//! CDC-ACM serial port example using polling in a busy loop.
#![no_std]
#![no_main]

extern crate panic_semihosting;
extern crate stm32wb_hal as hal;

use cortex_m_rt::{entry, exception, ExceptionFrame};

use hal::flash::FlashExt;
use hal::pac;
use hal::prelude::*;
use hal::rcc::{ApbDivider, Config, HDivider, HseDivider, PllConfig, PllSrc, SysClkSrc, UsbClkSrc};
use hal::usb::{Peripheral, UsbBus};

use usb_device::prelude::*;
use usbd_serial::{SerialPort, USB_CLASS_CDC};

#[entry]
fn main() -> ! {
    let dp = pac::Peripherals::take().unwrap();

    let rcc = dp.RCC.constrain();

    // Fastest clock configuration.
    // * 32 MHz HSE with PLL
    // * 64 MHz CPU1, 32 MHz CPU2
    // * 64 MHz for APB1, APB2
    // * USB clock source from PLLQ (32 / 2 * 3 = 48)
    let clock_config = Config::new(SysClkSrc::Pll(PllSrc::Hse(HseDivider::NotDivided)))
        .cpu1_hdiv(HDivider::NotDivided)
        .cpu2_hdiv(HDivider::Div2)
        .apb1_div(ApbDivider::NotDivided)
        .apb2_div(ApbDivider::NotDivided)
        .pll_cfg(PllConfig {
            m: 2,
            n: 12,
            r: 3,
            q: Some(4),
            p: Some(3),
        })
        .usb_src(UsbClkSrc::PllQ);

    let mut rcc = rcc.apply_clock_config(clock_config, &mut dp.FLASH.constrain().acr);

    // Enable USB power supply
    hal::pwr::set_usb(true);

    let mut gpioa = dp.GPIOA.split(&mut rcc);

    let usb = Peripheral {
        usb: dp.USB,
        pin_dm: gpioa.pa11.into_af10(&mut gpioa.moder, &mut gpioa.afrh),
        pin_dp: gpioa.pa12.into_af10(&mut gpioa.moder, &mut gpioa.afrh),
    };
    let usb_bus = UsbBus::new(usb);

    let mut serial = SerialPort::new(&usb_bus);

    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x27dd))
        .manufacturer("Fake company")
        .product("Serial port")
        .serial_number("TEST")
        .device_class(USB_CLASS_CDC)
        .build();

    loop {
        if !usb_dev.poll(&mut [&mut serial]) {
            continue;
        }

        let mut buf = [0u8; 64];

        match serial.read(&mut buf) {
            Ok(count) if count > 0 => {
                // Echo back in upper case
                for c in buf[0..count].iter_mut() {
                    if 0x61 <= *c && *c <= 0x7a {
                        *c &= !0x20;
                    }
                }

                let mut write_offset = 0;
                while write_offset < count {
                    match serial.write(&buf[write_offset..count]) {
                        Ok(len) if len > 0 => {
                            write_offset += len;
                        }
                        _ => {}
                    }
                }
            }
            _ => {}
        }
    }
}

#[exception]
#[allow(non_snake_case)]
fn HardFault(ef: &ExceptionFrame) -> ! {
    panic!("HardFault at {:#?}", ef);
}

#[exception]
#[allow(non_snake_case)]
fn DefaultHandler(irqn: i16) {
    panic!("Unhandled exception (IRQn = {})", irqn);
}