new/CommonFrame/照片选择器/MTImagePicker/Model/MTImagePickerAssetsModel.swift

//
//  MTImagePickerAssetsModel.swift
//  MTImagePicker
//
//  Created by Luo on 6/27/16.
//  Copyright © 2016 Luo. All rights reserved.
//
import UIKit
import AssetsLibrary
import AVFoundation

public class MTImagePickerAssetsModel: MTImagePickerModel {

    public var asset: ALAsset!
    var lib: ALAssetsLibrary = ALAsset.lib

    private lazy var rept: ALAssetRepresentation = {
        return self.asset.defaultRepresentation()
    }()

    init(mediaType: MTImagePickerMediaType, sortNumber: Int, asset: ALAsset) {
        super.init(mediaType: mediaType, sortNumber: sortNumber)
        self.asset = asset
    }

    override func getFileName() -> String? {
        return self.rept.filename()
    }

    override func getThumbImage(size: CGSize) -> UIImage? {
        return UIImage(cgImage: self.asset.thumbnail().takeUnretainedValue())
    }

    override func getPreviewImage() -> UIImage? {
        return UIImage(cgImage: self.asset.aspectRatioThumbnail().takeUnretainedValue())
    }

    override func getImageAsync(complete:@escaping (UIImage?) -> Void) {
        DispatchQueue.global(priority: .default).async {
            let image = UIImage(cgImage: self.rept.fullScreenImage().takeUnretainedValue())
            DispatchQueue.main.async {
                complete(image)
            }
        }
    }

    override func getVideoDurationAsync(complete:@escaping (Double) -> Void) {
        complete((self.asset.value(forProperty: ALAssetPropertyDuration) as AnyObject).doubleValue)
    }

    override func getAVPlayerItem() -> AVPlayerItem? {
        return AVPlayerItem(url: self.rept.url())
    }

    override func getFileSize() -> Int {
        return Int(self.rept.size())
    }

}

class MTImagePickerAssetsAlbumModel: MTImagePickerAlbumModel {

    private var group: ALAssetsGroup

    init(group: ALAssetsGroup) {
        self.group = group
    }

    override func getAlbumCount() -> Int {
        return self.group.numberOfAssets()
    }

    override func getAlbumName() -> String? {
        return self.group.value(forProperty: ALAssetsGroupPropertyName) as? String
    }

    override func getAlbumImage(size: CGSize) -> UIImage? {
        return UIImage(cgImage: self.group.posterImage().takeUnretainedValue())
    }

    override func getMTImagePickerModelsListAsync(complete: @escaping ([MTImagePickerModel]) -> Void) {
        var models = [MTImagePickerModel]()
        DispatchQueue.global(priority: .default).async {
            self.group.enumerateAssets({ (result, index, _) in
                if let asset = result {
                    let ALAssetType = result?.value(forProperty: ALAssetPropertyType) as! NSString
                    let mediaType: MTImagePickerMediaType = ALAssetType.isEqual(to: ALAssetTypePhoto) ? .Photo : .Video
                    let model = MTImagePickerAssetsModel(mediaType: mediaType, sortNumber: index, asset: asset)
                    models.append(model)
                }

            })
            DispatchQueue.main.async {
                complete(models)
            }
        }
    }

}