session-ios/SessionUIKit/Components/Input View/InputView.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import UIKit
import UniformTypeIdentifiers
import Combine

public final class InputView: UIView, InputViewButtonDelegate, InputTextViewDelegate, MentionSelectionViewDelegate {
    public struct Input: Equatable, OptionSet {
        public let rawValue: Int
        
        public init(rawValue: Int) {
            self.rawValue = rawValue
        }
        
        public static let text: Input = Input(rawValue: 1 << 0)
        public static let attachments: Input = Input(rawValue: 1 << 1)
        public static let voiceMessages: Input = Input(rawValue: 1 << 2)
        public static let attachmentsDisabled: Input = Input(rawValue: 1 << 3)
        public static let voiceMessagesDisabled: Input = Input(rawValue: 1 << 4)
        
        /// Used when we want to allow attachments/uploads but not show the attachments button
        public static let attachmentsHidden: Input = Input(rawValue: 1 << 5)
        
        public static let all: Input = [.text, .attachments, .voiceMessages]
        public static let disabled: Input = [.attachmentsDisabled, .voiceMessagesDisabled]
    }
    
    public struct InputState: Equatable {
        public let inputs: Input
        public let message: String?
        public let alwaysShowSendButton: Bool
        public let accessibility: Accessibility?
        public let messageAccessibility: Accessibility?
        
        public static var all: InputState = InputState(inputs: .all)
        
        // MARK: - Initialization
        
        public init(
            inputs: Input,
            message: String? = nil,
            alwaysShowSendButton: Bool = false,
            accessibility: Accessibility? = nil,
            messageAccessibility: Accessibility? = nil
        ) {
            self.inputs = inputs
            self.message = message
            self.alwaysShowSendButton = alwaysShowSendButton
            self.accessibility = accessibility
            self.messageAccessibility = messageAccessibility
        }
    }
    
    // MARK: - Variables
    
    private static let linkPreviewViewInset: CGFloat = 6
    private static let thresholdForCharacterLimit: Int = 200

    private let imageDataManager: ImageDataManagerType
    private let linkPreviewManager: LinkPreviewManagerType
    private let didLoadLinkPreview: (@MainActor (LinkPreviewViewModel.LoadResult) -> Void)?
    private let onQuoteCancelled: (() -> Void)?
    private weak var delegate: InputViewDelegate?
    private var sessionProManager: SessionProUIManagerType?
    
    public var quoteViewModel: QuoteViewModel? { didSet { handleQuoteDraftChanged() } }
    public var linkPreviewViewModel: LinkPreviewViewModel?
    private var proStatusObservationTask: Task<Void, Never>?
    private var linkPreviewLoadTask: Task<Void, Never>?
    private var voiceMessageRecordingView: VoiceMessageRecordingView?
    private lazy var mentionsViewHeightConstraint = mentionsView.set(.height, to: 0)

    private lazy var linkPreviewContainerView: UIView = {
        let result: UIView = UIView()
        result.isHidden = true
        result.addSubview(linkPreviewView)
        linkPreviewView.pin(.top, to: .top, of: result, withInset: 10)
        linkPreviewView.pin(.leading, to: .leading, of: result, withInset: (12 + InputView.linkPreviewViewInset))
        linkPreviewView.pin(.trailing, to: .trailing, of: result, withInset: -14)
        linkPreviewView.pin(.bottom, to: .bottom, of: result, withInset: -4)
        
        return result
    }()
    
    private lazy var linkPreviewView: LinkPreviewView = LinkPreviewView { [weak self] in
        self?.linkPreviewViewModel = nil
        self?.linkPreviewContainerView.isHidden = true
    }

    @MainActor public var text: String {
        get { inputTextView.text ?? "" }
        set { inputTextView.text = newValue }
    }
    
    @MainActor var selectedRange: NSRange {
        get { inputTextView.selectedRange }
        set { inputTextView.selectedRange = newValue }
    }
    
