////////////////////////////////////////////////////////////////////////////////////
// VeilidChat Protocol Buffer Definitions
//
// * Timestamps are in microseconds (us) since epoch
// * Durations are in microseconds (us)
////////////////////////////////////////////////////////////////////////////////////

syntax = "proto3";
package veilidchat;

import "veilid.proto";
import "dht.proto";

////////////////////////////////////////////////////////////////////////////////////
// Enumerations
////////////////////////////////////////////////////////////////////////////////////

// Contact availability
enum Availability {
    AVAILABILITY_UNSPECIFIED = 0;
    AVAILABILITY_OFFLINE = 1;
    AVAILABILITY_FREE = 2;
    AVAILABILITY_BUSY = 3;
    AVAILABILITY_AWAY = 4;
}

// Encryption used on secret keys
enum EncryptionKeyType {
    ENCRYPTION_KEY_TYPE_UNSPECIFIED = 0;
    ENCRYPTION_KEY_TYPE_NONE = 1;
    ENCRYPTION_KEY_TYPE_PIN = 2;
    ENCRYPTION_KEY_TYPE_PASSWORD = 3;
}

// Scope of a chat
enum Scope {
    // Can read chats but not send messages
    WATCHERS = 0;
    // Can send messages subject to moderation
    // If moderation is disabled, this is equivalent to WATCHERS
    MODERATED = 1;
    // Can send messages without moderation
    TALKERS = 2;
    // Can moderate messages sent my members if moderation is enabled
    MODERATORS = 3;
    // Can perform all actions
    ADMINS = 4;
}

////////////////////////////////////////////////////////////////////////////////////
// Attachments
////////////////////////////////////////////////////////////////////////////////////

// A single attachment
message Attachment {
    oneof kind {
        AttachmentMedia media = 1;
    }
    // Author signature over all attachment fields and content fields and bytes
    veilid.Signature signature = 2;
}

// A file, audio, image, or video attachment
message AttachmentMedia {
    // MIME type of the data
    string mime = 1;
    // Title or filename
    string name = 2;
    // Pointer to the data content
    dht.DataReference content = 3;
}


////////////////////////////////////////////////////////////////////////////////////
// Chat room controls
////////////////////////////////////////////////////////////////////////////////////

// Permissions of a chat
message Permissions {
    // Parties in this scope or higher can add members to their own group or lower
    Scope can_add_members = 1;
    // Parties in this scope or higher can change the 'info' of a group
    Scope can_edit_info = 2;
    // If moderation is enabled or not.
    bool moderated = 3;
}

// The membership of a chat
message Membership {
    // Conversation keys for parties in the 'watchers' group
    repeated veilid.TypedKey watchers = 1;
    // Conversation keys for parties in the 'moderated' group
    repeated veilid.TypedKey moderated = 2;
    // Conversation keys for parties in the 'talkers' group
    repeated veilid.TypedKey talkers = 3;
    // Conversation keys for parties in the 'moderators' group
    repeated veilid.TypedKey moderators = 4;
    // Conversation keys for parties in the 'admins' group
    repeated veilid.TypedKey admins = 5;
}

// The chat settings
message ChatSettings {
    // Title for the chat 
    string title = 1;
    // Description for the chat 
    string description = 2;
    // Icon for the chat 
    optional dht.DataReference icon = 3;
    // Default message expiration duration (in us)
    uint64 default_expiration = 4;
}

////////////////////////////////////////////////////////////////////////////////////
// Messages
////////////////////////////////////////////////////////////////////////////////////

// A single message as part of a series of messages
message Message {

    // A text message
    message Text {
        // Text of the message
        string text = 1;
        // Topic of the message / Content warning
        string topic = 2;
        // Message id replied to
        veilid.TypedKey reply_id = 3;
        // Message expiration timestamp
        uint64 expiration = 4;
        // Message view limit before deletion
        uint64 view_limit = 5;
        // Attachments on the message
        repeated Attachment attachments = 6;
    }
    
    // A secret message
    message Secret {
        // Text message protobuf encrypted by a key
        bytes ciphertext = 1;
        // Secret expiration timestamp
        // This is the time after which an un-revealed secret will get deleted
        uint64 expiration = 2;
    }

