// This is the simplest usage.
var randomSelectedItem = items
	.ToWeightedSelector(item => item.weight)
	.SelectItemWithUnityRandom();

// To use Choice, add this namespace.
using MackySoft.Choice;

public class WeightedItem {
	public string id;
	public float weight;
}

public WeightedItem SelectItem () {
	// Prepare weighted items.
	var items = new WeightedItem[] {
		new WeightedItem { id = "🍒", weight = 8f },
		new WeightedItem { id = "🍏", weight = 4f },
		new WeightedItem { id = "🍍", weight = 0f },
		new WeightedItem { id = "🍇", weight = 6f },
		new WeightedItem { id = "🍊", weight = -1f }
	};
	
	// Create the WeightedSelector.
	var weightedSelector = items.ToWeightedSelector(item => item.weight);
	
	// The probability of each item being selected,
	// 🍒 is 44%, 🍏 is 22%, and 🍇 is 33%.
	// 🍍 and 🍊 will never be selected because their weights are less or equal to 0.
	return weightedSelector.SelectItemWithUnityRandom();
	// Same as weightedSelector.SelectItem(UnityEngine.Random.value);
}

public struct ItemEntry {
	public Item item;
	public float weight;
}

public IWeightedSelector<Item> WeightedEntryPattern () {
	var entries = new ItemEntry[] {
		new ItemEntry { item = new Item { id = "🍒" }, weight = 1f },
		new ItemEntry { item = new Item { id = "🍏" }, weight = 5f },
		new ItemEntry { item = new Item { id = "🍍" }, weight = 3f }
	};

	// Create a WeightedSelector by selecting item and weight from entry respectively.
	return entries.ToWeightedSelector(
		itemSelector: entry => entry.item,
		weightSelector: entry => entry.weight
	);
}

public class WeightedItem {
	public string id;
	public float weight;
}

public IWeightedSelector<WeightedItem> WeightedItemPattern () {
	var items = new WeightedItem[] {
		new WeightedItem { id = "🍒", weight = 1f },
		new WeightedItem { id = "🍏", weight = 5f },
		new WeightedItem { id = "🍍", weight = 3f }
	};

	// Create a WeightedSelector using the weight of the WeightedItem.
	return fromWeightedItem = items.ToWeightedSelector(weightSelector: item => item.weight);
}

public class Item {
	public string id;
}

public IWeightedSelector<Item> DictionaryPattern () {
	// This need a Dictionary<TItem,float>. (Strictly speaking, IEnumerable<KeyValuePair<TItem,float>>)
	var dictionary = new Dictionary<Item,float>(
		{ new Item { id = "🍒" }, 1f },
		{ new Item { id = "🍏" }, 5f },
		{ new Item { id = "🍍" }, 3f }
	);

	// Create a WeightedSelector with the dictionary key as item and value as weight.
	return dictionary.ToWeightedSelector();
}

var randomSelectedItem = items
	.Where(item => item != null) // null check
	.ToWeightedSelector(item => item.weight)
	.SelectItemWithUnityRandom();

var weightedSelector = items.ToWeightedSelector(
	item => item.weight,
	WeightedSelectMethod.Binary // Use the binary search algorithm.
);