    @MainActor var inputState: InputState = .all {
        didSet { setMessageInputState(inputState) }
    }

    public override var intrinsicContentSize: CGSize { CGSize.zero }
    var lastSearchedText: String? { nil }
    
    public var isInputFirstResponder: Bool {
        inputTextView.isFirstResponder
    }

    // MARK: - UI
    
    private lazy var disabledInputTapGestureRecognizer: UITapGestureRecognizer = {
        let result: UITapGestureRecognizer = UITapGestureRecognizer()
        result.addTarget(self, action: #selector(disabledInputTapped))
        result.isEnabled = false
        
        return result
    }()

    private lazy var swipeGestureRecognizer: UISwipeGestureRecognizer = {
        let result: UISwipeGestureRecognizer = UISwipeGestureRecognizer()
        result.direction = .down
        result.addTarget(self, action: #selector(didSwipeDown))
        result.cancelsTouchesInView = false
        
        return result
    }()
    
    public lazy var attachmentsButton: InputViewButton = {
        let result = InputViewButton(icon: #imageLiteral(resourceName: "ic_plus_24"), delegate: self)
        result.accessibilityLabel = "Attachments button"
        result.accessibilityIdentifier = "Attachments button"
        result.isAccessibilityElement = true
        
        return result
    }()
    public lazy var attachmentsButtonContainer = InputViewButton.container(for: attachmentsButton)

    public lazy var voiceMessageButton: InputViewButton = {
        let result = InputViewButton(icon: #imageLiteral(resourceName: "Microphone"), delegate: self)
        result.accessibilityLabel = "New voice message"
        result.accessibilityIdentifier = "New voice message"
        result.isAccessibilityElement = true
        
        return result
    }()

    public lazy var sendButton: InputViewButton = {
        let result = InputViewButton(icon: #imageLiteral(resourceName: "ArrowUp"), isSendButton: true, delegate: self)
        result.isHidden = !inputState.alwaysShowSendButton
        result.accessibilityIdentifier = "Send message button"
        result.accessibilityLabel = "Send message button"
        result.isAccessibilityElement = true
        
        return result
    }()
    private lazy var voiceMessageButtonContainer = InputViewButton.container(for: voiceMessageButton)
    
    private lazy var bottomStackView: UIStackView = {
        let result: UIStackView = UIStackView(arrangedSubviews: [
            attachmentsButtonContainer,
            inputTextView,
            InputViewButton.container(for: sendButton)
        ])
        result.axis = .horizontal
        result.spacing = Values.smallSpacing
        result.alignment = .center
        result.isLayoutMarginsRelativeArrangement = true
        
        let adjustment: CGFloat = (InputViewButton.expandedSize - InputViewButton.size) / 2
        result.layoutMargins = UIEdgeInsets(
            top: 2,
            leading: Values.mediumSpacing - adjustment,
            bottom: 2,
            trailing: Values.mediumSpacing - adjustment
        )
        
        return result
    }()

    private lazy var mentionsView: MentionSelectionView = {
        let result: MentionSelectionView = MentionSelectionView(dataManager: imageDataManager)
        result.delegate = self
        
        return result
    }()

    private lazy var mentionsViewContainer: UIView = {
        let result: UIView = UIView()
        result.accessibilityLabel = "Mentions list"
        result.accessibilityIdentifier = "Mentions list"
        result.alpha = 0
        result.isHidden = true
        
        let backgroundView = UIView()
        backgroundView.themeBackgroundColor = .backgroundSecondary
        backgroundView.alpha = Values.lowOpacity
        result.addSubview(backgroundView)
        backgroundView.pin(to: result)
        
        let blurView: UIVisualEffectView = UIVisualEffectView()
        result.addSubview(blurView)
        blurView.pin(to: result)
        
