syntax = "proto3";

package chats;

option go_package = "./proto;chats";

import "google/protobuf/timestamp.proto";
import "google/protobuf/wrappers.proto";

service Chats {
	// Create a chat between two or more users, if a chat already exists for these users, the existing
	// chat will be returned
	rpc CreateChat(CreateChatRequest) returns (CreateChatResponse);
	// Create a message within a chat
	rpc CreateMessage(CreateMessageRequest) returns (CreateMessageResponse);
	// List the messages within a chat in reverse chronological order, using sent_before to
	// offset as older messages need to be loaded
	rpc ListMessages(ListMessagesRequest) returns (ListMessagesResponse);
}

message Chat {
	string id = 1;
	repeated string user_ids = 2;
	google.protobuf.Timestamp created_at = 3;
}

message Message {
	string id = 1;
	string author_id = 2;
	string chat_id = 3;
	string text = 4;
	google.protobuf.Timestamp sent_at = 5;
}

message CreateChatRequest {
	repeated string user_ids = 1;
}

message CreateChatResponse {
	Chat chat = 1;
}

message CreateMessageRequest {
	string id = 1;
	string chat_id = 2;
	string author_id = 3;
	string text = 4;
}

message CreateMessageResponse {
	Message message = 1;
}

message ListMessagesRequest {
	string chat_id = 1;
	google.protobuf.Timestamp sent_before = 2;
	google.protobuf.Int32Value limit = 3;
}

message ListMessagesResponse {
	repeated Message messages = 1;
}