using System;
using System.Buffers.Binary;
using System.Text;
using AcDream.Core.Chat;
using AcDream.Core.Combat;
using AcDream.Core.Items;
using AcDream.Core.Net;
using AcDream.Core.Net.Messages;
using AcDream.Core.Spells;
using Xunit;

namespace AcDream.Core.Net.Tests;

public sealed class GameEventWiringTests
{
    private static byte[] MakeString16L(string s)
    {
        byte[] data = Encoding.ASCII.GetBytes(s);
        int recordSize = 2 + data.Length;
        int padding = (4 - (recordSize & 3)) & 3;
        byte[] result = new byte[recordSize + padding];
        BinaryPrimitives.WriteUInt16LittleEndian(result, (ushort)data.Length);
        Array.Copy(data, 0, result, 2, data.Length);
        return result;
    }

    private static byte[] WrapEnvelope(GameEventType type, byte[] payload)
    {
        byte[] body = new byte[GameEventEnvelope.HeaderSize + payload.Length];
        BinaryPrimitives.WriteUInt32LittleEndian(body,             GameEventEnvelope.Opcode);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(4),   0u);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(8),   0u);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(12),  (uint)type);
        Array.Copy(payload, 0, body, GameEventEnvelope.HeaderSize, payload.Length);
        return body;
    }

    private static (GameEventDispatcher, ItemRepository, CombatState, Spellbook, ChatLog) MakeAll()
    {
        var dispatcher = new GameEventDispatcher();
        var items = new ItemRepository();
        var combat = new CombatState();
        var spellbook = new Spellbook();
        var chat = new ChatLog();
        GameEventWiring.WireAll(dispatcher, items, combat, spellbook, chat);
        return (dispatcher, items, combat, spellbook, chat);
    }

    [Fact]
    public void WireAll_ChannelBroadcast_RoutesToChatLog()
    {
        var (d, _, _, _, chat) = MakeAll();

        byte[] payload = new byte[4 + MakeString16L("Alice").Length + MakeString16L("hi").Length];
        BinaryPrimitives.WriteUInt32LittleEndian(payload, 42);
        int p = 4;
        var senderBytes = MakeString16L("Alice");
        Array.Copy(senderBytes, 0, payload, p, senderBytes.Length); p += senderBytes.Length;
        var msgBytes = MakeString16L("hi");
        Array.Copy(msgBytes, 0, payload, p, msgBytes.Length);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.ChannelBroadcast, payload));
        d.Dispatch(env!.Value);

        Assert.Equal(1, chat.Count);
        var entry = chat.Snapshot()[0];
        Assert.Equal(ChatKind.Channel, entry.Kind);
        Assert.Equal("Alice", entry.Sender);
    }

    [Fact]
    public void WireAll_UpdateHealth_RoutesToCombatState()
    {
        var (d, _, combat, _, _) = MakeAll();

        byte[] payload = new byte[8];
        BinaryPrimitives.WriteUInt32LittleEndian(payload,           0xCAFE);
        BinaryPrimitives.WriteSingleLittleEndian(payload.AsSpan(4), 0.42f);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.UpdateHealth, payload));
        d.Dispatch(env!.Value);

        Assert.Equal(0.42f, combat.GetHealthPercent(0xCAFE), 4);
    }

    [Fact]
    public void WireAll_MagicUpdateSpell_RoutesToSpellbook()
    {
        var (d, _, _, book, _) = MakeAll();

        byte[] payload = new byte[4];
        BinaryPrimitives.WriteUInt32LittleEndian(payload, 0x3E1);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.MagicUpdateSpell, payload));
        d.Dispatch(env!.Value);

        Assert.True(book.Knows(0x3E1));
    }

    [Fact]
    public void WireAll_WieldObject_RoutesToItemRepository()
    {
        var (d, items, _, _, _) = MakeAll();
        items.AddOrUpdate(new ItemInstance { ObjectId = 0x1000, WeenieClassId = 1 });

        byte[] payload = new byte[12];
        BinaryPrimitives.WriteUInt32LittleEndian(payload,            0x1000);
        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(4),  (uint)EquipMask.MeleeWeapon);
        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(8),  0x2000);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.WieldObject, payload));
        d.Dispatch(env!.Value);

        var item = items.GetItem(0x1000);
        Assert.NotNull(item);
        Assert.Equal(EquipMask.MeleeWeapon, item!.CurrentlyEquippedLocation);
        Assert.Equal(0x2000u, item.ContainerId);
    }

    [Fact]
    public void WireAll_PopupString_RoutesToChatLog()
    {
        var (d, _, _, _, chat) = MakeAll();

        byte[] payload = MakeString16L("A modal message");
        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.PopupString, payload));
        d.Dispatch(env!.Value);

        Assert.Equal(1, chat.Count);
        Assert.Equal(ChatKind.Popup, chat.Snapshot()[0].Kind);
    }

    [Fact]
    public void WireAll_MagicPurgeEnchantments_CallsOnPurgeAll()
    {
        var (d, _, _, book, _) = MakeAll();
        book.OnEnchantmentAdded(1, 1, 100f, 0);
        book.OnEnchantmentAdded(2, 2, 100f, 0);
        Assert.Equal(2, book.ActiveCount);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.MagicPurgeEnchantments, Array.Empty<byte>()));
        d.Dispatch(env!.Value);

        Assert.Equal(0, book.ActiveCount);
    }
}