        ThemeManager.onThemeChange(observer: blurView) { [weak blurView] theme, _, _ in
            blurView?.effect = UIBlurEffect(style: theme.blurStyle)
        }
        
        result.addSubview(mentionsView)
        mentionsView.pin(to: result)
        
        return result
    }()
    
    private lazy var separator: UIView = {
        let result: UIView = UIView()
        result.themeBackgroundColor = .borderSeparator
        result.set(.height, to: Values.separatorThickness)
        
        return result
    }()
    
    private lazy var quoteViewContainerView: UIView = {
        let result: UIView = UIView()
        result.isHidden = true
        
        result.addSubview(quoteView)
        quoteView.pin(.top, to: .top, of: result, withInset: 12)
        quoteView.pin(.leading, to: .leading, of: result, withInset: (12 + 6))
        quoteView.pin(.trailing, to: .trailing, of: result, withInset: -11)
        quoteView.pin(.bottom, to: .bottom, of: result, withInset: -6)
        
        return result
    }()
    
    private lazy var quoteView: QuoteView = QuoteView(
        viewModel: .emptyDraft,
        dataManager: imageDataManager,
        onCancel: { [weak self] in
            self?.quoteViewModel = nil
            self?.quoteViewContainerView.isHidden = true
            self?.onQuoteCancelled?()
        }
    )

    private lazy var inputTextView: InputTextView = {
        // HACK: When restoring a draft the input text view won't have a frame yet, and therefore it won't
        // be able to calculate what size it should be to accommodate the draft text. As a workaround, we
        // just calculate the max width that the input text view is allowed to be and pass it in. See
        // setUpViewHierarchy() for why these values are the way they are.
        let adjustment = (InputViewButton.expandedSize - InputViewButton.size) / 2
        let maxWidth = UIScreen.main.bounds.width - 2 * InputViewButton.expandedSize - 2 * Values.smallSpacing - 2 * (Values.mediumSpacing - adjustment)
        let result = InputTextView(delegate: self, maxWidth: maxWidth)
        result.accessibilityLabel = "contentDescriptionMessageComposition".localized()
        result.accessibilityIdentifier = "Message input box"
        result.isAccessibilityElement = true
        
        return result
    }()

    private lazy var disabledInputLabel: UILabel = {
        let label: UILabel = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.font = .systemFont(ofSize: Values.smallFontSize)
        label.themeTextColor = .textPrimary
        label.textAlignment = .center
        label.alpha = 0
        label.numberOfLines = 0
        label.lineBreakMode = .byWordWrapping

        return label
    }()
    
    private lazy var proStackView: UIStackView = {
        let result = UIStackView(arrangedSubviews: [ characterLimitLabel, sessionProBadge ])
        result.axis = .vertical
        result.spacing = Values.verySmallSpacing
        result.alignment = .center
        result.addGestureRecognizer(characterLimitLabelTapGestureRecognizer)
        result.alpha = 0
        
        return result
    }()
    private lazy var characterLimitLabelTapGestureRecognizer: UITapGestureRecognizer = {
        let result: UITapGestureRecognizer = UITapGestureRecognizer()
        result.addTarget(self, action: #selector(characterLimitLabelTapped))
        result.isEnabled = false
        
        return result
    }()
    
    private lazy var characterLimitLabel: UILabel = {
        let label: UILabel = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.font = .systemFont(ofSize: Values.smallFontSize)
        label.themeTextColor = .textPrimary
        label.textAlignment = .center
        
        return label
    }()
    
    private lazy var sessionProBadge: SessionProBadge = {
        let result: SessionProBadge = SessionProBadge(size: .medium)
        result.isHidden = (sessionProManager?.currentUserIsCurrentlyPro == true)
        
        return result
    }()
    
    private lazy var mainStackView: UIStackView = {
        let result: UIStackView = UIStackView(arrangedSubviews: [
            mentionsViewContainer,
            separator,
            linkPreviewContainerView,
            quoteViewContainerView,
            bottomStackView
        ])
        result.axis = .vertical
        result.alignment = .fill
        result.distribution = .fill
        
        return result
    }()
    
    public var inputContainerForBackground: UIView { mainStackView }
    
    private lazy var extraStackView: UIStackView = {
        let result: UIStackView = UIStackView(arrangedSubviews: [
            mentionsViewContainer,
            mainStackView
        ])
        result.axis = .vertical
        result.alignment = .fill
        result.distribution = .fill
        
        return result
    }()

