Add PreviewManger with Core Data cache and a URLPreviewView with a view model.

Changes to RoomDataSource still to come.

Riot/Modules/Room/Views/URLPreviews/URLPreviewView.swift

@@ -0,0 +1,145 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import UIKit
+import Reusable
+
+@objcMembers
+class URLPreviewView: UIView, NibLoadable, Themable {
+    // MARK: - Constants
+    
+    private enum Constants { }
+    
+    // MARK: - Properties
+    
+    var viewModel: URLPreviewViewModel! {
+        didSet {
+            viewModel.viewDelegate = self
+        }
+    }
+    
+    @IBOutlet weak var imageView: UIImageView!
+    @IBOutlet weak var faviconImageView: UIImageView!
+    
+    @IBOutlet weak var siteNameLabel: UILabel!
+    @IBOutlet weak var titleLabel: UILabel!
+    @IBOutlet weak var descriptionLabel: UILabel!
+    
+    override var intrinsicContentSize: CGSize {
+        CGSize(width: RoomBubbleCellLayout.urlPreviewViewWidth, height: RoomBubbleCellLayout.urlPreviewViewHeight)
+    }
+    
+    // MARK: - Setup
+    
+    static func instantiate(viewModel: URLPreviewViewModel) -> Self {
+        let view = Self.loadFromNib()
+        view.update(theme: ThemeService.shared().theme)
+        
+        view.viewModel = viewModel
+        viewModel.process(viewAction: .loadData)
+        
+        return view
+    }
+    
+    // MARK: - Life cycle
+    
+    override func awakeFromNib() {
+        super.awakeFromNib()
+        
+        layer.cornerRadius = 8
+        layer.masksToBounds = true
+        
+        imageView.contentMode = .scaleAspectFill
+        faviconImageView.layer.cornerRadius = 6
+        
+        siteNameLabel.isUserInteractionEnabled = false
+        titleLabel.isUserInteractionEnabled = false
+        descriptionLabel.isUserInteractionEnabled = false
+        
+        #warning("Debugging for previews - to be removed")
+        faviconImageView.backgroundColor = .systemBlue.withAlphaComponent(0.7)
+    }
+    
+    // MARK: - Public
+    
+    func update(theme: Theme) {
+        backgroundColor = theme.colors.navigation
+        
+        siteNameLabel.textColor = theme.colors.secondaryContent
+        siteNameLabel.font = theme.fonts.caption2SB
+        
+        titleLabel.textColor = theme.colors.primaryContent
+        titleLabel.font = theme.fonts.calloutSB
+        
+        descriptionLabel.textColor = theme.colors.secondaryContent
+        descriptionLabel.font = theme.fonts.caption1
+    }
+    
+    // MARK: - Private
+    private func renderLoading(_ url: URL) {
+        imageView.image = nil
+        
+        siteNameLabel.text = url.host
+        titleLabel.text = "Loading..."
+        descriptionLabel.text = ""
+    }
+    
+    private func renderLoaded(_ preview: URLPreviewViewData) {
+        imageView.image = preview.image
+        
+        siteNameLabel.text = preview.siteName ?? preview.url.host
+        titleLabel.text = preview.title
+        descriptionLabel.text = preview.text
+    }
+    
+    private func renderError(_ error: Error) {
+        imageView.image = nil
+        
+        siteNameLabel.text = "Error"
+        titleLabel.text = descriptionLabel.text
+        descriptionLabel.text = error.localizedDescription
+    }
+    
+    
+    // MARK: - Action
+    @IBAction private func openURL(_ sender: Any) {
+        MXLog.debug("[URLPreviewView] Link was tapped.")
+        viewModel.process(viewAction: .openURL)
+    }
+    
+    @IBAction private func close(_ sender: Any) {
+        
+    }
+}
+
+
+// MARK: URLPreviewViewModelViewDelegate
+extension URLPreviewView: URLPreviewViewModelViewDelegate {
+    func urlPreviewViewModel(_ viewModel: URLPreviewViewModelType, didUpdateViewState viewState: URLPreviewViewState) {
+        DispatchQueue.main.async {
+            switch viewState {
+            case .loading(let url):
+                self.renderLoading(url)
+            case .loaded(let preview):
+                self.renderLoaded(preview)
+            case .error(let error):
+                self.renderError(error)
+            case .hidden:
+                self.frame.size.height = 0
+            }
+        }
+    }
+}

