Telegram-iOS/submodules/ChatTextLinkEditUI/Sources/ChatTextLinkEditController.swift

import Foundation
import UIKit
import SwiftSignalKit
import AsyncDisplayKit
import Display
import TelegramCore
import TelegramPresentationData
import AccountContext
import UrlEscaping
import ComponentFlow
import AlertComponent
import AlertMultilineInputFieldComponent
import AlertWebpagePreviewComponent

public func chatTextLinkEditController(
    context: AccountContext,
    updatedPresentationData: (initial: PresentationData, signal: Signal<PresentationData, NoError>)? = nil,
    text: String,
    link: String?,
    preview: Bool = false,
    apply: @escaping (String?, TelegramMediaWebpage?) -> Void
) -> ViewController {
    let presentationData = context.sharedContext.currentPresentationData.with { $0 }
    let strings = presentationData.strings

    let inputState = AlertMultilineInputFieldComponent.ExternalState()

    var applyImpl: (() -> Void)?

    var effectiveUpdatedPresentationData: (PresentationData, Signal<PresentationData, NoError>)
    if let updatedPresentationData {
        effectiveUpdatedPresentationData = updatedPresentationData
    } else {
        effectiveUpdatedPresentationData = (presentationData, context.sharedContext.presentationData)
    }

    let makeContent: (TelegramMediaWebpage?) -> [AnyComponentWithIdentity<AlertComponentEnvironment>] = { webpage in
        var content: [AnyComponentWithIdentity<AlertComponentEnvironment>] = []
        content.append(AnyComponentWithIdentity(
            id: "title",
            component: AnyComponent(
                AlertTitleComponent(title: link != nil ? strings.TextFormat_EditLinkTitle : strings.TextFormat_AddLinkTitle)
            )
        ))
        content.append(AnyComponentWithIdentity(
            id: "text",
            component: AnyComponent(
                AlertTextComponent(content: .plain(text))
            )
        ))
        content.append(AnyComponentWithIdentity(
            id: "input",
            component: AnyComponent(
                AlertMultilineInputFieldComponent(
                    context: context,
                    initialValue: link.flatMap { NSAttributedString(string: $0) },
                    placeholder: strings.TextFormat_AddLinkPlaceholder,
                    returnKeyType: .done,
                    keyboardType: .URL,
                    autocapitalizationType: .none,
                    autocorrectionType: .no,
                    isInitiallyFocused: true,
                    externalState: inputState,
                    returnKeyAction: {
                        applyImpl?()
                    }
                )
            )
        ))
        if let webpage {
            content.append(AnyComponentWithIdentity(
                id: "webpagePreview",
                component: AnyComponent(AlertWebpagePreviewComponent(
                    context: context,
                    presentationData: effectiveUpdatedPresentationData.0,
                    webpage: webpage
                ))
            ))
        }
        return content
    }

    let contentPromise = Promise<[AnyComponentWithIdentity<AlertComponentEnvironment>]>()
    contentPromise.set(.single(makeContent(nil)))

    var dismissImpl: (() -> Void)?
    let alertController = AlertScreen(
        configuration: AlertScreen.Configuration(allowInputInset: true),
        contentSignal: contentPromise.get(),
        actionsSignal: .single([
            .init(title: strings.Common_Cancel),
            .init(title: strings.Common_Done, type: .default, action: {
                applyImpl?()
            }, autoDismiss: false)
        ]),
        updatedPresentationData: effectiveUpdatedPresentationData
    )

    let previewDisposable = MetaDisposable()
    var currentPreview: (link: String, webpage: TelegramMediaWebpage)?
    if preview {
        var currentDisplayedPreview: (link: String, webpage: TelegramMediaWebpage?)?
        previewDisposable.set((inputState.valueSignal
        |> map { value -> String in
            return explicitUrl(value.string)
        }
        |> distinctUntilChanged
        |> mapToSignal { link -> Signal<(String, TelegramMediaWebpage?), NoError> in
            guard !link.isEmpty && isValidUrl(link, validSchemes: ["http": true, "https": true, "tg": false, "ton": false, "tonsite": true]) else {
                return .single((link, nil))
            }

            let previewSignal = webpagePreview(account: context.account, urls: [link])
            |> map { result -> (String, TelegramMediaWebpage?) in
                guard case let .result(result) = result, let webpage = result?.webpage, case .Loaded = webpage.content else {
                    return (link, nil)
                }
                return (link, webpage)
            }

            return .single((link, nil))
            |> then((.complete() |> delay(1.0, queue: Queue.mainQueue())) |> then(previewSignal))
        }
        |> deliverOnMainQueue).startStrict(next: { link, webpage in
            if let currentDisplayedPreview, currentDisplayedPreview.link == link && currentDisplayedPreview.webpage == webpage {
                return
            }
            currentDisplayedPreview = (link, webpage)
            if let webpage {
                currentPreview = (link, webpage)
            } else {
                currentPreview = nil
            }
            contentPromise.set(.single(makeContent(webpage)))
        }))
    }
    alertController.dismissed = { _ in
        previewDisposable.dispose()
    }

    applyImpl = {
        let updatedLink = explicitUrl(inputState.value.string)
        if !updatedLink.isEmpty && isValidUrl(updatedLink, validSchemes: ["http": true, "https": true, "tg": false, "ton": false, "tonsite": true]) {
            dismissImpl?()
            apply(updatedLink, currentPreview?.link == updatedLink ? currentPreview?.webpage : nil)
        } else if inputState.value.string.isEmpty {
            dismissImpl?()
            apply("", nil)
        } else {
            inputState.animateError()
        }
    }
    dismissImpl = { [weak alertController] in
        alertController?.dismiss(completion: nil)
    }

    if link == nil {
        Queue.mainQueue().after(0.1, {
            let pasteboard = UIPasteboard.general
            if pasteboard.hasURLs {
                if inputState.value.string.isEmpty, let url = pasteboard.url?.absoluteString, !url.isEmpty {
                    let value = NSAttributedString(string: url)
                    inputState.setValue(value, selectionRange: 0 ..< value.length)
                }
            }
        })
    }

    return alertController
}