ASMR/src/main/kotlin/net/shadowfacts/asmr/ui/ProgramCanvasView.kt

package net.shadowfacts.asmr.ui

import net.shadowfacts.asmr.program.*
import net.shadowfacts.asmr.program.execution.ExecutableBlock
import net.shadowfacts.asmr.ui.block.ProgramBlockParamView
import net.shadowfacts.asmr.ui.block.ProgramBlockView
import net.shadowfacts.cacao.geometry.Point
import net.shadowfacts.cacao.util.Color
import net.shadowfacts.cacao.util.MouseButton
import net.shadowfacts.cacao.util.RenderHelper
import net.shadowfacts.cacao.view.View

/**
 * @author shadowfacts
 */
class ProgramCanvasView(val program: Program): View() {

	private lateinit var blocks: Map<ProgramBlock, ProgramBlockView>

	// map of starting block to (start, end) points
	private val executionFlowStartLinks = mutableMapOf<ExecutableBlock, Pair<Point, Point>>()
	private val parameterLinks = mutableMapOf<ProgramBlock, Pair<Point, Point>>()

	private var currentPartialLink: PartialLink? = null

	override fun wasAdded() {
		super.wasAdded()

		zIndex = 5.0

		blocks = program.blocks.associateWith { ProgramBlockView(it) }
		blocks.values.forEach {
			addSubview(it)
		}
	}

	private fun updateBlockLinks() {
		for ((startBlock, startView) in blocks) {
			(startBlock as? ExecutableBlock)?.let { startBlock ->
				for (outgoing in startBlock.outgoing) {
					val outgoingView = startView.outgoingViews[outgoing] ?: continue
					val start = outgoingView.convert(outgoingView.bounds.center, to = this)
					val incoming = outgoing.destination ?: continue
					val incomingBlockView = blocks[incoming.block] ?: continue
					val incomingView = incomingBlockView.incomingView!!
					val end = incomingView.convert(incomingView.bounds.center, to = this)

					executionFlowStartLinks[startBlock] = start to end
				}
			}

			for (output in startBlock.outputs) {
				val outputView = startView.outputViews[output] ?: continue
				val start = outputView.convert(outputView.bounds.center, to = this)

				for (destination in output.destinations) {
					val endView = blocks[destination.block] ?: continue
					val inputView = endView.inputViews[destination] ?: continue
					val end = inputView.convert(inputView.bounds.center, to = this)

					parameterLinks[startBlock] = start to end
				}
			}
		}
	}

	override fun didLayout() {
		super.didLayout()

		// we can't calculate the link points until layout is completed and all of the views have concrete positions/sizes
		updateBlockLinks()
	}

	override fun drawContent(mouse: Point, delta: Float) {
		super.drawContent(mouse, delta)

		for ((start, end) in executionFlowStartLinks.values) {
			RenderHelper.drawLine(start, end, zIndex, 5f, Color.GREEN)
		}

		for ((start, end) in parameterLinks.values) {
			RenderHelper.drawLine(start, end, zIndex, 5f, Color.RED)
		}

		val currentPartialLink = currentPartialLink
		when (currentPartialLink) {
			is ParamInputPartialLink<*>, is ParamOutputPartialLink<*> -> {
				RenderHelper.drawLine(currentPartialLink.startPoint, mouse, zIndex, 5f, Color.RED)
			}
		}
	}

	override fun mouseClicked(point: Point, mouseButton: MouseButton): Boolean {
		for ((block, blockView) in blocks) {
			if (convert(point, to = blockView) !in blockView.bounds) continue

			for ((input, inputView) in blockView.inputViews) {
				if (convert(point, to = inputView) in inputView.bounds) {
					return inputViewClicked(block, input, inputView)
				}
			}
			for ((output, outputView) in blockView.outputViews) {
				if (convert(point, to = outputView) in outputView.bounds) {
					return outputViewClicked(block, output, outputView)
				}
			}
		}

		return super.mouseClicked(point, mouseButton)
	}

	private fun <Type: Any> inputViewClicked(block: ProgramBlock, input: ProgramBlockInput<Type>, inputView: ProgramBlockParamView): Boolean {
		val currentPartialLink = currentPartialLink
		val result = if (currentPartialLink == null) {
			// no partial link in progress, begin a new one
			this.currentPartialLink = ParamInputPartialLink(input, inputView, inputView.convert(inputView.bounds.center, to = this))
			true
		} else if (currentPartialLink is ParamOutputPartialLink<*> && currentPartialLink.output.type == input.type)  {
			// current link in progress originated with an output param of same type as clicked input, so complete it
			// we can ignore the unchecked cast because we checked it ourselves above by comparing ProgramTypes, but the compiler doesn't know that
			@Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
			val currentPartialLink = currentPartialLink as ParamOutputPartialLink<Type>
			currentPartialLink.output.link(to = input)
			currentPartialLink.view.updateTexture()
			inputView.updateTexture()
			this.currentPartialLink = null
			true
		} else {
			// otherwise, click always fails
			false
		}

		if (result) {
			updateBlockLinks()
		}
		return result
	}

	private fun <Type: Any> outputViewClicked(block: ProgramBlock, output: ProgramBlockOutput<Type>, outputView: ProgramBlockParamView): Boolean {
		val currentPartialLink = currentPartialLink
		val result = if (currentPartialLink == null) {
			this.currentPartialLink = ParamOutputPartialLink(output, outputView, outputView.convert(outputView.bounds.center, to = this))
			true
		} else if (currentPartialLink is ParamInputPartialLink<*> && currentPartialLink.input.type == output.type) {
			// current link in progress originated with an input param of same type as clicked output, so complete it
			// we can ignore the unchecked cast because we checked it ourselves above by comparing ProgramTypes, but the compiler doesn't know that
			@Suppress("NAME_SHADOWING", "UNCHECKED_CAST")
			val currentPartialLink = currentPartialLink as ParamInputPartialLink<Type>
			currentPartialLink.input.link(from = output)
			currentPartialLink.view.updateTexture()
			outputView.updateTexture()
			this.currentPartialLink = null
			true
		} else {
			// otherwise, click always fails
			false
		}

		if (result) {
			updateBlockLinks()
		}
		return result
	}

	open class PartialLink(val view: ProgramBlockParamView, val startPoint: Point)
	class ParamInputPartialLink<Type: Any>(val input: ProgramBlockInput<Type>, view: ProgramBlockParamView, startPoint: Point): PartialLink(view, startPoint)
	class ParamOutputPartialLink<Type: Any>(val output: ProgramBlockOutput<Type>, view: ProgramBlockParamView, startPoint: Point): PartialLink(view, startPoint)
//	class ExecutionStartPartialLink<Type: Any>(val start: ExecutableBlock): PartialLink
//	class ExecutionEndPartialLink<Type: Any>(val end: ExecutableBlock): PartialLink

}