    // MARK: - Initialization
    
    public init(
        delegate: InputViewDelegate,
        imageDataManager: ImageDataManagerType,
        linkPreviewManager: LinkPreviewManagerType,
        sessionProManager: SessionProUIManagerType?,
        onQuoteCancelled: (() -> Void)? = nil,
        didLoadLinkPreview: (@MainActor (LinkPreviewViewModel.LoadResult) -> Void)?
    ) {
        self.imageDataManager = imageDataManager
        self.linkPreviewManager = linkPreviewManager
        self.delegate = delegate
        self.sessionProManager = sessionProManager
        self.didLoadLinkPreview = didLoadLinkPreview
        self.onQuoteCancelled = onQuoteCancelled
        
        super.init(frame: CGRect.zero)
        
        setUpViewHierarchy()
        
        self.proStatusObservationTask = Task(priority: .userInitiated) { [weak self] in
            guard let sessionProManager else { return }
            
            for await isPro in sessionProManager.currentUserIsPro {
                await MainActor.run { [weak self] in
                    /// The pro badge is a button to prompt a pro upgrade so hide it when already pro
                    self?.sessionProBadge.isHidden = isPro
                    self?.updateNumberOfCharactersLeft((self?.inputTextView.text ?? ""))
                }
            }
        }
    }

    override init(frame: CGRect) {
        preconditionFailure("Use init(delegate:) instead.")
    }

    required init?(coder: NSCoder) {
        preconditionFailure("Use init(delegate:) instead.")
    }
    
    deinit {
        linkPreviewLoadTask?.cancel()
        proStatusObservationTask?.cancel()
    }

    private func setUpViewHierarchy() {
        autoresizingMask = .flexibleHeight
        
        addGestureRecognizer(disabledInputTapGestureRecognizer)
        addGestureRecognizer(swipeGestureRecognizer)
        
        // Main stack view
        addSubview(extraStackView)
        extraStackView.pin(to: self)
        mentionsViewHeightConstraint.isActive = true
        
        // Pro stack view
        addSubview(proStackView)
        proStackView.pin(.bottom, to: .bottom, of: inputTextView)
        proStackView.center(.horizontal, in: sendButton)

        addSubview(disabledInputLabel)

        disabledInputLabel.pin(.top, to: .top, of: attachmentsButton)
        disabledInputLabel.pin(.leading, to: .leading, of: inputTextView)
        disabledInputLabel.pin(.trailing, to: .trailing, of: inputTextView)
        disabledInputLabel.set(.height, to: InputViewButton.expandedSize)
        
        // Voice message button
        addSubview(voiceMessageButtonContainer)
        voiceMessageButtonContainer.center(in: sendButton)
    }

    // MARK: - Updating
    
    @MainActor public func inputTextViewDidChangeSize(_ inputTextView: InputTextView) {
        invalidateIntrinsicContentSize()
        self.bottomStackView.alignment = (inputTextView.contentSize.height > inputTextView.minHeight) ? .top : .center
    }

