package net.shadowfacts.cacao

import net.minecraft.client.MinecraftClient
import net.minecraft.client.gui.screen.Screen
import net.minecraft.client.util.math.MatrixStack
import net.minecraft.sound.SoundEvents
import net.minecraft.text.LiteralText
import net.minecraft.text.Text
import net.shadowfacts.cacao.geometry.Point
import net.shadowfacts.cacao.util.KeyModifiers
import net.shadowfacts.cacao.util.MouseButton
import net.shadowfacts.cacao.util.RenderHelper
import net.shadowfacts.cacao.window.Window
import org.lwjgl.glfw.GLFW
import java.util.*

/**
 * This class serves as the bridge between Cacao and a Minecraft [Screen]. It renders Cacao [Window]s in Minecraft and
 * sends input events from Minecraft back to Cacao objects.
 *
 * @author shadowfacts
 */
open class CacaoScreen(title: Text = LiteralText("CacaoScreen")): Screen(title), AbstractCacaoScreen {

	// _windows is the internal, mutable object, since we only want it to by mutated by the add/removeWindow methods.
	private val _windows = LinkedList<Window>()
	/**
	 * The list of windows that belong to this screen.
	 *
	 * The window at the end of this list is the active window is the only window that will receive input events.
	 *
	 * This list should never be modified directly, only by using the [addWindow]/[removeWindow] methods.
	 */
	override val windows: List<Window> = _windows

	private var hasAppeared = false

	/**
	 * Adds the given window to this screen's window list at the given position.
	 *
	 * @param window The Window to add to this screen.
	 * @param index The index to insert the window into the window list at.
	 * @return The window that was added, as a convenience.
	 */
	override fun <T: Window> addWindow(window: T, index: Int): T {
		if (hasAppeared) {
			window.viewController.viewWillAppear()
		}

		_windows.add(index, window)

		window.screen = this
		window.wasAdded()
		window.resize(width, height)

		return window
	}

	/**
	 * Adds the given window to the end of this screen's window list, making it the active window.
	 */
	override fun <T : Window> addWindow(window: T): T {
		return addWindow(window, _windows.size)
	}

	/**
	 * Removes the given window from this screen's window list.
	 */
	override fun removeWindow(window: Window) {
		_windows.remove(window)
		if (windows.isEmpty()) {
			close()
		}
	}

	override fun screenWillAppear() {
		windows.forEach {
			it.viewController.viewWillAppear()
		}
	}

	override fun init() {
		super.init()

		windows.forEach {
			it.resize(width, height)
		}
	}

	override fun close() {
		super.close()

		windows.forEach {
			it.viewController.viewWillDisappear()
			it.viewController.viewDidDisappear()

			// resign the current first responder (if any)
			it.firstResponder = null
		}
	}

	override fun render(matrixStack: MatrixStack, mouseX: Int, mouseY: Int, delta: Float) {
		if (client != null) {
			// workaround this.minecraft sometimes being null causing a crash
			renderBackground(matrixStack)
		}

		val mouse = Point(mouseX, mouseY)
		windows.forEach {
			it.draw(matrixStack, mouse, delta)
		}
	}

	override fun mouseClicked(mouseX: Double, mouseY: Double, button: Int): Boolean {
		val window = windows.lastOrNull()
		val result = window?.mouseClicked(Point(mouseX, mouseY), MouseButton.fromMC(button))
		return if (result == true) {
			RenderHelper.playSound(SoundEvents.UI_BUTTON_CLICK)
			true
		} else {
			false
		}
	}

	override fun mouseDragged(mouseX: Double, mouseY: Double, button: Int, deltaX: Double, deltaY: Double): Boolean {
		val window = windows.lastOrNull()
		val startPoint = Point(mouseX, mouseY)
		val delta = Point(deltaX, deltaY)
		val result = window?.mouseDragged(startPoint, delta, MouseButton.fromMC(button))
		return result == true
	}

	override fun mouseReleased(mouseX: Double, mouseY: Double, button: Int): Boolean {
		val window = windows.lastOrNull()
		val result = window?.mouseReleased(Point(mouseX, mouseY), MouseButton.fromMC(button))
		return result == true
	}

	override fun mouseScrolled(mouseX: Double, mouseY: Double, amount: Double): Boolean {
		val window = windows.lastOrNull()
		val result = window?.mouseScrolled(Point(mouseX, mouseY), amount)
		return result == true
	}

	override fun keyPressed(keyCode: Int, scanCode: Int, modifiers: Int): Boolean {
		if (keyCode == GLFW.GLFW_KEY_ESCAPE) {
			windows.lastOrNull()?.removeFromScreen()
			return true
		} else {
			val modifiersSet by lazy { KeyModifiers(modifiers) }
			if (findResponder { it.keyPressed(keyCode, modifiersSet) }) {
				return true
			}
			return super.keyPressed(keyCode, scanCode, modifiers)
		}
	}

	override fun keyReleased(i: Int, j: Int, k: Int): Boolean {
		return super.keyReleased(i, j, k)
	}

	override fun charTyped(char: Char, modifiers: Int): Boolean {
		val modifiersSet by lazy { KeyModifiers(modifiers) }
		if (findResponder { it.charTyped(char, modifiersSet) }) {
			return true
		}
		return super.charTyped(char, modifiers)
	}

	override fun shouldCloseOnEsc(): Boolean {
		return false
	}

}

fun AbstractCacaoScreen.findResponder(fn: (Responder) -> Boolean): Boolean {
	var responder = windows.lastOrNull()?.firstResponder
	while (responder != null) {
		if (fn(responder)) {
			return true
		}
		responder = responder.nextResponder
	}
	return false
}