Signal-iOS/SignalServiceKit/Calls/OutgoingCallEventSyncMessage.swift

//
// Copyright 2022 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

/// Represents a call event that occurred on this device that we want to
/// communicate to our linked devices.
@objc(OutgoingCallEvent)
class OutgoingCallEvent: NSObject, NSSecureCoding {
    enum CallType: UInt {
        case audio
        case video
        case group
        case adHocCall
    }

    enum EventDirection: UInt {
        case incoming
        case outgoing
    }

    enum EventType: UInt {
        case accepted
        case notAccepted
        case deleted
        case observed
    }

    let timestamp: UInt64
    let conversationId: Data
    let callId: UInt64
    let callType: CallType
    let eventDirection: EventDirection
    let eventType: EventType

    init(
        timestamp: UInt64,
        conversationId: Data,
        callId: UInt64,
        callType: CallType,
        eventDirection: EventDirection,
        eventType: EventType,
    ) {
        self.timestamp = timestamp
        self.conversationId = conversationId
        self.callId = callId
        self.callType = callType
        self.eventDirection = eventDirection
        self.eventType = eventType
    }

    // MARK: NSSecureCoding

    private enum Keys {
        static let timestamp = "timestamp"
        static let conversationId = "peerUuid"
        static let callId = "callId"
        static let callType = "type"
        static let eventDirection = "direction"
        static let eventType = "event"
    }

    static var supportsSecureCoding: Bool { true }

    func encode(with coder: NSCoder) {
        coder.encode(NSNumber(value: timestamp), forKey: Keys.timestamp)
        coder.encode(conversationId as NSData, forKey: Keys.conversationId)
        coder.encode(NSNumber(value: callId), forKey: Keys.callId)
        coder.encode(NSNumber(value: callType.rawValue), forKey: Keys.callType)
        coder.encode(NSNumber(value: eventDirection.rawValue), forKey: Keys.eventDirection)
        coder.encode(NSNumber(value: eventType.rawValue), forKey: Keys.eventType)
    }

    required init?(coder: NSCoder) {
        guard
            let timestamp = coder.decodeObject(of: NSNumber.self, forKey: Keys.timestamp)?.uint64Value,
            let conversationId = coder.decodeObject(of: NSData.self, forKey: Keys.conversationId) as Data?,
            let callId = coder.decodeObject(of: NSNumber.self, forKey: Keys.callId)?.uint64Value,
            let callTypeRaw = coder.decodeObject(of: NSNumber.self, forKey: Keys.callType)?.uintValue,
            let callType = CallType(rawValue: callTypeRaw),
            let eventDirectionRaw = coder.decodeObject(of: NSNumber.self, forKey: Keys.eventDirection)?.uintValue,
            let eventDirection = EventDirection(rawValue: eventDirectionRaw),
            let eventTypeRaw = coder.decodeObject(of: NSNumber.self, forKey: Keys.eventType)?.uintValue,
            let eventType = EventType(rawValue: eventTypeRaw)
        else {
            owsFailDebug("Missing or unrecognized fields!")
            return nil
        }

        self.timestamp = timestamp
        self.conversationId = conversationId
        self.callId = callId
        self.callType = callType
        self.eventDirection = eventDirection
        self.eventType = eventType
    }
}

/// Represents a sync message containing a "call event".
///
/// Indicates to linked devices that a call has changed state. For example, that
/// we accepted a ringing call on this device.
///
/// - SeeAlso ``IncomingCallEventSyncMessageManager``
@objc(OutgoingCallEventSyncMessage)
public class OutgoingCallEventSyncMessage: OutgoingSyncMessage {
    override public class var supportsSecureCoding: Bool { true }

    public required init?(coder: NSCoder) {
        guard let callEvent = coder.decodeObject(of: OutgoingCallEvent.self, forKey: "event") else {
            return nil
        }
        self.callEvent = callEvent
        super.init(coder: coder)
    }

    override public func encode(with coder: NSCoder) {
        super.encode(with: coder)
        coder.encode(callEvent, forKey: "event")
    }

    override public var hash: Int {
        var hasher = Hasher()
        hasher.combine(super.hash)
        hasher.combine(callEvent)
        return hasher.finalize()
    }

    override public func isEqual(_ object: Any?) -> Bool {
        guard let object = object as? Self else { return false }
        guard super.isEqual(object) else { return false }
        guard self.callEvent == object.callEvent else { return false }
        return true
    }

    /// The call event.
    let callEvent: OutgoingCallEvent

    init(
        localThread: TSContactThread,
        event: OutgoingCallEvent,
        tx: DBReadTransaction,
    ) {
        self.callEvent = event
        super.init(localThread: localThread, tx: tx)
    }

    override public var isUrgent: Bool { false }

    override public func syncMessageBuilder(tx: DBReadTransaction) -> SSKProtoSyncMessageBuilder? {
        let callEventBuilder = SSKProtoSyncMessageCallEvent.builder()
        callEventBuilder.setCallID(callEvent.callId)
        callEventBuilder.setType(callEvent.callType.protoValue)
        callEventBuilder.setDirection(callEvent.eventDirection.protoValue)
        callEventBuilder.setEvent(callEvent.eventType.protoValue)
        callEventBuilder.setTimestamp(callEvent.timestamp)
        callEventBuilder.setConversationID(callEvent.conversationId)

        let builder = SSKProtoSyncMessage.builder()
        builder.setCallEvent(callEventBuilder.buildInfallibly())
        return builder
    }
}

private extension OutgoingCallEvent.CallType {
    var protoValue: SSKProtoSyncMessageCallEventType {
        switch self {
        case .audio:
            return .audioCall
        case .video:
            return .videoCall
        case .group:
            return .groupCall
        case .adHocCall:
            return .adHocCall
        }
    }
}

private extension OutgoingCallEvent.EventDirection {
    var protoValue: SSKProtoSyncMessageCallEventDirection {
        switch self {
        case .incoming:
            return .incoming
        case .outgoing:
            return .outgoing
        }
    }
}

private extension OutgoingCallEvent.EventType {
    var protoValue: SSKProtoSyncMessageCallEventEvent {
        switch self {
        case .accepted:
            return .accepted
        case .notAccepted:
            return .notAccepted
        case .deleted:
            return .deleted
        case .observed:
            return .observed
        }
    }
}