Add "snapshot" replay view during play.

Snapshots store game state without undo and only log length.
Combined with the final game state's log we can recreate the view
from any snapshot quickly.

Move replay code into separate script file, loaded only when used.

Prefix system "setup", "resign", and "restore" actions with a period.

1 files changed, 135 insertions, 89 deletions

diff --git a/server.js b/server.js
index 078a5c6..31a7def 100644
--- a/server.js
+++ b/server.js
@@ -1059,8 +1059,11 @@ const SQL_UPDATE_GAME_STATE = SQL("INSERT OR REPLACE INTO game_state (game_id,st
 const SQL_UPDATE_GAME_RESULT = SQL("UPDATE games SET status=?, result=? WHERE game_id=?")
 const SQL_UPDATE_GAME_PRIVATE = SQL("UPDATE games SET is_private=1 WHERE game_id=?")
 
-const SQL_INSERT_REPLAY = SQL("insert into game_replay (game_id,replay_id,role,action,arguments) values (?, (select count(1) + 1 from game_replay where game_id=?), ?,?,?)")
-const SQL_DELETE_REPLAY = SQL("delete from game_replay where game_id=?")
+const SQL_INSERT_REPLAY = SQL("insert into game_replay (game_id,replay_id,role,action,arguments) values (?, (select coalesce(max(replay_id), 0) + 1 from game_replay where game_id=?) ,?,?,?) returning replay_id").pluck()
+
+const SQL_INSERT_SNAP = SQL("insert into game_snap (game_id,snap_id,state) values (?, (select coalesce(max(snap_id), 0) + 1 from game_snap where game_id=?), ?) returning snap_id").pluck()
+const SQL_SELECT_SNAP = SQL("select state from game_snap where game_id = ? and snap_id = ?").pluck()
+const SQL_SELECT_SNAP_COUNT = SQL("select max(snap_id) from game_snap where game_id=?").pluck()
 
 const SQL_SELECT_REPLAY = SQL(`
 	select json_object(
@@ -1629,14 +1632,14 @@ app.post('/start/:game_id', must_be_logged_in, function (req, res) {
 	let options = game.options ? JSON.parse(game.options) : {}
 	let seed = random_seed()
 	let state = RULES[game.title_id].setup(seed, game.scenario, options)
-	put_replay(game_id, null, 'setup', [seed, game.scenario, options])
+
 	SQL_UPDATE_GAME_RESULT.run(1, null, game_id)
-	SQL_UPDATE_GAME_STATE.run(game_id, JSON.stringify(state), state.active)
 	if (is_solo(players))
 		SQL_UPDATE_GAME_PRIVATE.run(game_id)
-	update_join_clients_game(game_id)
 	mail_game_started_notification_to_offline_users(game_id)
-	mail_your_turn_notification_to_offline_users(game_id, null, state.active)
+
+	put_new_state(game_id, state, null, null, ".setup", [seed, game.scenario, options])
+
 	res.send("SUCCESS")
 })
 
@@ -2007,52 +2010,121 @@ function get_game_state(game_id) {
 	return JSON.parse(game_state)
 }
 
+function snap_from_state(state) {
+	// return JSON of game state without undo and with log replaced by log length
+	let save_undo = state.undo
+	let save_log = state.log
+	state.undo = undefined
+	state.log = save_log.length
+	let snap = JSON.stringify(state)
+	state.undo = save_undo
+	state.log = save_log
+	return snap
+}
+
+function put_replay(game_id, role, action, args) {
+	if (args !== undefined && args !== null && typeof args !== "number")
+		args = JSON.stringify(args)
+	return SQL_INSERT_REPLAY.get(game_id, game_id, role, action, args)
+}
+
+function put_snap(game_id, state) {
+	let snap_id = SQL_INSERT_SNAP.get(game_id, game_id, snap_from_state(state))
+	if (game_clients[game_id])
+		for (let other of game_clients[game_id])
+			send_message(other, "snapsize", snap_id)
+}
+
 function put_game_state(game_id, state, old_active) {
+	// TODO: separate state, undo, and log entries to reuse "snap" json stringifaction?
 	if (state.state === "game_over") {
 		SQL_UPDATE_GAME_RESULT.run(2, state.result, game_id)
 		SQL_DELETE_NOTIFIED_ALL.run(game_id)
 		mail_game_finished_notification_to_offline_users(game_id, state.result)
 	}
 	SQL_UPDATE_GAME_STATE.run(game_id, JSON.stringify(state), state.active)
-	for (let other of game_clients[game_id])
-		send_state(other, state)
+	if (game_clients[game_id])
+		for (let other of game_clients[game_id])
+			send_state(other, state)
 	update_join_clients_game(game_id)
 	mail_your_turn_notification_to_offline_users(game_id, old_active, state.active)
 }
 
