/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    An extension on `LevelScene` to provide additional debug drawing related to GameplayKit features. Debug drawing can be turned on by pressing the "/" key when running the game on OS X.

*/

import SpriteKit

import GameplayKit

// Extend LevelScene by adding functions for drawing graph connections and obstacles.

extension LevelScene {

    func debugDrawingEnabledDidChange() {

        // Draw or remove the pathfinding graph for this level.

        drawGraph()

        /*

            Turn on debug drawing for every obstacle in the level, to show their

            pathfinding buffer radius.

        */

        for obstacle in obstacleSpriteNodes {

            obstacle.debugDrawingEnabled = debugDrawingEnabled

        }

        // Notify any `beamNode`'s inside `BeamComponent`s of the new debug drawing state.

        for componentSystem in componentSystems {

            guard componentSystem.componentClass is BeamComponent.Type else { continue }

            for component in componentSystem.components as! [BeamComponent] {

                component.beamNode.debugDrawingEnabled = debugDrawingEnabled

            }

        }

    }

    /// Draws (or removes) a debug representation of the pathfinding graph for this level.

    func drawGraph() {

        guard debugDrawingEnabled else {

            graphLayer.removeAllChildren()

            return

        }

        for node in graph.nodes as! [GKGraphNode2D] {

            for destination in node.connectedNodes as! [GKGraphNode2D] {

                let points = [CGPoint(node.position), CGPoint(destination.position)]

                let shapeNode = SKShapeNode(points: UnsafeMutablePointer<CGPoint>(mutating: points), count: 2)

                shapeNode.strokeColor = SKColor(white: 1.0, alpha: 0.1)

                shapeNode.lineWidth = 2.0

                shapeNode.zPosition = -1

                graphLayer.addChild(shapeNode)

            }

        }

    }

}

/*

    Extend `SKSpriteNode` to draw a buffer radius around nodes that have physics bodies.

    This is useful when debugging `GKAgent2D` pathfinding around obstacles.

*/

extension SKSpriteNode {

    /// A convenience name for use when adding and removing the debug layer.

    private var debugBufferShapeName: String {

        return "debugBufferShape"

    }

    var debugDrawingEnabled: Bool {

        set {

            // Only enable buffer radius debug drawing for sprite nodes with a physics body.

            if physicsBody == nil { return }

            // Add a debug shape layer if we are turning on debug drawing for this node.

            if newValue == true {

                let bufferRadius = CGFloat(GameplayConfiguration.TaskBot.pathfindingGraphBufferRadius)

                let bufferFrame = frame.insetBy(dx: -bufferRadius, dy: -bufferRadius)

                let bufferedShape = SKShapeNode(rectOf: bufferFrame.size)

                bufferedShape.fillColor = SKColor(red: CGFloat(1.0), green: CGFloat(0.5), blue: CGFloat(0.0), alpha: CGFloat(0.2))

                bufferedShape.strokeColor = SKColor(red: CGFloat(1.0), green: CGFloat(0.5), blue: CGFloat(0.0), alpha: CGFloat(0.4))

                bufferedShape.name = debugBufferShapeName

                addChild(bufferedShape)

            }

            else {

                // Remove any existing debug shape layer if we are turning off debug drawing for this node.

                guard let debugBufferShape = childNode(withName: debugBufferShapeName) else { return }

                removeChildren(in: [debugBufferShape])

            }

        }

        get {

            // Debug drawing is considered "enabled" if we have the debug node as a child.

            return childNode(withName: debugBufferShapeName) != nil

        }

    }

}