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A collection of drawing/charting utilities
There is a newer version: 0.19.1
package com.juul.krayon.element

import com.juul.krayon.kanvas.Kanvas

public abstract class Element {

    public abstract val tag: String

    /**
     * This is a delicate API that exposes the raw attribute backing without any type safety. This
     * is frequently used by the internals of Krayon, but is likely something you shouldn't use as
     * a library consumer. That said, it's still exposed for the cases where it's necessary.
     * **When using this, be very careful not to clobber existing attributes.**
     */
    public val attributes: MutableMap = mutableMapOf()

    /** Analogous to an HTML class, except you can only have one. */
    public var kind: String? by attributes.withDefault { null }

    public var data: Any? by attributes.withDefault { null }

    public open var parent: Element? = null

    private val _children: MutableList = mutableListOf()
    public val children: List = _children

    public open fun  appendChild(child: E): E {
        child.parent?.removeChild(child)
        child.parent = this
        _children.add(child)
        return child
    }

    public open fun  insertBefore(child: E, reference: Element?): E {
        child.parent?.removeChild(child)
        child.parent = this
        when (reference) {
            null -> _children.add(child)
            else -> when (val index = children.indexOf(reference)) {
                -1 -> _children.add(child)
                else -> _children.add(index, child)
            }
        }
        return child
    }

    public fun matches(selector: ElementSelector<*>): Boolean =
        selector.trySelect(this) === this

    public open fun  query(selector: ElementSelector): E? {
        var selected = selector.trySelect(this)
        if (selected != null) return selected
        for (child in children) {
            selected = child.query(selector)
            if (selected != null) return selected
        }
        return null
    }

    public open fun  queryAll(selector: ElementSelector): Sequence = sequence {
        val selected = selector.trySelect(this@Element)
        if (selected != null) yield(selected)
        for (child in children) {
            yieldAll(child.queryAll(selector))
        }
    }

    public fun  removeChild(child: E): E {
        if (_children.remove(child)) {
            child.parent = null
        }
        return child
    }

    public abstract fun draw(kanvas: Kanvas)

    override fun toString(): String = buildString {
        append('(')
        append(tag)
        for ((key, value) in attributes) {
            append(" :$key $value")
        }
        for (child in children) {
            append(' ')
            append(child)
        }
        append(')')
    }

    public companion object : ElementSelector {
        override fun trySelect(element: Element): Element = element
    }
}