use std::fs::DirEntry;

use log::{debug, Record};
use mlua::{Function, FromLua, Lua, Table, Value};

pub struct Plugin<'lua> {
	pub table: Table<'lua>,
	pub id: String,
}

impl<'lua> FromLua<'lua> for Plugin<'lua> {
    fn from_lua(lua_value: Value<'lua>, lua: &'lua Lua) -> mlua::Result<Self> {
		let table = Table::from_lua(lua_value, lua)?;
		Ok(Plugin {
			id: table.get("id")?,
			table,
		})
	}
}

fn lua_locinfo(lua: &Lua) -> Option<(u32, String)> {
	let debug = lua.globals().get::<_, Table>("debug").ok()?;
	let getinfo = debug.get::<_, Function>("getinfo").ok()?;
	let data = getinfo.call::<_, Table>((2,)).ok()?;
	let line = data.get("currentline").ok()?;
	let file = data.get("short_src").ok()?;
	Some((line, file))
}

fn lua_log(level: log::Level, path: &'static str, msg: String, lua: &Lua) {
	let mut record = Record::builder();
	record.level(level);
	record.target(path);
	record.module_path_static(Some(path));
	let locinfo = lua_locinfo(lua);
	if let Some((line, file)) = &locinfo {
		record.line(Some(*line));
		record.file(Some(file));
	}
	log::logger().log(&record.args(format_args!("{}", msg)).build());

}

const LEVELS: [(&str, log::Level); 5] = [
	("trace", log::Level::Trace),
	("debug", log::Level::Debug),
	("info", log::Level::Info),
	("warn", log::Level::Warn),
	("error", log::Level::Error),
];

impl<'lua> Plugin<'lua> {
	pub fn load(entry: &DirEntry, lua: &'lua Lua) -> anyhow::Result<Self> {
		let ty = entry.file_type()?;
		let mut path = entry.path();
		if ty.is_dir() {
			path.push("main.lua");
		}
		let chunk = lua.load(&path);
		debug!("evaluating plugin");
		let plugin = Self::from_lua(chunk.eval()?, lua)?;

		// leak: plugins are only loaded at the beginning of the program
		// and the path needs to live forever anyway, so this is fine
		let path: &'static str = Box::leak(format!("qcplugin::{}", plugin.id).into_boxed_str());

		for (name, level) in LEVELS {
			plugin.table.set(name, lua.create_function(move |lua, (msg,): (String,)| {
				lua_log(level, path, msg, lua);
				Ok(())
			})?)?;
		}

		Ok(plugin)
	}
}