Riot/Modules/Room/Views/URLPreviews/URLPreviewView.xib

@@ -0,0 +1,118 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="18122" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES">
+    <device id="retina6_1" orientation="portrait" appearance="light"/>
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="18093"/>
+        <capability name="System colors in document resources" minToolsVersion="11.0"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <objects>
+        <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner"/>
+        <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>
+        <view contentMode="scaleToFill" id="iN0-l3-epB" customClass="URLPreviewView" customModule="Riot" customModuleProvider="target">
+            <rect key="frame" x="0.0" y="0.0" width="267" height="247"/>
+            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+            <subviews>
+                <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="sV7-z8-2ZW">
+                    <rect key="frame" x="0.0" y="0.0" width="267" height="140"/>
+                    <subviews>
+                        <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="9ew-qc-5BO">
+                            <rect key="frame" x="0.0" y="0.0" width="267" height="140"/>
+                        </imageView>
+                    </subviews>
+                    <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                    <constraints>
+                        <constraint firstAttribute="width" constant="267" id="1cA-Oe-Ffr"/>
+                        <constraint firstItem="9ew-qc-5BO" firstAttribute="top" secondItem="sV7-z8-2ZW" secondAttribute="top" id="PkK-wn-hNC"/>
+                        <constraint firstItem="9ew-qc-5BO" firstAttribute="leading" secondItem="sV7-z8-2ZW" secondAttribute="leading" id="bQt-a9-prT"/>
+                        <constraint firstAttribute="bottom" secondItem="9ew-qc-5BO" secondAttribute="bottom" id="dfh-UN-9f8"/>
+                        <constraint firstAttribute="trailing" secondItem="9ew-qc-5BO" secondAttribute="trailing" id="mRi-du-dck"/>
+                        <constraint firstAttribute="height" constant="140" id="ozL-dw-rED"/>
+                    </constraints>
+                    <connections>
+                        <outletCollection property="gestureRecognizers" destination="rSB-1V-Kev" appends="YES" id="LLc-zz-Ooa"/>
+                    </connections>
+                </view>
+                <imageView clipsSubviews="YES" userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="78m-NG-Oe7">
+                    <rect key="frame" x="8" y="108" width="24" height="24"/>
+                    <constraints>
+                        <constraint firstAttribute="width" constant="24" id="54e-3E-QhC"/>
+                        <constraint firstAttribute="height" constant="24" id="Ms9-sP-ceF"/>
+                    </constraints>
+                </imageView>
+                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Site Name" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="2D0-pg-81F">
+                    <rect key="frame" x="8" y="148" width="56" height="13.5"/>
+                    <fontDescription key="fontDescription" type="system" weight="semibold" pointSize="11"/>
+                    <nil key="textColor"/>
+                    <nil key="highlightedColor"/>
+                </label>
+                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" horizontalCompressionResistancePriority="250" text="Title" textAlignment="natural" lineBreakMode="tailTruncation" numberOfLines="2" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="bfQ-4X-PGU">
+                    <rect key="frame" x="8" y="163.5" width="33.5" height="19.5"/>
+                    <fontDescription key="fontDescription" type="system" weight="semibold" pointSize="16"/>
+                    <nil key="textColor"/>
+                    <nil key="highlightedColor"/>
+                </label>
+                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" horizontalCompressionResistancePriority="250" text="Description" textAlignment="natural" lineBreakMode="tailTruncation" numberOfLines="3" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="cSk-qu-c4j">
+                    <rect key="frame" x="8" y="185" width="251" height="14.5"/>
+                    <fontDescription key="fontDescription" type="system" pointSize="12"/>
+                    <nil key="textColor"/>
+                    <nil key="highlightedColor"/>
+                </label>
