# Usage Guide

## Running

```bash
# From project directory
derp

# With options
derp --config /path/to/derp.toml --verbose
```

## CLI Flags

| Flag | Description |
|------|-------------|
| `-c, --config PATH` | Config file path |
| `-v, --verbose` | Debug logging |
| `-V, --version` | Print version |
| `-h, --help` | Show help |

## Configuration

All settings in `config/derp.toml`:

```toml
[server]
host = "irc.libera.chat"    # IRC server hostname
port = 6697                   # Port (6697 = TLS, 6667 = plain)
tls = true                    # Enable TLS encryption
nick = "derp"                 # Bot nickname
user = "derp"                 # Username (ident)
realname = "derp IRC bot"     # Real name field
password = ""                 # Server password (optional)

[bot]
prefix = "!"                  # Command prefix character
channels = ["#test"]          # Channels to join on connect
plugins_dir = "plugins"       # Plugin directory path

[logging]
level = "info"                # Logging level: debug, info, warning, error
```

## Built-in Commands

| Command | Description |
|---------|-------------|
| `!ping` | Bot responds with "pong" |
| `!help` | List all available commands |
| `!help <cmd>` | Show help for a specific command |
| `!help <plugin>` | Show plugin description and its commands |
| `!version` | Show bot version |
| `!echo <text>` | Echo back text (example plugin) |
| `!cert <domain> [...]` | Lookup CT logs for up to 5 domains |
| `!load <plugin>` | Hot-load a plugin from the plugins directory |
| `!reload <plugin>` | Reload a plugin, picking up file changes |
| `!unload <plugin>` | Unload a plugin, removing its handlers |
| `!plugins` | List loaded plugins with handler counts |

### Command Shorthand

Commands can be abbreviated to any unambiguous prefix:

```
!h           -> !help (unique match)
!pi          -> !ping (unique match)
!p           -> error: ambiguous (ping, plugins)
```

Exact matches always take priority over prefix matches.

### `!cert` -- Certificate Transparency Lookup

Query [crt.sh](https://crt.sh) CT logs to enumerate SSL certificates for
domains. Reports totals (expired/valid) and flags domains still serving
expired certs.

```
!cert example.com
!cert example.com badsite.com another.org
```

Output format:

```
example.com -- 127 certs (23 expired, 104 valid)
badsite.com -- 45 certs (8 expired, 37 valid) | live cert EXPIRED
broken.test -- error: timeout
```

- Max 5 domains per invocation
- crt.sh can be slow; the bot confirms receipt before querying
- Live cert check runs only when expired CT entries exist

## Plugin Management

Plugins can be loaded, unloaded, and reloaded at runtime without
restarting the bot.

```
!load crtsh          # Hot-load a new plugin from plugins/
!reload crtsh        # Reload a changed plugin
!unload crtsh        # Remove a plugin and all its handlers
!plugins             # List loaded plugins with handler counts
```

The `core` plugin cannot be unloaded (prevents losing `!load`/`!reload`),
but it can be reloaded.

## Writing Plugins

Create a `.py` file in the `plugins/` directory:

```python
from derp.plugin import command, event

@command("hello", help="Greet the user")
async def cmd_hello(bot, message):
    """Handler receives bot instance and parsed Message."""
    await bot.reply(message, f"Hello, {message.nick}!")

@event("JOIN")
async def on_join(bot, message):
    """Event handlers fire on IRC events (JOIN, PART, QUIT, etc.)."""
    if message.nick != bot.nick:
        await bot.send(message.target, f"Welcome, {message.nick}")
```

### Plugin API

The `bot` object provides:

| Method | Description |
|--------|-------------|
| `bot.send(target, text)` | Send message to channel or nick |
| `bot.reply(msg, text)` | Reply to source (channel or PM) |
| `bot.action(target, text)` | Send `/me` action |
| `bot.join(channel)` | Join a channel |
| `bot.part(channel [, reason])` | Leave a channel |
| `bot.quit([reason])` | Disconnect from server |

The `message` object provides:

| Attribute | Description |
|-----------|-------------|
| `message.nick` | Sender's nickname |
| `message.prefix` | Full `nick!user@host` prefix |
| `message.command` | IRC command (PRIVMSG, JOIN, etc.) |
| `message.target` | First param (channel or nick) |
| `message.text` | Trailing text content |
| `message.is_channel` | Whether target is a channel |
| `message.params` | All message parameters |