// usb_descriptors.c — USB MIDI device descriptors for TinyUSB.
// Copy this file into your project and adjust VID, PID, and strings.

#include "tusb.h"

#define USB_VID   0xCafe
#define USB_PID   0x4001
#define USB_BCD   0x0200

// Device descriptor
tusb_desc_device_t const desc_device = {
    .bLength            = sizeof(tusb_desc_device_t),
    .bDescriptorType    = TUSB_DESC_DEVICE,
    .bcdUSB             = USB_BCD,
    .bDeviceClass       = 0x00,
    .bDeviceSubClass    = 0x00,
    .bDeviceProtocol    = 0x00,
    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
    .idVendor           = USB_VID,
    .idProduct          = USB_PID,
    .bcdDevice          = 0x0100,
    .iManufacturer      = 0x01,
    .iProduct           = 0x02,
    .iSerialNumber      = 0x03,
    .bNumConfigurations = 0x01
};

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

// Configuration descriptor (Audio + MIDI)
#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + TUD_MIDI_DESC_LEN)

uint8_t const desc_configuration[] = {
    TUD_CONFIG_DESCRIPTOR(1, 2, 0, CONFIG_TOTAL_LEN,
                          0x00, 100),
    TUD_MIDI_DESCRIPTOR(1, 0, 0x01, 0x81, 64)
};

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

// String descriptors
static char const *string_desc_arr[] = {
    (const char[]){0x09, 0x04}, // 0: English
    "cs-midi",                  // 1: Manufacturer
    "MIDI Controller",          // 2: Product
    "000001",                   // 3: Serial
};

static uint16_t _desc_str[32 + 1];

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

    if (index == 0) {
        memcpy(&_desc_str[1], string_desc_arr[0], 2);
        chr_count = 1;
    } else {
        if (index >= sizeof(string_desc_arr) / sizeof(string_desc_arr[0]))
            return NULL;
        const char *str = string_desc_arr[index];
        chr_count = (uint8_t)strlen(str);
        if (chr_count > 31) chr_count = 31;
        for (uint8_t i = 0; i < chr_count; i++)
            _desc_str[1 + i] = str[i];
    }

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