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//! Analog-digital conversion traits

/// Non-blocking ADC traits
pub mod nb {
    /// A marker trait to identify MCU pins that can be used as inputs to an ADC channel.
    ///
    /// This marker trait denotes an object, i.e. a GPIO pin, that is ready for use as an input to the
    /// ADC. As ADCs channels can be supplied by multiple pins, this trait defines the relationship
    /// between the physical interface and the ADC sampling buffer.
    ///
    /// ```
    /// # use core::marker::PhantomData;
    /// # use embedded_hal::adc::nb::Channel;
    ///
    /// struct Adc1; // Example ADC with single bank of 8 channels
    /// struct Gpio1Pin1<MODE>(PhantomData<MODE>);
    /// struct Analog(()); // marker type to denote a pin in "analog" mode
    ///
    /// // GPIO 1 pin 1 can supply an ADC channel when it is configured in Analog mode
    /// impl Channel<Adc1> for Gpio1Pin1<Analog> {
    ///     type ID = u8; // ADC channels are identified numerically
    ///
    ///     fn channel(&self) -> Self::ID {
    ///         7_u8 // GPIO pin 1 is connected to ADC channel 7
    ///     }
    /// }
    ///
    /// struct Adc2; // ADC with two banks of 16 channels
    /// struct Gpio2PinA<MODE>(PhantomData<MODE>);
    /// struct AltFun(()); // marker type to denote some alternate function mode for the pin
    ///
    /// // GPIO 2 pin A can supply an ADC channel when it's configured in some alternate function mode
    /// impl Channel<Adc2> for Gpio2PinA<AltFun> {
    ///     type ID = (u8, u8); // ADC channels are identified by bank number and channel number
    ///
    ///     fn channel(&self) -> Self::ID {
    ///         (0, 3) // bank 0 channel 3
    ///     }
    /// }
    /// ```
    pub trait Channel<ADC> {
        /// Channel ID type
        ///
        /// A type used to identify this ADC channel. For example, if the ADC has eight channels, this
        /// might be a `u8`. If the ADC has multiple banks of channels, it could be a tuple, like
        /// `(u8: bank_id, u8: channel_id)`.
        type ID: Copy;

        /// Get the specific ID that identifies this channel, for example `0_u8` for the first ADC
        /// channel, if Self::ID is u8.
        fn channel(&self) -> Self::ID;
    }

    /// ADCs that sample on single channels per request, and do so at the time of the request.
    ///
    /// This trait is the interface to an ADC that is configured to read a specific channel at the time
    /// of the request (in contrast to continuous asynchronous sampling).
    ///
    /// ```
    /// use embedded_hal::adc::nb::{Channel, OneShot};
    ///
    /// struct MyAdc; // 10-bit ADC, with 5 channels
    /// # impl MyAdc {
    /// #     pub fn power_up(&mut self) {}
    /// #     pub fn power_down(&mut self) {}
    /// #     pub fn do_conversion(&mut self, chan: u8) -> u16 { 0xAA55_u16 }
    /// # }
    ///
    /// impl<WORD, PIN> OneShot<MyAdc, WORD, PIN> for MyAdc
    /// where
    ///    WORD: From<u16>,
    ///    PIN: Channel<MyAdc, ID=u8>,
    /// {
    ///    type Error = ();
    ///
    ///    fn read(&mut self, pin: &mut PIN) -> nb::Result<WORD, Self::Error> {
    ///        let chan = 1 << pin.channel();
    ///        self.power_up();
    ///        let result = self.do_conversion(chan);
    ///        self.power_down();
    ///        Ok(result.into())
    ///    }
    /// }
    /// ```
    pub trait OneShot<ADC, Word, Pin: Channel<ADC>> {
        /// Error type returned by ADC methods
        type Error: core::fmt::Debug;

        /// Request that the ADC begin a conversion on the specified pin
        ///
        /// This method takes a `Pin` reference, as it is expected that the ADC will be able to sample
        /// whatever channel underlies the pin.
        fn read(&mut self, pin: &mut Pin) -> nb::Result<Word, Self::Error>;
    }
}