/*
 *  Copyright (C) 2017 The Contributors
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  General Public License for more details.
 *
 *  A copy of the GNU General Public License can be found in the file
 *  "gpl.txt" in the top directory of this repository.
 */

#include <all.h>
#include <rtmidi/rtmidi_c.h>

#define ver(...) _ver(mid_verbose, 0, __VA_ARGS__)
#define ver2(...) _ver(mid_verbose, 1, __VA_ARGS__)
#define ver3(...) _ver(mid_verbose, 2, __VA_ARGS__)

#define REG_IER_ISR 0
#define REG_CFR_SR  1
#define REG_CDR_TBR 2
#define REG_TDR_RDR 3

#define BUF_SZ 256

typedef struct {
	int32_t buf_hd;
	int32_t buf_tl;
	uint8_t buf[BUF_SZ];
	bool irq_r;
	bool irq_t;
	bool rdr_ok;
	uint8_t rdr;
} state_t;

static state_t state[] = {
	{ .buf_hd = 0, .buf_tl = 0, .irq_r = false, .irq_t = false, .rdr_ok = false, .rdr = 0x00 },
	{ .buf_hd = 0, .buf_tl = 0, .irq_r = false, .irq_t = false, .rdr_ok = false, .rdr = 0x00 }
};

int32_t mid_verbose = 0;

struct RtMidiWrapper* mid_in;

static void xmit(int32_t un)
{
	int32_t i = state[un].buf_tl;
	ver2("mid xmit %d %d", i, state[un].buf_hd);

	if (i >= state[un].buf_hd) {
		return;
	}

	uint8_t byte = state[un].buf[i % BUF_SZ];
	ver2("mid xmit 0x%02x", byte);

	state[un].rdr = byte;
	state[un].rdr_ok = true;
	state[un].irq_r = true;

	state[un].buf_tl = i + 1;

	if (state[un].buf_tl >= BUF_SZ) {
		state[un].buf_hd -= BUF_SZ;
		state[un].buf_tl -= BUF_SZ;
		ver2("mid adj %d %d", state[un].buf_tl, state[un].buf_hd);
	}
}

static void out_lk(int32_t un, uint8_t c)
{
	int32_t i = state[un].buf_hd;
	ver2("mid out %d %d 0x%02x", state[un].buf_tl, i, c);

	if (i >= state[un].buf_tl + BUF_SZ) {
		err("midi port %d losing data", un);
		return;
	}

	state[un].buf[i % BUF_SZ] = c;
	state[un].buf_hd = i + 1;

	if (!state[un].irq_r && !state[un].rdr_ok) {
		xmit(un);
	}
}

static void out(int32_t un, uint8_t c)
{
	if (SDL_LockMutex(cpu_mutex) < 0) {
		fail("SDL_LockMutex() failed: %s", SDL_GetError());
	}

	out_lk(un, c);

	if (SDL_UnlockMutex(cpu_mutex) < 0) {
		fail("SDL_UnlockMutex() failed: %s", SDL_GetError());
	}
}

static void mid_callback(double timeStamp, const unsigned char* message, size_t size, void *userData) {
	(void) size;
	(void) userData;

	ver2("Timestamp %f\n", timeStamp);

	for (uint8_t i = 0; i < sizeof(message); i++) {
		ver2("Message %i %u", i, (uint8_t) message[i]);
		out(0, message[i]);
	}
}

void mid_init(void)
{
	ver("mid init");

	mid_in = rtmidi_in_create_default();
	ver2("%p", mid_in->ptr);
	// check if null

	uint32_t portcount = rtmidi_get_port_count(mid_in);
	if (portcount == 0) {
		mid_in = NULL;
		ver2("No MIDI ports\n");
		return;
	}

	if (mid_port > portcount) {
		mid_in = NULL;
		ver2("Selected MIDI port larger than number of midi ports");
		return;
	}

	rtmidi_open_port(mid_in, mid_port, rtmidi_get_port_name(mid_in, mid_port));

	if(mid_in->ok == 0) {
		fail("Failed to open MIDI port");
	}

	ver2("Using MIDI port %u", mid_port);

	rtmidi_in_set_callback(mid_in, mid_callback, mid_in->data);

	if(mid_in->ok == 0) {
		fail("Failed to set MIDI Callback");
	}
}

void mid_quit(void)
{
	if(mid_in) {
		rtmidi_close_port(mid_in);
		rtmidi_in_free(mid_in);
	}

	ver("mid quit");
}

bool mid_exec(void)
{
	ver3("mid exec");
	return state[0].irq_r || state[0].irq_t || state[1].irq_r || state[1].irq_t;
}

uint32_t mid_read(uint32_t off, int32_t sz)
{
	ver2("mid rd %u:%d", off, sz * 8);

	if (sz != 1 || off > 7) {
		fail("invalid mid rd %u:%d", off, sz * 8);
	}

	int32_t rg = (int32_t)(off % 4);
	int32_t un = (int32_t)(off / 4);

	uint32_t rv;

	switch (rg) {
	case REG_IER_ISR:
		rv = (uint32_t)(0xc0 | (state[un].rdr_ok ? 0x01 : 0x00));
		state[un].irq_r = false;
		state[un].irq_t = false;
		ver2("ISR[%d] 0x%02x", un, rv);
		break;

	case REG_TDR_RDR:
		rv = state[un].rdr;
		state[un].rdr_ok = false;
		ver2("RDR[%d] 0x%02x", un, rv);
		break;

	default:
		rv = 0x00;
		break;
	}

	if (!state[un].irq_r && !state[un].rdr_ok) {
		xmit(un);
	}

	return rv;
}

void mid_write(uint32_t off, int32_t sz, uint32_t val)
{
	ver2("mid wr %u:%d 0x%0*x", off, sz * 8, sz * 2, val);

	if (sz != 1 || off > 7) {
		fail("invalid mid wr %u:%d", off, sz * 8);
	}

	int32_t rg = (int32_t)(off % 4);
	int32_t un = (int32_t)(off / 4);

	switch (rg) {
	case REG_CFR_SR:
		ver2("CFR[%d] 0x%02x", un, val);

		if (un == 1) {
			fdd_set_side((int32_t)val & 0x01);
		}
		else {
			fdd_set_sel((int32_t)val & 0x01);
		}

		break;

	default:
		break;
	}
}

void mid_list(void) {
	mid_in = rtmidi_in_create_default();

	uint32_t portcount = rtmidi_get_port_count(mid_in);

	if (portcount == 0) {
		mid_in = NULL;
		ver2("no MIDI ports\n");
		return;
	}

	fprintf(stdout, "the following MIDI ports are available:\n");

	for (uint32_t i = 0; i < portcount; i++) {
		fprintf(stdout, "port %d: %s\n", i, rtmidi_get_port_name(mid_in, i));
	}

	rtmidi_in_free(mid_in);
}