//! Type definitions.

use core::marker::PhantomData;

/// Errors in this crate
#[derive(Debug)]
pub enum Error<E> {
    /// I²C bus error
    I2C(E),
    /// Invalid input data provided
    InvalidInputData,
}

/// Error type for mode changes.
///
/// This allows to retrieve the unchanged device in case of an error.
pub enum ModeChangeError<E, DEV> {
    /// I²C bus error while changing mode.
    ///
    /// `E` is the error that happened.
    /// `DEV` is the device with the mode unchanged.
    I2C(E, DEV),
}

/// Mode marker types
pub mod mode {
    /// One-shot operating mode / power-down state (default)
    pub struct OneShot(());

    /// Continuous conversion mode
    pub struct Continuous(());
}

/// Data rate for ADS101x.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum DataRate12Bit {
    /// 128 SPS
    Sps128,
    /// 250 SPS
    Sps250,
    /// 490 SPS
    Sps490,
    /// 920 SPS
    Sps920,
    #[default]
    /// 1600 SPS (default)
    Sps1600,
    /// 2400 SPS
    Sps2400,
    /// 3300 SPS
    Sps3300,
}

/// Data rate for ADS111x.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum DataRate16Bit {
    /// 8 SPS
    Sps8,
    /// 16 SPS
    Sps16,
    /// 32 SPS
    Sps32,
    /// 64 SPS
    Sps64,
    #[default]
    /// 128 SPS (default)
    Sps128,
    /// 250 SPS
    Sps250,
    /// 475 SPS
    Sps475,
    /// 860 SPS
    Sps860,
}

/// Comparator mode (only for ADS1x14, ADS1x15).
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum ComparatorMode {
    #[default]
    /// Traditional comparator (default)
    ///
    /// In this mode the ALERT/RDY pin asserts (according to selected active
    /// polarity) when the conversion data exceeds the limit set as *high*
    /// threshold and remains active until the conversion data falls below the
    /// value set as *low* threshold.
    Traditional,
    /// Window comparator
    ///
    /// In this mode the ALERT/RDY pin asserts (according to selected active
    /// polarity) when the conversion data exceeds the value set as *high*
    /// threshold or goes below the value set as *low* temperature threshold.
    Window,
}

/// Comparator polarity (only for ADS1x14, ADS1x15).
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum ComparatorPolarity {
    #[default]
    /// Active low (default)
    ActiveLow,
    /// Active high
    ActiveHigh,
}

/// Comparator latching (only for ADS1x14, ADS1x15).
///
/// Select whether the ALERT/RDY pin latches after being asserted or clears
/// after conversions are within the margin of the upper and lower
/// threshold values.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum ComparatorLatching {
    #[default]
    /// Nonlatching (default)
    ///
    /// The ALERT/RDY pin does not latch when asserted.
    Nonlatching,
    /// Latching
    ///
    /// The asserted ALERT/RDY pin remains latched until conversion data are
    /// read by the controller or an appropriate SMBus alert response is sent by
    /// the controller. The device responds with its address, and it is the
    /// lowest address currently asserting the ALERT/RDY bus line.
    Latching,
}

/// Comparator alert queue (only for ADS1x14, ADS1x15).
///
/// The default state of the comparator is deactivated. It can be activated by setting
/// the comparator queue.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum ComparatorQueue {
    /// Activate comparator and assert after one conversion exceeding thresholds
    One,
    /// Activate comparator and assert after two consecutive conversions exceeding thresholds
    Two,
    #[default]
    /// Activate comparator and assert after four consecutive conversions exceeding thresholds (default)
    Four,
}

/// Full-scale range configuration for the programmable gain amplifier (PGA) (only for ADS1x14, ADS1x15).
///
/// This sets the input voltage measurable range.
/// The FSR is fixed at ±2.048 V in the ADS1x13.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
#[allow(non_camel_case_types)]
pub enum FullScaleRange {
    /// ±6.144V
    Within6_144V,
    /// ±4.096V
    Within4_096V,
    /// ±2.048V (default)
    #[default]
    Within2_048V,
    /// ±1.024V
    Within1_024V,
    /// ±0.512V
    Within0_512V,
    /// ±0.256V
    Within0_256V,
}

/// A target address.
///
/// See [Table 4 in the datasheet](https://www.ti.com/lit/ds/symlink/ads1115.pdf#%5B%7B%22num%22%3A716%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22XYZ%22%7D%2C0%2C602.2%2C0%5D).
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub enum TargetAddr {
    /// Address when the ADDR pin is connected to GND. (default)
    #[default]
    Gnd,
    /// Address when the ADDR pin is connected to VDD.
    Vdd,
    /// Address when the ADDR pin is connected to SDA.
    ///
    /// If SDA is used as the device address, hold the SDA line low for at
    /// least 100 ns after the SCL line goes low to make sure the device
    /// decodes the address correctly during I²C communication.
    Sda,
    /// Address when the ADDR pin is connected to SCL.
    Scl,
}

impl TargetAddr {
    pub(crate) const fn bits(self) -> u8 {
        match self {
            Self::Gnd => 0b1001000,
            Self::Vdd => 0b1001001,
            Self::Sda => 0b1001010,
            Self::Scl => 0b1001011,
        }
    }
}

#[derive(Debug, Clone, PartialEq)]
pub(crate) struct Config {
    pub(crate) bits: u16,
}

impl Config {
    pub(crate) fn is_high(&self, mask: u16) -> bool {
        (self.bits & mask) != 0
    }

    pub(crate) fn with_high(&self, mask: u16) -> Self {
        Config {
            bits: self.bits | mask,
        }
    }

    pub(crate) fn with_low(&self, mask: u16) -> Self {
        Config {
            bits: self.bits & !mask,
        }
    }
}

impl Default for Config {
    fn default() -> Self {
        Config { bits: 0x8583 }
    }
}

/// ADS1x1x ADC driver
#[derive(Debug, Default)]
pub struct Ads1x1x<I2C, IC, CONV, MODE> {
    pub(crate) i2c: I2C,
    pub(crate) address: u8,
    pub(crate) config: Config,
    pub(crate) fsr: FullScaleRange,
    pub(crate) a_conversion_was_started: bool,
    pub(crate) _conv: PhantomData<CONV>,
    pub(crate) _ic: PhantomData<IC>,
    pub(crate) _mode: PhantomData<MODE>,
}

#[cfg(test)]
mod tests {
    use crate::{FullScaleRange, TargetAddr};

    #[test]
    fn target_addr_default() {
        assert_eq!(0b100_1000, TargetAddr::default().bits());
    }

    #[test]
    fn target_addr_bits() {
        assert_eq!(0b100_1000, TargetAddr::Gnd.bits());
        assert_eq!(0b100_1001, TargetAddr::Vdd.bits());
        assert_eq!(0b100_1010, TargetAddr::Sda.bits());
        assert_eq!(0b100_1011, TargetAddr::Scl.bits());
    }

    #[test]
    fn default_full_scale_range() {
        assert_eq!(FullScaleRange::Within2_048V, FullScaleRange::default());
    }
}