mastodon-ios/Mastodon/Scene/Compose/View/AttachmentContainerView+EmptyStateView.swift

//
//  AttachmentContainerView+EmptyStateView.swift
//  Mastodon
//
//  Created by MainasuK Cirno on 2021-3-18.
//

import UIKit
import MastodonUI

extension AttachmentContainerView {
    final class EmptyStateView: UIView {
        
        static let photoFillSplitImage = Asset.Connectivity.photoFillSplit.image.withRenderingMode(.alwaysTemplate)
        static let videoSplashImage: UIImage = {
            let image = UIImage(systemName: "video.slash")!.withConfiguration(UIImage.SymbolConfiguration(pointSize: 64))
            return image
        }()
        
        let imageView: UIImageView = {
            let imageView = UIImageView()
            imageView.tintColor = Asset.Colors.Label.secondary.color
            imageView.image = AttachmentContainerView.EmptyStateView.photoFillSplitImage
            return imageView
        }()
        let label: UILabel = {
            let label = UILabel()
            label.font = .preferredFont(forTextStyle: .body)
            label.textColor = Asset.Colors.Label.secondary.color
            label.textAlignment = .center
            label.text = L10n.Scene.Compose.Attachment.attachmentBroken(L10n.Scene.Compose.Attachment.photo)
            label.numberOfLines = 2
            label.adjustsFontSizeToFitWidth = true
            label.minimumScaleFactor = 0.3
            return label
        }()
        
        override init(frame: CGRect) {
            super.init(frame: frame)
            _init()
        }
        
        required init?(coder: NSCoder) {
            super.init(coder: coder)
            _init()
        }
        
    }
}

extension AttachmentContainerView.EmptyStateView {
    private func _init() {
        layer.masksToBounds = true
        layer.cornerRadius = AttachmentContainerView.containerViewCornerRadius
        layer.cornerCurve = .continuous
        backgroundColor = ThemeService.shared.currentTheme.value.systemGroupedBackgroundColor
        
        let stackView = UIStackView()
        stackView.axis = .vertical
        stackView.alignment = .center
        stackView.translatesAutoresizingMaskIntoConstraints = false
        addSubview(stackView)
        NSLayoutConstraint.activate([
            stackView.topAnchor.constraint(equalTo: topAnchor),
            stackView.leadingAnchor.constraint(equalTo: leadingAnchor),
            stackView.trailingAnchor.constraint(equalTo: trailingAnchor),
            stackView.bottomAnchor.constraint(equalTo: bottomAnchor),
        ])
        let topPaddingView = UIView()
        let middlePaddingView = UIView()
        let bottomPaddingView = UIView()
        
        topPaddingView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(topPaddingView)
        imageView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(imageView)
        NSLayoutConstraint.activate([
            imageView.widthAnchor.constraint(equalToConstant: 92).priority(.defaultHigh),
            imageView.heightAnchor.constraint(equalToConstant: 76).priority(.defaultHigh),
        ])
        imageView.setContentHuggingPriority(.required - 1, for: .vertical)
        middlePaddingView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(middlePaddingView)
        stackView.addArrangedSubview(label)
        bottomPaddingView.translatesAutoresizingMaskIntoConstraints = false
        stackView.addArrangedSubview(bottomPaddingView)
        NSLayoutConstraint.activate([
            topPaddingView.heightAnchor.constraint(equalTo: middlePaddingView.heightAnchor, multiplier: 1.5),
            bottomPaddingView.heightAnchor.constraint(equalTo: middlePaddingView.heightAnchor, multiplier: 1.5),
        ])
    }
}

#if canImport(SwiftUI) && DEBUG
import SwiftUI

struct AttachmentContainerView_EmptyStateView_Previews: PreviewProvider {
    
    static var previews: some View {
        Group {
            UIViewPreview(width: 375) {
                let emptyStateView = AttachmentContainerView.EmptyStateView()
                NSLayoutConstraint.activate([
                    emptyStateView.heightAnchor.constraint(equalToConstant: 205)
                ])
                return emptyStateView
            }
            .previewLayout(.fixed(width: 375, height: 205))
            UIViewPreview(width: 375) {
                let emptyStateView = AttachmentContainerView.EmptyStateView()
                NSLayoutConstraint.activate([
                    emptyStateView.heightAnchor.constraint(equalToConstant: 205)
                ])
                return emptyStateView
            }
            .preferredColorScheme(.dark)
            .previewLayout(.fixed(width: 375, height: 205))
            UIViewPreview(width: 375) {
                let emptyStateView = AttachmentContainerView.EmptyStateView()
                emptyStateView.imageView.image = AttachmentContainerView.EmptyStateView.videoSplashImage
                emptyStateView.label.text = L10n.Scene.Compose.Attachment.attachmentBroken(L10n.Scene.Compose.Attachment.video)

                NSLayoutConstraint.activate([
                    emptyStateView.heightAnchor.constraint(equalToConstant: 205)
                ])
                return emptyStateView
            }
            .previewLayout(.fixed(width: 375, height: 205))
        }
    }
    
}

#endif