var Mexp = require('./postfix.js')
Mexp.prototype.postfixEval = function (UserDefined) {
	'use strict'
	UserDefined = UserDefined || {}
	UserDefined.PI = Math.PI
	UserDefined.E = Math.E
	var stack = [],
		pop1,
		pop2,
		pop3
	var disp = []
	var temp = ''
	var arr = this.value
	var bool = typeof UserDefined.n !== 'undefined'
	for (var i = 0; i < arr.length; i++) {
		if (arr[i].type === 1) {
			stack.push({ value: arr[i].value, type: 1 })
		} else if (arr[i].type === 3) {
			stack.push({ value: UserDefined[arr[i].value], type: 1 })
		} else if (arr[i].type === 0) {
			if (typeof stack[stack.length - 1].type === 'undefined') {
				stack[stack.length - 1].value.push(arr[i])
			} else stack[stack.length - 1].value = arr[i].value(stack[stack.length - 1].value)
		} else if (arr[i].type === 7) {
			if (typeof stack[stack.length - 1].type === 'undefined') {
				stack[stack.length - 1].value.push(arr[i])
			} else stack[stack.length - 1].value = arr[i].value(stack[stack.length - 1].value)
		} else if (arr[i].type === 8) {
			var popped = []
			for (var x = 0; x < arr[i].numberOfArguments; x++) {
				popped.push(stack.pop().value)
			}
			stack.push({ type: 1, value: arr[i].value.apply(arr[i], popped.reverse()) })
		} else if (arr[i].type === 10) {
			pop1 = stack.pop()
			pop2 = stack.pop()
			if (typeof pop2.type === 'undefined') {
				pop2.value = pop2.concat(pop1)
				pop2.value.push(arr[i])
				stack.push(pop2)
			} else if (typeof pop1.type === 'undefined') {
				pop1.unshift(pop2)
				pop1.push(arr[i])
				stack.push(pop1)
			} else {
				stack.push({ type: 1, value: arr[i].value(pop2.value, pop1.value) })
			}
		} else if (arr[i].type === 2 || arr[i].type === 9) {
			pop1 = stack.pop()
			pop2 = stack.pop()
			if (typeof pop2.type === 'undefined') {
				pop2 = pop2.concat(pop1)
				pop2.push(arr[i])
				stack.push(pop2)
			} else if (typeof pop1.type === 'undefined') {
				pop1.unshift(pop2)
				pop1.push(arr[i])
				stack.push(pop1)
			} else {
				stack.push({ type: 1, value: arr[i].value(pop2.value, pop1.value) })
			}
		} else if (arr[i].type === 12) {
			pop1 = stack.pop()
			if (typeof pop1.type !== 'undefined') {
				pop1 = [pop1]
			}
			pop2 = stack.pop()
			pop3 = stack.pop()
			stack.push({ type: 1, value: arr[i].value(pop3.value, pop2.value, new Mexp(pop1)) })
		} else if (arr[i].type === 13) {
			if (bool) {
				stack.push({ value: UserDefined[arr[i].value], type: 3 })
			} else stack.push([arr[i]])
		}
	}
	if (stack.length > 1) {
		throw new Mexp.Exception('Uncaught Syntax error')
	}
	return stack[0].value > 1000000000000000 ? 'Infinity' : parseFloat(stack[0].value.toFixed(15))
}
Mexp.eval = function (str, tokens, obj) {
	if (typeof tokens === 'undefined') {
		return this.lex(str).toPostfix().postfixEval()
	} else if (typeof obj === 'undefined') {
		if (typeof tokens.length !== 'undefined') return this.lex(str, tokens).toPostfix().postfixEval()
		else return this.lex(str).toPostfix().postfixEval(tokens)
	} else return this.lex(str, tokens).toPostfix().postfixEval(obj)
}
module.exports = Mexp