package store

import (
	"context"
	"fmt"
	"os"
	"testing"
	"time"

	"github.com/loyaly/behavision-server/internal/api"
)

// Live database tests for the arrivals feed.
//
// Skipped unless TEST_DATABASE_URL is set, following the same rule as the
// bucket tests: the suite must stay runnable with no network and no services.
// They exist because the rest of the arrivals suite runs against an in-memory
// fake, and a fake cannot catch what actually goes wrong in this file - a
// keyset comparison Postgres plans differently than expected, a LEFT JOIN
// silently promoted to an inner one by a WHERE clause, a column list that
// drifts between the two directions of the query. Those only fail against a
// real planner.
//
//	docker run -d -p 55432:5432 -e POSTGRES_PASSWORD=test \
//	  -e POSTGRES_DB=behavision pgvector/pgvector:pg16
//	psql < server/migrations/*.sql
//	TEST_DATABASE_URL='postgres://postgres:test@127.0.0.1:55432/behavision' go test ./internal/store/
func liveStore(t *testing.T) *Store {
	t.Helper()
	dsn := os.Getenv("TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("set TEST_DATABASE_URL to run the live store tests")
	}
	st, err := Open(context.Background(), dsn)
	if err != nil {
		t.Fatalf("open: %v", err)
	}
	t.Cleanup(st.Close)
	return st
}

// dropTenant removes a seeded tenant when the test that made it finishes.
//
// Without this these tests are a slow leak. Every one of them seeds its own
// tenant - deliberately, so they can run in any order and so the isolation
// assertions have a real neighbour - and none of them ever removed it. A dev
// database reached 242 abandoned tenants against the single real one, which is
// not merely untidy: the platform admin's Companies screen lists every client,
// so the one real company was buried under pages of `walk1788761685056287000`.
//
// Registered against the CLIENT rather than each table because every foreign
// key onto clients is ON DELETE CASCADE, so one delete takes the sites,
// visitors, visits, face images, embeddings, cameras and agents with it. A
// per-table list would rot the first time a migration adds a table, and it
// would rot silently - which is the shape of the bug it is cleaning up after.
//
// t.Cleanup runs LIFO and liveStore registers st.Close before any seeding, so
// the delete still has a live pool when it runs.
func dropTenant(t *testing.T, st *Store, clientID string) {
	t.Helper()
	t.Cleanup(func() {
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		if _, err := st.pool.Exec(ctx,
			`DELETE FROM clients WHERE id = $1::uuid`, clientID); err != nil {
			// Reported rather than ignored: a tenant left behind is the very
			// thing this exists to prevent, and swallowing the error would let
			// the leak return with nothing to show for it.
			t.Errorf("cleanup tenant %s: %v", clientID, err)
		}
	})
}

// seedTenant builds a client, a site and n visits, and returns the client id.
// Every test gets its own tenant so they can run in any order without a
// truncate between them - and so the isolation assertions below have a real
// neighbour to be isolated from.
func seedTenant(t *testing.T, st *Store, name string, n int, withImages bool) (clientID, siteID string) {
	t.Helper()
	ctx := context.Background()

	err := st.pool.QueryRow(ctx, `
		INSERT INTO clients (name, slug) VALUES ($1, $1) RETURNING id::text`, name).Scan(&clientID)
	if err != nil {
		t.Fatalf("seed client: %v", err)
	}
	dropTenant(t, st, clientID)
	err = st.pool.QueryRow(ctx, `
		INSERT INTO sites (client_id, name, slug) VALUES ($1::uuid, $2, $3)
		RETURNING id::text`, clientID, name+" Main", name+"-main").Scan(&siteID)
	if err != nil {
		t.Fatalf("seed site: %v", err)
	}

	start := time.Date(2026, 9, 2, 10, 0, 0, 0, time.UTC)
	for i := 0; i < n; i++ {
		var visitorID string
		if err := st.pool.QueryRow(ctx, `
			INSERT INTO visitors (client_id, number, label, first_seen_at)
			VALUES ($1::uuid, $2, $3, $4) RETURNING id::text`,
			clientID, i+1, fmt.Sprintf("Visitor %d", i+1), start).Scan(&visitorID); err != nil {
			t.Fatalf("seed visitor: %v", err)
		}
		key := ""
		if withImages {
			key = fmt.Sprintf("behavision/v2/%s/main/2026/09/02/%d.jpg", name, i)
		}
		if _, err := st.pool.Exec(ctx, `
			INSERT INTO visits (client_id, site_id, visitor_id, source_event_id,
			                    occurred_at, camera_id, is_new_visitor,
			                    similarity, quality, image_key)
			VALUES ($1::uuid, $2::uuid, $3::uuid, $4, $5, 'door', $6, 0.71, 0.66, $7)`,
			clientID, siteID, visitorID, fmt.Sprintf("%s-e%d", name, i),
			start.Add(time.Duration(i)*time.Second), i == 0, key); err != nil {
			t.Fatalf("seed visit: %v", err)
		}
	}
	return clientID, siteID
}

