package cz.svitalsky.barclays.simplehtmlbuilder

fun main(args: Array<String>) = println(createHtml())

fun createHtml() =
    html {
        span {
            div {
                 this + "Hello World"
            }
        }
    }

interface Element {
    fun render(builder: StringBuilder, indent: String = "")
}

class TextElement(private val text: String) : Element {
    override fun render(builder: StringBuilder, indent: String) {
        builder.append(text)
    }
}

abstract class Tag(protected val name: String) : Element {
    val children = arrayListOf<Element>()

    protected fun <T: Element> initTag(tag: T, init: T.() -> Unit) = tag.apply {
        init()
        children.add(this)
    }

    override fun render(builder: StringBuilder, indent: String) {
        builder.append("$indent<$name>\n")
        children.forEach { it.render(builder, "$indent  ") }
        builder.append("$indent</$name>\n")
    }

    override fun toString() = StringBuilder().also { render(it) }.toString()
}

class HTML : Tag("html") {
    fun span(init: SPAN.() -> Unit) = initTag(SPAN(), init)
}

class SPAN : Tag("span") {
    fun div(init: DIV.() -> Unit) = initTag(DIV(), init)
}

class DIV : Tag("div") {
    override fun render(builder: StringBuilder, indent: String) {
        builder.append("$indent<$name>")
        children.forEach { it.render(builder) }
        builder.append("</$name>\n")
    }
}

operator fun Tag.plus(s: String) {
    children.add(TextElement(s))
}

fun html(init: HTML.() -> Unit) = HTML().apply(init)