//
// main.cpp
//
// Piano LED Visualizer on RP2040 / RP2350.
//
// The board is a USB MIDI device: the PC is the host and owns the piano
// connection and everything else. From the PC's side this enumerates as an
// ordinary ALSA MIDI port. See PIANO-LED-CIRCLE-PLAN.md section 2.
//
#include "pianoleds.h"
#include "picostrip.h"
#include "pico/stdlib.h"
#include "tusb.h"

static CPicoLEDStrip s_Strip (LED_COUNT, WS2812_PIN);
static CPianoLEDs s_PianoLEDs (s_Strip);

// Number of MIDI bytes carried by a USB MIDI event packet, indexed by its
// Code Index Number (USB MIDI 1.0, table 4-1). 0 means "not a message we
// forward".
static const uint8_t s_CINLength[16] =
{
	0, 0, 2, 3, 3, 1, 2, 3,
	3, 3, 3, 3, 2, 2, 3, 1
};

// --------------------------------------------------------------------------
// TinyUSB device callbacks
// --------------------------------------------------------------------------

extern "C" void tud_mount_cb (void)
{
	// Fresh session: nothing should still be lit from the last one.
	s_PianoLEDs.AllOff ();
}

extern "C" void tud_umount_cb (void)
{
	// Host went away, possibly mid-chord. Do not leave keys lit.
	s_PianoLEDs.AllOff ();
}

extern "C" void tud_suspend_cb (bool remote_wakeup_en)
{
	(void) remote_wakeup_en;
	s_PianoLEDs.AllOff ();
}

extern "C" void tud_resume_cb (void)
{
	s_PianoLEDs.AllOff ();
}

// --------------------------------------------------------------------------

static void PollMIDI (void)
{
	uint8_t Packet[4];

	while (tud_midi_available ())
	{
		if (!tud_midi_packet_read (Packet))
		{
			break;
		}

		// Packet[0] is cable number (high nibble) and Code Index Number
		// (low nibble); the message itself is in Packet[1..3].
		unsigned nLength = s_CINLength[Packet[0] & 0x0F];
		if (nLength == 0)
		{
			continue;
		}

		s_PianoLEDs.OnMIDIPacket (&Packet[1], nLength);
	}
}

int main (void)
{
	stdio_init_all ();

	if (!s_Strip.Initialize ())
	{
		// Nothing sensible left to do; make the failure visible rather
		// than sitting dark and looking like a power problem.
		while (true)
		{
			tight_loop_contents ();
		}
	}

	s_PianoLEDs.Initialize ();

	tusb_init ();

	while (true)
	{
		tud_task ();

		PollMIDI ();

		// Rendering blocks for the strip's frame time, so it runs here
		// rather than in the USB callback. Returns immediately when
		// nothing has changed.
		s_PianoLEDs.Update ();
	}

	return 0;
}