acdream/src/AcDream.Core/Items/ItemInstance.cs

using System;
using System.Collections.Generic;

namespace AcDream.Core.Items;

// ─────────────────────────────────────────────────────────────────────
// Scaffold for R6 — items + inventory data model.
// Full research: docs/research/deepdives/r06-items-inventory.md
// ─────────────────────────────────────────────────────────────────────

/// <summary>
/// AC's <c>ItemType</c> is a 32-bit flags enum — a single dat weenie can
/// assert multiple type bits. From <c>ACE.Entity.Enum.ItemType</c>
/// cross-checked against the decompile paperdoll tooltip dispatcher.
/// Full bit list in the research doc §1.
/// </summary>
[Flags]
public enum ItemType : uint
{
    None                    = 0,
    MeleeWeapon             = 0x00000001,
    Armor                   = 0x00000002,
    Clothing                = 0x00000004,
    Jewelry                 = 0x00000008,
    Creature                = 0x00000010,
    Food                    = 0x00000020,
    Money                   = 0x00000040,
    Misc                    = 0x00000080,
    MissileWeapon           = 0x00000100,
    Container               = 0x00000200,
    Useless                 = 0x00000400,
    Gem                     = 0x00000800,
    SpellComponents         = 0x00001000,
    Writable                = 0x00002000,
    Key                     = 0x00004000,
    Caster                  = 0x00008000,
    Portal                  = 0x00010000,
    Lockable                = 0x00020000,
    PromissoryNote          = 0x00040000,
    ManaStone               = 0x00080000,
    Service                 = 0x00100000,
    MagicWieldable          = 0x00200000,
    CraftCookingBase        = 0x00400000,
    CraftAlchemyBase        = 0x00800000,
    CraftFletchingBase      = 0x01000000,
    CraftAlchemyIntermediate= 0x02000000,
    CraftCookingIntermediate= 0x04000000,
    CraftFletchingIntermediate = 0x08000000,
    LifeStone               = 0x10000000,
    TinkeringTool           = 0x20000000,
    TinkeringMaterial       = 0x40000000,
    Gameboard               = 0x80000000u,
    Vestements              = Armor | Clothing,
    Weapon                  = MeleeWeapon | MissileWeapon | Caster,
    WeaponOrCaster          = Weapon,
    Item                    = Weapon | Armor | Clothing | Jewelry | Container,
}

/// <summary>
/// Equipment slot bitmask. 31 slots from head to Aetheria. Paperdoll
/// widget offsets <c>+0x604..+0x660</c> in the retail panel correspond
/// to these bits 1:1 (see r06 §2 and UI slice 05 paperdoll section).
/// </summary>
[Flags]
public enum EquipMask : uint
{
    None          = 0,
    HeadWear      = 0x00000001,
    ChestWear     = 0x00000002,
    AbdomenWear   = 0x00000004,
    UpperArmWear  = 0x00000008,
    LowerArmWear  = 0x00000010,
    HandWear      = 0x00000020,
    UpperLegWear  = 0x00000040,
    LowerLegWear  = 0x00000080,
    FootWear      = 0x00000100,
    ChestArmor    = 0x00000200,
    AbdomenArmor  = 0x00000400,
    UpperArmArmor = 0x00000800,
    LowerArmArmor = 0x00001000,
    HandArmor     = 0x00002000,
    UpperLegArmor = 0x00004000,
    LowerLegArmor = 0x00008000,
    FootArmor     = 0x00010000,
    Necklace      = 0x00020000,
    LeftBracelet  = 0x00040000,
    RightBracelet = 0x00080000,
    LeftRing      = 0x00100000,
    RightRing     = 0x00200000,
    MeleeWeapon   = 0x00400000,
    Shield        = 0x00800000,
    MissileWeapon = 0x01000000,
    Held          = 0x02000000,       // lit torch, book in hand
    MissileAmmo   = 0x04000000,
    Cloak         = 0x08000000,
    TrinketOne    = 0x10000000,
    AetheriaRed   = 0x20000000,
    AetheriaYellow= 0x40000000,
    AetheriaBlue  = 0x80000000u,
}

