iOS/WAStickersThirdParty/StickerPackViewController.swift

//
// Copyright (c) WhatsApp Inc. and its affiliates.
// All rights reserved.
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree.
//

import UIKit

class StickerPackViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

    @IBOutlet private weak var stickerPackPublisherLabel: UILabel!
    @IBOutlet private weak var stickerPackAnimationIcon: UIImageView!
    @IBOutlet private weak var stickersCollectionView: UICollectionView!
    @IBOutlet private weak var bottomCollectionViewConstraint: NSLayoutConstraint!

    private let topMarginInset: CGFloat = 5.0
    private let marginInset: CGFloat = 22
    private let interimMargin: CGFloat = 16.0
    private var itemsPerRow: Int = 4
    private let portraitItems = 4
    private let landscapeItems = 8

    private var portraitConstraints: [NSLayoutConstraint] = []
    private var landscapeConstraints: [NSLayoutConstraint] = []

    private var bottomGradientView: GradientView = GradientView(topColor: UIColor.white.withAlphaComponent(0.0), bottomColor: UIColor.white)
    private var topDivider: UIView = UIView()

    private var portraitOrientation: Bool {
        let currentOrientation = UIDevice.current.orientation
        return currentOrientation == .portrait || currentOrientation == .faceUp || currentOrientation == .faceDown || currentOrientation == .portraitUpsideDown
    }

    var stickerPack: StickerPack!

    override func viewDidLoad() {
        super.viewDidLoad()

        if #available(iOS 11.0, *) {
            navigationItem.largeTitleDisplayMode = .always
        }

        if #available(iOS 10.0, *) {
            stickersCollectionView.isPrefetchingEnabled = false
        }
        stickersCollectionView.register(StickerCell.self, forCellWithReuseIdentifier: "StickerCell")
        stickersCollectionView.scrollIndicatorInsets.bottom = 10

        itemsPerRow = portraitOrientation ? portraitItems : landscapeItems

        let infoButton: UIButton = UIButton(type: .infoLight)
        infoButton.addTarget(self, action: #selector(infoPressed(button:)), for: .touchUpInside)
        navigationItem.rightBarButtonItem = UIBarButtonItem(customView: infoButton)

        bottomGradientView.isUserInteractionEnabled = false
        bottomGradientView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(bottomGradientView)

        topDivider.isUserInteractionEnabled = false
        topDivider.backgroundColor = UIColor(red: 164.0/255.0, green: 164.0/255.0, blue: 164.0/255.0, alpha: 1.0).withAlphaComponent(0.2)
        topDivider.alpha = 0.0
        topDivider.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(topDivider)

        let buttonImage: UIImage = UIImage(named: "WALogoIcon")!.withRenderingMode(.alwaysTemplate)
        let shareImage: UIImage = UIImage(named: "ShareIcon")!.withRenderingMode(.alwaysTemplate)

        let addButton: AquaButton = AquaButton(frame: .zero)
        addButton.setTitle("Add to WhatsApp", for: .normal)
        addButton.setImage(buttonImage, for: .normal)
        addButton.addTarget(self, action: #selector(addButtonPressed(button:)), for: .touchUpInside)
        addButton.translatesAutoresizingMaskIntoConstraints = false
        addButton.isEnabled = Interoperability.canSend()
        view.addSubview(addButton)

        let shareButton: GrayRoundedButton = GrayRoundedButton(frame: .zero)
        shareButton.setTitle("Share", for: .normal)
        shareButton.setImage(shareImage, for: .normal)
        shareButton.addTarget(self, action: #selector(shareButtonPressed(button:)), for: .touchUpInside)
        shareButton.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(shareButton)

        stickerPackPublisherLabel.text = "\(stickerPack.publisher) • \(stickerPack.formattedSize)"
        stickerPackAnimationIcon.isHidden = !stickerPack.animated

        let tapGuideLabel: UILabel = UILabel()
        tapGuideLabel.text = "Tap on any sticker to copy or share it"
        tapGuideLabel.font = UIFont.systemFont(ofSize: 15)
        tapGuideLabel.textColor = UIColor(red: 0.6, green: 0.6, blue: 0.6, alpha: 1.0)
        tapGuideLabel.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(tapGuideLabel)

        let buttonSize: CGSize = CGSize(width: 280.0, height: 50.0)
        let buttonLandscapeSize: CGSize = CGSize(width: 250.0, height: 50.0)
        let buttonBottomMargin: CGFloat = 20.0

