+class user { key pubkey; }
+class channel_member { key channel, member: user; }
+ key channel, timestamp;
+ mutable amount: integer;
+operation init (founder_pubkey: pubkey) {
+ require( (user@*{} limit 1).len() == 0 );
+ val founder = create user (founder_pubkey);
+ create balance (founder, 1000000);
+function decrease_balance (user, deduct_amount: integer) {
+ require( balance@{user}.amount >= deduct_amount);
+ update balance@{user} (amount -= deduct_amount);
+operation register_user (
+ existing_user_pubkey: pubkey,
+ new_user_pubkey: pubkey,
+ transfer_amount: integer
+ require( is_signer(existing_user_pubkey) );
+ val registration_cost = 100;
+ val existing_user = user@{existing_user_pubkey};
+ require( transfer_amount > 0 );
+ decrease_balance(existing_user, transfer_amount + registration_cost);
+ val new_user = create user (new_user_pubkey);
+ create balance (new_user, transfer_amount);
+operation create_channel ( admin_pubkey: pubkey, name) {
+ require( is_signer(admin_pubkey) );
+ val admin = user@{admin_pubkey};
+ decrease_balance(admin, 100);
+ val channel = create channel (admin, name);
+ create channel_member (channel, admin);
+operation add_channel_member (admin_pubkey: pubkey, channel_name: name, member_pubkey: pubkey) {
+ require( is_signer(admin_pubkey) );
+ val admin_usr = user@{admin_pubkey};
+ decrease_balance(admin_usr, 1);
+ val channel = channel@{channel_name, admin==user@{admin_pubkey}};
+ create channel_member (channel, member=user@{member_pubkey});
+operation post_message (channel_name: name, pubkey, message: text, nop: byte_array) {
+ require( is_signer(pubkey) );
+ val channel = channel@{channel_name};
+ val member = user@{pubkey};
+ require( channel_member@?{channel, member} );
+ decrease_balance(member, 1);
+ create message (channel, member, text=message, op_context.last_block_time);
+query get_last_messages(channel_name: name) {
+ return message@*{ channel@{channel_name} }
+ ( text, poster_pubkey=posted_by.pubkey, -sort timestamp );
+query get_last_message(channel_name: name) {
+ return message@?{channel@{channel_name} } (text, poster_pubkey=posted_by.pubkey, -sort timestamp) limit 1;
+query get_balance(user_pubkey: text) {
+ return balance@{user@{byte_array(user_pubkey)}}.amount;
+query get_channels(user_pubkey: text) {
+ return channel_member@*{member=user@{byte_array(user_pubkey)}}.channel.name;
