using System.Buffers.Binary;
using AcDream.Core.Net.Messages;
using Xunit;

namespace AcDream.Core.Net.Tests.Messages;

/// <summary>
/// Campaign FA slice FA1 (2026-08-11), D6: completes Core.Net's typed
/// representation of the shared confirmation triple
/// (<c>0x0274</c>/<c>0x0275</c>/<c>0x0276</c>). Grepping the tree before
/// this slice showed <c>0x0274</c> (<see cref="GameEvents.ParseCharacterConfirmationRequest"/>)
/// and <c>0x0276</c> (<see cref="GameEvents.ParseCharacterConfirmationDone"/>)
/// already had typed record + parser pairs; <c>0x0275</c> — the CLIENT→
/// SERVER leg — already had a byte-correct builder
/// (<c>ClientCommandRequests.BuildConfirmationResponse</c>, lane C §3.3)
/// but no typed record, no <see cref="GameEvents.ConfirmationType"/>
/// enum, and no parser. This file pins the completed triple: the new
/// <see cref="GameEvents.ConfirmationType"/> enum (1 = SwearAllegiance,
/// 4 = Fellowship — D6), and <see cref="GameEvents.ParseConfirmationResponse"/>
/// round-tripping against the EXISTING builder byte-for-byte.
/// </summary>
public sealed class ConfirmationTripleTests
{
    [Fact]
    public void ConfirmationType_SwearAllegianceIsOne_FellowshipIsFour()
    {
        // Handle_Character__ConfirmationRequest @0x005640A0 switch vs ACE
        // ConfirmationType.cs:5-12 — identical (lane B §3.15).
        Assert.Equal(1u, (uint)GameEvents.ConfirmationType.SwearAllegiance);
        Assert.Equal(4u, (uint)GameEvents.ConfirmationType.Fellowship);
    }

    [Fact]
    public void ParseConfirmationResponse_RoundTripsAgainstExistingBuilder()
    {
        byte[] wire = ClientCommandRequests.BuildConfirmationResponse(
            sequence: 5,
            confirmationType: (uint)GameEvents.ConfirmationType.Fellowship,
            contextId: 0x1234u,
            accepted: true);

        // Strip the 12-byte envelope/seq/opcode header the same way every
        // other GameEvents.Parse* function receives its payload (header
        // already stripped by the dispatcher) — here we strip the GameACTION
        // header by hand since BuildConfirmationResponse is a C→S builder.
        var response = GameEvents.ParseConfirmationResponse(wire.AsSpan(12));

        Assert.NotNull(response);
        Assert.Equal(GameEvents.ConfirmationType.Fellowship, response.Value.Type);
        Assert.Equal(0x1234u, response.Value.ContextId);
        Assert.True(response.Value.Accepted);
    }

    [Fact]
    public void ParseConfirmationResponse_GoldenByteVector_SwearAllegianceDeclined()
    {
        // Hand-computed from CM_Character::Event_ConfirmationResponse
        // @0x006A1210 (lane B §3.15 / lane C §3.3):
        // [u32 confirmType][u32 context][u32 accepted].
        byte[] payload =
        [
            0x01, 0x00, 0x00, 0x00, // confirmType = 1 (SwearAllegiance)
            0x99, 0x00, 0x00, 0x00, // context = 0x99
            0x00, 0x00, 0x00, 0x00, // accepted = 0 (declined)
        ];

        var response = GameEvents.ParseConfirmationResponse(payload);

        Assert.NotNull(response);
        Assert.Equal(GameEvents.ConfirmationType.SwearAllegiance, response.Value.Type);
        Assert.Equal(0x99u, response.Value.ContextId);
        Assert.False(response.Value.Accepted);
    }

    [Fact]
    public void ParseConfirmationResponse_TruncatedPayload_ReturnsNull()
    {
        Assert.Null(GameEvents.ParseConfirmationResponse(new byte[8]));
    }
}