using System;
using System.Collections.Generic;

public class Inventory
{
    public List<Item> items = new List<Item>();

    public int maxInventorySize = 16;
    public event EventHandler OnInventoryUpdate;

    public bool AddItem(Item item, int amount)
    {
        if (GetFreeCapacity(item.data.Id, item.data.StackSize) < amount)
        {
            return false;
        }

        int remainingAmount = amount;

        foreach (Item inventoryItem in items)
        {
            if (inventoryItem.data.Id != item.data.Id) continue;
            if (inventoryItem.currentAmount >= inventoryItem.data.StackSize) continue;

            int amountToAdd = Math.Min(
                remainingAmount,
                inventoryItem.data.StackSize - inventoryItem.currentAmount
            );

            inventoryItem.currentAmount += amountToAdd;
            remainingAmount -= amountToAdd;

            if (remainingAmount <= 0)
            {
                NotifyInventoryChanged();
                return true;
            }
        }

        while (remainingAmount > 0 && items.Count < maxInventorySize * GameData.maxRobotCount)
        {
            int amountToAdd = Math.Min(remainingAmount, item.data.StackSize);
            items.Add(new Item { data = item.data, currentAmount = amountToAdd });
            remainingAmount -= amountToAdd;
        }

        NotifyInventoryChanged();
        return remainingAmount <= 0;
    }

    public bool CanCraft(List<Ingredient> neededIngredients, int amount)
    {
        foreach (Ingredient ingredient in neededIngredients)
        {
            if (GetItemAmount(ingredient.Item) < ingredient.Amount * amount)
            {
                return false;
            }
        }

        return true;
    }

    public void RemoveItem(string id, int amount)
    {
        TryRemoveItem(id, amount);
    }

    public bool TryRemoveItem(string id, int amount)
    {
        if (GetItemAmount(id) < amount)
        {
            return false;
        }

        int remainingAmount = amount;
        for (int i = items.Count - 1; i >= 0 && remainingAmount > 0; i--)
        {
            Item item = items[i];
            if (item.data.Id != id) continue;

            int removedAmount = Math.Min(item.currentAmount, remainingAmount);
            item.currentAmount -= removedAmount;
            remainingAmount -= removedAmount;

            if (item.currentAmount <= 0)
            {
                items.RemoveAt(i);
            }
        }

        NotifyInventoryChanged();
        return true;
    }

    public int GetItemAmount(string id)
    {
        int amount = 0;
        foreach (Item item in items)
        {
            if (item.data.Id == id)
            {
                amount += item.currentAmount;
            }
        }

        return amount;
    }

    private void NotifyInventoryChanged()
    {
        OnInventoryUpdate?.Invoke(this, EventArgs.Empty);
    }

    private int GetFreeCapacity(string id, int stackSize)
    {
        int freeCapacity = 0;

        foreach (Item item in items)
        {
            if (item.data.Id == id)
            {
                freeCapacity += stackSize - item.currentAmount;
            }
        }

        int freeSlots = maxInventorySize * GameData.maxRobotCount - items.Count;
        freeCapacity += freeSlots * stackSize;
        return freeCapacity;
    }
}