//
//  LargeImageContentView.swift
//  Tusker
//
//  Created by Shadowfacts on 6/17/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm
import AVFoundation

protocol LargeImageContentView: UIView {
    var animationImage: UIImage? { get }
    var animationGifData: Data? { get }
    var activityItemsForSharing: [Any] { get }
    func grayscaleStateChanged()
}

class LargeImageImageContentView: GIFImageView, LargeImageContentView {
    
    var animationImage: UIImage? { image! }
    let animationGifData: Data?
    
    var activityItemsForSharing: [Any] {
        [image!]
    }
    
    private var sourceData: Data?
    
    convenience init(sourceData data: Data, isGif: Bool) {
        self.init(image: UIImage(data: data)!, gifData: isGif ? data : nil)
        
        self.sourceData = data
    }
    
    init(image: UIImage, gifData: Data?) {
        self.animationGifData = gifData
        
        super.init(image: image)
        
        contentMode = .scaleAspectFit
        
        if let data = gifData {
            self.animate(withGIFData: data)
        }
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func grayscaleStateChanged() {
        guard let data = sourceData else {
            return
        }
        
        let image: UIImage?
        if Preferences.shared.grayscaleImages {
            image = ImageGrayscalifier.convert(url: nil, data: data)
        } else {
            image = UIImage(data: data)
        }
        
        if let image = image {
            self.image = image
        }
    }
}

class LargeImageGifvContentView: GifvAttachmentView, LargeImageContentView {
    private(set) var animationImage: UIImage?
    var animationGifData: Data? { nil }
    var activityItemsForSharing: [Any] {
        // todo: what should we share for gifvs?
        // some SO posts indicate that just sharing a URL to the video should work, but that may need to be a local URL?
        []
    }
    
    private let asset: AVURLAsset
    
    // The content view needs to supply an intrinsicContentSize for the LargeImageViewController to handle layout/scrolling/zooming correctly
    override var intrinsicContentSize: CGSize {
        // This is a really sucky workaround for the fact that in the content view, we don't have access to the size of the underlying video.
        // There's probably some way of getting this from the AVPlayer/AVAsset directly
        animationImage?.size ?? CGSize(width: UIView.noIntrinsicMetric, height: UIView.noIntrinsicMetric)
    }

    init(attachment: Attachment, source: UIImageView) {
        precondition(attachment.kind == .gifv)
        
        self.asset = AVURLAsset(url: attachment.url)
        
        super.init(asset: asset, gravity: .resizeAspect)
        
        self.animationImage = source.image
        
        self.player.play()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func grayscaleStateChanged() {
        // no-op, GifvAttachmentView observes the grayscale state itself
    }
}