+                <button opaque="NO" contentMode="scaleToFill" fixedFrame="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="CL2-R3-bYG">
+                    <rect key="frame" x="242" y="9" width="10" height="22"/>
+                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                    <state key="normal" image="close_banner">
+                        <preferredSymbolConfiguration key="preferredSymbolConfiguration" scale="large"/>
+                    </state>
+                    <connections>
+                        <action selector="close:" destination="iN0-l3-epB" eventType="touchUpInside" id="iNI-q6-N3g"/>
+                    </connections>
+                </button>
+            </subviews>
+            <color key="backgroundColor" systemColor="tertiarySystemFillColor"/>
+            <gestureRecognizers/>
+            <constraints>
+                <constraint firstAttribute="trailing" secondItem="cSk-qu-c4j" secondAttribute="trailing" constant="8" id="1QZ-IV-b1E"/>
+                <constraint firstAttribute="top" secondItem="sV7-z8-2ZW" secondAttribute="top" id="8AQ-S7-Fm0"/>
+                <constraint firstItem="2D0-pg-81F" firstAttribute="leading" secondItem="iN0-l3-epB" secondAttribute="leading" constant="8" id="A6d-x8-mDG"/>
+                <constraint firstItem="cSk-qu-c4j" firstAttribute="leading" secondItem="bfQ-4X-PGU" secondAttribute="leading" id="IT4-7h-n5y"/>
+                <constraint firstItem="bfQ-4X-PGU" firstAttribute="leading" secondItem="2D0-pg-81F" secondAttribute="leading" id="Qxt-SR-d1M"/>
+                <constraint firstItem="bfQ-4X-PGU" firstAttribute="top" secondItem="2D0-pg-81F" secondAttribute="bottom" constant="2" id="ZBc-MM-pl2"/>
+                <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="bfQ-4X-PGU" secondAttribute="trailing" constant="8" id="bk2-2s-hgS"/>
+                <constraint firstItem="sV7-z8-2ZW" firstAttribute="leading" secondItem="iN0-l3-epB" secondAttribute="leading" id="cfa-wh-EzA"/>
+                <constraint firstItem="78m-NG-Oe7" firstAttribute="leading" secondItem="sV7-z8-2ZW" secondAttribute="leading" constant="8" id="ecO-IN-wTm"/>
+                <constraint firstAttribute="trailing" secondItem="sV7-z8-2ZW" secondAttribute="trailing" id="gUP-5s-qWI"/>
+                <constraint firstItem="2D0-pg-81F" firstAttribute="top" secondItem="sV7-z8-2ZW" secondAttribute="bottom" constant="8" id="neh-8P-aFx"/>
+                <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="2D0-pg-81F" secondAttribute="trailing" constant="8" id="tnX-Fo-b79"/>
+                <constraint firstItem="cSk-qu-c4j" firstAttribute="top" secondItem="bfQ-4X-PGU" secondAttribute="bottom" constant="2" id="xp1-2j-xl8"/>
+                <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="cSk-qu-c4j" secondAttribute="bottom" constant="8" id="yHd-Fp-jPo"/>
+                <constraint firstItem="sV7-z8-2ZW" firstAttribute="bottom" secondItem="78m-NG-Oe7" secondAttribute="bottom" constant="8" id="zsc-zO-UkD"/>
+            </constraints>
+            <freeformSimulatedSizeMetrics key="simulatedDestinationMetrics"/>
+            <connections>
+                <outlet property="descriptionLabel" destination="cSk-qu-c4j" id="gC7-Pu-nHx"/>
+                <outlet property="faviconImageView" destination="78m-NG-Oe7" id="u26-zc-JwX"/>
+                <outlet property="imageView" destination="9ew-qc-5BO" id="nzz-xV-mae"/>
+                <outlet property="siteNameLabel" destination="2D0-pg-81F" id="72o-l1-f7x"/>
+                <outlet property="titleLabel" destination="bfQ-4X-PGU" id="Jzt-75-caa"/>
+                <outletCollection property="gestureRecognizers" destination="rSB-1V-Kev" appends="YES" id="qPD-mR-YpO"/>
+            </connections>
+            <point key="canvasLocation" x="131.15942028985509" y="73.995535714285708"/>
+        </view>
+        <tapGestureRecognizer id="rSB-1V-Kev">
+            <connections>
+                <action selector="openURL:" destination="iN0-l3-epB" id="sUF-br-ODY"/>
+            </connections>
+        </tapGestureRecognizer>
+    </objects>
+    <resources>
+        <image name="close_banner" width="10" height="10"/>
+        <systemColor name="systemBackgroundColor">
+            <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
+        <systemColor name="tertiarySystemFillColor">
+            <color red="0.46274509803921571" green="0.46274509803921571" blue="0.50196078431372548" alpha="0.12" colorSpace="custom" customColorSpace="sRGB"/>
+        </systemColor>
+    </resources>
+</document>

