/*

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

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This is the main Document class which reads and writes our document objects using proper file coordination.

*/

import UIKit

import SceneKit

/// We save and restore the camera state as an object to be able to use `NSCoding`.

class CameraState: NSObject, NSCoding {

    // MARK: - Properties

    var position: SCNVector3!

    var rotation: SCNVector4

    // MARK: - Initialization

    override init() {

        position = SCNVector3(x: 0, y: 0, z: 4)

        rotation = SCNVector4()

        super.init()

    }

    // MARK: - NSCoding

    required init?(coder aDecoder: NSCoder) {

        position = SCNVector3(x: 0, y: 0, z: 4)

        rotation = SCNVector4()

        position.x = aDecoder.decodeFloatForKey("x")

        position.y = aDecoder.decodeFloatForKey("y")

        position.z = aDecoder.decodeFloatForKey("z")

        rotation.x = aDecoder.decodeFloatForKey("rx")

        rotation.y = aDecoder.decodeFloatForKey("ry")

        rotation.z = aDecoder.decodeFloatForKey("rz")

        rotation.w = aDecoder.decodeFloatForKey("rw")

        super.init()

    }

    func encodeWithCoder(aCoder: NSCoder) {

        aCoder.encodeFloat(position.x, forKey: "x")

        aCoder.encodeFloat(position.y, forKey: "y")

        aCoder.encodeFloat(position.z, forKey: "z")

        aCoder.encodeFloat(rotation.x, forKey: "rx")

        aCoder.encodeFloat(rotation.y, forKey: "ry")

        aCoder.encodeFloat(rotation.z, forKey: "rz")

        aCoder.encodeFloat(rotation.w, forKey: "rw")

    }

}

/**

    The `ShapeDocument` is our main document class which manages loading and saving

    of shape files on disk.  We subclass from `UIDocument` in order to load and 

    save with proper file coordination handled automatically.

*/

class ShapeDocument: UIDocument {

    // MARK: - Types

    enum Shape: Int {

        case Sphere

        case Cube

        case Cylinder

        case Cone

        case Torus

        case Pyramid

    }

    // MARK: - Declarations

    static let shapeKey       = "shape"

    static let cameraStateKey = "cameraState"

    // MARK: - Properties

    var shape: Shape?

    var cameraState = CameraState()

    // MARK: - Document loading override

    override func loadFromContents(contents: AnyObject, ofType typeName: String?) throws {

        guard let data = contents as? NSData else {

            fatalError("Cannot handle contents of type \(contents.dynamicType).")

        }

        // Our document format is a simple plist.

        guard let plist = try NSPropertyListSerialization.propertyListWithData(data, options: .MutableContainersAndLeaves, format: nil) as? [String: AnyObject] else {

            throw ShapeEditError.PlistReadFailed

        }

        // The shape is saved as a number corresponding to our enum.

        guard let shapeRawValue = plist[ShapeDocument.shapeKey] as? Int else {

            throw ShapeEditError.NoShape

        }

        shape = Shape(rawValue: shapeRawValue)

        // The camera state is saved using NSCoding.

        if let cameraStateData = plist[ShapeDocument.cameraStateKey] as? NSData,

              cameraState = NSKeyedUnarchiver.unarchiveObjectWithData(cameraStateData) as? CameraState {

            self.cameraState = cameraState

        }

        else {

            // This is a new document so save it to disk to generate the thumbnail.

            updateChangeCount(.Done)

        }

    }

    // MARK: - Document Saving Override

    override func contentsForType(typeName: String) throws -> AnyObject {

        /*

            Saving the document consists of creating the property list, then 

            creating an `NSData` object using plist serialization.

