#![deny(missing_docs, unsafe_code)]

use super::{BitMode, DeviceType, FtStatus, FtdiCommon, TimeoutError};
use ftdi_mpsse::mpsse;
use ftdi_mpsse::{ClockData, ClockDataIn, ClockDataOut};
use ftdi_mpsse::{MpsseCmdBuilder, MpsseSettings};
use std::convert::From;

// seemingly arbitrary values from libmpsse
// const ECHO_CMD_1: u8 = 0xAA;
const ECHO_CMD_2: u8 = 0xAB;

fn check_limits(device: DeviceType, frequency: u32, max: u32) {
    const MIN: u32 = 92;
    assert!(
        frequency >= MIN,
        "frequency of {frequency} exceeds minimum of {MIN} for {device:?}"
    );
    assert!(
        frequency <= max,
        "frequency of {frequency} exceeds maximum of {max} for {device:?}"
    );
}

// calculate the clock divisor from a frequency
fn clock_divisor(device: DeviceType, frequency: u32) -> (u32, Option<bool>) {
    match device {
        // FT2232D appears as FT2232C in FTD2XX
        DeviceType::FT2232C => {
            check_limits(device, frequency, 6_000_000);
            (6_000_000 / frequency - 1, None)
        }
        DeviceType::FT2232H | DeviceType::FT4232H | DeviceType::FT232H => {
            check_limits(device, frequency, 30_000_000);
            if frequency <= 6_000_000 {
                (6_000_000 / frequency - 1, Some(true))
            } else {
                (30_000_000 / frequency - 1, Some(false))
            }
        }
        _ => panic!("Unknown device type: {device:?}"),
    }
}

#[cfg(test)]
mod clock_divisor {
    use super::*;

    macro_rules! pos {
        ($NAME:ident, $DEVICE:expr, $FREQ:expr, $OUT:expr) => {
            #[test]
            fn $NAME() {
                assert_eq!(clock_divisor($DEVICE, $FREQ), $OUT);
            }
        };
    }

    macro_rules! neg {
        ($NAME:ident, $DEVICE:expr, $FREQ:expr) => {
            #[test]
            #[should_panic]
            fn $NAME() {
                clock_divisor($DEVICE, $FREQ);
            }
        };
    }

    pos!(ft232c_min, DeviceType::FT2232C, 92, (65216, None));
    pos!(ft232c_max, DeviceType::FT2232C, 6_000_000, (0, None));
    pos!(min, DeviceType::FT2232H, 92, (65216, Some(true)));
    pos!(
        max_with_div,
        DeviceType::FT2232H,
        6_000_000,
        (0, Some(true))
    );
    pos!(
        min_without_div,
        DeviceType::FT2232H,
        6_000_001,
        (3, Some(false))
    );
    pos!(max, DeviceType::FT4232H, 30_000_000, (0, Some(false)));

    neg!(panic_unknown, DeviceType::Unknown, 1_000);
    neg!(panic_ft232c_min, DeviceType::FT2232C, 91);
    neg!(panic_ft232c_max, DeviceType::FT2232C, 6_000_001);
    neg!(panic_min, DeviceType::FT232H, 91);
    neg!(panic_max, DeviceType::FT232H, 30_000_001);
}

/// FTDI Multi-Protocol Synchronous Serial Engine (MPSSE).
///
/// For details about the MPSSE read the [FTDI MPSSE Basics].
///
/// [FTDI MPSSE Basics]: https://www.ftdichip.com/Support/Documents/AppNotes/AN_135_MPSSE_Basics.pdf
pub trait FtdiMpsse: FtdiCommon {
    /// Set the clock frequency.
    ///
    /// # Frequency Limits
    ///
    /// | Device Type              | Minimum | Maximum |
    /// |--------------------------|---------|---------|
    /// | FT2232D                  | 92 Hz   | 6 MHz   |
    /// | FT4232H, FT2232H, FT232H | 92 Hz   | 30 MHz  |
    ///
    /// Values outside of these limits will result in panic.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft4232h, FtdiMpsse};
    ///
    /// let mut ft = Ft4232h::with_serial_number("FT4PWSEOA")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.set_clock(100_000)?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn set_clock(&mut self, frequency: u32) -> Result<(), TimeoutError> {
        let (divisor, clkdiv) = clock_divisor(Self::DEVICE_TYPE, frequency);
        debug_assert!(divisor <= 0xFFFF);

        let cmd = MpsseCmdBuilder::new().set_clock(divisor, clkdiv);
        self.write_all(cmd.as_slice())
    }

