"use strict"

var Vnode = require("./vnode")
var hyperscriptVnode = require("./hyperscriptVnode")
var hasOwn = require("../util/hasOwn")

var selectorParser = /(?:(^|#|\.)([^#\.\[\]]+))|(\[(.+?)(?:\s*=\s*("|'|)((?:\\["'\]]|.)*?)\5)?\])/g
var selectorCache = {}

function isEmpty(object) {
	for (var key in object) if (hasOwn.call(object, key)) return false
	return true
}

function compileSelector(selector) {
	var match, tag = "div", classes = [], attrs = {}
	while (match = selectorParser.exec(selector)) {
		var type = match[1], value = match[2]
		if (type === "" && value !== "") tag = value
		else if (type === "#") attrs.id = value
		else if (type === ".") classes.push(value)
		else if (match[3][0] === "[") {
			var attrValue = match[6]
			if (attrValue) attrValue = attrValue.replace(/\\(["'])/g, "$1").replace(/\\\\/g, "\\")
			if (match[4] === "class") classes.push(attrValue)
			else attrs[match[4]] = attrValue === "" ? attrValue : attrValue || true
		}
	}
	if (classes.length > 0) attrs.className = classes.join(" ")
	return selectorCache[selector] = {tag: tag, attrs: attrs}
}

function execSelector(state, vnode) {
	var attrs = vnode.attrs
	var hasClass = hasOwn.call(attrs, "class")
	var className = hasClass ? attrs.class : attrs.className

	vnode.tag = state.tag
	vnode.attrs = {}

	if (!isEmpty(state.attrs) && !isEmpty(attrs)) {
		var newAttrs = {}

		for (var key in attrs) {
			if (hasOwn.call(attrs, key)) newAttrs[key] = attrs[key]
		}

		attrs = newAttrs
	}

	for (var key in state.attrs) {
		if (hasOwn.call(state.attrs, key) && key !== "className" && !hasOwn.call(attrs, key)){
			attrs[key] = state.attrs[key]
		}
	}
	if (className != null || state.attrs.className != null) attrs.className =
		className != null
			? state.attrs.className != null
				? String(state.attrs.className) + " " + String(className)
				: className
			: state.attrs.className != null
				? state.attrs.className
				: null

	if (hasClass) attrs.class = null

	for (var key in attrs) {
		if (hasOwn.call(attrs, key) && key !== "key") {
			vnode.attrs = attrs
			break
		}
	}

	return vnode
}

function hyperscript(selector) {
	if (selector == null || typeof selector !== "string" && typeof selector !== "function" && typeof selector.view !== "function") {
		throw Error("The selector must be either a string or a component.");
	}

	var vnode = hyperscriptVnode.apply(1, arguments)

	if (typeof selector === "string") {
		vnode.children = Vnode.normalizeChildren(vnode.children)
		if (selector !== "[") return execSelector(selectorCache[selector] || compileSelector(selector), vnode)
	}

	vnode.tag = selector
	return vnode
}

module.exports = hyperscript