func TestLiveArrivalsWalkTheFeedWithoutLosingAnyone(t *testing.T) {
	st := liveStore(t)
	clientID, _ := seedTenant(t, st, "walk"+stamp(), 25, true)
	ctx := context.Background()

	seen := map[string]int{}
	// Position zero: replay from the very beginning. Positions start at 1, so
	// nothing is excluded.
	from := int64(0)
	after := &from

	for poll := 0; poll < 6; poll++ {
		rows, err := st.Arrivals(ctx, api.ArrivalQuery{
			ClientID: clientID, AfterSeq: after, Limit: 10})
		if err != nil {
			t.Fatalf("poll %d: %v", poll, err)
		}
		for _, a := range rows {
			seen[a.VisitID]++
		}
		if len(rows) == 0 {
			break
		}
		last := rows[len(rows)-1].Seq
		after = &last
	}

	if len(seen) != 25 {
		t.Fatalf("saw %d of 25 visits", len(seen))
	}
	for id, n := range seen {
		if n != 1 {
			t.Errorf("visit %s delivered %d times", id, n)
		}
	}
}

// The case the tuple comparison exists for. Four people through a door at once
// share a timestamp to the microsecond; ordering on time alone either repeats
// them forever or skips three of them.
func TestLiveArrivalsPageThroughASimultaneousBurst(t *testing.T) {
	st := liveStore(t)
	name := "burst" + stamp()
	clientID, siteID := seedTenant(t, st, name, 0, false)
	ctx := context.Background()

	at := time.Date(2026, 9, 2, 11, 0, 0, 0, time.UTC)
	for i := 0; i < 4; i++ {
		if _, err := st.pool.Exec(ctx, `
			INSERT INTO visits (client_id, site_id, source_event_id, occurred_at, camera_id)
			VALUES ($1::uuid, $2::uuid, $3, $4, 'door')`,
			clientID, siteID, fmt.Sprintf("%s-b%d", name, i), at); err != nil {
			t.Fatal(err)
		}
	}

	seen := map[string]bool{}
	from := int64(0)
	after := &from
	for poll := 0; poll < 5; poll++ {
		rows, err := st.Arrivals(ctx, api.ArrivalQuery{
			ClientID: clientID, AfterSeq: after, Limit: 2})
		if err != nil {
			t.Fatal(err)
		}
		if len(rows) == 0 {
			break
		}
		for _, a := range rows {
			if seen[a.VisitID] {
				t.Fatalf("visit %s came back twice - the cursor is stuck", a.VisitID)
			}
			seen[a.VisitID] = true
		}
		last := rows[len(rows)-1].Seq
		after = &last
	}
	if len(seen) != 4 {
		t.Fatalf("paged a 4-person burst two at a time and saw %d", len(seen))
	}
}

// One tenant's feed must never contain another's customers. The site filter is
// caller-supplied, so this asks for a site id that exists - and belongs to
// somebody else.
func TestLiveArrivalsCannotReadAnotherTenant(t *testing.T) {
	st := liveStore(t)
	mine, _ := seedTenant(t, st, "mine"+stamp(), 3, false)
	_, theirSite := seedTenant(t, st, "theirs"+stamp(), 3, false)
	ctx := context.Background()

	rows, err := st.Arrivals(ctx, api.ArrivalQuery{
		ClientID: mine, SiteID: theirSite, Limit: 50})
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) != 0 {
		t.Fatalf("read %d visits from another tenant's site", len(rows))
	}
}