    /// Initialize the MPSSE.
    ///
    /// This method does the following:
    ///
    /// 1. Optionally [`reset`]s the device.
    /// 2. Sets USB transfer sizes using values provided.
    /// 3. Disables special characters.
    /// 4. Sets the transfer timeouts using values provided.
    /// 5. Sets latency timers using values provided.
    /// 6. Sets the flow control to RTS CTS.
    /// 7. Resets the bitmode, then sets it to MPSSE.
    /// 8. Enables loopback.
    /// 9. Synchronizes the MPSSE.
    /// 10. Disables loopback.
    /// 11. Optionally sets the clock frequency.
    ///
    /// Upon failure cleanup is not guaranteed.
    ///
    /// # Example
    ///
    /// Initialize the MPSSE with a 5 second read timeout.
    ///
    /// ```no_run
    /// use ftdi_mpsse::MpsseSettings;
    /// use libftd2xx::{Ft232h, FtdiMpsse};
    /// use std::time::Duration;
    ///
    /// let mut settings = MpsseSettings::default();
    /// settings.read_timeout = Duration::from_secs(5);
    /// let mut ft = Ft232h::with_serial_number("FT59UO4C")?;
    /// ft.initialize_mpsse(&settings)?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    ///
    /// [`reset`]: FtdiCommon::reset
    fn initialize_mpsse(&mut self, settings: &MpsseSettings) -> Result<(), TimeoutError> {
        if settings.reset {
            self.reset()?;
        }
        self.purge_rx()?;
        debug_assert_eq!(self.queue_status()?, 0);
        self.set_usb_parameters(settings.in_transfer_size)?;
        self.set_chars(0, false, 0, false)?;
        self.set_timeouts(settings.read_timeout, settings.write_timeout)?;
        self.set_latency_timer(settings.latency_timer)?;
        self.set_flow_control_rts_cts()?;
        self.set_bit_mode(0x0, BitMode::Reset)?;
        self.set_bit_mode(settings.mask, BitMode::Mpsse)?;
        self.enable_loopback()?;
        self.synchronize_mpsse()?;
        self.disable_loopback()?;

        if let Some(frequency) = settings.clock_frequency {
            self.set_clock(frequency)?;
        }

        Ok(())
    }

    /// Initializes the MPSSE to default settings.
    ///
    /// This simply calles [`initialize_mpsse`] with the default
    /// [`MpsseSettings`].
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft232h, FtdiMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT59UO4C")?;
    /// ft.initialize_mpsse_default()?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    ///
    /// [`initialize_mpsse`]: FtdiMpsse::initialize_mpsse
    fn initialize_mpsse_default(&mut self) -> Result<(), TimeoutError> {
        self.initialize_mpsse(&MpsseSettings::default())
    }

    /// Synchronize the MPSSE port with the application.
    ///
    /// There are various implementations of the synchronization flow, this
    /// uses the flow from [FTDI MPSSE Basics].
    ///
    /// [FTDI MPSSE Basics]: https://www.ftdichip.com/Support/Documents/AppNotes/AN_135_MPSSE_Basics.pdf
    fn synchronize_mpsse(&mut self) -> Result<(), TimeoutError> {
        self.purge_rx()?;
        debug_assert_eq!(self.queue_status()?, 0);
        self.write_all(&[ECHO_CMD_2])?;

        // the FTDI MPSSE basics polls the queue status here
        // we purged the RX buffer so the response should always be 2 bytes
        // this allows us to leverage the timeout built into read
        let mut buf: [u8; 2] = [0; 2];
        self.read_all(&mut buf)?;

        if buf[0] == 0xFA && buf[1] == ECHO_CMD_2 {
            Ok(())
        } else {
            Err(TimeoutError::from(FtStatus::OTHER_ERROR))
        }
    }

