//! High-level PN532 command driver.

use crate::commands::*;
use crate::error::Error;
use crate::interface::Interface;
use crate::StatusCode;
use core::time::Duration;

/// A card UID read by [`Pn532::read_passive_target_id`].
#[derive(Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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")]
        {
            write!(f, "{}", hex::encode(&self.bytes))
        }
        #[cfg(not(feature = "alloc"))]
        {
            write!(f, "{:?}", self)
        }
    }
}

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

/// Driver for the NXP PN532 NFC controller.
pub struct Pn532<B: Interface, const N: usize = 64> {
    pub(crate) interface: B,
    pub(crate) in_listed_tag: u8,
    pub(crate) buffer: [u8; N],
}

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

    /// 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: Duration) -> Result<usize, Error<B::TransportError>> {
        self.interface.read_response(&mut self.buffer, timeout.as_millis() as u16)
    }

    // -- 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::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::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::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::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::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::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::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::RFCONFIGURATION;
        self.buffer[1] = 1;
        self.buffer[2] = 0x00 | auto_rfca | rf_on_off;
        self.send(3)?;
        self.read()?;
        Ok(())
    }
    
    /// return error if current buffer contains an error code
    pub(crate) fn validate_buffer(&self, len: usize) -> Result<(), Error<B::TransportError>> {
        if len == 0 || (self.buffer[0] & 0x3F) != 0 {
            Err(Error::Status(StatusCode::from_bits(self.buffer[0] & 0x3F)))
        } else {
            Ok(())
        }
    }



    /// Release the card.
    pub fn release(&mut self) -> Result<(), Error<B::TransportError>> {
        self.buffer[0] = pn532::INRELEASE;
        self.buffer[1] = 0x00;
        self.send(2)?;

        let len = self.read_timeout(Duration::from_secs(1))?;
        self.validate_buffer(len)?;
        Ok(())
    }
}