//! Bootloader entry helpers shared between power-on checks and runtime combos.

use crate::{KeyMatrix, StatusLed, layout, status::StatusMode};
#[cfg(all(test, feature = "std"))]
use crate::NUMBER_OF_KEYS;
use cortex_m::asm;
use rp2040_hal::{
    gpio::AnyPin,
    pio::{PIOExt, StateMachineIndex},
};
use usbd_human_interface_device::page::Keyboard;

/// Returns true when the runtime bootloader chord is held.
///
/// The chord requires two Fn buttons, both Shift buttons and the primary Ctrl.
pub fn chord_requested(pressed_keys: &KeyMatrix) -> bool {
    if !modifier_pressed(pressed_keys, Keyboard::LeftShift)
        || !modifier_pressed(pressed_keys, Keyboard::RightShift)
    {
        return false;
    }

    if !modifier_pressed(pressed_keys, Keyboard::LeftControl) {
        return false;
    }

    let active_fn = layout::FN_BUTTONS
        .iter()
        .filter(|index| pressed_keys[**index as usize])
        .count();

    active_fn >= 2
}

fn modifier_pressed(pressed_keys: &KeyMatrix, key: Keyboard) -> bool {
    layout::MAP[0]
        .iter()
        .enumerate()
        .any(|(index, mapped)| *mapped == key && pressed_keys[index])
}

/// Puts the RP2040 into the ROM bootloader.
pub fn enter<P, SM, I>(status_led: &mut StatusLed<P, SM, I>) -> !
where
    P: PIOExt,
    SM: StateMachineIndex,
    I: AnyPin<Function = P::PinFunction>,
{
    status_led.update(StatusMode::Bootloader);
    let gpio_activity_pin_mask: u32 = 0;
    let disable_interface_mask: u32 = 0;
    rp2040_hal::rom_data::reset_to_usb_boot(gpio_activity_pin_mask, disable_interface_mask);
    loop {
        asm::nop();
    }
}

#[cfg(all(test, feature = "std"))]
mod tests {
    use super::*;

    #[test]
    fn chord_requires_all_modifier_keys_and_two_fn() {
        let mut pressed = [false; NUMBER_OF_KEYS];
        for (index, key) in layout::MAP[0].iter().enumerate() {
            match key {
                Keyboard::LeftShift | Keyboard::RightShift | Keyboard::LeftControl => {
                    pressed[index] = true;
                }
                _ => {}
            }
        }
        pressed[layout::FN_BUTTONS[0] as usize] = true;
        assert!(!chord_requested(&pressed));

        pressed[layout::FN_BUTTONS[1] as usize] = true;
        assert!(chord_requested(&pressed));
    }
}