    // A 'delete' control message
    // Deletes a set of messages by their ids
    message ControlDelete {
        repeated veilid.TypedKey ids = 1;
    } 
    // A 'clear' control message
    // Deletes a set of messages from before some timestamp
    message ControlClear {
        // The latest timestamp to delete messages before
        // If this is zero then all messages are cleared
        uint64 timestamp = 1;
    }
    // A 'change settings' control message
    message ControlSettings {
        ChatSettings settings = 1;
    }

    // A 'change permissions' control message
    // Changes the permissions of a chat
    message ControlPermissions {
        Permissions permissions = 1;
    }

    // A 'change membership' control message
    // Changes the 
    message ControlMembership {
        Membership membership = 1;
    }

    // A 'moderation' control message
    // Accepts or rejects a set of messages
    message ControlModeration {
        repeated veilid.TypedKey accepted_ids = 1;
        repeated veilid.TypedKey rejected_ids = 2;
    }

    //////////////////////////////////////////////////////////////////////////

    // Hash of previous message from the same author, 
    // including its previous hash.
    // Also serves as a unique key for the message.
    veilid.TypedKey id = 1;
    // Author of the message (identity public key)
    veilid.TypedKey author = 2;
    // Time the message was sent according to sender
    uint64 timestamp = 3;

    // Message kind
    oneof kind {
        Text text = 4;
        Secret secret = 5;
        ControlDelete delete = 6;
        ControlClear clear = 7;
        ControlSettings settings = 8;
        ControlPermissions permissions = 9;
        ControlMembership membership = 10;
        ControlModeration moderation = 11;
    }
    
    // Author signature over all of the fields and attachment signatures
    veilid.Signature signature = 12;
}

// Locally stored messages for chats
message ReconciledMessage {
    // The message as sent
    Message content = 1;
    // The timestamp the message was reconciled
    uint64 reconciled_time = 2;
}

////////////////////////////////////////////////////////////////////////////////////
// Chats
////////////////////////////////////////////////////////////////////////////////////

// The means of direct communications that is synchronized between
// two users. Visible and encrypted for the other party.
// Includes communications for:
//  * Profile changes
//  * Identity changes
//  * 1-1 chat messages
//  * Group chat messages
//
// DHT Schema: SMPL(0,1,[identityPublicKey])
// DHT Key (UnicastOutbox): localConversation
// DHT Secret: None
// Encryption: DH(IdentityA, IdentityB)
message Conversation {
    // Profile to publish to friend
    Profile profile = 1;
    // Identity master (JSON) to publish to friend or chat room
    string identity_master_json = 2;
    // Messages DHTLog
    veilid.TypedKey messages = 3;
}

// Either a 1-1 conversation or a group chat
// Privately encrypted, this is the local user's copy of the chat
message Chat {
    // Settings
    ChatSettings settings = 1;
    // Conversation key for this user
    veilid.TypedKey local_conversation_record_key = 2;
    // Conversation key for the other party
    veilid.TypedKey remote_conversation_record_key = 3;
}

// A group chat
// Privately encrypted, this is the local user's copy of the chat
message GroupChat {
    // Settings
    ChatSettings settings = 1;
    // Conversation key for this user
    veilid.TypedKey local_conversation_record_key = 2;
    // Conversation keys for the other parties
    repeated veilid.TypedKey remote_conversation_record_keys = 3;
}

////////////////////////////////////////////////////////////////////////////////////
// Accounts
////////////////////////////////////////////////////////////////////////////////////

// Publicly shared profile information for both contacts and accounts
// Contains:
// Name - Friendly name
// Pronouns - Pronouns of user
// Icon - Little picture to represent user in contact list
message Profile  {
    // Friendy name
    string name = 1;
    // Pronouns of user
    string pronouns = 2;
    // Description of the user
    string about = 3;
    // Status/away message
    string status = 4;
    // Availability
    Availability availability = 5;
    // Avatar DHTData
    optional veilid.TypedKey avatar = 6;
}

// A record of an individual account
// Pointed to by the identity account map in the identity key
//
// DHT Schema: DFLT(1)
// DHT Private: accountSecretKey
message Account {
    // The user's profile that gets shared with contacts
    Profile profile = 1;
    // Invisibility makes you always look 'Offline'
    bool invisible = 2;
    // Auto-away sets 'away' mode after an inactivity time
    uint32 auto_away_timeout_sec = 3;
    // The contacts DHTList for this account
    // DHT Private
    dht.OwnedDHTRecordPointer contact_list = 4;
    // The ContactInvitationRecord DHTShortArray for this account
    // DHT Private
    dht.OwnedDHTRecordPointer contact_invitation_records = 5;
    // The Chats DHTList for this account
    // DHT Private
    dht.OwnedDHTRecordPointer chat_list = 6;
    // The GroupChats DHTList for this account
    // DHT Private
    dht.OwnedDHTRecordPointer group_chat_list = 7;
}