        */

        let cameraStateData = NSKeyedArchiver.archivedDataWithRootObject(cameraState)

        guard let shapeRawValue = shape?.rawValue else {

            throw ShapeEditError.NoShape

        }

        let plist: [NSObject: AnyObject] = [

            ShapeDocument.shapeKey: shapeRawValue,

            ShapeDocument.cameraStateKey: cameraStateData

        ]

        return try NSPropertyListSerialization.dataWithPropertyList(plist, format: .BinaryFormat_v1_0, options: 0)

    }

    override func fileAttributesToWriteToURL(url: NSURL, forSaveOperation saveOperation: UIDocumentSaveOperation) throws -> [NSObject: AnyObject] {

        let aspectRatio = 220.0 / 270.0

        let thumbnailSize = CGSize(width: CGFloat(1024.0 * aspectRatio), height: 1024.0)

        let image = renderThumbnailOfSize(thumbnailSize)

        return [

            NSURLHasHiddenExtensionKey: true,

            NSURLThumbnailDictionaryKey: [

                NSThumbnail1024x1024SizeKey: image

            ]

        ]

    }

    // MARK: - View Interaction

    func updateCameraState(node: SCNNode) {

        // Called by the view after the user has changed the camera state.

        cameraState.position = node.position

        cameraState.rotation = node.rotation

        updateChangeCount(.Done)

    }

    // MARK: - Thumbnail Generation

    var color: UIColor {

        switch shape {

            case nil:

                return UIColor.grayColor()

            case .Sphere?:

                return UIColor(red: 253/255, green: 61/255, blue: 57/255, alpha: 1)

            case .Cube?:

                return UIColor(red: 60/255, green: 171/255, blue: 219/255, alpha: 1)

            case .Cylinder?:

                return UIColor(red: 83/255, green: 216/255, blue: 106/255, alpha: 1)

            case .Cone?:

                return UIColor(red: 89/255, green: 91/255, blue: 212/255, alpha: 1)

            case .Torus?:

                return UIColor(red: 255/255, green: 204/255, blue: 0/255, alpha: 1)

            case .Pyramid?:

                return UIColor(red: 254/255, green: 149/255, blue: 38/255, alpha: 1)

        }

    }

    var backgroundColor: UIColor {

        return color.colorWithAlphaComponent(0.3)

    }

    func setSceneOnRenderer(renderer: SCNSceneRenderer) {

        let node: SCNNode

        let geometry: SCNGeometry

        switch shape {

            case nil:

                geometry = SCNGeometry()

            case .Sphere?:

                geometry = SCNSphere(radius: 1)

            case .Cube?:

                geometry = SCNBox(width: 2, height: 2, length: 2, chamferRadius: 0.1)

            case .Cylinder?:

                geometry = SCNCylinder(radius: 0.75, height: 2)

            case .Cone?:

                geometry = SCNCone(topRadius: 0.5, bottomRadius: 1.5, height: 1.5)

            case .Torus?:

                geometry = SCNTorus(ringRadius: 1.0, pipeRadius: 0.2)

            case .Pyramid?:

                geometry = SCNPyramid(width: 1.5, height: 1.5, length: 1.5)

        }

        let colorMaterial = SCNMaterial()

        colorMaterial.diffuse.contents = color

        geometry.firstMaterial = colorMaterial

        node = SCNNode(geometry: geometry)

        let scene = SCNScene()

        scene.rootNode.addChildNode(node)

        let camera = SCNCamera()

        let pov = SCNNode()

        pov.camera = camera

        pov.position = cameraState.position

        pov.rotation = cameraState.rotation

        scene.rootNode.addChildNode(pov)

        let ambientLight = SCNLight()

        let ambientLightNode = SCNNode()

        ambientLight.type = SCNLightTypeAmbient

        ambientLight.color = UIColor(white: 0.3, alpha: 1)

        ambientLightNode.light = ambientLight

        scene.rootNode.addChildNode(ambientLightNode);

        renderer.scene = scene

        renderer.scene = scene

        renderer.pointOfView = pov

    }

    func renderThumbnailOfSize(size: CGSize) -> UIImage {

        /*

            We want to create a thumbnail while running on the background thread.

            The obvious choice would be to use `SCNView`'s snapshot method, but we

            have a problem: we don't have an `SCNView`, and we can't create a view

            while on the background thread. Instead of eagerly creating a view

            that is only used for snapshotting, we create our own renderer, frame,

            color and depth buffers, and then render and read the pixels into a

            `CGImage`.