    /// Enable the MPSSE loopback state.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft4232h, FtdiMpsse};
    ///
    /// let mut ft = Ft4232h::with_serial_number("FT4PWSEOA")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.enable_loopback()?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn enable_loopback(&mut self) -> Result<(), TimeoutError> {
        mpsse! {
            let cmd = { enable_loopback(); };
        }

        self.write_all(&cmd)
    }

    /// Disable the MPSSE loopback state.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft4232h, FtdiMpsse};
    ///
    /// let mut ft = Ft4232h::with_serial_number("FT4PWSEOA")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.disable_loopback()?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn disable_loopback(&mut self) -> Result<(), TimeoutError> {
        mpsse! {
            let cmd = { disable_loopback(); };
        }

        self.write_all(&cmd)
    }

    /// Set the pin direction and state of the lower byte (0-7) GPIO pins on the
    /// MPSSE interface.
    ///
    /// The pins that this controls depends on the device.
    ///
    /// * On the FT232H this will control the AD0-AD7 pins.
    ///
    /// # Arguments
    ///
    /// * `state` - GPIO state mask, `0` is low (or input pin), `1` is high.
    /// * `direction` - GPIO direction mask, `0` is input, `1` is output.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft232h, FtdiMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT5AVX6B")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.set_gpio_lower(0xFF, 0xFF)?;
    /// ft.set_gpio_lower(0x00, 0xFF)?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn set_gpio_lower(&mut self, state: u8, direction: u8) -> Result<(), TimeoutError> {
        let cmd = MpsseCmdBuilder::new().set_gpio_lower(state, direction);
        self.write_all(cmd.as_slice())
    }

    /// Get the pin state state of the lower byte (0-7) GPIO pins on the MPSSE
    /// interface.
    ///
    /// # Example
    ///
    /// Set the first GPIO, without modify the state of the other GPIOs.
    ///
    /// ```no_run
    /// use libftd2xx::{Ft232h, FtdiMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT59UO4C")?;
    /// ft.initialize_mpsse_default()?;
    /// let mut gpio_state: u8 = ft.gpio_lower()?;
    /// gpio_state |= 0x01;
    /// ft.set_gpio_lower(gpio_state, 0xFF)?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn gpio_lower(&mut self) -> Result<u8, TimeoutError> {
        let cmd = MpsseCmdBuilder::new().gpio_lower().send_immediate();
        let mut buf: [u8; 1] = [0];

        self.write_all(cmd.as_slice())?;
        self.read_all(&mut buf)?;

        Ok(buf[0])
    }

    /// Set the pin direction and state of the upper byte (8-15) GPIO pins on
    /// the MPSSE interface.
    ///
    /// The pins that this controls depends on the device.
    /// This method may do nothing for some devices, such as the FT4232H that
    /// only have 8 pins per port.
    ///
    /// See [`set_gpio_lower`] for an example.
    ///
    /// # Arguments
    ///
    /// * `state` - GPIO state mask, `0` is low (or input pin), `1` is high.
    /// * `direction` - GPIO direction mask, `0` is input, `1` is output.
    ///
    /// # FT232H Corner Case
    ///
    /// On the FT232H only CBUS5, CBUS6, CBUS8, and CBUS9 can be controlled.
    /// These pins confusingly map to the first four bits in the direction and
    /// state masks.
    ///
    /// [`set_gpio_lower`]: FtdiMpsse::set_gpio_lower
    fn set_gpio_upper(&mut self, state: u8, direction: u8) -> Result<(), TimeoutError> {
        let cmd = MpsseCmdBuilder::new().set_gpio_upper(state, direction);
        self.write_all(cmd.as_slice())
    }

    /// Get the pin state state of the upper byte (8-15) GPIO pins on the MPSSE
    /// interface.
    ///
    /// See [`gpio_lower`] for an example.
    ///
    /// See [`set_gpio_upper`] for additional information about physical pin
    /// mappings.
    ///
    /// [`gpio_lower`]: FtdiMpsse::gpio_lower
    /// [`set_gpio_upper`]: FtdiMpsse::set_gpio_upper
    fn gpio_upper(&mut self) -> Result<u8, TimeoutError> {
        let cmd = MpsseCmdBuilder::new().gpio_upper().send_immediate();
        let mut buf: [u8; 1] = [0];

        self.write_all(cmd.as_slice())?;
        self.read_all(&mut buf)?;

