package net.shadowfacts.cacao.view

import net.minecraft.client.MinecraftClient
import net.minecraft.client.font.TextRenderer
import net.shadowfacts.cacao.geometry.Point
import net.shadowfacts.cacao.geometry.Size
import net.shadowfacts.cacao.util.Color
import net.shadowfacts.cacao.util.RenderHelper

/**
 * A simple View that displays text. Allows for controlling the color and shadow of the text. Label cannot be used
 * for multi-line text, instead use [TextView].
 *
 * @author shadowfacts
 * @param text The text of this label.
 * @param shadow Whether the text should be rendered with a shadow or not.
 * @param maxLines The maximum number of lines of text to render.
 * 					`0` means that there is no line limit and all lines will be rendered.
 * 					When using a non-zero [maxLines] value, the [intrinsicContentSize] of the Label still assumes all
 * 					content on one line. So, constraints must be provided to calculate the actual width to use for line
 * 					wrapping.
 */
class Label(
		text: String,
		val shadow: Boolean = true,
		val maxLines: Int = 0,
		val wrappingMode: WrappingMode = WrappingMode.WRAP
): View() {

	companion object {
		private val textRenderer: TextRenderer
			get() = MinecraftClient.getInstance().textRenderer
	}

	enum class WrappingMode {
		WRAP, NO_WRAP
	}

	/**
	 * The text of this label. Mutating this field will update the intrinsic content size and trigger a layout.
	 */
	var text: String = text
		set(value) {
			field = value
			updateIntrinsicContentSize()
			// todo: setNeedsLayout instead of force unwrapping window
			window!!.layout()
		}
	private lateinit var lines: List<String>

	var textColor = Color.WHITE
		set(value) {
			field = value
			textColorARGB = value.argb
		}
	private var textColorARGB: Int = textColor.argb

	private val drawFunc by lazy {
		if (shadow) textRenderer::drawWithShadow else textRenderer::draw
	}

	override fun wasAdded() {
		super.wasAdded()

		updateIntrinsicContentSize()
	}

	private fun updateIntrinsicContentSize() {
		if (RenderHelper.disabled) return

		val width = textRenderer.getStringWidth(text)
		val height = textRenderer.fontHeight
		intrinsicContentSize = Size(width.toDouble(), height.toDouble())
	}

	override fun drawContent(mouse: Point, delta: Float) {
		if (!this::lines.isInitialized) {
			computeLines()
		}

		for (i in 0 until lines.size) {
			val y = i * textRenderer.fontHeight
			drawFunc(lines[i], 0f, y.toFloat(), textColorARGB)
		}
	}

	override fun didLayout() {
		super.didLayout()

		computeLines()
	}

	private fun computeLines() {
		var lines = text.split("\n")
		if (wrappingMode == WrappingMode.WRAP) {
			lines = lines.flatMap {
				wrapStringToWidthAsList(it, bounds.width)
			}
		}
		if (0 < maxLines && maxLines < lines.size) {
			lines = lines.dropLast(lines.size - maxLines)
		}
		this.lines = lines
	}

	private fun wrapStringToWidthAsList(string: String, width: Double): List<String> {
		if (RenderHelper.disabled) return listOf(string)
		return textRenderer.wrapStringToWidthAsList(string, width.toInt())
	}

}