/* Copyright 2020 Ilya Zhuravlev
 *
 * 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, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 "vial.h"

#include <string.h>
#include "protocol/usb_descriptor.h"

#include "vial_generated_keyboard_definition.h"

enum {
    vial_get_keyboard_id = 0x00,
    vial_get_size = 0x01,
    vial_get_def = 0x02,
};

void vial_handle_cmd(uint8_t *msg, uint8_t length) {
    /* All packets must be fixed 32 bytes */
    if (length != RAW_EPSIZE)
        return;

    /* msg[0] is 0xFE -- prefix vial magic */
    switch (msg[1]) {
        /* Get keyboard ID and Vial protocol version */
        case vial_get_keyboard_id: {
            uint8_t keyboard_uid[] = VIAL_KEYBOARD_UID;

            msg[0] = VIAL_PROTOCOL_VERSION & 0xFF;
            msg[1] = (VIAL_PROTOCOL_VERSION >> 8) & 0xFF;
            msg[2] = (VIAL_PROTOCOL_VERSION >> 16) & 0xFF;
            msg[3] = (VIAL_PROTOCOL_VERSION >> 24) & 0xFF;
            memcpy(&msg[4], keyboard_uid, 8);
            break;
        }
        /* Retrieve keyboard definition size */
        case vial_get_size: {
            uint32_t sz = sizeof(keyboard_definition);
            msg[0] = sz & 0xFF;
            msg[1] = (sz >> 8) & 0xFF;
            msg[2] = (sz >> 16) & 0xFF;
            msg[3] = (sz >> 24) & 0xFF;
            break;
        }
        /* Retrieve 32-bytes block of the definition, page ID encoded within 2 bytes */
        case vial_get_def: {
            uint32_t page = msg[2] + (msg[3] << 8);
            uint32_t start = page * RAW_EPSIZE;
            uint32_t end = start + RAW_EPSIZE;
            if (end < start || start >= sizeof(keyboard_definition))
                return;
            if (end > sizeof(keyboard_definition))
                end = sizeof(keyboard_definition);
            memcpy_P(msg, &keyboard_definition[start], end - start);
            break;
        }
    }
}