        guard let view = view else { return }

        // Share button constraints
        view.addConstraint(NSLayoutConstraint(item: view, attribute: .bottomMargin, relatedBy: .equal, toItem: shareButton, attribute: .bottom, multiplier: 1.0, constant: buttonBottomMargin))
        let centerPortraitShareConstraint = NSLayoutConstraint(item: view, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: shareButton, attribute: .centerXWithinMargins, multiplier: 1.0, constant: 0.0)
        let centerLandscapeShareConstraint = NSLayoutConstraint(item: view, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: shareButton, attribute: .centerXWithinMargins, multiplier: 1.0, constant: -buttonSize.width / 2.0 - 5.0)
        portraitConstraints.append(centerPortraitShareConstraint)
        landscapeConstraints.append(centerLandscapeShareConstraint)
        view.addConstraint(centerPortraitShareConstraint)
        view.addConstraint(centerLandscapeShareConstraint)
        let widthPortraitShareConstraint = NSLayoutConstraint(item: shareButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1.0, constant: buttonSize.width)
        let widthLandscapeShareConstraint = NSLayoutConstraint(item: shareButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1.0, constant: buttonLandscapeSize.width)
        shareButton.addConstraint(widthPortraitShareConstraint)
        shareButton.addConstraint(widthLandscapeShareConstraint)
        portraitConstraints.append(widthPortraitShareConstraint)
        landscapeConstraints.append(widthLandscapeShareConstraint)
        shareButton.addConstraint(NSLayoutConstraint(item: shareButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: buttonSize.height))

        // Add button constraints
        let bottomPortraitAddConstraint = NSLayoutConstraint(item: shareButton, attribute: .top, relatedBy: .equal, toItem: addButton, attribute: .bottom, multiplier: 1.0, constant: 7.0)
        let bottomLandscapeAddConstraint = NSLayoutConstraint(item: view, attribute: .bottomMargin, relatedBy: .equal, toItem: addButton, attribute: .bottom, multiplier: 1.0, constant: buttonBottomMargin)
        portraitConstraints.append(bottomPortraitAddConstraint)
        landscapeConstraints.append(bottomLandscapeAddConstraint)
        view.addConstraint(bottomPortraitAddConstraint)
        view.addConstraint(bottomLandscapeAddConstraint)
        let centerPortraitAddConstraint = NSLayoutConstraint(item: view, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: addButton, attribute: .centerXWithinMargins, multiplier: 1.0, constant: 0.0)
        let centerLandscapeAddConstraint = NSLayoutConstraint(item: view, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: addButton, attribute: .centerXWithinMargins, multiplier: 1.0, constant: buttonSize.width / 2.0 + 5.0)
        portraitConstraints.append(centerPortraitAddConstraint)
        landscapeConstraints.append(centerLandscapeAddConstraint)
        view.addConstraint(centerPortraitAddConstraint)
        view.addConstraint(centerLandscapeAddConstraint)
        let widthPortraitAddConstraint = NSLayoutConstraint(item: addButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1.0, constant: buttonSize.width)
        let widthLandscapeAddConstraint = NSLayoutConstraint(item: addButton, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .width, multiplier: 1.0, constant: buttonLandscapeSize.width)
        addButton.addConstraint(widthPortraitAddConstraint)
        addButton.addConstraint(widthLandscapeAddConstraint)
        portraitConstraints.append(widthPortraitAddConstraint)
        landscapeConstraints.append(widthLandscapeAddConstraint)
        addButton.addConstraint(NSLayoutConstraint(item: addButton, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: buttonSize.height))

        // Tap guide label constraints
        view.addConstraint(NSLayoutConstraint(item: addButton, attribute: .top, relatedBy: .equal, toItem: tapGuideLabel, attribute: .bottom, multiplier: 1.0, constant: 14.0))
        view.addConstraint(NSLayoutConstraint(item: tapGuideLabel, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: view, attribute: .centerXWithinMargins, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: tapGuideLabel, attribute: .leading, relatedBy: .greaterThanOrEqual, toItem: view, attribute: .leading, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: view, attribute: .trailing, relatedBy: .greaterThanOrEqual, toItem: tapGuideLabel, attribute: .trailing, multiplier: 1.0, constant: 0.0))

        // Collection view constraint
        var bottomCollectionViewConstraint = self.bottomCollectionViewConstraint!
        view.removeConstraint(bottomCollectionViewConstraint)
        bottomCollectionViewConstraint = NSLayoutConstraint(item: tapGuideLabel, attribute: .top, relatedBy: .equal, toItem: stickersCollectionView, attribute: .bottom, multiplier: 1.0, constant: 10.0)
        view.addConstraint(bottomCollectionViewConstraint)

        // Gradient constraints
        view.addConstraint(NSLayoutConstraint(item: bottomGradientView, attribute: .bottom, relatedBy: .equal, toItem: stickersCollectionView, attribute: .bottom, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: bottomGradientView, attribute: .centerXWithinMargins, relatedBy: .equal, toItem: view, attribute: .centerXWithinMargins, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: bottomGradientView, attribute: .width, relatedBy: .equal, toItem: stickersCollectionView, attribute: .width, multiplier: 1.0, constant: 0.0))
        bottomGradientView.addConstraint(NSLayoutConstraint(item: bottomGradientView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: 50.0))

