use std::process::Stdio;

use mlua::{AnyUserData, IntoLuaMulti, Lua, Table, UserData, Value};

use super::{output::Output, Child};

pub struct Command {
	inner: tokio::process::Command,
}

const NULL: u8 = 0;
const PIPED: u8 = 1;
const INHERIT: u8 = 2;

impl Command {
	pub fn install(lua: &Lua) -> mlua::Result<()> {
		let new = lua.create_function(|_, (_, program): (Table, String)| {
			let mut inner = tokio::process::Command::new(program);
			inner.kill_on_drop(true).stdin(Stdio::null()).stdout(Stdio::null()).stderr(Stdio::null());

			Ok(Self { inner })
		})?;

		let command = lua.create_table_from([
			// Stdio
			("NULL", NULL),
			("PIPED", PIPED),
			("INHERIT", INHERIT),
		])?;

		command.set_metatable(Some(lua.create_table_from([("__call", new)])?));

		lua.globals().raw_set("Command", command)
	}
}

impl UserData for Command {
	fn add_methods<'lua, M: mlua::UserDataMethods<'lua, Self>>(methods: &mut M) {
		methods.add_function("arg", |_, (ud, arg): (AnyUserData, mlua::String)| {
			ud.borrow_mut::<Self>()?.inner.arg(arg.to_string_lossy().as_ref());
			Ok(ud)
		});
		methods.add_function("args", |_, (ud, args): (AnyUserData, Vec<mlua::String>)| {
			{
				let mut me = ud.borrow_mut::<Self>()?;
				for arg in args {
					me.inner.arg(arg.to_string_lossy().as_ref());
				}
			}
			Ok(ud)
		});
		methods.add_function("cwd", |_, (ud, dir): (AnyUserData, mlua::String)| {
			ud.borrow_mut::<Self>()?.inner.current_dir(dir.to_str()?);
			Ok(ud)
		});
		methods.add_function(
			"env",
			|_, (ud, key, value): (AnyUserData, mlua::String, mlua::String)| {
				ud.borrow_mut::<Self>()?
					.inner
					.env(key.to_string_lossy().as_ref(), value.to_string_lossy().as_ref());
				Ok(ud)
			},
		);
		methods.add_function("stdin", |_, (ud, stdio): (AnyUserData, u8)| {
			ud.borrow_mut::<Self>()?.inner.stdin(match stdio {
				PIPED => Stdio::piped(),
				INHERIT => Stdio::inherit(),
				_ => Stdio::null(),
			});
			Ok(ud)
		});
		methods.add_function("stdout", |_, (ud, stdio): (AnyUserData, u8)| {
			ud.borrow_mut::<Self>()?.inner.stdout(match stdio {
				PIPED => Stdio::piped(),
				INHERIT => Stdio::inherit(),
				_ => Stdio::null(),
			});
			Ok(ud)
		});
		methods.add_function("stderr", |_, (ud, stdio): (AnyUserData, u8)| {
			ud.borrow_mut::<Self>()?.inner.stderr(match stdio {
				PIPED => Stdio::piped(),
				INHERIT => Stdio::inherit(),
				_ => Stdio::null(),
			});
			Ok(ud)
		});
		methods.add_method_mut("spawn", |lua, me, ()| match me.inner.spawn() {
			Ok(child) => (Child::new(child), Value::Nil).into_lua_multi(lua),
			Err(e) => (Value::Nil, e.raw_os_error()).into_lua_multi(lua),
		});
		methods.add_async_method_mut("output", |lua, me, ()| async move {
			match me.inner.output().await {
				Ok(output) => (Output::new(output), Value::Nil).into_lua_multi(lua),
				Err(e) => (Value::Nil, e.raw_os_error()).into_lua_multi(lua),
			}
		});
	}
}