#![no_std]
#![no_main]

use esp_backtrace as _;
use esp_println::println;
use hal::{
    clock::ClockControl,
    gpio::{IO},
    peripherals::Peripherals,
    prelude::*,
    prelude::nb::block,
    Delay,
    uart::{
        TxRxPins,
        config::{
            Config,
            Parity,
            StopBits,
            DataBits,
        },
        Uart,
    }
};

#[entry]
fn main() -> ! {
    let peripherals = Peripherals::take();
    let mut system = peripherals.DPORT.split();
    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
    let mut delay = Delay::new(&clocks);

    let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);

    // LilyGo A7670E serial pins.
    // LilyGo TTGO T-Call sim800l board power / reset pins.
    let modem_uart_pins = TxRxPins::new_tx_rx(
        io.pins.gpio26.into_push_pull_output(),
        io.pins.gpio27.into_floating_input(),
    );

    let mut power = io.pins.gpio4.into_push_pull_output();
    power.set_high().ok();

    let config = Config {
        baudrate: 115200,
        data_bits: DataBits::DataBits8,
        parity: Parity::ParityNone,
        stop_bits: StopBits::STOP1,
    };

    // UART interface for the GSM modem
    let mut serial = Uart::new_with_config(
        peripherals.UART1,
        Some(config),
        Some(modem_uart_pins),
        &clocks,
        &mut system.peripheral_clock_control,
    );

    println!("Start");
    loop {
        serial.write(0x42).ok();
        let read = block!(serial.read()).unwrap();
        println!("{}", read);

        delay.delay_ms(1000_u32);
    }
}