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.Player;
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);
    }

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

    /// <summary>
    /// Build a minimal AppraiseInfo body containing only a CreatureProfile
    /// blob with ShowAttributes (flag 0x08) so stamina + mana fields are
    /// present. Mirrors the wire shape that PlayerDescription (0x0013)
    /// carries for the local player.
    /// </summary>
    private static byte[] MakePlayerDescriptionPayload(
        uint guid, uint health, uint healthMax,
        uint stamina, uint mana, uint staminaMax, uint manaMax)
    {
        // Outer header: u32 guid, u32 outerFlags, u32 success.
        // Outer flags: just CreatureProfile (0x2000).
        // Profile blob: u32 innerFlags, u32 health, u32 healthMax, then 10 u32s
        //   (str/end/quic/coord/focus/self/sta/mana/staMax/manaMax) when 0x08 set.
        const uint outerFlags = 0x0000_2000u;        // CreatureProfile
        const uint innerFlags = 0x08u;                // ShowAttributes

        byte[] body = new byte[12 + 12 + 10 * 4];
        int p = 0;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), guid);              p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), outerFlags);        p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 1u);                p += 4; // success
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), innerFlags);        p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), health);            p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), healthMax);         p += 4;
        // Stub attributes — VM doesn't read these, parser still has to skip them.
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // str
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // end
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // quic
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // coord
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // focus
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), 50u);  p += 4; // self
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), stamina);    p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), mana);       p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), staminaMax); p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), manaMax);    p += 4;
        return body;
    }

    [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);
    }

    [Fact]
    public void WireAll_PlayerDescription_PopulatesLocalPlayerState()
    {
        // Issue #5 — the PlayerDescription (0x0013) opcode shares the
        // AppraiseInfo payload with IdentifyObjectResponse (0x00C9). Now
        // also funnels CreatureProfile.{Stamina, Mana, StaminaMax, ManaMax}
        // into LocalPlayerState so the Vitals HUD can render those bars.
        var (d, _, _, _, _, local) = MakeAllWithLocal();

        byte[] payload = MakePlayerDescriptionPayload(
            guid: 0x5000_000Au,
            health: 100, healthMax: 200,
            stamina: 75, mana: 150, staminaMax: 100, manaMax: 200);

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

        Assert.Equal(75u, local.CurrentStamina);
        Assert.Equal(100u, local.MaxStamina);
        Assert.Equal(150u, local.CurrentMana);
        Assert.Equal(200u, local.MaxMana);
        Assert.Equal(0.75f, local.StaminaPercent!.Value, precision: 3);
        Assert.Equal(0.75f, local.ManaPercent!.Value, precision: 3);
    }

    [Fact]
    public void WireAll_PlayerDescription_NoOp_WhenLocalPlayerStateNotProvided()
    {
        // Back-compat: the original 5-arg overload still works; without a
        // LocalPlayerState reference there's no place to push the parsed
        // CreatureProfile, but the dispatch must not throw.
        var (d, _, _, _, _) = MakeAll();

        byte[] payload = MakePlayerDescriptionPayload(
            guid: 0x5000_000Au,
            health: 100, healthMax: 200,
            stamina: 75, mana: 150, staminaMax: 100, manaMax: 200);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.PlayerDescription, payload));
        d.Dispatch(env!.Value); // must not throw
    }
}