    @MainActor public func inputTextViewDidChangeContent(_ inputTextView: InputTextView) {
        let hasText = !text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
        sendButton.isHidden = (
            !inputState.inputs.contains(.text) || (
                !hasText &&
                !inputState.alwaysShowSendButton
            )
        )
        voiceMessageButtonContainer.isHidden = (
            !sendButton.isHidden || (
                !inputState.inputs.contains(.voiceMessages) &&
                !inputState.inputs.contains(.voiceMessagesDisabled)
            )
        )
        autoGenerateLinkPreviewIfPossible()

        delegate?.inputTextViewDidChangeContent(inputTextView)
    }
    
    @MainActor public func updateNumberOfCharactersLeft(_ text: String) {
        let numberOfCharactersLeft: Int = SNUIKit.numberOfCharactersLeft(for: text)
        characterLimitLabel.text = "\(numberOfCharactersLeft.formatted(format: .abbreviated(decimalPlaces: 1)))"
        characterLimitLabel.themeTextColor = (numberOfCharactersLeft < 0) ? .danger : .textPrimary
        proStackView.alpha = (numberOfCharactersLeft <= Self.thresholdForCharacterLimit) ? 1 : 0
        characterLimitLabelTapGestureRecognizer.isEnabled = (numberOfCharactersLeft < Self.thresholdForCharacterLimit)
    }

    @MainActor public func didPasteImageDataFromPasteboard(_ inputTextView: InputTextView, imageData: Data) {
        delegate?.didPasteImageDataFromPasteboard(imageData)
    }

    // We want to show either a link preview or a quote draft, but never both at the same time. When trying to
    // generate a link preview, wait until we're sure that we'll be able to build a link preview from the given
    // URL before removing the quote draft.

    private func handleQuoteDraftChanged() {
        linkPreviewViewModel = nil
        linkPreviewContainerView.isHidden = true
        
        guard let quoteViewModel: QuoteViewModel = quoteViewModel else {
            quoteViewContainerView.isHidden = true
            return
        }
        
        quoteView.update(viewModel: quoteViewModel)
        quoteViewContainerView.isHidden = false
    }

    private func autoGenerateLinkPreviewIfPossible() {
        // If attachments aren't enabled then don't allow link previews
        guard inputState.inputs.contains(.attachments) else { return }

        // Suggest that the user enable link previews if they haven't already and we haven't
        // told them about link previews yet
        let text: String = (inputTextView.text ?? "")
        
        Task.detached(priority: .userInitiated) { [weak self] in
            guard let self else { return }
            guard await !linkPreviewManager.allPreviewUrls(forMessageBodyText: text).isEmpty else { return }
            
            let areLinkPreviewsEnabled: Bool = await linkPreviewManager.areLinkPreviewsEnabled
            let hasSeenLinkPreviewSuggestion: Bool = await linkPreviewManager.hasSeenLinkPreviewSuggestion
            
            if !areLinkPreviewsEnabled && !hasSeenLinkPreviewSuggestion {
                await MainActor.run { [weak self] in
                    self?.delegate?.showLinkPreviewSuggestionModal()
                }
                await linkPreviewManager.setHasSeenLinkPreviewSuggestion(true)
                return
            }
            
            // Proceed
            do {
                try await linkPreviewManager.ensureLinkPreviewsEnabled()
                await autoGenerateLinkPreview()
            }
            catch { await didLoadLinkPreview?(.error(error)) }
        }
    }

    public func autoGenerateLinkPreview() async {
        // Check that a valid URL is present
        guard
            let linkPreviewUrl: String = await linkPreviewManager.previewUrl(
                for: text,
                selectedRange: inputTextView.selectedRange
            ),
            linkPreviewUrl != self.linkPreviewViewModel?.urlString  /// Guard against obsolete updates
        else { return }
        
        await MainActor.run { [weak self] in
            guard let self else { return }
            
            /// Clear content container
            quoteViewModel = nil
            quoteViewContainerView.isHidden = true
            
            // Set the state to loading (but don't show yet)
            linkPreviewViewModel = LinkPreviewViewModel(state: .loading, urlString: linkPreviewUrl)
            linkPreviewView.update(
                with: LinkPreviewViewModel(state: .loading, urlString: linkPreviewUrl),
                isOutgoing: false,
                dataManager: imageDataManager
            )
            
