another.im-ios/ConversationsClassic/AppData/Model/Message+OMEMO.swift

import Foundation
import GRDB
import Martin

extension Message {
    static func map(_ martinMessage: Martin.Message, context: Martin.Context?) -> Message? {
        // Check that the message type is supported
        var martinMessage = martinMessage
        let chatTypes: [StanzaType] = [.chat, .groupchat]
        guard let mType = martinMessage.type, chatTypes.contains(mType) else {
            #if DEBUG
                print("Unsupported martinMessage type: \(martinMessage.type?.rawValue ?? "nil")")
            #endif
            return nil
        }

        // Type
        let type = MessageType(rawValue: martinMessage.type?.rawValue ?? "") ?? .chat

        // Content type
        var contentType: MessageContentType = .text
        if let oob = martinMessage.oob {
            contentType = .attachment(.init(
                type: oob.attachmentType,
                localName: nil,
                thumbnailName: nil,
                remotePath: oob
            ))
        } else if martinMessage.hints.contains(.noStore) {
            contentType = .typing
            // skip for now
            return nil
        }

        // Try to recognize if message is omemo-encoded and decode it
        var secure = false
        if let omemo = context?.module(.omemo) {
            let decodingResult = omemo.decode(message: martinMessage)
            switch decodingResult {
            case .successMessage(let decodedMessage, _):
                martinMessage = decodedMessage
                if let oob = martinMessage.oob {
                    contentType = .attachment(.init(
                        type: oob.attachmentType,
                        localName: nil,
                        thumbnailName: nil,
                        remotePath: oob
                    ))
                }
                secure = true

            case .successTransportKey:
                return nil

            case .failure(let error):
                logIt(.error, "Error decoding omemo message: \(error)")
                logIt(.error, "Message: \(martinMessage)")
            }
        }

        // skip for non-visible messages
        if martinMessage.body == nil, martinMessage.oob == nil, martinMessage.type == .chat {
            return nil
        }

        // From/To
        let from = martinMessage.from?.bareJid.stringValue ?? ""
        let to = martinMessage.to?.bareJid.stringValue

        // Msg
        let msg = Message(
            id: martinMessage.id ?? UUID().uuidString,
            type: type,
            date: Date(),
            contentType: contentType,
            status: .sent,
            from: from,
            to: to,
            body: martinMessage.body,
            subject: martinMessage.subject,
            thread: martinMessage.thread,
            oobUrl: martinMessage.oob,
            secure: secure
        )
        return msg
    }
}