package net.shadowfacts.cacao.view.textfield

import net.minecraft.client.MinecraftClient
import net.minecraft.client.gui.widget.TextFieldWidget
import net.minecraft.client.util.math.MatrixStack
import net.minecraft.text.LiteralText
import net.shadowfacts.cacao.geometry.Point
import net.shadowfacts.cacao.util.KeyModifiers
import net.shadowfacts.cacao.util.MouseButton
import net.shadowfacts.cacao.view.View
import net.shadowfacts.phycon.mixin.client.TextFieldWidgetAccessor
import org.lwjgl.glfw.GLFW

/**
 * An abstract text field class. Cannot be constructed directly, use for creating other text fields with more specific
 * behavior. Use [TextField] for a plain text field.
 *
 * @author shadowfacts
 * @param Impl The type of the concrete implementation of the text field. Used to allow the [handler] to receive the
 *             the exact type of text field.
 * @param initialText The initial value of the text field.
 */
abstract class AbstractTextField<Impl: AbstractTextField<Impl>>(
	initialText: String
): View() {

	/**
	 * A function that is invoked when the text in this text field changes.
	 */
	var handler: ((Impl) -> Unit)? = null

	/**
	 * Whether the text field is disabled.
	 * Disabled text fields cannot be interacted with.
	 */
	var disabled = false

	/**
	 * Whether this text field is focused (i.e. [isFirstResponder]) and receives key events.
	 */
	val focused: Boolean
		get() = isFirstResponder

	/**
	 * The current text of this text field.
	 */
	var text: String
		get() = minecraftWidget.text
		set(value) {
			minecraftWidget.text = value
		}

	/**
	 * The maximum length of text that this text field can hold.
	 *
	 * Defaults to the Minecraft text field's maximum length (currently 32, subject to change).
	 */
	var maxLength: Int
		get() = (minecraftWidget as TextFieldWidgetAccessor).cacao_getMaxLength()
		set(value) {
			minecraftWidget.setMaxLength(value)
		}

	/**
	 * Whether the Minecraft builtin black background and border are drawn. Defaults to true.
	 */
	var drawBackground = true
		set(value) {
			field = value
			minecraftWidget.setDrawsBackground(value)
		}

	private lateinit var originInWindow: Point
	private var minecraftWidget = ProxyWidget()

	init {
		minecraftWidget.text = initialText
		minecraftWidget.setTextPredicate { this.validate(it) }
		minecraftWidget.setDrawsBackground(drawBackground)
	}

	/**
	 * A function used by subclasses to determine whether a proposed value is acceptable for this field.
	 */
	abstract fun validate(proposedText: String): Boolean

	override fun didLayout() {
		super.didLayout()

		originInWindow = convert(bounds.origin, to = null)

		// offset View dimensions by 1 on each side because TextFieldWidget draws the border outside its dimensions
		minecraftWidget.x = originInWindow.x.toInt() + 1
		minecraftWidget.y = originInWindow.y.toInt() + 1
		minecraftWidget.width = bounds.width.toInt() - 2
		minecraftWidget.height = bounds.height.toInt() - 2

		// after dimensions change call setText on the widget to make sure its internal scroll position is up-to-date
		minecraftWidget.text = text
	}

	override fun drawContent(matrixStack: MatrixStack, mouse: Point, delta: Float) {
		matrixStack.push()
		matrixStack.translate(-originInWindow.x, -originInWindow.y, 0.0)

		val mouseXInWindow = (mouse.x + originInWindow.x).toInt()
		val mouseYInWindow = (mouse.y + originInWindow.y).toInt()
		minecraftWidget.render(matrixStack, mouseXInWindow, mouseYInWindow, delta)

		matrixStack.pop()
	}

	override fun mouseClicked(point: Point, mouseButton: MouseButton): Boolean {
		if (!disabled) {
			if (focused) {
				val mouseXInWindow = (point.x + originInWindow.x)
				val mouseYInWindow = (point.y + originInWindow.y)
				minecraftWidget.mouseClicked(mouseXInWindow, mouseYInWindow, mouseButton.ordinal)
			} else {
				becomeFirstResponder()
			}
		}
		// don't play sound when interacting with text field
		return false
	}

	override fun mouseClickedOutside(point: Point, mouseButton: MouseButton) {
		if (focused) {
			resignFirstResponder()
		}
	}

	override fun didBecomeFirstResponder() {
		super.didBecomeFirstResponder()
		minecraftWidget.setTextFieldFocused(true)
	}

	override fun didResignFirstResponder() {
		super.didResignFirstResponder()
		minecraftWidget.setTextFieldFocused(false)
	}

	override fun charTyped(char: Char, modifiers: KeyModifiers): Boolean {
		val oldText = text
		val result = minecraftWidget.charTyped(char, modifiers.value)
		if (text != oldText) {
			@Suppress("UNCHECKED_CAST")
			handler?.invoke(this as Impl)
		}
		return result
	}

	override fun keyPressed(keyCode: Int, modifiers: KeyModifiers): Boolean {
		val oldText = text
		// scanCode isn't used by TextFieldWidget, hopefully this doesn't break :/
		val result = minecraftWidget.keyPressed(keyCode, -1, modifiers.value)
		if (text != oldText) {
			@Suppress("UNCHECKED_CAST")
			handler?.invoke(this as Impl)
		}
		return result || (isFirstResponder && keyCode != GLFW.GLFW_KEY_ESCAPE)
	}

	fun tick() {
		minecraftWidget.tick()
	}

	// todo: label for the TextFieldWidget?
	private class ProxyWidget: TextFieldWidget(MinecraftClient.getInstance().textRenderer, 0, 0, 0, 0, LiteralText("")) {
		// AbstractButtonWidget.height is protected
		fun setHeight(height: Int) {
			this.height = height
		}
	}

}