package growthreport

import (
	"testing"
	"time"

	"git.amiirkhl.ir/starcoach-hackathon/zarinpal-analytics-backend/internal/growth"
)

func TestUpcomingEventsKeepsFiveChronologicalEligibleCandidates(t *testing.T) {
	t.Parallel()
	start := time.Date(2026, time.August, 22, 0, 0, 0, 0, time.UTC)
	catalog := []growth.Event{
		{ID: "past", TitleFA: "رویداد گذشته", StartDate: start.AddDate(0, 0, -1)},
		{ID: "one", TitleFA: "رویداد اول", StartDate: start},
		{ID: "two", TitleFA: "رویداد دوم", StartDate: start.AddDate(0, 0, 40)},
		{ID: "three", TitleFA: "رویداد سوم", StartDate: start.AddDate(0, 0, 100)},
		{ID: "four", TitleFA: "رویداد چهارم", StartDate: start.AddDate(0, 0, 190)},
		{ID: "five", TitleFA: "رویداد پنجم", StartDate: start.AddDate(0, 0, 280), OfficialHoliday: true},
		{ID: "six", TitleFA: "رویداد ششم", StartDate: start.AddDate(0, 0, 320)},
	}

	got := upcomingEvents(catalog, start, 5)
	if len(got) != 5 {
		t.Fatalf("upcomingEvents() returned %d events, want 5", len(got))
	}
	for index, want := range []string{"event:one", "event:two", "event:three", "event:four", "event:five"} {
		if got[index].EvidenceID != want {
			t.Fatalf("upcomingEvents()[%d] = %q, want %q", index, got[index].EvidenceID, want)
		}
	}
	if !got[4].OfficialHoliday {
		t.Fatal("eligible official holiday was removed from the candidate set")
	}
}

func TestFallbackEventRecommendationsUseTheFirstThreeCandidates(t *testing.T) {
	t.Parallel()
	events := []UpcomingEvent{{EvidenceID: "event:first"}, {EvidenceID: "event:second"}, {EvidenceID: "event:third"}, {EvidenceID: "event:fourth"}}
	got := fallbackEventRecommendations(events)
	if len(got) != 3 || got[0].EvidenceID != "event:first" || got[2].EvidenceID != "event:third" {
		t.Fatalf("fallbackEventRecommendations() = %+v", got)
	}
	for _, item := range got {
		if item.RelevanceReason == "" {
			t.Fatal("fallback recommendation lacks a relevance reason")
		}
	}
}