/*
 * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
 * Copyright (c) 2022 Pol Henarejos.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "apdu.h"
#include "pico_keys.h"
#include "usb.h"
#include <stdio.h>

uint8_t *rdata_gr = NULL;
uint16_t rdata_bk = 0x0;
extern uint32_t timeout;
bool is_chaining = false;
uint8_t chain_buf[4096];
uint8_t *chain_ptr = NULL;

int process_apdu() {
    led_set_blink(BLINK_PROCESSING);
    if (CLA(apdu) & 0x10) {
        if (!is_chaining) {
            chain_ptr = chain_buf;
        }
        if (chain_ptr - chain_buf + apdu.nc >= sizeof(chain_buf)) {
            return SW_CLA_NOT_SUPPORTED();
        }
        memcpy(chain_ptr, apdu.data, apdu.nc);
        chain_ptr += apdu.nc;
        is_chaining = true;
        return SW_OK();
    }
    else {
        if (is_chaining) {
            memmove(apdu.data + (chain_ptr - chain_buf), apdu.data, apdu.nc);
            memcpy(apdu.data, chain_buf, chain_ptr - chain_buf);
            apdu.nc += chain_ptr - chain_buf;
            is_chaining = false;
        }
    }
    if (INS(apdu) == 0xA4 && P1(apdu) == 0x04 && (P2(apdu) == 0x00 || P2(apdu) == 0x4)) { //select by AID
        for (int a = 0; a < num_apps; a++) {
            if (!memcmp(apps[a].aid + 1, apdu.data, MIN(apdu.nc, apps[a].aid[0]))) {
                if (current_app) {
                    if (current_app->aid && !memcmp(current_app->aid + 1, apdu.data, apdu.nc)) {
                        current_app->select_aid(current_app);
                        return SW_OK();
                    }
                    if (current_app->unload) {
                        current_app->unload();
                    }
                }
                current_app = &apps[a];
                if (current_app->select_aid(current_app) == CCID_OK) {
                    return SW_OK();
                }
            }
        }
        return SW_FILE_NOT_FOUND();
    }
    if (current_app && current_app->process_apdu) {
        return current_app->process_apdu();
    }
    return SW_FILE_NOT_FOUND();
}

uint16_t apdu_process(uint8_t itf, const uint8_t *buffer, uint16_t buffer_size) {
    apdu.header = (uint8_t *) buffer;
    apdu.nc = apdu.ne = 0;
    if (buffer_size == 4) {
        apdu.nc = apdu.ne = 0;
        if (apdu.ne == 0) {
            apdu.ne = 256;
        }
    }
    else if (buffer_size == 5) {
        apdu.nc = 0;
        apdu.ne = apdu.header[4];
        if (apdu.ne == 0) {
            apdu.ne = 256;
        }
    }
    else if (apdu.header[4] == 0x0 && buffer_size >= 7) {
        if (buffer_size == 7) {
            apdu.ne = (apdu.header[5] << 8) | apdu.header[6];
            if (apdu.ne == 0) {
                apdu.ne = 65536;
            }
        }
        else {
            apdu.ne = 0;
            apdu.nc = (apdu.header[5] << 8) | apdu.header[6];
            apdu.data = apdu.header + 7;
            if (apdu.nc + 7 + 2 == buffer_size) {
                apdu.ne = (apdu.header[buffer_size - 2] << 8) | apdu.header[buffer_size - 1];
                if (apdu.ne == 0) {
                    apdu.ne = 65536;
                }
            }
        }
    }
    else {
        apdu.nc = apdu.header[4];
        apdu.data = apdu.header + 5;
        apdu.ne = 0;
        if (apdu.nc + 5 + 1 == buffer_size) {
            apdu.ne = apdu.header[buffer_size - 1];
            if (apdu.ne == 0) {
                apdu.ne = 256;
            }
        }
    }
    //printf("apdu.nc %ld, apdu.ne %ld\n",apdu.nc,apdu.ne);
    if (apdu.header[1] == 0xc0) {
        //printf("apdu.ne %u, apdu.rlen %d, bk %x\n",apdu.ne,apdu.rlen,rdata_bk);
        timeout_stop();
        *(uint16_t *) rdata_gr = rdata_bk;
        if (apdu.rlen <= apdu.ne) {
#ifndef ENABLE_EMULATION
#ifdef USB_ITF_HID
            if (itf == ITF_HID) {
                driver_exec_finished_cont_hid(apdu.rlen + 2, rdata_gr - (usb_get_tx(itf)));
            }
#endif
#ifdef USB_ITF_CCID
            if (itf == ITF_CCID || itf == ITF_WCID) {
                driver_exec_finished_cont_ccid(itf, apdu.rlen + 2, rdata_gr - (usb_get_tx(itf) + 34));
            }
#endif
#else
            driver_exec_finished_cont_emul(itf, apdu.rlen + 2, (uint16_t)(rdata_gr - (usb_get_tx(itf))));
#endif
            //Prepare next RAPDU
            apdu.sw = 0;
            apdu.rlen = 0;
            usb_prepare_response(itf);
        }
        else {
            rdata_gr += apdu.ne;
            rdata_bk = *(uint16_t *) rdata_gr;
            rdata_gr[0] = 0x61;
            if (apdu.rlen - apdu.ne >= 256) {
                rdata_gr[1] = 0;
            }
            else {
                rdata_gr[1] = (uint8_t)(apdu.rlen - apdu.ne);
            }
#ifndef ENABLE_EMULATION
#ifdef USB_ITF_HID
            if (itf == ITF_HID) {
                driver_exec_finished_cont_hid(apdu.ne + 2, rdata_gr - apdu.ne - (usb_get_tx(itf)));
            }
#endif
#ifdef USB_ITF_CCID
            if (itf == ITF_CCID || itf == ITF_WCID) {
                driver_exec_finished_cont_ccid(itf, apdu.ne + 2, rdata_gr - apdu.ne - (usb_get_tx(itf) + 34));
            }
#endif
#else
            driver_exec_finished_cont_emul(itf, (uint16_t)(apdu.ne + 2), (uint16_t)(rdata_gr - apdu.ne - (usb_get_tx(itf))));
#endif
            apdu.rlen -= (uint16_t)apdu.ne;
        }
    }
    else {
        apdu.sw = 0;
        apdu.rlen = 0;
        apdu.rdata = usb_prepare_response(itf);
        rdata_gr = apdu.rdata;
        return 1;
    }
    return 0;
}