// A record of a contact that has accepted a contact invitation
// Contains a copy of the most recent remote profile as well as
// a locally edited profile.
// Contains a copy of the most recent identity from the contact's
// Master identity dht key
//
// Stored in ContactList DHTList
message Contact {
    // Friend's profile as locally edited
    Profile edited_profile = 1;
    // Copy of friend's profile from remote conversation
    Profile remote_profile = 2;
    // Copy of friend's IdentityMaster in JSON from remote conversation
    string identity_master_json = 3;
    // Copy of friend's most recent identity public key from their identityMaster
    veilid.TypedKey identity_public_key = 4;
    // Remote conversation key to sync from friend
    veilid.TypedKey remote_conversation_record_key = 5;
    // Our conversation key for friend to sync
    veilid.TypedKey local_conversation_record_key = 6;
    // Show availability to this contact
    bool show_availability = 7;
}

////////////////////////////////////////////////////////////////////////////////////
// Invitations
////////////////////////////////////////////////////////////////////////////////////

// Invitation that is shared for VeilidChat contact connections
// serialized to QR code or data blob, not send over DHT, out of band.
// Writer secret is unique to this invitation. Writer public key is in the ContactRequestPrivate
// in the ContactRequestInbox subkey 0 DHT key
message ContactInvitation {
    // Contact request DHT record key
    veilid.TypedKey contact_request_inbox_key = 1;
    // Writer secret key bytes possibly encrypted with nonce appended
    bytes writer_secret = 2;
}

// Signature of invitation with identity
message SignedContactInvitation {
    // The serialized bytes for the contact invitation
    bytes contact_invitation = 1;
    // The signature of the contact_invitation bytes with the identity
    veilid.Signature identity_signature = 2;
}

// Contact request unicastinbox on the DHT
// DHTSchema: SMPL 1 owner key, 1 writer key symmetrically encrypted with writer secret
message ContactRequest {
    // The kind of encryption used on the unicastinbox writer key
    EncryptionKeyType encryption_key_type = 1;
    // The private part encoded and symmetrically encrypted with the unicastinbox writer secret
    bytes private = 2;
}

// The private part of a possibly encrypted contact request
// Symmetrically encrypted with writer secret
message ContactRequestPrivate {
    // Writer public key for signing writes to contact request unicastinbox
    veilid.CryptoKey writer_key = 1;
    // Snapshot of profile
    Profile profile = 2;
    // Identity master DHT record key
    veilid.TypedKey identity_master_record_key = 3;
    // Local chat DHT record key
    veilid.TypedKey chat_record_key = 4;
    // Expiration timestamp
    uint64 expiration = 5;
}

// To accept or reject a contact request, fill this out and send to the ContactRequest unicastinbox
message ContactResponse {
    // Accept or reject
    bool accept = 1;
    // Remote identity master DHT record key
    veilid.TypedKey identity_master_record_key = 2;
    // Remote chat DHT record key if accepted
    veilid.TypedKey remote_conversation_record_key = 3;
}

// Signature of response with identity
// Symmetrically encrypted with writer secret
message SignedContactResponse {
    // Serialized bytes for ContactResponse
    bytes contact_response = 1;
    // Signature of the contact_accept bytes with the identity
    veilid.Signature identity_signature = 2;
}

// Contact request record kept in Account DHTList to keep track of extant contact invitations
message ContactInvitationRecord {
    // Contact request unicastinbox DHT record key (parent is accountkey)
    dht.OwnedDHTRecordPointer contact_request_inbox = 1;
    // Writer key sent to contact for the contact_request_inbox smpl inbox subkey
    veilid.CryptoKey writer_key = 2;
    // Writer secret sent encrypted in the invitation
    veilid.CryptoKey writer_secret = 3; 
    // Local chat DHT record key (parent is accountkey, will be moved to Contact if accepted)
    veilid.TypedKey local_conversation_record_key = 4;
    // Expiration timestamp
    uint64 expiration = 5;
    // A copy of the raw SignedContactInvitation invitation bytes post-encryption and signing
    bytes invitation = 6;
    // The message sent along with the invitation
    string message = 7;
}