"""Core plugin: ping, help, version, plugin management."""

from collections import Counter

from derp import __version__
from derp.plugin import command


@command("ping", help="Check if the bot is alive")
async def cmd_ping(bot, message):
    """Respond with pong."""
    await bot.reply(message, "pong")


@command("help", help="List commands or show command/plugin help")
async def cmd_help(bot, message):
    """Show available commands, or help for a specific command or plugin.

    Usage: !help [command|plugin]
    """
    parts = message.text.split(None, 2)
    if len(parts) > 1:
        name = parts[1].lower().lstrip(bot.prefix)

        # Check command first
        handler = bot.registry.commands.get(name)
        if handler:
            help_text = handler.help or "No help available."
            await bot.reply(message, f"{bot.prefix}{name} -- {help_text}")
            return

        # Check plugin
        module = bot.registry._modules.get(name)
        if module:
            desc = (getattr(module, "__doc__", "") or "").split("\n")[0].strip()
            cmds = sorted(
                k for k, v in bot.registry.commands.items() if v.plugin == name
            )
            lines = [f"{name} -- {desc}" if desc else name]
            if cmds:
                lines.append(f"Commands: {', '.join(bot.prefix + c for c in cmds)}")
            await bot.reply(message, " | ".join(lines))
            return

        await bot.reply(message, f"Unknown command or plugin: {name}")
        return

    # List all commands
    names = sorted(bot.registry.commands.keys())
    await bot.reply(message, f"Commands: {', '.join(bot.prefix + n for n in names)}")


@command("version", help="Show bot version")
async def cmd_version(bot, message):
    """Report the running version."""
    await bot.reply(message, f"derp {__version__}")


@command("uptime", help="Show how long the bot has been running")
async def cmd_uptime(bot, message):
    """Report bot uptime."""
    import time

    elapsed = int(time.monotonic() - bot._started)
    days, rem = divmod(elapsed, 86400)
    hours, rem = divmod(rem, 3600)
    minutes, secs = divmod(rem, 60)
    parts = []
    if days:
        parts.append(f"{days}d")
    if hours:
        parts.append(f"{hours}h")
    if minutes:
        parts.append(f"{minutes}m")
    parts.append(f"{secs}s")
    await bot.reply(message, f"up {' '.join(parts)}")


@command("load", help="Hot-load a plugin: !load <name>")
async def cmd_load(bot, message):
    """Load a new plugin from the plugins directory."""
    parts = message.text.split(None, 2)
    if len(parts) < 2:
        await bot.reply(message, "Usage: !load <plugin>")
        return
    name = parts[1].lower()
    ok, reason = bot.load_plugin(name)
    if ok:
        await bot.reply(message, f"Loaded plugin: {name} ({reason})")
    else:
        await bot.reply(message, f"Failed to load plugin: {reason}")


@command("reload", help="Reload a plugin: !reload <name>")
async def cmd_reload(bot, message):
    """Unload and reload a plugin, picking up file changes."""
    parts = message.text.split(None, 2)
    if len(parts) < 2:
        await bot.reply(message, "Usage: !reload <plugin>")
        return
    name = parts[1].lower()
    ok, reason = bot.reload_plugin(name)
    if ok:
        await bot.reply(message, f"Reloaded plugin: {name}")
    else:
        await bot.reply(message, f"Failed to reload plugin: {reason}")


@command("unload", help="Unload a plugin: !unload <name>")
async def cmd_unload(bot, message):
    """Unload a plugin, removing all its handlers."""
    parts = message.text.split(None, 2)
    if len(parts) < 2:
        await bot.reply(message, "Usage: !unload <plugin>")
        return
    name = parts[1].lower()
    ok, reason = bot.unload_plugin(name)
    if ok:
        await bot.reply(message, f"Unloaded plugin: {name}")
    else:
        await bot.reply(message, f"Failed to unload plugin: {reason}")


@command("plugins", help="List loaded plugins")
async def cmd_plugins(bot, message):
    """List all loaded plugins with handler counts."""
    counts: Counter[str] = Counter()
    for handler in bot.registry.commands.values():
        counts[handler.plugin] += 1
    for handlers in bot.registry.events.values():
        for handler in handlers:
            counts[handler.plugin] += 1
    parts = [f"{name} ({counts[name]})" for name in sorted(counts)]
    await bot.reply(message, f"Plugins: {', '.join(parts)}")