# Plugins

If Chatterino is compiled with the `CHATTERINO_PLUGINS` CMake option, it can
load and execute Lua files. Note that while there are attempts at making this
decently safe, we cannot guarantee safety.

## API

The following parts of the Lua standard library are loaded:
 - `_G` (all globals)
 - `table`
 - `string`
 - `math`
 - `utf8`

The official manual for them is available [here](https://www.lua.org/manual/5.4/manual.html#6).

### Chatterino API

All Chatterino functions are exposed in a global table called `c2`. The following functions are available

### `register_command(name, handler)`

Registers a new command called `name` which when executed will call `handler`.
Returns `true` if everything went ok, `false` if there already exists another
command with this name.

Example:
```lua
function cmdWords(ctx)
    -- ctx contains:
    -- words - table of words supplied to the command including the trigger
    -- channelName - name of the channel the command is being run in
    c2.system_msg(ctx.channelName, "Words are: " .. table.concat(ctx.words, " "))
end

c2.register_command("/wordsl", cmdWords)
```

Limitations/known issues:
 - commands registered in functions, not in the global scope might not show up in the settings UI,
   rebuilding the window content caused by reloading another plugin will solve this
 - spaces in command names aren't handled very well (https://github.com/Chatterino/chatterino2/issues/1517)

### `send_msg(channel, text)`

Sends a message to `channel` with the specified text. Also executes commands.

Example:
```
function cmdShout(ctx)
    table.remove(ctx.words, 1)
    local output = table.concat(ctx.words, " ")
    c2.send_msg(ctx.channelName, string.upper(output))
end
c2.register_command("/shout", cmdShout)
```

Limitations/Known issues:
 - it is possible to trigger your own Lua command with this causing a potentially infinite loop

### `system_msg(channel, text)`

Creates a system message and adds it to the twitch channel specified by
`channel`. Returns `true` if everything went ok, `false` otherwise. It will
throw an error if the number of arguments received doesn't match what it
expects.

Example:
```lua
local ok = c2.system_msg("pajlada", "test")
if (not ok)
    -- channel not found
end
```