            /// Build the link preview
            linkPreviewLoadTask?.cancel()
            linkPreviewLoadTask = Task.detached(priority: .userInitiated) { [weak self, inputs = inputState.inputs] in
                await withThrowingTaskGroup(of: Void.self) { [weak self] group in
                    /// Wait for a short period before showing the link preview UI (this is to avoid a situation where an invalid URL shows
                    /// the loading state very briefly before it disappears
                    group.addTask { [weak self] in
                        try await Task.sleep(for: .milliseconds(50))
                        
                        await MainActor.run { [weak self] in
                            guard let self else { return }
                            guard linkPreviewViewModel?.urlString == linkPreviewUrl else {
                                didLoadLinkPreview?(.obsolete) /// Obsolete
                                return
                            }
                            
                            linkPreviewContainerView.isHidden = false
                        }
                    }
                    group.addTask { [weak self] in
                        guard let self else { return }
                        
                        do {
                            /// Load the draft (If attachments aren't enabled then don't download link preview images)
                            let viewModel: LinkPreviewViewModel = try await linkPreviewManager.tryToBuildPreviewInfo(
                                previewUrl: linkPreviewUrl,
                                skipImageDownload: (
                                    !inputs.contains(.attachments) &&
                                    !inputs.contains(.attachmentsHidden)
                                )
                            )
                            try Task.checkCancellation()
                            
                            await MainActor.run { [weak self] in
                                guard let self else { return }
                                guard linkPreviewViewModel?.urlString == linkPreviewUrl else {
                                    didLoadLinkPreview?(.obsolete) /// Obsolete
                                    return
                                }
                                
                                linkPreviewViewModel = viewModel
                                didLoadLinkPreview?(.success(viewModel))
                                linkPreviewView.update(
                                    with: viewModel,
                                    isOutgoing: false,
                                    dataManager: imageDataManager
                                )
                                linkPreviewContainerView.isHidden = false
                                setNeedsLayout()
                                layoutIfNeeded()
                            }
                        }
                        catch {
                            await MainActor.run { [weak self] in
                                guard let self else { return }
                                guard linkPreviewViewModel?.urlString == linkPreviewUrl else {
                                    didLoadLinkPreview?(.obsolete) /// Obsolete
                                    return
                                }
                                
                                didLoadLinkPreview?(.error(error))
                                linkPreviewViewModel = nil
                                linkPreviewContainerView.isHidden = true
                                setNeedsLayout()
                                layoutIfNeeded()
                            }
                        }
                    }
                    
                    try? await group.waitForAll()
                }
            }
        }
    }

    @MainActor public func setMessageInputState(_ updatedInputState: InputState) {
        guard inputState != updatedInputState else { return }

        self.accessibilityIdentifier = updatedInputState.accessibility?.identifier
        self.accessibilityLabel = updatedInputState.accessibility?.label
        
        let hasText: Bool = ((inputTextView.text ?? "")
            .trimmingCharacters(in: .whitespacesAndNewlines).isEmpty == false)
        inputState = updatedInputState
        sendButton.isHidden = (
            !inputState.inputs.contains(.text) || (
                !hasText &&
                !inputState.alwaysShowSendButton
            )
        )
        disabledInputLabel.text = (updatedInputState.message ?? "")
        disabledInputLabel.accessibilityIdentifier = updatedInputState.messageAccessibility?.identifier
        disabledInputLabel.accessibilityLabel = updatedInputState.messageAccessibility?.label
        
        disabledInputTapGestureRecognizer.isEnabled = (
            updatedInputState.inputs.isEmpty ||
            updatedInputState.inputs == .disabled
        )
        attachmentsButtonContainer.isHidden = (
            !updatedInputState.inputs.contains(.attachments) &&
            !updatedInputState.inputs.contains(.attachmentsDisabled)
        )
        voiceMessageButtonContainer.isHidden = (
            !sendButton.isHidden || (
                !updatedInputState.inputs.contains(.voiceMessages) &&
                !updatedInputState.inputs.contains(.voiceMessagesDisabled)
            )
        )
        attachmentsButton.isSoftDisabled = updatedInputState.inputs.contains(.attachmentsDisabled)
        voiceMessageButton.isSoftDisabled = updatedInputState.inputs.contains(.voiceMessagesDisabled)