/// <summary>
/// AC's property model is split across 7 typed tables. See r06 §3 for
/// the full property enumeration. This struct is a thin wrapper; real
/// bundles come over the wire in <c>ObjectDesc</c> / <c>IdentifyResponse</c>.
/// </summary>
public sealed class PropertyBundle
{
    public Dictionary<uint, int>    Ints      { get; } = new();
    public Dictionary<uint, long>   Int64s    { get; } = new();
    public Dictionary<uint, bool>   Bools     { get; } = new();
    public Dictionary<uint, double> Floats    { get; } = new();
    public Dictionary<uint, string> Strings   { get; } = new();
    public Dictionary<uint, uint>   DataIds   { get; } = new();
    public Dictionary<uint, uint>   InstanceIds { get; } = new();

    public int    GetInt   (uint k, int    def = 0)       => Ints.TryGetValue(k, out var v) ? v : def;
    public bool   GetBool  (uint k, bool   def = false)   => Bools.TryGetValue(k, out var v) ? v : def;
    public double GetFloat (uint k, double def = 0)       => Floats.TryGetValue(k, out var v) ? v : def;
    public string GetString(uint k, string def = "")      => Strings.TryGetValue(k, out var v) ? v : def;
}

/// <summary>
/// Per-item live state. The server owns item identity (ObjectId);
/// acdream mirrors properties here on <c>CreateObject</c> and updates
/// via <c>UpdateProperty*</c> messages.
/// </summary>
public sealed class ItemInstance
{
    public uint ObjectId      { get; init; }
    public uint WeenieClassId { get; init; }   // "blueprint"
    public string Name         { get; set; } = "";
    public ItemType Type      { get; set; }
    public EquipMask ValidLocations { get; set; }
    public EquipMask CurrentlyEquippedLocation { get; set; }
    public uint IconId        { get; set; }    // 0x06xxxxxx
    public uint IconUnderlayId{ get; set; }    // "magic" underlay
    public uint IconOverlayId { get; set; }    // "enchanted" overlay
    public int  StackSize     { get; set; } = 1;
    public int  StackSizeMax  { get; set; } = 1;
    public int  Burden        { get; set; }    // per-stack total
    public int  Value         { get; set; }    // pyreals
    public uint ContainerId   { get; set; }    // parent container ObjectId, or 0
    public int  ContainerSlot { get; set; } = -1;
    public bool Attuned       { get; set; }
    public bool Bonded        { get; set; }
    public PropertyBundle Properties { get; } = new();
}

/// <summary>
/// Container = inventory pack. Hierarchy is strictly 2-deep: character
/// → side packs; a side pack cannot hold another side pack (r06 §7).
/// </summary>
public sealed class Container
{
    public uint ObjectId        { get; init; }
    public int  Capacity        { get; set; } = 102;   // main inv default
    public int  SideCapacity    { get; set; } = 0;     // 0 for side-pack
    public int  BurdenLimit     { get; set; }
    public List<ItemInstance> Items { get; } = new();
    public List<Container>    SidePacks { get; } = new();   // empty for side-pack
    public bool IsSidePack      => SideCapacity == 0;
}

/// <summary>
/// Burden math — r06 §6. <c>maxBurden = 150 × Strength + Strength × bonusBurden</c>;
/// carry limit is <c>3 × maxBurden</c> before you can't pick up at all.
/// </summary>
public static class BurdenMath
{
    public const int BurdenPerStrength = 150;

    public static int ComputeMax(int strength, int bonusBurden)
        => BurdenPerStrength * strength + strength * bonusBurden;

    public static int ComputeCarryLimit(int strength, int bonusBurden)
        => 3 * ComputeMax(strength, bonusBurden);

    /// <summary>
    /// Retail's "encumbered" multiplier interpolates between 1.0 at
    /// zero burden and a low value at max. See r06 §6 for the curve.
    /// </summary>
    public static float ComputeEncumbranceMod(int currentBurden, int maxBurden)
    {
        if (maxBurden <= 0) return 1f;
        float ratio = (float)currentBurden / maxBurden;
        // Roughly 1.0 until 50%, then linear decay to ~0.7 at 100%, 0.1 at 300%.
        if (ratio <= 0.5f) return 1f;
        if (ratio <= 1.0f) return 1f - (ratio - 0.5f) * 0.6f;        // 1.0 → 0.7
        if (ratio <= 3.0f) return 0.7f - (ratio - 1.0f) * 0.3f;      // 0.7 → 0.1
        return 0.1f;
    }
}