// A visit with no visitor_id is a site sending counts without templates. It is
// real footfall by an unknown person and an inner join would delete it from the
// feed while the footfall report still counted it.
func TestLiveArrivalsKeepVisitsWithNoVisitor(t *testing.T) {
	st := liveStore(t)
	name := "anon" + stamp()
	clientID, siteID := seedTenant(t, st, name, 0, false)
	ctx := context.Background()

	if _, err := st.pool.Exec(ctx, `
		INSERT INTO visits (client_id, site_id, source_event_id, occurred_at, camera_id)
		VALUES ($1::uuid, $2::uuid, $3, now(), 'door')`,
		clientID, siteID, name+"-anon"); err != nil {
		t.Fatal(err)
	}
	rows, err := st.Arrivals(ctx, api.ArrivalQuery{ClientID: clientID, Limit: 10})
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) != 1 {
		t.Fatalf("an anonymous visit vanished from the feed (%d rows)", len(rows))
	}
	if rows[0].VisitorID != "" {
		t.Errorf("visitor id should be empty, got %q", rows[0].VisitorID)
	}
}

// An erased customer's visits stay, unlinked - that is the documented erasure
// contract. The feed must still show them, or a shop's live count silently
// drops every time someone exercises their rights.
func TestLiveArrivalsKeepVisitsOfAnErasedCustomer(t *testing.T) {
	st := liveStore(t)
	clientID, _ := seedTenant(t, st, "erased"+stamp(), 2, false)
	ctx := context.Background()

	if _, err := st.pool.Exec(ctx,
		`UPDATE visitors SET deleted_at = now() WHERE client_id = $1::uuid`,
		clientID); err != nil {
		t.Fatal(err)
	}
	rows, err := st.Arrivals(ctx, api.ArrivalQuery{ClientID: clientID, Limit: 10})
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) != 2 {
		t.Fatalf("erasing a customer removed %d visits from the feed", 2-len(rows))
	}
	if rows[0].Label != "" {
		t.Errorf("an erased customer's label leaked into the feed: %q", rows[0].Label)
	}
}

// A profile name must reach the feed, or a shop screen shows "Visitor 12" for
// a regular whose name staff typed in last week.
func TestLiveArrivalsCarryTheProfileName(t *testing.T) {
	st := liveStore(t)
	clientID, _ := seedTenant(t, st, "named"+stamp(), 1, false)
	ctx := context.Background()

	var visitorID string
	if err := st.pool.QueryRow(ctx,
		`SELECT id::text FROM visitors WHERE client_id = $1::uuid`, clientID).
		Scan(&visitorID); err != nil {
		t.Fatal(err)
	}
	if _, err := st.pool.Exec(ctx, `
		INSERT INTO visitor_profiles (client_id, visitor_id, full_name)
		VALUES ($1::uuid, $2::uuid, 'Asha Menon')`, clientID, visitorID); err != nil {
		t.Fatal(err)
	}
	rows, err := st.Arrivals(ctx, api.ArrivalQuery{ClientID: clientID, Limit: 10})
	if err != nil {
		t.Fatal(err)
	}
	if rows[0].Name != "Asha Menon" {
		t.Fatalf("profile name did not reach the feed: %q", rows[0].Name)
	}
	if rows[0].Label == "" {
		t.Error("the system label should travel alongside the typed name")
	}
}

// No cursor means "an app that has just opened": it wants the LAST few
// arrivals, not the first few ever recorded - but still ascending, so the
// caller's cursor handling is identical on every poll.
func TestLiveArrivalsFirstPollIsTheNewestWindowAscending(t *testing.T) {
	st := liveStore(t)
	clientID, _ := seedTenant(t, st, "newest"+stamp(), 12, false)
	ctx := context.Background()

	rows, err := st.Arrivals(ctx, api.ArrivalQuery{ClientID: clientID, Limit: 4})
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) != 4 {
		t.Fatalf("got %d rows", len(rows))
	}
	for i := 1; i < len(rows); i++ {
		if rows[i-1].OccurredAt >= rows[i].OccurredAt {
			t.Fatalf("not ascending at %d", i)
		}
	}
	// Seeded one second apart from 10:00:00, so the newest four start at :08.
	if want := "2026-09-02T10:00:08Z"; rows[0].OccurredAt != want {
		t.Errorf("first poll started at %s, want the newest window at %s",
			rows[0].OccurredAt, want)
	}
}

func TestLiveArrivalsCarryTheImageKeyForPresigning(t *testing.T) {
	st := liveStore(t)
	clientID, _ := seedTenant(t, st, "img"+stamp(), 1, true)