        UIView.animate(withDuration: 0.3) { [weak self] in
            self?.bottomStackView.arrangedSubviews.forEach { $0.alpha = updatedInputState.inputs.isEmpty ? 0 : 1 }
            self?.disabledInputLabel.alpha = ((self?.disabledInputLabel.text ?? "").isEmpty ? 0 : Values.mediumOpacity)
            self?.inputTextView.alpha = (updatedInputState.inputs.contains(.text) ? 1 : 0)
            self?.attachmentsButton.alpha = (updatedInputState.inputs.contains(.attachmentsDisabled) ? 0.4 : 1)
            self?.voiceMessageButton.alpha = (updatedInputState.inputs.contains(.voiceMessagesDisabled) ? 0.4 : 1)
            
            self?.attachmentsButton.updateAppearance(isEnabled: updatedInputState.inputs.contains(.attachments))
            self?.voiceMessageButton.updateAppearance(isEnabled: updatedInputState.inputs.contains(.voiceMessages))
        }
    }

    // MARK: - Interaction

    @MainActor public func handleInputViewButtonTapped(_ inputViewButton: InputViewButton) {
        if inputState.inputs.contains(.attachments) && inputViewButton == attachmentsButton {
            delegate?.handleAttachmentButtonTapped()
        }
        else if inputState.inputs.contains(.attachmentsDisabled) && inputViewButton == attachmentsButton {
            delegate?.handleDisabledAttachmentButtonTapped()
        }
        else if inputState.inputs.contains(.voiceMessagesDisabled) && inputViewButton == voiceMessageButton {
            delegate?.handleDisabledVoiceMessageButtonTapped()
        }
        else if inputViewButton == sendButton {
            delegate?.handleSendButtonTapped()
        }
    }

    @MainActor public func handleInputViewButtonLongPressBegan(_ inputViewButton: InputViewButton?) {
        guard inputViewButton == voiceMessageButton else { return }
        guard inputState.inputs.contains(.voiceMessages) else { return }
        
        // Note: The 'showVoiceMessageUI' call MUST come before triggering 'startVoiceMessageRecording'
        // because if something goes wrong it'll trigger `hideVoiceMessageUI` and we don't want it to
        // end up in a state with the input content hidden
        showVoiceMessageUI()
        delegate?.startVoiceMessageRecording()
    }

    @MainActor public func handleInputViewButtonLongPressMoved(_ inputViewButton: InputViewButton, with touch: UITouch?) {
        guard
            let voiceMessageRecordingView: VoiceMessageRecordingView = voiceMessageRecordingView,
            inputViewButton == voiceMessageButton,
            let location = touch?.location(in: voiceMessageRecordingView)
        else { return }
        
        voiceMessageRecordingView.handleLongPressMoved(to: location)
    }

    @MainActor public func handleInputViewButtonLongPressEnded(_ inputViewButton: InputViewButton, with touch: UITouch?) {
        guard
            let voiceMessageRecordingView: VoiceMessageRecordingView = voiceMessageRecordingView,
            inputViewButton == voiceMessageButton,
            let location = touch?.location(in: voiceMessageRecordingView)
        else { return }
        
        voiceMessageRecordingView.handleLongPressEnded(at: location)
    }

    public override func resignFirstResponder() -> Bool {
        inputTextView.resignFirstResponder()
    }
    
    @discardableResult
    public override func becomeFirstResponder() -> Bool {
        inputTextView.becomeFirstResponder()
    }

    func handleLongPress(_ gestureRecognizer: UITapGestureRecognizer) {
        // Not relevant in this case
    }

