using System.Collections.Generic;

namespace WeaveLoader.API.Item;

/// <summary>
/// Represents an item that has been registered with the game engine.
/// </summary>
public class RegisteredItem
{
    /// <summary>The namespaced string ID (e.g. "mymod:ruby").</summary>
    public Identifier StringId { get; }

    /// <summary>The numeric ID allocated by the engine.</summary>
    public int NumericId { get; }

    internal RegisteredItem(Identifier id, int numericId)
    {
        StringId = id;
        NumericId = numericId;
    }
}

/// <summary>
/// Item registration via the WeaveLoader registry.
/// Accessed through <see cref="Registry.Item"/>.
/// </summary>
public static class ItemRegistry
{
    private static readonly object s_lock = new();
    private static readonly Dictionary<int, Identifier> s_idByNumeric = new();

    /// <summary>
    /// Register a new item with the game engine.
    /// </summary>
    /// <param name="id">Namespaced identifier (e.g. "mymod:ruby").</param>
    /// <param name="properties">Item properties built with <see cref="ItemProperties"/>.</param>
    /// <returns>A handle to the registered item.</returns>
    public static RegisteredItem Register(Identifier id, ItemProperties properties)
    {
        return RegisterInternal(id, properties, null);
    }

    /// <summary>
    /// Register a managed custom item implementation.
    /// </summary>
    /// <param name="id">Namespaced identifier (e.g. "mymod:ruby_pickaxe").</param>
    /// <param name="item">Managed item instance that can override callbacks.</param>
    /// <param name="properties">Item properties built with <see cref="ItemProperties"/>.</param>
    /// <returns>A handle to the registered item.</returns>
    public static RegisteredItem Register(Identifier id, Item item, ItemProperties properties)
    {
        return RegisterInternal(id, properties, item);
    }

    private static RegisteredItem RegisterInternal(Identifier id, ItemProperties properties, Item? managedItem)
    {
        int numericId;
        if (managedItem is PickaxeItem pickaxeItem)
        {
            numericId = NativeInterop.native_register_pickaxe_item(
                id.ToString(),
                (int)pickaxeItem.Tier,
                properties.MaxDamageValue,
                properties.IconValue,
                properties.NameValue ?? "");
        }
        else
        {
            numericId = NativeInterop.native_register_item(
                id.ToString(),
                properties.MaxStackSizeValue,
                properties.MaxDamageValue,
                properties.IconValue,
                properties.NameValue ?? "");
        }

        if (numericId < 0)
            throw new InvalidOperationException($"Failed to register item '{id}'. No free IDs or invalid parameters.");

        if (properties.CreativeTabValue != CreativeTab.None)
        {
            NativeInterop.native_add_to_creative(numericId, 1, 0, (int)properties.CreativeTabValue);
            Logger.Debug($"Item '{id}' added to creative tab {properties.CreativeTabValue}");
        }

        if (managedItem != null)
        {
            ManagedItemDispatcher.RegisterItem(id, numericId, managedItem);
            Logger.Debug($"Managed item dispatcher mapped '{id}' -> numeric ID {numericId} ({managedItem.GetType().FullName})");
        }

        Logger.Debug($"Registered item '{id}' -> numeric ID {numericId}");
        lock (s_lock)
        {
            s_idByNumeric[numericId] = id;
        }
        return new RegisteredItem(id, numericId);
    }

    internal static bool TryGetIdentifier(int numericId, out Identifier id)
    {
        lock (s_lock)
        {
            return s_idByNumeric.TryGetValue(numericId, out id);
        }
    }
}