#include <cstring>
#include "pico/unique_id.h"
#include "tusb.h"

constexpr uint16_t USB_VID = 0x2E8A;
constexpr uint16_t USB_PID = 0x000A;

static constexpr tusb_desc_device_t desc_device = {
    sizeof(tusb_desc_device_t),
    TUSB_DESC_DEVICE,
    0x0200,
    TUSB_CLASS_MISC,
    MISC_SUBCLASS_COMMON,
    MISC_PROTOCOL_IAD,
    CFG_TUD_ENDPOINT0_SIZE,
    USB_VID,
    USB_PID,
    0x0100,
    1, 2, 3,
    1,
};

enum { ITF_NUM_CDC, ITF_NUM_CDC_DATA, ITF_NUM_TOTAL };

constexpr uint8_t EPNUM_CDC_NOTIF = 0x81;
constexpr uint8_t EPNUM_CDC_OUT   = 0x02;
constexpr uint8_t EPNUM_CDC_IN    = 0x82;
constexpr uint16_t CONFIG_TOTAL_LEN = TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN;

static uint8_t const desc_configuration[] = {
    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 0, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
};

static constexpr const char* string_desc[] = {
    "\x09\x04",
    "picomap",
    "picomap",
    nullptr,
};

static uint16_t desc_str_buf[33];

extern "C" {

uint8_t const* tud_descriptor_device_cb(void) {
    return reinterpret_cast<uint8_t const*>(&desc_device);
}

uint8_t const* tud_descriptor_configuration_cb(uint8_t index) {
    return desc_configuration;
}

uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
    uint8_t chr_count;

    if (index == 0) {
        memcpy(&desc_str_buf[1], string_desc[0], 2);
        chr_count = 1;
    } else if (index == 3) {
        pico_unique_board_id_t uid;
        pico_get_unique_board_id(&uid);
        chr_count = 0;
        for (int i = 0; i < 8; i++) {
            desc_str_buf[1 + chr_count++] = "0123456789ABCDEF"[uid.id[i] >> 4];
            desc_str_buf[1 + chr_count++] = "0123456789ABCDEF"[uid.id[i] & 0xF];
        }
    } else {
        if (index >= sizeof(string_desc) / sizeof(string_desc[0])) return nullptr;
        const char* str = string_desc[index];
        if (!str) return nullptr;
        chr_count = strlen(str);
        if (chr_count > 31) chr_count = 31;
        for (uint8_t i = 0; i < chr_count; i++)
            desc_str_buf[1 + i] = str[i];
    }

    desc_str_buf[0] = static_cast<uint16_t>((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
    return desc_str_buf;
}

} // extern "C"