simplex-chat/apps/ios/Shared/Views/Chat/ChatItem/CIMetaView.swift

//
//  CIMetaView.swift
//  SimpleX
//
//  Created by Evgeny Poberezkin on 11/02/2022.
//  Copyright © 2022 SimpleX Chat. All rights reserved.
//
// Spec: spec/client/chat-view.md

import SwiftUI
import SimpleXChat

// Spec: spec/client/chat-view.md#CIMetaView
struct CIMetaView: View {
    @ObservedObject var chat: Chat
    @EnvironmentObject var theme: AppTheme
    @Environment(\.showTimestamp) var showTimestamp: Bool
    var chatItem: ChatItem
    var metaColor: Color
    var paleMetaColor = Color(uiColor: .tertiaryLabel)
    var showStatus = true
    var showEdited = true
    var invertedMaterial = false

    @AppStorage(DEFAULT_SHOW_SENT_VIA_RPOXY) private var showSentViaProxy = false
    @AppStorage(DEFAULT_PRIVACY_SHOW_SIGNATURE) private var showSignature = true
    @AppStorage(DEFAULT_PRIVACY_SHOW_FILE_ENCRYPTION) private var showFileEncryption = true

    var body: some View {
        if chatItem.isDeletedContent {
            chatItem.timestampText.font(.caption).foregroundColor(metaColor)
        } else {
            ZStack {
                ciMetaText(
                    chatItem.meta,
                    chatTTL: chat.chatInfo.timedMessagesTTL,
                    encrypted: chatItem.encryptedFile,
                    color: metaColor,
                    paleColor: paleMetaColor,
                    colorMode: invertedMaterial
                        ? .invertedMaterial
                        : .normal,
                    showStatus: showStatus,
                    showEdited: showEdited,
                    showViaProxy: showSentViaProxy,
                    showTimesamp: showTimestamp,
                    signedFileVerified: chatItem.file?.loaded,
                    showSignature: showSignature,
                    showFileEncryption: showFileEncryption
                ).invertedForegroundStyle(enabled: invertedMaterial)
                if invertedMaterial {
                    ciMetaText(
                        chatItem.meta,
                        chatTTL: chat.chatInfo.timedMessagesTTL,
                        encrypted: chatItem.encryptedFile,
                        colorMode: .normal,
                        onlyOverrides: true,
                        showStatus: showStatus,
                        showEdited: showEdited,
                        showViaProxy: showSentViaProxy,
                        showTimesamp: showTimestamp,
                        signedFileVerified: chatItem.file?.loaded,
                        showSignature: showSignature,
                        showFileEncryption: showFileEncryption
                    )
                }
            }
        }
    }
}

enum MetaColorMode {
    // Renders provided colours
    case normal
    // Fully transparent meta - used for reserving space
    case transparent
    // Renders white on dark backgrounds and black on light ones
    case invertedMaterial

    func resolve(_ c: Color?) -> Color? {
        switch self {
        case .normal: c
        case .transparent: .clear
        case .invertedMaterial: nil
        }
    }

    func statusSpacer(_ sent: Bool) -> Text {
        switch self {
        case .normal, .transparent:
            Text(
                sent
                ? Image("checkmark.wide")
                : Image(systemName: "circlebadge.fill")
            ).foregroundColor(.clear)
        case .invertedMaterial: textSpace.kerning(13)
        }
    }
}

func ciMetaText(
    _ meta: CIMeta,
    chatTTL: Int?,
    encrypted: Bool?,
    color: Color = .clear, // we use this function to reserve space without rendering meta
    paleColor: Color? = nil,
    primaryColor: Color = .accentColor,
    colorMode: MetaColorMode = .normal,
    onlyOverrides: Bool = false, // only render colors that differ from base
    showStatus: Bool = true,
    showEdited: Bool = true,
    showViaProxy: Bool,
    showTimesamp: Bool,
    signedFileVerified: Bool? = nil,
    showSignature: Bool = true,
    showFileEncryption: Bool = true,
    unbreakable: Bool = false
) -> Text {
    var r = Text("")
    var space: Text? = nil
    let separator = unbreakable ? Text(verbatim: "\u{00A0}") : textSpace
    let joiner = Text(verbatim: unbreakable ? "\u{2060}" : "")
    let appendSpace = {
        if let sp = space {
            r = r + sp
            space = nil
        }
    }
    let resolved = colorMode.resolve(color)
    if showEdited, meta.itemEdited {
        r = r + statusIconText("pencil", resolved) + joiner
    }
    if meta.disappearing {
        r = r + statusIconText("timer", resolved).font(.caption2) + joiner
        let ttl = meta.itemTimed?.ttl
        if ttl != chatTTL {
            r = r + colored(Text(shortTimeText(ttl)), resolved)
        }
        space = separator
    }
    if showViaProxy, meta.sentViaProxy == true {
        appendSpace()
        r = r + statusIconText("arrow.forward", resolved?.opacity(0.67)).font(.caption2) + joiner
    }
    if showStatus {
        appendSpace()
        if let (image, statusColor) = meta.itemStatus.statusIcon(color, paleColor ?? color, primaryColor) {
            let metaColor = if onlyOverrides && statusColor == color {
                Color.clear
            } else {
                colorMode.resolve(statusColor)
            }
            r = r + colored(Text(image), metaColor)
        } else if !meta.disappearing {
            r = r + colorMode.statusSpacer(meta.itemStatus.sent)
        }
        space = separator
    }
    if let enc = encrypted, showFileEncryption {
        appendSpace()
        r = r + statusIconText(enc ? "lock" : "lock.open", resolved)
        space = separator
    }
    if showSignature, meta.msgVerified?.verified == true && signedFileVerified != false {
        appendSpace()
        r = r + colored(Text(Image(systemName: "checkmark.seal")), resolved)
        space = separator
    } else if meta.msgVerified == .sigMissing {
        appendSpace()
        r = r + colored(Text(Image(systemName: "xmark.seal")), colorMode.resolve(.red))
        space = separator
    }
    if showTimesamp {
        appendSpace()
        r = r + colored(unbreakable ? Text(verbatim: formatTimestampMeta(meta.itemTs).replacingOccurrences(of: " ", with: "\u{00A0}")) : meta.timestampText, resolved)
    }
    return r.font(.caption)
}

@inline(__always)
private func statusIconText(_ icon: String, _ color: Color?) -> Text {
    colored(Text(Image(systemName: icon)), color)
}

// Applying `foregroundColor(nil)` breaks `.invertedForegroundStyle` modifier
@inline(__always)
private func colored(_ t: Text, _ color: Color?) -> Text {
    if let color {
        t.foregroundColor(color)
    } else {
        t
    }
}

struct CIMetaView_Previews: PreviewProvider {
    static let metaColor = Color.secondary
    static var previews: some View {
        Group {
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndSent(sndProgress: .complete)), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndSent(sndProgress: .partial)), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndRcvd(msgRcptStatus: .ok, sndProgress: .complete)), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndRcvd(msgRcptStatus: .ok, sndProgress: .partial)), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndRcvd(msgRcptStatus: .badMsgHash, sndProgress: .complete)), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getSample(2, .directSnd, previewDate, "https://simplex.chat", .sndSent(sndProgress: .complete), itemEdited: true), metaColor: metaColor)
            CIMetaView(chat: Chat.sampleData, chatItem: ChatItem.getDeletedContentSample(1, previewDate), metaColor: metaColor)
        }
        .previewLayout(.fixed(width: 360, height: 100))
    }
}