uint16_t set_res_sw(uint8_t sw1, uint8_t sw2) {
    apdu.sw = (sw1 << 8) | sw2;
    if (sw1 != 0x90) {
        res_APDU_size = 0;
    }
    return make_uint16_t(sw1, sw2);
}

#ifndef ENABLE_EMULATION
void apdu_thread() {
    card_init_core1();
    while (1) {
        uint32_t m = 0;
        queue_remove_blocking(&usb_to_card_q, &m);

        if (m == EV_VERIFY_CMD_AVAILABLE || m == EV_MODIFY_CMD_AVAILABLE) {
            set_res_sw(0x6f, 0x00);
            goto done;
        }
        else if (m == EV_EXIT) {
            break;
        }

        process_apdu();

done:   ;
        apdu_finish();

        finished_data_size = apdu_next();
        uint32_t flag = EV_EXEC_FINISHED;
        queue_add_blocking(&card_to_usb_q, &flag);
    }
    //printf("EXIT !!!!!!\n");
    if (current_app && current_app->unload) {
        current_app->unload();
        current_app = NULL;
    }
}
#endif

void apdu_finish() {
    apdu.rdata[apdu.rlen] = apdu.sw >> 8;
    apdu.rdata[apdu.rlen + 1] = apdu.sw & 0xff;
    // timeout_stop();
#ifndef ENABLE_EMULATION
    if ((apdu.rlen + 2 + 10) % 64 == 0) {     // FIX for strange behaviour with PSCS and multiple of 64
        apdu.ne = apdu.rlen - 2;
    }
#endif
}

uint16_t apdu_next() {
    if (apdu.sw != 0) {
        if (apdu.rlen <= apdu.ne) {
            return apdu.rlen + 2;
        }
        else {
            rdata_gr = apdu.rdata + apdu.ne;
            rdata_bk = *(uint16_t *) rdata_gr;
            rdata_gr[0] = 0x61;
            if (apdu.rlen - apdu.ne >= 256) {
                rdata_gr[1] = 0;
            }
            else {
                rdata_gr[1] = (uint8_t)(apdu.rlen - apdu.ne);
            }
            apdu.rlen -= (uint16_t)apdu.ne;
        }
        return (uint16_t)(apdu.ne + 2);
    }
    return 0;
}