//! Static electrical routes selected by the Kakute F7 Mini V3.
//!
//! The board describes which controller and pins are connected. Protocol
//! framing and controller state remain in their respective reusable crates.

use kaptan_spi::{SpiCompletion, SpiDevice};
use kaptan_stm32f7::stm32f722::{Spi1, Spi1Error};
use stm32f7::stm32f722;

/// Chip-select-scoped SPI1/PB2 route wired to the MPU6000.
pub struct KakuteMpu6000SpiRoute {
    spi: Spi1,
    chip_select: stm32f722::GPIOB,
}

impl KakuteMpu6000SpiRoute {
    /// Configures board-selected PB2 chip select and combines it with SPI1.
    pub(crate) fn new(rcc: &stm32f722::RCC, spi: Spi1, chip_select: stm32f722::GPIOB) -> Self {
        rcc.ahb1enr().modify(|_, write| write.gpioben().set_bit());
        chip_select
            .moder()
            .modify(|_, write| write.moder2().output());
        chip_select
            .otyper()
            .modify(|_, write| write.ot2().push_pull());
        chip_select
            .ospeedr()
            .modify(|_, write| write.ospeedr2().low_speed());
        chip_select
            .pupdr()
            .modify(|_, write| write.pupdr2().floating());
        chip_select.bsrr().write(|write| write.bs2().set_bit());

        Self { spi, chip_select }
    }

    fn select(&self) {
        self.chip_select.bsrr().write(|write| write.br2().set_bit());
    }

    fn deselect(&self) {
        self.chip_select.bsrr().write(|write| write.bs2().set_bit());
    }
}

impl SpiDevice for KakuteMpu6000SpiRoute {
    type StartError = Spi1Error;

    fn start_transfer(
        &mut self,
        transmit: &[u8],
        receive: &mut [u8],
    ) -> Result<(), Self::StartError> {
        self.select();
        if let Err(error) = self.spi.start_transfer(transmit, receive) {
            self.deselect();
            return Err(error);
        }

        Ok(())
    }

    fn complete_transfer(&mut self, completion: SpiCompletion) {
        self.spi.complete_transfer(completion);
        if matches!(
            completion,
            SpiCompletion::Complete | SpiCompletion::TransferFault
        ) {
            self.deselect();
        }
    }
}