package app

import (
	"testing"
	"time"
)

func TestDeduplicateJoinLeaveEventsIgnoresRepeatedReplays(t *testing.T) {
	at := time.Date(2026, 7, 1, 1, 23, 45, 0, time.FixedZone("JST", 9*60*60))
	events := []JoinLeaveEvent{
		{At: at, Kind: "join", Name: "Alice", Count: 10},
		{At: at, Kind: "join", Name: "Alice", Count: 11},
		{At: at.Add(5 * time.Second), Kind: "leave", Name: "Alice", Count: 9},
	}

	got := dedupeJoinLeaveEvents(events)
	if len(got) != 2 {
		t.Fatalf("expected 2 unique events, got %d: %#v", len(got), got)
	}
	if got[0].Count != 10 {
		t.Fatalf("expected first event to remain stable, got %#v", got[0])
	}
	if got[1].Kind != "leave" {
		t.Fatalf("expected leave event to remain, got %#v", got[1])
	}
}