//! High-level PN532 command driver.

use crate::commands::*;
use crate::error::{Error};
use crate::interface::Interface;

pub(crate) const PACKET_BUFFER_SIZE: usize = 64;

/// A card UID read by [`Pn532::read_passive_target_id`].
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Uid {
    pub bytes: heapless::Vec<u8, 7>,
}

impl core::fmt::Display for Uid {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        #[cfg(feature = "alloc")]
        return write!(f, "{}", hex::encode(&self.bytes));
        #[cfg(not(feature = "alloc"))]
        {
            let mut buf: heapless::Vec<u8, 14> = heapless::Vec::new();
            hex::encode_to_slice(&self.bytes, &mut buf)
                .map_err(|_| core::fmt::Error)?;
            let s = heapless::String::from_utf8(buf)
                .map_err(|_| core::fmt::Error)?;
            write!(f, "{}", s)
        }
    }
}

#[cfg(feature = "defmt")]
impl defmt::Format for Uid {
    fn format(&self, fmt: defmt::Formatter) {
        defmt::write!(fmt, "{}", defmt::Display2Format(self));
    }
}

/// Outcome of [`Pn532::tg_init_as_target`] / [`Pn532::tg_init_as_target_default`].
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum TargetInitStatus {
    /// The PN532 entered target mode.
    Success,
    /// No initiator appeared within the timeout.
    Timeout,
    /// The operation failed.
    Failed,
}

/// Result of a successful FeliCa polling request.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct FelicaPollingResponse {
    /// The card's IDm (NFCID2).
    pub idm: [u8; 8],
    /// The card's PMm (PAD).
    pub pmm: [u8; 8],
    /// The card's system code, when returned.
    pub system_code_response: Option<u16>,
}

/// Driver for the NXP PN532 NFC controller.
pub struct Pn532<B: Interface> {
    pub(crate) interface: B,
    pub(crate) in_listed_tag: u8,
    pub(crate) felica_idm: [u8; 8],
    pub(crate) felica_pmm: [u8; 8],
    pub(crate) buffer: [u8; PACKET_BUFFER_SIZE],
}

impl<B: Interface> Pn532<B> {
    /// Create a driver over the given transport interface.
    pub fn new(interface: B) -> Self {
        Self {
            interface,
            in_listed_tag: 0,
            felica_idm: [0; 8],
            felica_pmm: [0; 8],
            buffer: [0; PACKET_BUFFER_SIZE],
        }
    }

    /// Initialise the PN532: pulse the reset pin (if provided) and wait for it
    /// to become ready.
    pub fn begin(&mut self) -> Result<(), Error<B::TransportError>> {
        self.interface.begin()
    }

    // -- internal helpers ---------------------------------------------------

    pub(crate) fn send(&mut self, header_len: usize) -> Result<(), Error<B::TransportError>> {
        self.interface.write_command(&self.buffer[..header_len], &[])
    }

    pub(crate) fn send_with_body(
        &mut self,
        header_len: usize,
        body: &[u8],
    ) -> Result<(), Error<B::TransportError>> {
        self.interface
            .write_command(&self.buffer[..header_len], body)
    }

    pub(crate) fn read(&mut self) -> Result<usize, Error<B::TransportError>> {
        self.interface.read_response(&mut self.buffer, 1000)
    }

    pub(crate) fn read_timeout(&mut self, timeout_ms: u16) -> Result<usize, Error<B::TransportError>> {
        self.interface.read_response(&mut self.buffer, timeout_ms)
    }

    // -- generic PN532 functions -------------------------------------------

    /// Read the PN532 firmware version and ID.
    pub fn get_firmware_version(&mut self) -> Result<u32, Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_GETFIRMWAREVERSION;
        self.send(1)?;
        let len = self.read()?;
        if len < 4 {
            return Err(Error::InvalidFrame);
        }
        Ok(u32::from_be_bytes([
            self.buffer[0],
            self.buffer[1],
            self.buffer[2],
            self.buffer[3],
        ]))
    }

    /// Read a 16-bit PN532 register.
    pub fn read_register(&mut self, reg: u16) -> Result<u8, Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_READREGISTER;
        self.buffer[1] = (reg >> 8) as u8;
        self.buffer[2] = reg as u8;
        self.send(3)?;
        let len = self.read()?;
        if len < 1 {
            return Err(Error::InvalidFrame);
        }
        Ok(self.buffer[0])
    }

    /// Write to a 16-bit PN532 register.
    pub fn write_register(&mut self, reg: u16, val: u8) -> Result<(), Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_WRITEREGISTER;
        self.buffer[1] = (reg >> 8) as u8;
        self.buffer[2] = reg as u8;
        self.buffer[3] = val;
        self.send(4)?;
        self.read()?;
        Ok(())
    }

    /// Set the PN532's GPIO pins (see the PN532 user manual for valid pins).
    pub fn write_gpio(&mut self, pinstate: u8) -> Result<(), Error<B::TransportError>> {
        let pinstate = pinstate | (1 << PN532_GPIO_P32) | (1 << PN532_GPIO_P34);
        self.buffer[0] = PN532_COMMAND_WRITEGPIO;
        self.buffer[1] = PN532_GPIO_VALIDATIONBIT | pinstate;
        self.buffer[2] = 0x00;
        self.send(3)?;
        let len = self.read()?;
        if len == 0 {
            return Err(Error::InvalidFrame);
        }
        Ok(())
    }

    /// Read the state of the PN532's GPIO pins.
    pub fn read_gpio(&mut self) -> Result<u8, Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_READGPIO;
        self.send(1)?;
        self.read()?;
        Ok(self.buffer[0])
    }

    /// Configure the SAM (Secure Access Module) in normal mode.
    pub fn sam_config(&mut self) -> Result<(), Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_SAMCONFIGURATION;
        self.buffer[1] = 0x01; // normal mode
        self.buffer[2] = 0x14; // timeout 50 ms * 20 = 1 second
        self.buffer[3] = 0x01; // use IRQ pin
        self.send(4)?;
        self.read()?;
        Ok(())
    }

    /// Set the `MxRtyPassiveActivation` RF configuration item.
    pub fn set_passive_activation_retries(
        &mut self,
        max_retries: u8,
    ) -> Result<(), Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_RFCONFIGURATION;
        self.buffer[1] = 5;
        self.buffer[2] = 0xFF;
        self.buffer[3] = 0x01;
        self.buffer[4] = max_retries;
        self.send(5)?;
        self.read()?;
        Ok(())
    }

    /// Switch the RF field on/off.
    pub fn set_rf_field(
        &mut self,
        auto_rfca: u8,
        rf_on_off: u8,
    ) -> Result<(), Error<B::TransportError>> {
        self.buffer[0] = PN532_COMMAND_RFCONFIGURATION;
        self.buffer[1] = 1;
        self.buffer[2] = 0x00 | auto_rfca | rf_on_off;
        self.send(3)?;
        self.read()?;
        Ok(())
    }
}