use crate::uart::Uart;
use crate::mutex::Mutex;

const UART_RATE: u32 = 115_200;
static mut UART: Option<Uart> = None;
static mut UART_MUTEX: Mutex = Mutex::new_unlocked();

#[doc(hidden)]
fn get_uart() -> &'static mut Uart {
    unsafe {
        match &mut UART {
            None => {
                let uart = Uart::serial(UART_RATE);
                UART = Some(uart);
                UART.as_mut().unwrap()
            }
            Some(uart) => uart,
        }
    }
}

// call f(UART) with UART locked via UART_MUTEX
pub fn with_uart<F>(f: F) where F: Fn(&mut Uart) -> () {
    unsafe {
        UART_MUTEX.acquire();
    }
    f(get_uart());
    unsafe {
        UART_MUTEX.release();
    }
}

#[macro_export]
macro_rules! print {
    ($($arg:tt)*) => ({
        crate::stdio::with_uart(|uart| {
            use core::fmt::Write;
            let _ = write!(uart, $($arg)*);
        });
    })
}

#[macro_export]
macro_rules! println {
    ($($arg:tt)*) => ({
        crate::stdio::with_uart(|uart| {
            use core::fmt::Write;
            let _ = write!(uart, $($arg)*);
            let _ = write!(uart, "\r\n");
            while !uart.tx_fifo_empty() {}
        });
    })
}