	rows, err := st.Arrivals(context.Background(),
		api.ArrivalQuery{ClientID: clientID, Limit: 10})
	if err != nil {
		t.Fatal(err)
	}
	if rows[0].ImageKey == "" {
		t.Fatal("no image key reached the handler, so no photo can be signed")
	}
	if rows[0].Image.URL != "" {
		t.Error("the store must not presign - it has no bucket and checks nobody")
	}
}

func stamp() string { return fmt.Sprintf("%d", time.Now().UnixNano()) }

// The regression test for the bug that shipped, and was caught only by running
// the real thing against a real broker.
//
// The feed used to be ordered by (occurred_at, id). Four people through one
// door share occurred_at to the microsecond, so the tie-break fell to `id` - a
// RANDOM uuid. A visit that committed AFTER the reader had moved its cursor but
// carried a lower uuid sorted behind that cursor and was never delivered.
// Measured live: four simultaneous visits published, two delivered, and no
// counter anywhere that would show the other two had been dropped.
//
// This reproduces the exact shape: read, move the cursor, THEN insert more rows
// carrying the same occurred_at. Every one of them must still arrive.
func TestLiveArrivalsDeliverLateInsertsThatShareATimestamp(t *testing.T) {
	st := liveStore(t)
	name := "late" + stamp()
	clientID, siteID := seedTenant(t, st, name, 0, false)
	ctx := context.Background()

	// One instant for everybody - this is a single frame of one camera.
	at := time.Date(2026, 9, 2, 12, 0, 0, 0, time.UTC)
	insert := func(tag string) {
		t.Helper()
		if _, err := st.pool.Exec(ctx, `
			INSERT INTO visits (client_id, site_id, source_event_id, occurred_at, camera_id)
			VALUES ($1::uuid, $2::uuid, $3, $4, 'door')`,
			clientID, siteID, name+"-"+tag, at); err != nil {
			t.Fatal(err)
		}
	}

	insert("a")
	insert("b")

	from := int64(0)
	rows, err := st.Arrivals(ctx, api.ArrivalQuery{
		ClientID: clientID, AfterSeq: &from, Limit: 50})
	if err != nil {
		t.Fatal(err)
	}
	if len(rows) != 2 {
		t.Fatalf("first read got %d rows, want 2", len(rows))
	}
	cursor := rows[len(rows)-1].Seq

	// Now two more arrive at the SAME instant, after the cursor has moved.
	// Under the old ordering roughly half of these vanished, depending on how
	// their random uuids happened to sort.
	insert("c")
	insert("d")

	rest, err := st.Arrivals(ctx, api.ArrivalQuery{
		ClientID: clientID, AfterSeq: &cursor, Limit: 50})
	if err != nil {
		t.Fatal(err)
	}
	if len(rest) != 2 {
		t.Fatalf("late inserts sharing a timestamp: got %d of 2 - people are being dropped from the feed",
			len(rest))
	}
}

// Run the same shape many times over. The old bug was probabilistic - it
// depended on how random uuids happened to sort - so a single pass could pass
// by luck. This one cannot.
func TestLiveArrivalsNeverDropAnyoneAcrossManySimultaneousBursts(t *testing.T) {
	st := liveStore(t)
	name := "many" + stamp()
	clientID, siteID := seedTenant(t, st, name, 0, false)
	ctx := context.Background()

	at := time.Date(2026, 9, 2, 13, 0, 0, 0, time.UTC)
	cursor := int64(0)
	delivered := 0

	for round := 0; round < 30; round++ {
		for i := 0; i < 4; i++ {
			if _, err := st.pool.Exec(ctx, `
				INSERT INTO visits (client_id, site_id, source_event_id, occurred_at, camera_id)
				VALUES ($1::uuid, $2::uuid, $3, $4, 'door')`,
				clientID, siteID, fmt.Sprintf("%s-r%d-%d", name, round, i), at); err != nil {
				t.Fatal(err)
			}
		}
		rows, err := st.Arrivals(ctx, api.ArrivalQuery{
			ClientID: clientID, AfterSeq: &cursor, Limit: 50})
		if err != nil {
			t.Fatal(err)
		}
		delivered += len(rows)
		if len(rows) > 0 {
			cursor = rows[len(rows)-1].Seq
		}
	}

	if delivered != 120 {
		t.Fatalf("30 bursts of 4 people delivered %d of 120", delivered)
	}
}