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);
    }


    [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_PlayerDescription_PopulatesLocalPlayerStateVitals()
    {
        // Issue #5 — the full pipeline: synthetic 0xF7B0 envelope wrapping
        // a PlayerDescription body with Health/Stam/Mana entries, dispatched
        // through WireAll, lands in LocalPlayerState with the right
        // ranks/start/current values.
        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);

        // Body: empty property tables, ATTRIBUTE vector flag, all 9 attrs
        // present. Primary attrs:
        //   Endurance (id=2): ranks=50 + start=150 → current=200
        //   Self      (id=6): ranks=50 + start=50  → current=100
        // Vitals (ranks+start = 0 — typical retail values):
        //   Health  (id=7) cur=90  → MaxApprox = 0 + 200/2 = 100 → percent 0.9
        //   Stamina (id=8) cur=140 → MaxApprox = 0 + 200   = 200 → percent 0.7
        //   Mana    (id=9) cur=50  → MaxApprox = 0 + 100   = 100 → percent 0.5
        byte[] body = new byte[140];
        int p = 0;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p),  0u); p += 4;          // propertyFlags
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p),  0x52u); p += 4;       // weenieType
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p),  0x01u); p += 4;       // vectorFlags = ATTRIBUTE
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p),  1u); p += 4;          // has_health
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p),  0x1FFu); p += 4;      // attribute_flags = Full

        // Primary attrs in order 1..6.
        WritePrimaryAttr(body, ref p, ranks: 0, start: 50, xp: 0);   // 1 Strength
        WritePrimaryAttr(body, ref p, ranks: 50, start: 150, xp: 0); // 2 Endurance — current=200
        WritePrimaryAttr(body, ref p, ranks: 0, start: 50, xp: 0);   // 3 Quickness
        WritePrimaryAttr(body, ref p, ranks: 0, start: 50, xp: 0);   // 4 Coordination
        WritePrimaryAttr(body, ref p, ranks: 0, start: 50, xp: 0);   // 5 Focus
        WritePrimaryAttr(body, ref p, ranks: 50, start: 50, xp: 0);  // 6 Self — current=100
        // Vitals 7/8/9.
        WriteVitalBlock(body, ref p, ranks: 0, start: 0, xp: 0, current: 90);   // Health
        WriteVitalBlock(body, ref p, ranks: 0, start: 0, xp: 0, current: 140);  // Stamina
        WriteVitalBlock(body, ref p, ranks: 0, start: 0, xp: 0, current: 50);   // Mana

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

        var health = local.Get(LocalPlayerState.VitalKind.Health);
        var stam   = local.Get(LocalPlayerState.VitalKind.Stamina);
        var mana   = local.Get(LocalPlayerState.VitalKind.Mana);
        Assert.NotNull(health);
        Assert.NotNull(stam);
        Assert.NotNull(mana);
        Assert.Equal(90u,  health!.Value.Current);
        Assert.Equal(140u, stam!.Value.Current);
        Assert.Equal(50u,  mana!.Value.Current);
        // Primary attrs landed too — formula contributions feed the max.
        Assert.Equal(200u, local.GetAttribute(LocalPlayerState.AttributeKind.Endurance)!.Value.Current);
        Assert.Equal(100u, local.GetAttribute(LocalPlayerState.AttributeKind.Self)!.Value.Current);
        Assert.Equal(0.9f, local.HealthPercent!.Value, precision: 3);
        Assert.Equal(0.7f, local.StaminaPercent!.Value, precision: 3);
        Assert.Equal(0.5f, local.ManaPercent!.Value, precision: 3);
    }

    [Fact]
    public void WireAll_PlayerDescription_FeedsSpellbook()
    {
        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);

        // Body: SPELL vector flag + a spell table with 2 entries.
        var sb = new MemoryStream();
        using var w = new BinaryWriter(sb);
        w.Write(0u);     // propertyFlags
        w.Write(0x52u);  // weenieType
        w.Write(0x100u); // vectorFlags = SPELL only
        w.Write(0u);     // has_health = false
        w.Write((ushort)2);  // spell count
        w.Write((ushort)64); // buckets
        w.Write(0x3E1u); w.Write(2.0f);
        w.Write(0x3E2u); w.Write(2.0f);

        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.PlayerDescription, sb.ToArray()));
        dispatcher.Dispatch(env!.Value);

        Assert.True(spellbook.Knows(0x3E1u));
        Assert.True(spellbook.Knows(0x3E2u));
    }

    private static void WriteVitalBlock(byte[] body, ref int p, uint ranks, uint start, uint xp, uint current)
    {
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), ranks);   p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), start);   p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), xp);      p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), current); p += 4;
    }

    private static void WritePrimaryAttr(byte[] body, ref int p, uint ranks, uint start, uint xp)
    {
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), ranks); p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), start); p += 4;
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(p), xp);    p += 4;
    }

    [Fact]
    public void WireAll_KillerNotification_AppendsCombatLine()
    {
        var (d, _, _, _, chat) = MakeAll();
        byte[] payload = MakeString16L("You killed the drudge!");

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

        Assert.Equal(1, chat.Count);
        var entry = chat.Snapshot()[0];
        Assert.Equal(ChatKind.Combat, entry.Kind);
        Assert.Equal(CombatLineKind.Info, entry.CombatKind);
        Assert.Equal("You killed the drudge!", entry.Text);
    }

    [Fact]
    public void WireAll_CombatCommenceAttack_FiresCombatStateEvent()
    {
        var (d, _, combat, _, _) = MakeAll();
        bool commenced = false;
        combat.AttackCommenced += () => commenced = true;

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

        Assert.True(commenced);
    }

    [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_WeenieError_RoutesToChatLog()
    {
        // Phase I.5: 0x028A previously had a parser
        // (GameEvents.ParseWeenieError) but no dispatcher registration. The
        // server fires this for plain game-logic failures (e.g. "you can't
        // pick that up"). Now wired → ChatLog.OnWeenieError.
        var (d, _, _, _, chat) = MakeAll();

        byte[] payload = new byte[4];
        BinaryPrimitives.WriteUInt32LittleEndian(payload, 0x9C);  // arbitrary error code

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

        Assert.Equal(1, chat.Count);
        var e = chat.Snapshot()[0];
        Assert.Equal(ChatKind.System, e.Kind);
        Assert.Equal(0x9Cu, e.ChannelId);
        Assert.Contains("0x009C", e.Text);
    }

    [Fact]
    public void WireAll_WeenieErrorWithString_RoutesToChatLogWithInterpolation()
    {
        // Phase I.5: 0x028B carries an interpolated substring (e.g. the
        // target's name in "you can't pick up the {Mana Stone}"). Now
        // wired → ChatLog.OnWeenieError with the param.
        var (d, _, _, _, chat) = MakeAll();

        byte[] interpBytes = MakeString16L("Mana Stone");
        byte[] payload = new byte[4 + interpBytes.Length];
        BinaryPrimitives.WriteUInt32LittleEndian(payload, 0x42u);
        Array.Copy(interpBytes, 0, payload, 4, interpBytes.Length);

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

        Assert.Equal(1, chat.Count);
        var e = chat.Snapshot()[0];
        Assert.Equal(ChatKind.System, e.Kind);
        Assert.Equal(0x42u, e.ChannelId);
        Assert.Contains("Mana Stone", e.Text);
    }

}