Swiftgram/submodules/TelegramUI/Components/EmptyStateIndicatorComponent/Sources/EmptyStateIndicatorComponent.swift

import Foundation
import UIKit
import Display
import ComponentFlow
import AnimatedStickerComponent
import ButtonComponent
import TelegramPresentationData
import AccountContext
import MultilineTextComponent

public final class EmptyStateIndicatorComponent: Component {
    public let context: AccountContext
    public let animationName: String
    public let title: String
    public let text: String
    public let theme: PresentationTheme
    public let action: () -> Void
    
    public init(
        context: AccountContext,
        theme: PresentationTheme,
        animationName: String,
        title: String,
        text: String,
        action: @escaping () -> Void
    ) {
        self.context = context
        self.theme = theme
        self.animationName = animationName
        self.title = title
        self.text = text
        self.action = action
    }

    public static func ==(lhs: EmptyStateIndicatorComponent, rhs: EmptyStateIndicatorComponent) -> Bool {
        if lhs.context !== rhs.context {
            return false
        }
        if lhs.theme !== rhs.theme {
            return false
        }
        if lhs.animationName != rhs.animationName {
            return false
        }
        if lhs.title != rhs.title {
            return false
        }
        if lhs.text != rhs.text {
            return false
        }
        return true
    }

    public final class View: UIView {
        private var component: EmptyStateIndicatorComponent?
        private weak var componentState: EmptyComponentState?

        private let animation = ComponentView<Empty>()
        private let title = ComponentView<Empty>()
        private let text = ComponentView<Empty>()
        private let button = ComponentView<Empty>()
        
        override public init(frame: CGRect) {
            super.init(frame: frame)
        }

        required public init(coder: NSCoder) {
            preconditionFailure()
        }

        public func update(component: EmptyStateIndicatorComponent, availableSize: CGSize, state: EmptyComponentState, environment: Environment<Empty>, transition: Transition) -> CGSize {
            self.component = component
            self.componentState = state
            
            let animationSize = self.animation.update(
                transition: transition,
                component: AnyComponent(AnimatedStickerComponent(
                    account: component.context.account,
                    animation: AnimatedStickerComponent.Animation(source: .bundle(name: component.animationName), loop: true),
                    size: CGSize(width: 200.0, height: 200.0)
                )),
                environment: {},
                containerSize: CGSize(width: 200.0, height: 200.0)
            )
            let titleSize = self.title.update(
                transition: .immediate,
                component: AnyComponent(MultilineTextComponent(
                    text: .plain(NSAttributedString(string: component.title, font: Font.semibold(17.0), textColor: component.theme.list.itemPrimaryTextColor)),
                    horizontalAlignment: .center,
                    maximumNumberOfLines: 0
                )),
                environment: {},
                containerSize: CGSize(width: min(300.0, availableSize.width - 16.0 * 2.0), height: 1000.0)
            )
            let textSize = self.text.update(
                transition: .immediate,
                component: AnyComponent(MultilineTextComponent(
                    text: .plain(NSAttributedString(string: component.text, font: Font.regular(15.0), textColor: component.theme.list.itemSecondaryTextColor)),
                    horizontalAlignment: .center,
                    maximumNumberOfLines: 0
                )),
                environment: {},
                containerSize: CGSize(width: min(300.0, availableSize.width - 16.0 * 2.0), height: 1000.0)
            )
            
            let animationSpacing: CGFloat = 16.0
            let titleSpacing: CGFloat = 16.0
            
            let totalHeight: CGFloat = animationSize.height + animationSpacing + titleSize.height + titleSpacing + textSize.height
            
            var contentY = floor((availableSize.height - totalHeight) * 0.5)
            
            if let animationView = self.animation.view {
                if animationView.superview == nil {
                    self.addSubview(animationView)
                }
                transition.setFrame(view: animationView, frame: CGRect(origin: CGPoint(x: floor((availableSize.width - animationSize.width) * 0.5), y: contentY), size: animationSize))
                contentY += animationSize.height + animationSpacing
            }
            if let titleView = self.title.view {
                if titleView.superview == nil {
                    self.addSubview(titleView)
                }
                transition.setFrame(view: titleView, frame: CGRect(origin: CGPoint(x: floor((availableSize.width - titleSize.width) * 0.5), y: contentY), size: titleSize))
                contentY += titleSize.height + titleSpacing
            }
            if let textView = self.text.view {
                if textView.superview == nil {
                    self.addSubview(textView)
                }
                transition.setFrame(view: textView, frame: CGRect(origin: CGPoint(x: floor((availableSize.width - textSize.width) * 0.5), y: contentY), size: textSize))
                contentY += textSize.height + titleSpacing
            }
            
            return availableSize
        }
    }

    public func makeView() -> View {
        return View(frame: CGRect())
    }

    public func update(view: View, availableSize: CGSize, state: EmptyComponentState, environment: Environment<Empty>, transition: Transition) -> CGSize {
        return view.update(component: self, availableSize: availableSize, state: state, environment: environment, transition: transition)
    }
}