        // Top divider constraints
        view.addConstraint(NSLayoutConstraint(item: topDivider, attribute: .top, relatedBy: .equal, toItem: stickersCollectionView, attribute: .top, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: topDivider, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1.0, constant: 0.0))
        view.addConstraint(NSLayoutConstraint(item: topDivider, attribute: .trailing, relatedBy: .equal, toItem: view, attribute: .trailing, multiplier: 1.0, constant: 0.0))
        topDivider.addConstraint(NSLayoutConstraint(item: topDivider, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .height, multiplier: 1.0, constant: 1.0))

        changeConstraints()
    }

    private func changeConstraints() {
        portraitConstraints.forEach { $0.isActive = portraitOrientation }
        landscapeConstraints.forEach { $0.isActive = !portraitOrientation }
    }

    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        itemsPerRow = portraitOrientation ? portraitItems : landscapeItems
        changeConstraints()
    }

    // MARK: Scrollview

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if scrollView.contentOffset.y > topMarginInset {
            topDivider.alpha = 1.0
        } else {
            topDivider.alpha = 0.0
        }
    }

    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        if scrollView.contentOffset.y > topMarginInset {
            topDivider.alpha = 1.0
        } else {
            topDivider.alpha = 0.0
        }
    }

    // MARK: Collectionview

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return interimMargin
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: topMarginInset, left: marginInset, bottom: 60, right: marginInset)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let length = (collectionView.bounds.size.width - marginInset * 2 - interimMargin * CGFloat(itemsPerRow - 1)) / CGFloat(itemsPerRow)
        return CGSize(width: length, height: length)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return stickerPack.stickers.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "StickerCell", for: indexPath) as! StickerCell
        cell.sticker = stickerPack.stickers[indexPath.row]
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let sticker: Sticker = stickerPack.stickers[indexPath.item]
        let cell = collectionView.cellForItem(at: indexPath)
        showActionSheet(withSticker: sticker, overCell: cell!)
    }

    // MARK: Targets

    func showActionSheet(withSticker sticker: Sticker, overCell cell: UICollectionViewCell) {
        var emojisString: String?

        #if DEBUG
        if let emojis = sticker.emojis {
            emojisString = emojis.joined(separator: " ")
        }
        #endif

        let actionSheet: UIAlertController = UIAlertController(title: "\n\n\n\n\n\n\n", message: emojisString, preferredStyle: .actionSheet)
        
        actionSheet.popoverPresentationController?.sourceView = cell.contentView
        actionSheet.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection()
        actionSheet.popoverPresentationController?.sourceRect = CGRect(x: cell.contentView.bounds.midX, y: cell.contentView.bounds.midY, width: 0, height: 0)

        actionSheet.addAction(UIAlertAction(title: "Copy to Clipboard", style: .default, handler: { _ in
            sticker.copyToPasteboardAsImage()
        }))
        actionSheet.addAction(UIAlertAction(title: "Share via", style: .default, handler: { _ in
            self.showShareSheet(withSticker: sticker)
        }))
        actionSheet.addAction(UIAlertAction(title: "Cancel", style: .cancel))

        if let stickerImage = sticker.imageData.image {
            actionSheet.addImageView(withImage: stickerImage, animated: sticker.imageData.animated)
        }
        present(actionSheet, animated: true)
    }

    func showShareSheet(withSticker sticker: Sticker) {
        guard let image = sticker.imageData.image else { return }

        let shareViewController: UIActivityViewController = UIActivityViewController(activityItems: [image], applicationActivities: nil)
        shareViewController.popoverPresentationController?.sourceView = self.view
        shareViewController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection()
        shareViewController.popoverPresentationController?.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
        present(shareViewController, animated: true)
    }

    @objc func infoPressed(button: UIButton) {
        performSegue(withIdentifier: "info", sender: self)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let nc = segue.destination as? UINavigationController,
            let infoVC = nc.viewControllers.first as? StickerPackInfoViewController {
            infoVC.stickerPack = stickerPack
        }
    }

    @objc func addButtonPressed(button: AquaButton) {
        let loadingAlert: UIAlertController = UIAlertController(title: "Sending to WhatsApp", message: "\n\n", preferredStyle: .alert)
        loadingAlert.addSpinner()
        present(loadingAlert, animated: true)

        stickerPack.sendToWhatsApp { completed in
            loadingAlert.dismiss(animated: true)
        }
    }

    @objc func shareButtonPressed(button: GrayRoundedButton) {
        var stickerImages: [UIImage] = []

        for sticker in stickerPack.stickers {
            if let image = sticker.imageData.image {
                stickerImages.append(image)
            }
        }

        let activityViewController: UIActivityViewController = UIActivityViewController(activityItems: stickerImages, applicationActivities: nil)
        let parentView = button as UIView
        activityViewController.popoverPresentationController?.sourceView = parentView
        activityViewController.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection()
        activityViewController.popoverPresentationController?.sourceRect = CGRect(x: parentView.bounds.midX, y: parentView.bounds.midY, width: 0, height: 0)
        present(activityViewController, animated: true)
    }
}