/* -----------------------------------------------
FileName:calculation.js
UpdatedBy:2008/1/15
----------------------------------------------- */

//ご希望返済額から価格を決める
function check_numeric( obj, name, check_zero, max ){
	if(obj.value == ""){obj.value = 0;}
	if(isNaN(obj.value) || obj.value < 0){
		alert(name + 'は半角数値で入力してください');
		obj.focus();
		return false;
	}
	if(check_zero && obj.value == 0){
		alert(name + 'が設定されていません');
		obj.focus();
		return false;
	}
	if(obj.value > max){
		alert(name + 'は' + max + '以内で設定してください');
		obj.focus();
		return false;
	}
	return true;
}
function calc_price(){
	if(check_numeric(document.forms[0].capital, '頭金(自己資金)',false,9999999)==false){return false;}
	if(check_numeric(document.forms[0].bonus, 'ボーナス月の支払い',false,9999999)==false){return false;}
	if(check_numeric(document.forms[0].m_recapital, '毎月の返済額',false,9999999)==false){return false;}
	if(check_numeric(document.forms[0].bonus_num, 'ボーナス回数',false,2)==false){return false;}
	if(check_numeric(document.forms[0].years, '年数', true,35)==false){return false;}
	if(check_numeric(document.forms[0].a_interest, '年利', true,4)==false){return false;}

	var capital = document.forms[0].capital.value * 10000;
	var m_recapital = document.forms[0].m_recapital.value * 10000 + (document.forms[0].bonus.value * document.forms[0].bonus_num.value * 10000 / 12);
	var years = document.forms[0].years.value;
	var a_interest = document.forms[0].a_interest.value / 100 / 12;
	var price = (m_recapital * (1 - (1 / Math.pow(1 + a_interest, years * 12))) / a_interest) + capital;

	document.getElementById("dsp_price").innerHTML = Math.floor(price / 10000);

	if(price > 200){
		document.forms[0].priceFrom.value = Math.floor(price / 10000 - 200);
	}else if(price < 200){
		document.forms[0].priceFrom.value = 0;
	}
	document.forms[0].priceTo.value = Math.floor(price / 10000 + 200);
	document.getElementById('price').value = Math.floor(price / 10000);

	return true;
}



//価格から月々の返済額を計算する

function calc_monthly_price(){
	if(check_numeric(document.calc_form02.object_price, '購入不動産の価格', true,9999999)==false){return false;}
	if(check_numeric(document.calc_form02.capital, '頭金(自己資金)',false,9999999)==false){return false;}
	if(check_numeric(document.calc_form02.bonus, 'ボーナス月の支払い',false,9999999)==false){return false;}
	if(check_numeric(document.calc_form02.bonus_num, 'ボーナス回数',false,3)==false){return false;}
	if(check_numeric(document.calc_form02.years, '年数', true,35)==false){return false;}
	if(check_numeric(document.calc_form02.a_interest, '年利', true,4)==false){return false;}

//実質借入金額 = 購入不動産の価格 - 頭金
	var object_price = document.calc_form02.object_price.value * 10000;
	var capital = document.calc_form02.capital.value * 10000;
	var principal = object_price - capital;
//ボーナス返済分 = 年ボーナス * 年数
	var bonus = (document.calc_form02.bonus.value * document.calc_form02.bonus_num.value * 10000) * document.calc_form02.years.value;
//年利
	var a_interest = document.calc_form02.a_interest.value;
//年数
	var years = document.calc_form02.years.value * 12;
//月利
	var m_interest = a_interest / 100 / 12;
//月額
	var monthly = (principal - bonus) * m_interest * Math.pow((m_interest+1),years) / (Math.pow((m_interest+1),years) - 1);
	var monthly_price = Math.round(monthly / 1000) / 10;
//月額が0以下の場合アラートを出す
	if(monthly_price > 0){
		document.getElementById("monthly_price").innerHTML = monthly_price;
	} else {
		alert('条件を見直してください');
	}

	return true;
}