using Xunit;
using ytLive.Models;

namespace ytLive.Tests;

/// <summary>Session-scoped scoreboard tallies. The rules that matter: money is never added across
/// currencies, and a gifted membership is counted ONCE (from the purchase), never again from the
/// recipient's event — that double-count is the easy mistake, and the creator called it out.</summary>
public class ScoreboardStateTests
{
    private static ChatMessage Message(ChatEventKind kind, string author = "viewer", double amount = 0,
        string? currency = "USD", int giftCount = 0, string? display = null) => new()
    {
        Kind = kind, AuthorName = author, SuperChatAmount = amount,
        SuperChatCurrency = currency, GiftNewMembersCount = giftCount, SuperChatDisplayString = display,
    };

    [Fact]
    public void Tallies_follow_the_six_events_and_never_double_count_a_gift()
    {
        var state = new ScoreboardState();

        state.Apply(Message(ChatEventKind.NewMember, "Paid"));
        Assert.Equal(1, state.NewMembers);
        Assert.Equal("Paid", state.LastMemberName);

        // A gift purchase of 5 memberships counts 5...
        state.Apply(Message(ChatEventKind.MemberGift, "Gifter", giftCount: 5));
        Assert.Equal(6, state.NewMembers);
        Assert.Equal(5, state.LastGiftCount);
        Assert.Equal("Gifter", state.LastGifterName);

        // ...and the recipients' own events add NOTHING (they are the same memberships).
        for (var i = 0; i < 5; i++) state.Apply(Message(ChatEventKind.GiftReceived, $"Recipient{i}", giftCount: 1));
        Assert.Equal(6, state.NewMembers);
        Assert.Equal(5, state.LastGiftCount);
        Assert.Equal("Gifter", state.LastGifterName);

        state.Apply(Message(ChatEventKind.MemberMilestone, "Longtimer"));
        Assert.Equal(1, state.MilestoneCount);

        // Super Chat and Super Sticker both carry money; the last one drives the "latest" tile.
        state.Apply(Message(ChatEventKind.SuperChat, "Tipper", 10, "USD", display: "$10.00"));
        state.Apply(Message(ChatEventKind.SuperSticker, "Sticker", 5, "USD"));
        Assert.Equal(15, state.SessionTotal.Total, 3);
        Assert.Equal("USD", state.SessionTotal.Currency);
        Assert.Equal("Sticker", state.LastSuperChatAuthor);
        Assert.False(state.HasMixedCurrencies);

        // A second currency is tracked separately, never summed into the first.
        state.Apply(Message(ChatEventKind.SuperChat, "Euro", 3, "EUR"));
        Assert.Equal(15, state.MoneyByCurrency["USD"], 3);
        Assert.Equal(3, state.MoneyByCurrency["EUR"], 3);
        Assert.True(state.HasMixedCurrencies);
        Assert.Equal("USD", state.SessionTotal.Currency);   // dominant by value, not by recency

        // Plain chat is ignored entirely.
        state.Apply(Message(ChatEventKind.None, "Chatter"));
        Assert.Equal(6, state.NewMembers);
        Assert.Equal(1, state.MilestoneCount);

        // A new session starts clean.
        state.Reset();
        Assert.Equal(0, state.NewMembers);
        Assert.Equal(0, state.SessionTotal.Total);
        Assert.Null(state.LastMemberName);
    }
}