Riot/Modules/Room/Views/URLPreviews/URLPreviewViewAction.swift

@@ -0,0 +1,24 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+/// URLPreviewView actions exposed to view model
+enum URLPreviewViewAction {
+    case loadData
+    case openURL
+    case close
+}

Riot/Modules/Room/Views/URLPreviews/URLPreviewViewData.swift

@@ -0,0 +1,42 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+@objc
+class URLPreviewViewData: NSObject {
+    /// The URL that's represented by the preview data.
+    let url: URL
+    
+    /// The OpenGraph site name for the URL.
+    let siteName: String?
+    
+    /// The OpenGraph title for the URL.
+    let title: String?
+    
+    /// The OpenGraph description for the URL.
+    let text: String?
+    
+    /// The OpenGraph image for the URL.
+    var image: UIImage?
+    
+    init(url: URL, siteName: String?, title: String?, text: String?) {
+        self.url = url
+        self.siteName = siteName
+        self.title = title
+        self.text = text
+    }
+}

Riot/Modules/Room/Views/URLPreviews/URLPreviewViewModel.swift

@@ -0,0 +1,89 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+import MatrixSDK
+
+@objcMembers
+class URLPreviewViewModel: NSObject, URLPreviewViewModelType {
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+
+    private let url: URL
+    private let session: MXSession
+    
+    private var currentOperation: MXHTTPOperation?
+    private var urlPreview: MXURLPreview?
+    
+    // MARK: Public
+
+    weak var viewDelegate: URLPreviewViewModelViewDelegate?
+    
+    // MARK: - Setup
+    
+    init(url: URL, session: MXSession) {
+        self.url = url
+        self.session = session
+    }
+    
+    deinit {
+        cancelOperations()
+    }
+    
+    // MARK: - Public
+    
+    func process(viewAction: URLPreviewViewAction) {
+        switch viewAction {
+        case .loadData:
+            loadData()
+        case .openURL:
+            openURL()
+        case .close:
+            cancelOperations()
+        }
+    }
+    
+    // MARK: - Private
+    
+    private func loadData() {
+        update(viewState: .loading(url))
+        
+        AppDelegate.theDelegate().previewManager.preview(for: url) { [weak self] preview in
+            guard let self = self else { return }
+            
+            self.update(viewState: .loaded(preview))
+        } failure: { error in
+            #warning("REALLY?!")
+            if let error = error {
+                self.update(viewState: .error(error))
+            }
+        }
+    }
+    
+    private func openURL() {
+        UIApplication.shared.open(url)
+    }
+    
+    private func update(viewState: URLPreviewViewState) {
+        viewDelegate?.urlPreviewViewModel(self, didUpdateViewState: viewState)
+    }
+    
+    private func cancelOperations() {
+        currentOperation?.cancel()
+    }
+}

Riot/Modules/Room/Views/URLPreviews/URLPreviewViewModelType.swift

@@ -0,0 +1,29 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+protocol URLPreviewViewModelViewDelegate: AnyObject {
+    func urlPreviewViewModel(_ viewModel: URLPreviewViewModelType, didUpdateViewState viewState: URLPreviewViewState)
+}
+
+/// Protocol describing the view model used by `URLPreviewView`
+protocol URLPreviewViewModelType {
+        
+    var viewDelegate: URLPreviewViewModelViewDelegate? { get set }
+    
+    func process(viewAction: URLPreviewViewAction)
+}

Riot/Modules/Room/Views/URLPreviews/URLPreviewViewState.swift

@@ -0,0 +1,25 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+/// URLPreviewView state
+enum URLPreviewViewState {
+    case loading(_ url: URL)
+    case loaded(_ preview: URLPreviewViewData)
+    case error(Error)
+    case hidden
+}