dbq.InsertNotificationParams{UserID: user, Kind: string(k), Payload: []byte(`{}`)})
		require.NoError(t, err, "user_notifications rejects %s", k)
		require.NoError(t, q.UpsertNotificationPref(ctx, dbq.UpsertNotificationPrefParams{
			UserID: user, Kind: string(k), Inbox: true, Phone: true, Email: true,
		}), "user_notification_prefs rejects %s", k)
	}
	// And the check is real: an unknown kind is refused.
	_, err := q.InsertNotification(ctx, dbq.InsertNotificationParams{UserID: user, Kind: "bogus", Payload: []byte(`{}`)})
	require.Error(t, err)
}

func TestRetention_TrimsOldReadRowsAndAncientUnreadOnes(t *testing.T) {
	pool := testPool(t)
	q := dbq.New(pool)
	ctx := context.Background()
	user := mkUser(t, q, "retention", false)

	now := time.Now()
	insert := func(created time.Time, read *time.Time) {
		var readAt any
		if read != nil {
			readAt = *read
		}
		_, err := pool.Exec(ctx,
			`INSERT INTO user_notifications (user_id, kind, created_at, read_at) VALUES ($1, 'request_approved', $2, $3)`,
			user, created, readAt)
		require.NoError(t, err)
	}
	day := 24 * time.Hour
	oldRead := now.Add(-100 * day)
	recentRead := now.Add(-10 * day)
	insert(now.Add(-120*day), &oldRead)   // read 100 days ago: goes
	insert(now.Add(-20*day), &recentRead) // read 10 days ago: stays
	insert(now.Add(-400*day), nil)        // unread but over a year old: goes
	insert(now.Add(-200*day), nil)        // unread, 200 days: stays

	r := notifications.NewRetention(pool, slog.New(slog.NewTextHandler(io.Discard, nil)))
	require.Equal(t, int64(2), r.TrimOnce(ctx, now))
	require.Len(t, rowsFor(t, q, user), 2)
}