using AcDream.Core.Chat;
using AcDream.UI.Abstractions.Panels.Chat;

namespace AcDream.UI.Abstractions.Tests;

public sealed class ChatVMTests
{
    [Fact]
    public void RecentLines_ReturnsEmpty_ForEmptyLog()
    {
        var log = new ChatLog();
        var vm = new ChatVM(log);

        Assert.Empty(vm.RecentLines());
    }

    [Fact]
    public void RecentLines_ReturnsAllEntries_WhenBelowLimit()
    {
        var log = new ChatLog();
        log.OnLocalSpeech(sender: "Caith", text: "hello", senderGuid: 0x5000_0001u, isRanged: false);
        log.OnLocalSpeech(sender: "Regal", text: "world", senderGuid: 0x5000_0002u, isRanged: false);

        var vm = new ChatVM(log, displayLimit: 20);
        var lines = vm.RecentLines();

        Assert.Equal(2, lines.Count);
        Assert.Equal("Caith: hello", lines[0]);
        Assert.Equal("Regal: world", lines[1]);
    }

    [Fact]
    public void RecentLines_ReturnsTail_WhenAboveLimit_InOldestFirstOrder()
    {
        var log = new ChatLog();
        for (int i = 0; i < 30; i++)
            log.OnLocalSpeech(sender: "A", text: $"msg{i}", senderGuid: 0x5000_0001u, isRanged: false);

        var vm = new ChatVM(log, displayLimit: 5);
        var lines = vm.RecentLines();

        // Tail = msg25..msg29 (5 entries, oldest first).
        Assert.Equal(5, lines.Count);
        Assert.Equal("A: msg25", lines[0]);
        Assert.Equal("A: msg29", lines[4]);
    }

    [Fact]
    public void FormatEntry_LocalSpeech_SenderColonText()
    {
        var entry = new ChatEntry(ChatKind.LocalSpeech, "Caith", "hello", 0x5000_0001u, 0);
        Assert.Equal("Caith: hello", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void FormatEntry_RangedSpeech_IncludesDistanceHint()
    {
        var entry = new ChatEntry(ChatKind.RangedSpeech, "Caith", "hello", 0x5000_0001u, 0);
        Assert.Equal("Caith says distantly: hello", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void FormatEntry_Channel_IncludesChannelId()
    {
        var entry = new ChatEntry(ChatKind.Channel, "Caith", "g'day", 0x5000_0001u, 7u);
        Assert.Equal("[ch 7] Caith: g'day", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void FormatEntry_Tell_PrefixedWithTellTag()
    {
        var entry = new ChatEntry(ChatKind.Tell, "Regal", "psst", 0x5000_0002u, 0);
        Assert.Equal("[Tell] Regal: psst", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void FormatEntry_System_NoSenderShown()
    {
        var entry = new ChatEntry(ChatKind.System, Sender: "", "Your spell fizzled!", 0, 0);
        Assert.Equal("[System] Your spell fizzled!", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void FormatEntry_Popup_Prefixed()
    {
        var entry = new ChatEntry(ChatKind.Popup, Sender: "", "A door stands before you.", 0, 0);
        Assert.Equal("[Popup] A door stands before you.", ChatVM.FormatEntry(entry));
    }

    [Fact]
    public void Constructor_ThrowsOnNullLog()
    {
        Assert.Throws<ArgumentNullException>(() => new ChatVM(null!));
    }

    [Fact]
    public void Constructor_ThrowsOnZeroOrNegativeLimit()
    {
        var log = new ChatLog();
        Assert.Throws<ArgumentOutOfRangeException>(() => new ChatVM(log, displayLimit: 0));
        Assert.Throws<ArgumentOutOfRangeException>(() => new ChatVM(log, displayLimit: -1));
    }

    [Fact]
    public void RecentLines_ReturnsNewLineData_AfterSubsequentAppend()
    {
        // Confirm the VM isn't caching — each call re-snapshots the log.
        var log = new ChatLog();
        var vm = new ChatVM(log);

        Assert.Empty(vm.RecentLines());

        log.OnLocalSpeech("Caith", "hello", 0x5000_0001u, false);
        var after = vm.RecentLines();
        Assert.Single(after);
        Assert.Equal("Caith: hello", after[0]);
    }
}