isleward/src/server/items/generators/quality.js

module.exports = {
	qualities: [
		2000,
		350,
		80,
		17,
		1
	],

	magicFindMult: 7,

	generate: function (item, blueprint) {
		if (blueprint.quality !== null) {
			item.quality = ~~blueprint.quality;
			return;
		}

		let qualities = extend(true, [], this.qualities);

		let magicFind = (blueprint.magicFind || 0);
		if (!(magicFind instanceof Array))
			magicFind = [magicFind];
		else
			magicFind = extend(true, [], magicFind);

		let bonusMagicFind = blueprint.bonusMagicFind || 0;

		let mLen = magicFind.length;
		for (let i = 0; i < mLen; i++) {
			qualities[i] = Math.max(0, qualities[i] - magicFind[i]);
			if (qualities[i] > 0) {
				if (i === 0) {
					qualities[i] -= (bonusMagicFind * this.magicFindMult);
					if (qualities[i] < 0)
						qualities[i] = 0;
				}

				break;
			}
		}

		let max = qualities.reduce((p, n) => p + n);
		let gen = ~~(Math.random() * max);

		let total = 0;
		for (let i = 0; i < qualities.length; i++) {
			total += qualities[i];

			if (gen < total) {
				item.quality = i;
				return;
			}
		}

		item.quality = qualities.length - 1;
	}
};