-function put_replay(game_id, role, action, args) {
-	if (args !== undefined && args !== null)
-		args = JSON.stringify(args)
-	SQL_INSERT_REPLAY.run(game_id, game_id, role, action, args)
+function put_new_state(game_id, state, old_active, role, action, args) {
+	let replay_id = put_replay(game_id, role, action, args)
+	if (state.active !== old_active)
+		put_snap(game_id, state)
+	put_game_state(game_id, state, old_active)
 }
 
-function on_action(socket, action, arg) {
-	if (arg !== undefined)
-		SLOG(socket, "ACTION", action, JSON.stringify(arg))
+function on_action(socket, action, args) {
+	if (args !== undefined)
+		SLOG(socket, "ACTION", action, JSON.stringify(args))
 	else
 		SLOG(socket, "ACTION", action)
 	try {
 		let state = get_game_state(socket.game_id)
 		let old_active = state.active
-		state = socket.rules.action(state, socket.role, action, arg)
-		put_game_state(socket.game_id, state, old_active)
-		put_replay(socket.game_id, socket.role, action, arg)
+		state = socket.rules.action(state, socket.role, action, args)
+		put_new_state(socket.game_id, state, old_active, socket.role, action, args)
 	} catch (err) {
 		console.log(err)
 		return send_message(socket, 'error', err.toString())
 	}
 }
 
-function on_query(socket, q) {
-	let params = undefined
-	if (Array.isArray(q)) {
-		params = q[1]
-		q = q[0]
+function on_resign(socket) {
+	SLOG(socket, "RESIGN")
+	try {
+		// TODO: shared "resign" function
+		let state = get_game_state(socket.game_id)
+		let old_active = state.active
+		state = socket.rules.resign(state, socket.role)
+		put_new_state(socket.game_id, state, old_active, socket.role, ".resign", null)
+	} catch (err) {
+		console.log(err)
+		return send_message(socket, 'error', err.toString())
 	}
-	if (params !== undefined)
-		SLOG(socket, "QUERY", q, JSON.stringify(params))
-	else
-		SLOG(socket, "QUERY", q)
+}
+
+function on_restore(socket, state_text) {
+	if (!DEBUG)
+		send_message(socket, 'error', "Debugging is not enabled on this server.")
+	SLOG(socket, "RESTORE")
+	try {
+		let state = JSON.parse(state_text)
+
+		// reseed!
+		state.seed = random_seed()
+
+		// resend full log!
+		for (let other of game_clients[socket.game_id])
+			other.seen = 0
+
+		put_new_state(socket.game_id, state, null, null, "$restore", state)
+	} catch (err) {
+		console.log(err)
+		return send_message(socket, 'error', err.toString())
+	}
+}
+
+function on_save(socket) {
+	if (!DEBUG)
+		send_message(socket, 'error', "Debugging is not enabled on this server.")
+	SLOG(socket, "SAVE")
+	try {
+		let game_state = SQL_SELECT_GAME_STATE.get(socket.game_id)
+		if (!game_state)
+			return send_message(socket, 'error', "No game with that ID.")
+		send_message(socket, 'save', game_state)
+	} catch (err) {
+		console.log(err)
+		return send_message(socket, 'error', err.toString())
+	}
+}
+
+function on_query(socket, q, params) {
+	SLOG(socket, "QUERY", q, JSON.stringify(params))
 	try {
 		if (socket.rules.query) {
 			let state = get_game_state(socket.game_id)
@@ -2065,15 +2137,14 @@ function on_query(socket, q) {
 	}
 }
 
-function on_resign(socket) {
-	SLOG(socket, "RESIGN")
+function on_query_snap(socket, snap_id, q, params) {
+	SLOG(socket, "QUERYSNAP", snap_id, JSON.stringify(params))
 	try {
-		let state = get_game_state(socket.game_id)
-		let old_active = state.active
-		// TODO: shared "resign" function
-		state = socket.rules.resign(state, socket.role)
-		put_game_state(socket.game_id, state, old_active)
-		put_replay(socket.game_id, socket.role, 'resign', null)
+		if (socket.rules.query) {
+			let state = JSON.parse(SQL_SELECT_SNAP.get(socket.game_id, snap_id))
+			let reply = socket.rules.query(state, socket.role, q, params)
+			send_message(socket, 'reply', [q, reply])
+		}
 	} catch (err) {
 		console.log(err)
 		return send_message(socket, 'error', err.toString())
@@ -2148,35 +2219,17 @@ function on_chat(socket, message) {
 	}
 }
 
