use std::ffi::CString;

use pcsc::{Protocols, ReaderState, State};

use crate::{Card, ResultAPDU};

pub struct PCSCCard {
    pub ctx: pcsc::Context,
    pub reader: CString,
    pub card: pcsc::Card,
    pub buf: [u8; 0x10002],
}

impl Card for PCSCCard {
    async fn transmit(
        &mut self,
        apdu: crate::OwnedCommandAPDU,
    ) -> std::io::Result<crate::ResultAPDU> {
        let mut apdu_buf = vec![
            apdu.class.encode().unwrap(),
            apdu.instruction,
            apdu.parameter[0],
            apdu.parameter[1],
        ];
        let extended =
            apdu.command.len() > 0xFF || apdu.expected_length.map(|f| f > 0xFF) == Some(true);

        if extended {
            apdu_buf.push(0);
            apdu_buf.extend_from_slice(&(apdu.command.len() as u16).to_be_bytes());
        } else if !apdu.command.is_empty() {
            apdu_buf.push(apdu.command.len() as u8);
        }

        apdu_buf.extend_from_slice(&apdu.command);

        if extended {
            apdu_buf.extend_from_slice(
                &(apdu.expected_length.unwrap_or_default() as u16).to_be_bytes(),
            );
        } else if apdu.expected_length != Some(0) {
            apdu_buf.push(apdu.expected_length.unwrap_or_default() as u8);
        }

        self.transmit_raw(&apdu_buf).await
    }
    async fn transmit_raw(&mut self, apdu_buf: &[u8]) -> std::io::Result<crate::ResultAPDU> {
        let ret_len = self
            .card
            .transmit(apdu_buf, &mut self.buf)
            .map_err(|f| std::io::Error::new(std::io::ErrorKind::BrokenPipe, f))?
            .len();

        let data = self.buf[..ret_len - 2].to_vec();
        let sw = (self.buf[ret_len - 2] as u16) << 8 | (self.buf[ret_len - 1] as u16);

        Ok(ResultAPDU { data, status: sw })
    }
}

impl PCSCCard {
    pub fn new() -> Self {
        let ctx = pcsc::Context::establish(pcsc::Scope::User).unwrap();
        let readers = ctx.list_readers_owned().unwrap();
        let reader = readers.first().unwrap();

        let mut rs = [ReaderState::new(reader.to_owned(), State::empty())];
        loop {
            ctx.get_status_change(None, &mut rs[..]).unwrap();
            rs[0].sync_current_state();

            if rs[0].event_state().contains(State::PRESENT) {
                let card = ctx
                    .connect(reader, pcsc::ShareMode::Shared, Protocols::ANY)
                    .unwrap();

                return Self {
                    ctx,
                    reader: reader.to_owned(),
                    card,
                    buf: [0; 0x10002],
                };
            }
        }
    }

    pub fn wait_for_remove(self) {
        let mut rs = [ReaderState::new(self.reader, State::empty())];
        loop {
            self.ctx.get_status_change(None, &mut rs[..]).unwrap();
            if rs[0].event_state().contains(State::PRESENT) {
                rs[0].sync_current_state();
                continue;
            }
            break;
        }
    }
}