//
// usb_descriptors.c
//
// A single USB MIDI 1.0 streaming interface. From the PC this enumerates as
// an ordinary ALSA MIDI port, exactly as the Circle gadget build does.
//
#include "tusb.h"

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

static const tusb_desc_device_t 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
};

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

enum { ITF_NUM_MIDI = 0, ITF_NUM_MIDI_STREAMING, ITF_NUM_TOTAL };

#define EPNUM_MIDI_OUT	0x01
#define EPNUM_MIDI_IN	0x81

#define CONFIG_TOTAL_LEN  (TUD_CONFIG_DESC_LEN + TUD_MIDI_DESC_LEN)

static const uint8_t desc_configuration[] =
{
	TUD_CONFIG_DESCRIPTOR (1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
	TUD_MIDI_DESCRIPTOR (ITF_NUM_MIDI, 0, EPNUM_MIDI_OUT, EPNUM_MIDI_IN, 64)
};

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

static const char *const string_desc_arr[] =
{
	(const char[]) { 0x09, 0x04 },	// 0: English (0x0409)
	"PianoLED",			// 1: Manufacturer
	"Piano LED Visualizer",		// 2: Product
	"000000000001",			// 3: Serial
	"Piano LED MIDI",		// 4: MIDI interface
};

static uint16_t _desc_str[32];

const uint16_t *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;
}