memby/server/internal/api/home_rows_test.go

package api

import (
	"encoding/json"
	"testing"
	"time"

	"github.com/ponzischeme89/memby/server/internal/recommend"
	"github.com/ponzischeme89/memby/server/internal/store"
)

func TestPersonalizeHomeRowsGraduallyDemotesIgnoredRows(t *testing.T) {
	rows := []recommend.Row{
		{ID: "continue"},
		{ID: "ignored"},
		{ID: "new-row"},
		{ID: "engaged"},
	}
	stats := []store.RowStat{
		{RowID: "ignored", Impressions: 20},
		// Under the five-impression confidence floor, new-row keeps its authored score.
		{RowID: "new-row", Impressions: 4},
		{RowID: "engaged", Impressions: 20, Focuses: 8, Selects: 3, DwellMs: 120_000},
	}

	got := personalizeHomeRows(rows, stats)
	want := []string{"continue", "engaged", "new-row", "ignored"}
	for i, id := range want {
		if got[i].ID != id {
			t.Fatalf("row %d = %q, want %q; rows=%+v", i, got[i].ID, id, got)
		}
	}
}

func TestDifferentHistoriesChangeRowAndPosterOrdering(t *testing.T) {
	now := time.Date(2026, 7, 31, 20, 0, 0, 0, time.UTC)
	item := func(id, name, genre string) recommend.Item {
		raw, _ := json.Marshal(map[string]any{
			"Id": id, "Name": name, "Type": "Movie", "Genres": []string{genre},
			"CommunityRating": 7.0,
		})
		return recommend.Item{
			ID: id, Name: name, Type: "Movie", Genres: []string{genre},
			CommunityRating: 7, Raw: raw,
		}
	}
	dramaA, dramaB := item("drama-a", "Drama A", "Drama"), item("drama-b", "Drama B", "Drama")
	comedyA, comedyB := item("comedy-a", "Comedy A", "Comedy"), item("comedy-b", "Comedy B", "Comedy")
	profileFor := func(genre string) recommend.WeightedProfile {
		return recommend.BuildWeightedProfile([]recommend.ViewingEvidence{
			{Item: item("seen-1", "Seen 1", genre), Completion: 1, OccurredAt: now.Add(-time.Hour)},
			{Item: item("seen-2", "Seen 2", genre), Completion: 1, OccurredAt: now.Add(-2 * time.Hour)},
		}, now, time.UTC)
	}
	pageFor := func(profile recommend.WeightedProfile) []recommend.Row {
		row := func(id string, items []recommend.Item) recommend.Row {
			ranked := recommend.WeightedRank(
				profile, items, nil, recommend.RankIntent{Now: now},
				recommend.DefaultWeightedConfig(), 10,
			)
			raws := make([]json.RawMessage, 0, len(ranked))
			for _, value := range ranked {
				raws = append(raws, recommend.EnrichRankedItem(value))
			}
			return recommend.Row{ID: id, Items: raws}
		}
		return personalizeRowsByTitleScores([]recommend.Row{
			row("drama-row", []recommend.Item{dramaA, dramaB}),
			row("comedy-row", []recommend.Item{comedyA, comedyB}),
			row("mixed-row", []recommend.Item{comedyA, dramaA}),
		})
	}
	dramaPage := pageFor(profileFor("Drama"))
	comedyPage := pageFor(profileFor("Comedy"))
	if dramaPage[0].ID != "drama-row" || comedyPage[0].ID != "comedy-row" {
		t.Fatalf("row orders did not personalize: drama=%s comedy=%s",
			dramaPage[0].ID, comedyPage[0].ID)
	}
	firstMixedID := func(rows []recommend.Row) string {
		for _, row := range rows {
			if row.ID == "mixed-row" {
				return recommend.Decode(row.Items)[0].ID
			}
		}
		return ""
	}
	if firstMixedID(dramaPage) != "drama-a" || firstMixedID(comedyPage) != "comedy-a" {
		t.Fatalf("poster orders did not personalize: drama=%s comedy=%s",
			firstMixedID(dramaPage), firstMixedID(comedyPage))
	}
}

func TestPersonalizeHomeRowsPreservesColdStartDefaults(t *testing.T) {
	rows := []recommend.Row{{ID: "continue"}, {ID: "next-up"}, {ID: "latest"}}
	got := personalizeHomeRows(rows, nil)
	for i := range rows {
		if got[i].ID != rows[i].ID {
			t.Fatalf("cold-start order changed: %+v", got)
		}
	}
}

func TestPreparedHomeRowsPromotesAbandonedShowsAndTimeAwarePicks(t *testing.T) {
	prepared := []recommend.Row{
		{
			ID: "for-you:pick-up", Title: "old pickup title", Kind: "for-you",
			Items: []json.RawMessage{json.RawMessage(`{"Id":"abandoned"}`)},
		},
		{
			ID: "for-you:picks", Title: "old picks title", Kind: "for-you",
			Items: []json.RawMessage{json.RawMessage(`{"Id":"pick"}`)},
		},
		{ID: "for-you:genre:drama", Title: "Drama", Kind: "for-you"},
	}

	rows := preparedHomeForYouRows(prepared, homeForYouWindow{
		ID: "afternoon", Title: "An hour for your afternoon", Minutes: 60,
	})
	if len(rows) != 2 {
		t.Fatalf("home For You rows = %+v", rows)
	}
	if rows[0].ID != "for-you:pick-up" ||
		rows[0].Title != "Pick this show up again" {
		t.Fatalf("pickup row = %+v", rows[0])
	}
	if rows[1].ID != "for-you:home:afternoon" ||
		rows[1].Title != "An hour for your afternoon" {
		t.Fatalf("time-aware row = %+v", rows[1])
	}
}