-function on_save(socket) {
-	if (!DEBUG)
-		send_message(socket, 'error', "Debugging is not enabled on this server.")
-	SLOG(socket, "SAVE")
-	try {
-		let game_state = SQL_SELECT_GAME_STATE.get(socket.game_id)
-		if (!game_state)
-			return send_message(socket, 'error', "No game with that ID.")
-		send_message(socket, 'save', game_state)
-	} catch (err) {
-		console.log(err)
-		return send_message(socket, 'error', err.toString())
-	}
-}
-
-function on_restore(socket, state_text) {
-	if (!DEBUG)
-		send_message(socket, 'error', "Debugging is not enabled on this server.")
-	SLOG(socket, "RESTORE")
+function on_snap(socket, snap_id) {
+	SLOG(socket, "SNAP", snap_id)
 	try {
-		let state = JSON.parse(state_text)
-		state.seed = random_seed() // reseed!
-		state_text = JSON.stringify(state)
-		SQL_UPDATE_GAME_RESULT.run(1, null, socket.game_id)
-		SQL_UPDATE_GAME_STATE.run(socket.game_id, state_text, state.active)
-		put_replay(socket.game_id, null, 'debug-restore', state_text)
-		for (let other of game_clients[socket.game_id]) {
-			other.seen = 0
-			send_state(other, state)
+		let snap_state = SQL_SELECT_SNAP.get(socket.game_id, snap_id)
+		if (snap_state) {
+			let state = JSON.parse(snap_state)
+			let view = socket.rules.view(state, socket.role)
+			view.prompt = undefined
+			view.actions = undefined
+			view.log = state.log
+			send_message(socket, "snap", [snap_id, state.active, view])
 		}
 	} catch (err) {
 		console.log(err)
@@ -2193,34 +2246,13 @@ function broadcast_presence(game_id) {
 		send_message(socket, 'presence', presence)
 }
 
-function on_restart(socket, scenario) {
-	if (!DEBUG)
-		send_message(socket, 'error', "Debugging is not enabled on this server.")
-	try {
-		let seed = random_seed()
-		let options = JSON.parse(SQL_SELECT_GAME.get(socket.game_id).options)
-		let state = socket.rules.setup(seed, scenario, options)
-		put_replay(socket.game_id, null, 'setup', [seed, scenario, options])
-		for (let other of game_clients[socket.game_id]) {
-			other.seen = 0
-			send_state(other, state)
-		}
-		let state_text = JSON.stringify(state)
-		SQL_UPDATE_GAME_RESULT.run(1, null, socket.game_id)
-		SQL_UPDATE_GAME_STATE.run(socket.game_id, state_text, state.active)
-	} catch (err) {
-		console.log(err)
-		return send_message(socket, 'error', err.toString())
-	}
-}
-
 function handle_player_message(socket, cmd, arg) {
 	switch (cmd) {
 	case "action":
 		on_action(socket, arg[0], arg[1])
 		break
 	case "query":
-		on_query(socket, arg)
+		on_query(socket, arg[0], arg[1])
 		break
 	case "resign":
 		on_resign(socket)
@@ -2237,22 +2269,31 @@ function handle_player_message(socket, cmd, arg) {
 	case "chat":
 		on_chat(socket, arg)
 		break
+	case "getsnap":
+		on_snap(socket, arg | 0)
+		break
+	case "querysnap":
+		on_query_snap(socket, arg[0], arg[1], arg[2])
+		break
 	case "save":
 		on_save(socket)
 		break
 	case "restore":
 		on_restore(socket, arg)
 		break
-	case "restart":
-		on_restart(socket, arg)
-		break
 	}
 }
 
 function handle_observer_message(socket, cmd, arg) {
 	switch (cmd) {
+	case "getsnap":
+		on_snap(socket, arg)
+		break
+	case "querysnap":
+		on_query_snap(socket, arg[0], arg[1], arg[2])
+		break
 	case 'query':
-		on_query(socket, arg)
+		on_query(socket, arg[0], arg[1])
 		break
 	}
 }
@@ -2331,6 +2372,11 @@ wss.on('connection', (socket, req) => {
 		})
 
 		broadcast_presence(socket.game_id)
+
+		let snapsize = SQL_SELECT_SNAP_COUNT.get(socket.game_id)
+		if (snapsize > 0)
+			send_message(socket, "snapsize", snapsize)
+
 		send_state(socket, get_game_state(socket.game_id))
 	} catch (err) {
 		console.log(err)