        */

        let width = Int(size.width)

        let height = Int(size.height)

        // Create and setup a context and renderer.

        let glContext = EAGLContext(API: .OpenGLES2)!

        let renderer = SCNRenderer(context: glContext, options: [:])

        renderer.autoenablesDefaultLighting = true

        setSceneOnRenderer(renderer)

        // Make the context current.

        let previousContext = EAGLContext.currentContext()

        defer {

            EAGLContext.setCurrentContext(previousContext)

        }

        EAGLContext.setCurrentContext(glContext)

        // Create our frame buffer.

        var frameBuffer: GLuint = 0

        glGenFramebuffers(1, &frameBuffer)

        defer {

            glDeleteFramebuffers(1, &frameBuffer)

        }

        glBindFramebuffer(GLenum(GL_FRAMEBUFFER), frameBuffer)

        // Create a color buffer (RGBA) and attach it to our frame buffer.

        var colorBuffer: GLuint = 0

        glGenRenderbuffers(1, &colorBuffer)

        defer {

            glDeleteRenderbuffers(1, &colorBuffer)

        }

        glBindRenderbuffer(GLenum(GL_RENDERBUFFER), colorBuffer)

        // RGBA.

        glRenderbufferStorage(GLenum(GL_RENDERBUFFER), GLenum(GL_RGBA8), GLsizei(width), GLsizei(height))

        glFramebufferRenderbuffer(GLenum(GL_FRAMEBUFFER), GLenum(GL_COLOR_ATTACHMENT0), GLenum(GL_RENDERBUFFER), colorBuffer)

        // Create a depth buffer and attach it to out frame buffer.

        var depthBuffer: GLuint = 0

        glGenRenderbuffers(1, &depthBuffer)

        defer {

            glDeleteRenderbuffers(1, &depthBuffer)

        }

        glBindRenderbuffer(GLenum(GL_RENDERBUFFER), depthBuffer)

        glRenderbufferStorage(GLenum(GL_RENDERBUFFER), GLenum(GL_DEPTH_COMPONENT24), GLsizei(width), GLsizei(height))

        glFramebufferRenderbuffer(GLenum(GL_FRAMEBUFFER), GLenum(GL_DEPTH_ATTACHMENT), GLenum(GL_RENDERBUFFER), depthBuffer)

        // Set the background color.

        var red: CGFloat = 0

        var green: CGFloat = 0

        var blue: CGFloat = 0

        var alpha: CGFloat = 0

        backgroundColor.getRed(&red, green: &green, blue: &blue, alpha: &alpha)

        glClearColor(Float(red), Float(green), Float(blue), Float(alpha))

        // Set our viewport, clear out the buffers and render.

        glViewport(0, 0, GLsizei(width), GLsizei(height))

        glClear(GLbitfield(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT))

        renderer.renderAtTime(0.0)

        // Read the contents of our framebuffer into an `NSMutableData`.

        // RGBA.

        let componentsPerPixel = 4

        // 8-bit.

        let bitsPerComponent = 8

        let imageBits = NSMutableData(length: width * height * componentsPerPixel)!

        glReadPixels(0, 0, GLsizei(width), GLsizei(height), GLenum(GL_RGBA), GLenum(GL_UNSIGNED_BYTE), imageBits.mutableBytes)

        // Create a `CGImage` off that data.

        let colorSpace = CGColorSpaceCreateDeviceRGB()

        let dataProvider = CGDataProviderCreateWithCFData(imageBits)

        let cgBitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.Last.rawValue)

        let cgImage = CGImageCreate(width, height, bitsPerComponent, componentsPerPixel * bitsPerComponent, width * componentsPerPixel, colorSpace, cgBitmapInfo, dataProvider!, nil, false, .RenderingIntentDefault)!

        // Flip the image to match our Editor view's coordinate system.

        let image = UIImage(CGImage: cgImage)

        UIGraphicsBeginImageContextWithOptions(image.size, false, 1.0)

        let context = UIGraphicsGetCurrentContext()

        let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: image.size.height)

        CGContextConcatCTM(context!, flipVertical)

        let imageRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)

        image.drawInRect(imageRect)

        let flippedImage = UIGraphicsGetImageFromCurrentImageContext()

        UIGraphicsEndImageContext()

        return flippedImage!

    }

}