/* global m: false */
// TODO: ensure this targets the current API.
window.templateConverter = (function () {
	"use strict"

	function each(list, f) {
		for (var i = 0; i < list.length; i++) {
			f(list[i], i)
		}
	}

	function createFragment(markup) {
		if (markup.indexOf("<!doctype") >= 0) {
			return [
				new DOMParser()
					.parseFromString(markup, "text/html")
					.childNodes[1]
			]
		}

		var container = document.createElement("div")
		container.insertAdjacentHTML("beforeend", markup)
		return container.childNodes
	}

	function createVirtual(fragment) {
		var list = []

		each(fragment, function (el) {
			if (el.nodeType === 3) {
				list.push(el.nodeValue)
			} else if (el.nodeType === 1) {
				var attrs = {}

				each(el.attributes, function (attr) {
					attrs[attr.name] = attr.value
				})

				list.push({
					tag: el.nodeName.toLowerCase(),
					attrs: attrs,
					children: createVirtual(el.childNodes)
				})
			}
		})

		return list
	}

	function TemplateBuilder(virtual, level) {
		this.virtual = virtual
		this.level = level
		this.virtuals = []
		this.indented = false
	}

	TemplateBuilder.prototype = {
		addVirtualString: function (el) {
			if (/\t| {2,}/.test(el) && /^\s*/.test(el)) {
				this.indented = true
			} else {
				this.virtuals.push('"' + el.replace(/(["\r\n])/g, "\\$1") + '"')
			}
		},

		addVirtualAttrs: function (el) {
			var virtual = el.tag === "div" ? "" : el.tag

			if (el.attrs.class) {
				virtual += "." + el.attrs.class.replace(/\s+/g, ".")
				delete el.attrs.class
			}

			each(Object.keys(el.attrs).sort(), function (attrName) {
				if (attrName === "style") return
				virtual += "[" + attrName + "='"
				virtual += el.attrs[attrName].replace(/'/g, "\\'") + "']"
			})

			if (virtual === "") virtual = "div"
			virtual = '"' + virtual + '"'

			if (el.attrs.style) {
				var style = "{\"" + el.attrs.style
					.replace(/:/g, "\": \"")
					.replace(/;/g, "\", \"") + "}"
				virtual += ", {style: " + style.replace(/(, )"}/, "}") + "}"
			}

			if (el.children.length !== 0) {
				var builder = new TemplateBuilder(el.children, this.level + 1)
				virtual += ", " + builder.complete()
			}

			this.virtuals.push("m(" + virtual + ")")
		},

		complete: function () {
			var tab = "\n"
			for (var i = 0; i <= this.level; i++) tab += "\t"

			each(this.virtual, function (el) {
				if (typeof el === "string") {
					this.addVirtualString(el)
				} else {
					this.addVirtualAttrs(el)
				}
			}.bind(this))

			if (!this.indented) tab = ""

			if (this.virtuals.length === 1 && this.virtuals[0][0] === "\"") {
				return this.virtuals.join(", ")
			} else {
				var body = this.virtuals.join("," + tab)
				return "[" + tab + body + tab.slice(0, -1) + "]"
			}
		}
	}

	return {
		controller: function () {
			this.source = m.prop("")
			this.output = m.prop("")

			this.convert = function () {
				var source = createVirtual(createFragment(this.source()))
				return this.output(new TemplateBuilder(source, 1).complete())
			}.bind(this)
		},

		view: function (ctrl) {
			return m("div", [
				m("textarea", {
					autofocus: true,
					style: {width: "100%", height: "40%"},
					onchange: m.withAttr("value", ctrl.source)
				}, ctrl.source()),
				m("button", {onclick: ctrl.convert}, "Convert"),
				m("textarea", {style: {width: "100%", height: "40%"}},
					ctrl.output())
			])
		}
	}
})()