    @objc private func showVoiceMessageUI() {
        guard let targetSuperview: UIView = voiceMessageButton.superview else { return }
        
        voiceMessageRecordingView?.removeFromSuperview()
        let voiceMessageButtonFrame = targetSuperview.convert(voiceMessageButton.frame, to: self)
        let voiceMessageRecordingView = VoiceMessageRecordingView(
            voiceMessageButtonFrame: voiceMessageButtonFrame,
            delegate: delegate
        )
        voiceMessageRecordingView.alpha = 0
        addSubview(voiceMessageRecordingView)
        
        voiceMessageRecordingView.pin(to: self)
        self.voiceMessageRecordingView = voiceMessageRecordingView
        voiceMessageRecordingView.animate()
        let allOtherViews = [ attachmentsButton, sendButton, inputTextView ]
        UIView.animate(withDuration: 0.25) {
            allOtherViews.forEach { $0.alpha = 0 }
        }
    }

    @MainActor public func hideVoiceMessageUI() {
        let allOtherViews = [ attachmentsButton, sendButton, inputTextView ]
        UIView.animate(
            withDuration: 0.25,
            animations: {
                allOtherViews.forEach { $0.alpha = 1 }
                self.voiceMessageRecordingView?.alpha = 0
            },
            completion: { [weak self] _ in
                self?.voiceMessageRecordingView?.removeFromSuperview()
                self?.voiceMessageRecordingView = nil
            }
        )
    }

    @MainActor public func showMentionsUI(for candidates: [MentionSelectionView.ViewModel]) {
        mentionsView.candidates = candidates
        
        let mentionCellHeight = (ProfilePictureView.Info.Size.message.viewSize + 2 * Values.smallSpacing)
        mentionsViewHeightConstraint.constant = CGFloat(min(3, candidates.count)) * mentionCellHeight
        
        if mentionsViewContainer.isHidden {
            self.mentionsViewContainer.alpha = 0
            self.mentionsViewContainer.isHidden = false
        }
        layoutIfNeeded()
        
        if mentionsViewContainer.alpha < 1 {
            UIView.animate(withDuration: 0.15) { [weak self] in
                self?.mentionsViewContainer.alpha = 1
            }
        }
    }
    
    @MainActor public func hideMentionsUI() {
        UIView.animate(
            withDuration: 0.15,
            animations: { [weak self] in
                self?.mentionsViewContainer.alpha = 0
            },
            completion: { [weak self] _ in
                self?.mentionsViewContainer.isHidden = true
                self?.mentionsViewHeightConstraint.constant = 0
                self?.mentionsView.contentOffset = CGPoint.zero
            }
        )
    }

    @MainActor public func handleMentionSelected(_ viewModel: MentionSelectionView.ViewModel, from view: MentionSelectionView) {
        delegate?.handleMentionSelected(viewModel, from: view)
    }
    
    @objc private func disabledInputTapped() {
        delegate?.handleDisabledInputTapped()
    }
    
    @objc private func characterLimitLabelTapped() {
        delegate?.handleCharacterLimitLabelTapped()
    }
    
    @objc private func didSwipeDown() {
        inputTextView.resignFirstResponder()
    }
}

// MARK: - Delegate

public protocol InputViewDelegate: VoiceMessageRecordingViewDelegate, AnyObject {
    @MainActor func showLinkPreviewSuggestionModal()
    @MainActor func handleSendButtonTapped()
    @MainActor func handleDisabledInputTapped()
    @MainActor func handleAttachmentButtonTapped()
    @MainActor func handleDisabledAttachmentButtonTapped()
    @MainActor func handleDisabledVoiceMessageButtonTapped()
    @MainActor func handleCharacterLimitLabelTapped()
    @MainActor func inputTextViewDidChangeContent(_ inputTextView: InputTextView)
    @MainActor func handleMentionSelected(_ viewModel: MentionSelectionView.ViewModel, from view: MentionSelectionView)
    @MainActor func didPasteImageDataFromPasteboard(_ imageData: Data)
}