Day night cycle

MODS.md

@@ -497,6 +497,8 @@ interface ServerWorld {
 	drop_item(x: number, y: number, z: number, item: ItemStack): void; // pops out of the block, like drops
 	is_loaded(x: number, z: number): boolean;
 	readonly seed: string;
+	readonly time: number; // world time, see below
+	set_time(time: number): void; // synced to every player
 }
 
 interface Player {
@@ -533,6 +535,12 @@ interface ModStorage {
 }
 ```
 
+**World time** counts ticks since 06:00 of day 1 and never wraps around. A day (06:00 to 18:00) is 36000 ticks, 30
+minutes, and a night (18:00 to 06:00) is 12000 ticks, 10 minutes, so in game hours are shorter at night. Dusk is the
+first minute of the night and dawn the last, so it's bright all day. `common/time.ts` has `clock`, `format_clock`,
+`is_day` and `daylight` for turning it into something readable. Client scripts can read it as `ctx.world.time`, and
+players can use `/time`, `/time set <ticks|day|noon|sunset|night|midnight>` and `/time add <ticks>`.
+
 The server loads chunks around every player (its simulation distance) and generates them itself with the same generator
 as the clients. Blocks in unloaded chunks can't be read or changed, and don't tick.
 
@@ -549,7 +557,7 @@ ctx.commands.register("heal", {
 ```
 
 Commands run on the server when a player types `/name` in chat. Two mods using the same name, or a mod using one of the
-engine's (`give` and `tps`), is a load error. `/copper_tools:heal` always works as the unambiguous form.
+engine's (`give`, `time` and `tps`), is a load error. `/copper_tools:heal` always works as the unambiguous form.
 
 ## Client scripts