// https://gamefaqs.gamespot.com/snes/563501-the-7th-saga/faqs/54038

(function(exports) {
	exports.physicalAttack = (
		attackerPowerInnate,
		attackerPowerWeapon,
		targetGuardInnate,
		targetGuardArmor,
		targetGuardAccessory,
		options = {},
	) => {
		let attackPower = attackerPowerInnate;
		if (options.attackerDefending) {
			attackPower *= 1.5;
		}
		if (options.attackerPowerUp) {
			attackPower *= 2;
		}

		let weaponPower = attackerPowerWeapon;
		if (options.attackerDefending) {
			weaponPower *= 1.5;
		}

		let guardPower = targetGuardInnate;
		if (options.targetGuardDown) {
			guardPower /= 2;
		}

		const totalAttackPower = attackPower + weaponPower;
		const totalGuardPower = guardPower + targetGuardArmor + targetGuardAccessory;

		let averageDamage = totalAttackPower - (totalGuardPower / 2);

		if (options.targetGuardUp) {
			averageDamage /= 2;
		}
		if (options.targetDefending) {
			averageDamage /= 2;
		}

		let minDamage = averageDamage * 0.75;
		let maxDamage = averageDamage * 1.25;

		const absoluteMin = 1;

		return {
			normal: {
				avg: Math.max(absoluteMin, averageDamage),
				min: Math.max(absoluteMin, minDamage),
				max: Math.max(absoluteMin, maxDamage),
			},
			critical: {
				avg: Math.max(absoluteMin, averageDamage * 2),
				min: Math.max(absoluteMin, minDamage * 2),
				max: Math.max(absoluteMin, maxDamage * 2),
			},
		};
	};

	exports.magicalAttack = (
		attackerMagicInnate,
		targetMagicInnate,
		targetResistanceInnate,
		targetResistanceArmor,
		targetResistanceAccessory,
		spellPower,
		options = {},
	) => {
		let attackerPower = attackerMagicInnate;

		let targetPower = targetMagicInnate;
		if (options.targetMagicUp) {
			targetPower += 40;
		}

		const targetResistance = 100 - targetResistanceInnate - targetResistanceArmor - targetResistanceAccessory;

		const spellBonusAttackPower = attackerPower + (options.attackerMagicUp ? 40 : 0);
		const spellBonus = ((spellBonusAttackPower / 2) + spellPower) * (targetResistance / 100);

		const averageDamage = attackerPower - targetPower + spellBonus;

		return {
			avg: Math.max(1, averageDamage),
			min: Math.max(1, averageDamage * 0.75),
			max: Math.max(1, averageDamage * 1.25),
		};
	};

	exports.hpCatcherAttack = (
		attackerMagicInnate,
		attackerMaxHP,
		attackerCurrentHP,
		targetCurrentHP,
		options = {},
	) => {
		let attackerPower = attackerMagicInnate;
		if (options.attackerMagicUp) {
			attackerPower += 40;
		}

		const adjust = dmg => Math.min(attackerMaxHP - attackerCurrentHP, Math.min(Math.min(dmg, 50), targetCurrentHP));
		const minDamage = attackerPower / 2;

		return {
			min: adjust(minDamage),
			max: adjust(minDamage + 15),
		};
	};

	exports.mpCatcherAttack = (
		attackerMagicInnate,
		attackerMaxMP,
		attackerCurrentMP,
		targetCurrentMP,
		options = {},
	) => {
		let attackerPower = attackerMagicInnate;
		if (options.attackerMagicUp) {
			attackerPower += 40;
		}

		const adjust = dmg => Math.min(attackerMaxMP - attackerCurrentMP, Math.min(Math.min(dmg, 40), targetCurrentMP));
		const minDamage = attackerPower / 2;

		return {
			min: adjust(minDamage),
			max: adjust(minDamage + 15),
		};
	};

	exports.effectSpellHitRate = (
		targetResistanceInnate,
		targetResistanceArmor,
		targetResistanceAccessory,
	) => {
		if (targetResistanceInnate === null) {
			// e.g. "Class 1" enemies
			return 0;
		}

		return Math.max(5, 100 - targetResistanceInnate - targetResistanceArmor - targetResistanceAccessory);
	};

	exports.hitRate = (
		attackerSpeedInnate,
		targetSpeedInnate,
		options = {},
	) => {
		let attackerSpeed = attackerSpeedInnate;
		if (options.attackerSpeedUp) {
			attackerSpeed += 30;
		}

		let targetSpeed = targetSpeedInnate;
		if (options.targetSpeedUp) {
			targetSpeed += 30;
		}

		const hitRate = 85 + (0.8 * (attackerSpeed - targetSpeed));
		return Math.max(10, Math.min(98, hitRate));
	};

	exports.runRate = (
		attackerSpeedInnate,
		targetSpeedInnate,
		options = {},
	) => {
		let attackerSpeed = attackerSpeedInnate;
		if (options.attackerSpeedUp) {
			attackerSpeed += 30;
		}

		let targetSpeed = targetSpeedInnate;
		if (options.targetSpeedUp) {
			targetSpeed += 30;
		}

		const runRate = 0.25 + (1.6 * (attackerSpeed - targetSpeed));
		return Math.max(10, Math.min(80, runRate));
	};

}(typeof(module) !== 'undefined' ? module.exports : window.saga.calc));