#![no_std]
#![no_main]

use esp_backtrace as _;
use esp_hal::{
    analog::adc::{Adc, AdcConfig, Attenuation},
    clock::CpuClock,
    delay::Delay,
    gpio::{Level, Output},
    main,
};

#[main]
fn main() -> ! {
    esp_println::logger::init_logger_from_env();

    // Common Setup Code
    let config = esp_hal::Config::default().with_cpu_clock(CpuClock::max());
    let peripherals = esp_hal::init(config);
    let delay = Delay::new();
    // End Common Setup Code

    let analog_pin = peripherals.GPIO0;
    let mut adc_config = AdcConfig::new();
    let mut pin = adc_config.enable_pin(analog_pin, Attenuation::_11dB);

    let mut adc = Adc::new(peripherals.ADC1, adc_config);

    let mut output_pins = [
        Output::new(peripherals.GPIO10, Level::Low),
        Output::new(peripherals.GPIO9, Level::Low),
        Output::new(peripherals.GPIO8, Level::Low),
        Output::new(peripherals.GPIO7, Level::Low),
        Output::new(peripherals.GPIO6, Level::Low),
        Output::new(peripherals.GPIO5, Level::Low),
        Output::new(peripherals.GPIO4, Level::Low),
        Output::new(peripherals.GPIO3, Level::Low),
        Output::new(peripherals.GPIO2, Level::Low),
        Output::new(peripherals.GPIO1, Level::Low),
    ];

    let min = 0_u32;
    let max = 4_095_u32;

    loop {
        let reading = u32::from(nb::block!(adc.read_oneshot(&mut pin)).unwrap());
        let leds_lit_up = usize::try_from(map_linear(
            reading,
            min,
            max,
            0_u32,
            u32::try_from(output_pins.len()).unwrap(),
        ))
        .unwrap();
        for led in &mut output_pins[..leds_lit_up] {
            led.set_high();
        }
        for led in &mut output_pins[leds_lit_up..] {
            led.set_low();
        }
        delay.delay_millis(100);
    }
}

fn map_linear(x: u32, min_in: u32, max_in: u32, min_out: u32, max_out: u32) -> u32 {
    ((x - min_in) * (max_out - min_out) / (max_in - min_in)) + min_out
}