//! Cardholder Capability Container (CCC) ID Support

// Adapted from yubico-piv-tool:
// <https://github.com/Yubico/yubico-piv-tool/>
//
// Copyright (c) 2014-2016 Yubico AB
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//
//   * Redistributions in binary form must reproduce the above
//     copyright notice, this list of conditions and the following
//     disclaimer in the documentation and/or other materials provided
//     with the distribution.
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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use crate::{Error, Result, YubiKey};
use rand_core::{OsRng, RngCore};
use std::fmt::{self, Debug, Display};

/// CCCID offset
const CCC_ID_OFFS: usize = 9;

/// CCC Object ID
const OBJ_CAPABILITY: u32 = 0x005f_c107;

/// Cardholder Capability Container (CCC) Template
///
/// f0: Card Identifier
///
///  - 0xa000000116 == GSC-IS RID
///  - 0xff == Manufacturer ID (dummy)
///  - 0x02 == Card type (javaCard)
///  - next 14 bytes: card ID
const CCC_TMPL: &[u8] = &[
    0xf0, 0x15, 0xa0, 0x00, 0x00, 0x01, 0x16, 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf1, 0x01, 0x21, 0xf2, 0x01, 0x21, 0xf3, 0x00, 0xf4,
    0x01, 0x00, 0xf5, 0x01, 0x10, 0xf6, 0x00, 0xf7, 0x00, 0xfa, 0x00, 0xfb, 0x00, 0xfc, 0x00, 0xfd,
    0x00, 0xfe, 0x00,
];

/// Cardholder Capability Container (CCC) Identifier Card ID.
#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
pub struct CardId(pub [u8; Self::BYTE_SIZE]);

impl CardId {
    /// CCCID size in bytes
    pub const BYTE_SIZE: usize = 14;

    /// Generate a random CCC Card ID
    pub fn generate() -> Self {
        let mut id = [0u8; Self::BYTE_SIZE];
        OsRng.fill_bytes(&mut id);
        Self(id)
    }
}

/// Cardholder Capability Container (CCC) Identifier.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct CccId(pub [u8; Self::BYTE_SIZE]);

impl CccId {
    /// CCC size in bytes
    pub const BYTE_SIZE: usize = 51;

    /// Return CardId component of CCC
    pub fn card_id(&self) -> Result<CardId> {
        let mut cccid = [0u8; CardId::BYTE_SIZE];
        cccid.copy_from_slice(&self.0[CCC_ID_OFFS..(CCC_ID_OFFS + CardId::BYTE_SIZE)]);
        Ok(CardId(cccid))
    }

    /// Get Cardholder Capability Container (CCC) ID
    pub fn get(yubikey: &mut YubiKey) -> Result<Self> {
        let txn = yubikey.begin_transaction()?;
        let response = txn.fetch_object(OBJ_CAPABILITY)?;

        if response.len() != CCC_TMPL.len() {
            return Err(Error::GenericError);
        }

        Ok(Self(response[..Self::BYTE_SIZE].try_into().unwrap()))
    }

    /// Set Cardholder Capability Container (CCC) ID
    #[cfg(feature = "untested")]
    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn set(&self, yubikey: &mut YubiKey) -> Result<()> {
        let mut buf = CCC_TMPL.to_vec();
        buf[0..self.0.len()].copy_from_slice(&self.0);

        let txn = yubikey.begin_transaction()?;
        txn.save_object(OBJ_CAPABILITY, &buf)
    }
}

impl AsRef<[u8]> for CccId {
    fn as_ref(&self) -> &[u8] {
        &self.0
    }
}

impl Display for CccId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(&hex::upper::encode_string(self.as_ref()))
    }
}