/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include "tusb.h"

//--------------------------------------------------------------------+
// Device Descriptors
//--------------------------------------------------------------------+
tusb_desc_device_t const desc_device = {
    .bLength            = sizeof(tusb_desc_device_t),
    .bDescriptorType    = TUSB_DESC_DEVICE,
    .bcdUSB             = 0x0200,

    // Use Interface Association Descriptor (IAD) for CDC
    // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
    .bDeviceClass       = TUSB_CLASS_MISC,
    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
    .bDeviceProtocol    = MISC_PROTOCOL_IAD,

    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,

    .idVendor           = 0x1209,
    .idProduct          = 0x2151,
    .bcdDevice          = 0x0100,

    .iManufacturer      = 0x01,
    .iProduct           = 0x02,
    .iSerialNumber      = 0x03,

    .bNumConfigurations = 0x01
};

// Invoked when received GET DEVICE DESCRIPTOR
// Application return pointer to descriptor
uint8_t const * tud_descriptor_device_cb(void) {
  return (uint8_t const *) &desc_device;
}

//--------------------------------------------------------------------+
// Configuration Descriptor
//--------------------------------------------------------------------+

enum {
    ITF_NUM_CDC = 0,
    ITF_NUM_CDC_DATA,
    ITF_NUM_TOTAL
};

#define CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)

#define EPNUM_CDC_NOTIF   0x81
#define EPNUM_CDC_OUT     0x02
#define EPNUM_CDC_IN      0x82

uint8_t const desc_fs_configuration[] = {
    // Config number, interface count, string index, total length, attribute, power in mA
    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, 100),

    // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
};

// Invoked when received GET CONFIGURATION DESCRIPTOR
// Application return pointer to descriptor
// Descriptor contents must exist long enough for transfer to complete
uint8_t const * tud_descriptor_configuration_cb(uint8_t index) {
    (void) index; // for multiple configurations
    return desc_fs_configuration;
}

//--------------------------------------------------------------------+
// String Descriptors
//--------------------------------------------------------------------+

static char serialnum[32 * 2 + 1] = {'\0'}; // 2 chars per hexnumber + '\0'

// array of pointer to string descriptors
char const* string_desc_arr [] = {
    (const char[]) { 0x09, 0x04 },  // 0: is supported language is English (0x0409)
    "Oddly Specific Objects",       // 1: Manufacturer
    "Sensor Watch",                 // 2: Product
    serialnum,                      // 3: Serial number
    "TinyUSB CDC",                  // 4: CDC Interface
};

static uint16_t _desc_str[32];
static bool serial_number_written = false;

// Invoked when received GET STRING DESCRIPTOR request
// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
    (void) langid;
    uint8_t chr_count;

    if (!serial_number_written) {
        // Generate serial number based on chip unique ID
        uint32_t chipid[4];
        chipid[0] = *((uint32_t *)0x0080A00C);
        chipid[1] = *((uint32_t *)0x0080A040);
        chipid[2] = *((uint32_t *)0x0080A044);
        chipid[3] = *((uint32_t *)0x0080A048);

        sprintf(serialnum, "%08lX%08lX%08lX%08lX", chipid[0], chipid[1], chipid[2], chipid[3]);
        serial_number_written = true;
    }

    if (index == 0) {
        memcpy(&_desc_str[1], string_desc_arr[0], 2);
        chr_count = 1;
    } else {
        // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
        // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors

        if ( !(index < sizeof(string_desc_arr)/sizeof(string_desc_arr[0])) ) return NULL;

        const char* str = string_desc_arr[index];

        // Cap at max char
        chr_count = strlen(str);
        if ( chr_count > 31 ) chr_count = 31;

        // Convert ASCII string into UTF-16
        for(uint8_t i=0; i<chr_count; i++) {
            _desc_str[1+i] = str[i];
        }
    }

    // first byte is length (including header), second byte is string type
    _desc_str[0] = (TUSB_DESC_STRING << 8 ) | (2*chr_count + 2);

    return _desc_str;
}