        Ok(buf[0])
    }

    /// Clock data out.
    ///
    /// This will clock out bytes on TDI/DO.
    /// No data is clocked into the device on TDO/DI.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use ftdi_mpsse::ClockDataOut;
    /// use libftd2xx::{Ft232h, FtdiMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT5AVX6B")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.set_clock(100_000)?;
    /// ft.set_gpio_lower(0xFA, 0xFB)?;
    /// ft.set_gpio_lower(0xF2, 0xFB)?;
    /// ft.clock_data_out(ClockDataOut::MsbNeg, &[0x12, 0x34, 0x56])?;
    /// ft.set_gpio_lower(0xFA, 0xFB)?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn clock_data_out(&mut self, mode: ClockDataOut, data: &[u8]) -> Result<(), TimeoutError> {
        if data.is_empty() {
            return Ok(());
        }

        let cmd = MpsseCmdBuilder::new().clock_data_out(mode, data);
        self.write_all(cmd.as_slice())
    }

    /// Clock data in.
    ///
    /// This will clock in bytes on TDO/DI.
    /// No data is clocked out of the device on TDI/DO.
    fn clock_data_in(&mut self, mode: ClockDataIn, data: &mut [u8]) -> Result<(), TimeoutError> {
        if data.is_empty() {
            return Ok(());
        }

        let cmd = MpsseCmdBuilder::new().clock_data_in(mode, data.len());
        self.write_all(cmd.as_slice())?;
        self.read_all(data)
    }

    /// Clock data in and out at the same time.
    fn clock_data(&mut self, mode: ClockData, data: &mut [u8]) -> Result<(), TimeoutError> {
        if data.is_empty() {
            return Ok(());
        }

        let cmd = MpsseCmdBuilder::new().clock_data(mode, data);
        self.write_all(cmd.as_slice())?;
        self.read_all(data)
    }
}

/// This contains MPSSE commands that are only available on the the FT232H,
/// FT2232H, and FT4232H devices.
///
/// For details about the MPSSE read the [FTDI MPSSE Basics].
///
/// [FTDI MPSSE Basics]: https://www.ftdichip.com/Support/Documents/AppNotes/AN_135_MPSSE_Basics.pdf
pub trait Ftx232hMpsse: FtdiMpsse {
    /// Enable 3 phase data clocking.
    ///
    /// This will give a 3 stage data shift for the purposes of supporting
    /// interfaces such as I2C which need the data to be valid on both edges of
    /// the clock.
    ///
    /// It will appears as:
    ///
    /// 1. Data setup for 1/2 clock period
    /// 2. Pulse clock for 1/2 clock period
    /// 3. Data hold for 1/2 clock period
    ///
    /// # Example
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft232h, FtdiMpsse, Ftx232hMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT5AVX6B")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.enable_3phase_data_clocking()?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn enable_3phase_data_clocking(&mut self) -> Result<(), TimeoutError> {
        mpsse! {
            let cmd = { enable_3phase_data_clocking(); };
        }

        self.write_all(&cmd)
    }

    /// Disable 3 phase data clocking.
    ///
    /// This will give a 2 stage data shift which is the default state.
    ///
    /// It will appears as:
    ///
    /// 1. Data setup for 1/2 clock period
    /// 2. Pulse clock for 1/2 clock period
    ///
    /// # Example
    ///
    /// ```no_run
    /// use libftd2xx::{Ft232h, FtdiMpsse, Ftx232hMpsse};
    ///
    /// let mut ft = Ft232h::with_serial_number("FT5AVX6B")?;
    /// ft.initialize_mpsse_default()?;
    /// ft.disable_3phase_data_clocking()?;
    /// # Ok::<(), std::boxed::Box<dyn std::error::Error>>(())
    /// ```
    fn disable_3phase_data_clocking(&mut self) -> Result<(), TimeoutError> {
        mpsse! {
            let cmd = { disable_3phase_data_clocking(); };
        }

        self.write_all(&cmd)
    }
}