/*
 * Copyright (c) 2015, Vladimir Komendantskiy
 * MIT License
 *
 * OLED is a 128x64 dot matrix display driver and controller by Solomon
 * Systech. It is used by HelTec display modules.
 *
 * Reference:
 *
 * [1] OLED Advance Information. 128x64 Dot Matrix Segment/Common
 *     Driver with Controller. (Solomon Systech)
 */

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>

// real-time features
#include <sys/mman.h>
#include <sched.h>

#include "oled.h"
#include "font.h"
#include <wiringPiI2C.h>


int oled_close(struct display_info *disp) {
	if (close(disp->file) < 0)
		return -1;

	return 0;
}

void cleanup(int status, void *disp) {
	oled_close((struct display_info *)disp);
}

int oled_open(struct display_info *disp, char *filename) {

	disp->file = wiringPiI2CSetupInterface (filename, disp->address);
	if (disp->file < 0)
		return -1;

	return 0;
}

// write commands and data to /dev/i2c*
int oled_send(struct display_info *disp, struct sized_array *payload) {
	if (write(disp->file, payload->array, payload->size) != payload->size)
		return -1;

	return 0;
}

int oled_init(struct display_info *disp) {
	struct sched_param sch;
	int status = 0;
	struct sized_array payload;

	//	sch.sched_priority = 49;
	//
	//	status = sched_setscheduler(0, SCHED_FIFO, &sch);
	//	if (status < 0)
	//		return status;
	//
	//	status = mlockall(MCL_CURRENT | MCL_FUTURE);
	//	if (status < 0)
	//		return status;

	payload.size = sizeof(display_config);
	payload.array = display_config;

	status = oled_send(disp, &payload);
	if (status < 0)
		return 666;

	memset(disp->buffer, 0, sizeof(disp->buffer));

	return 0;
}

// send buffer to oled (show)
int oled_send_buffer(struct display_info *disp) {
	struct sized_array payload;
	uint8_t packet[129];
	int index;

	for (index = 0; index < 8; index++) {	
		packet[0] = OLED_CTRL_BYTE_DATA_STREAM;
		memcpy(packet + 1, disp->buffer[index], 128);
		payload.size = 129;
		payload.array = packet;
		oled_send(disp, &payload);
	}
	return 0;
}

// clear screen
void oled_clear(struct display_info *disp) {
	memset(disp->buffer, 0, sizeof(disp->buffer));
	oled_send_buffer(disp);
}

// put string to one of the 8 pages (128x8 px) 
void oled_putstr(struct display_info *disp, uint8_t line, uint8_t *str) {
	uint8_t a;
	int slen = strlen(str);
	uint8_t fwidth = disp->font.width;
	uint8_t foffset = disp->font.offset;
	uint8_t fspacing = disp->font.spacing;
	int i=0;

	for (i=0; i<slen; i++) {
		a=(uint8_t)str[i];
		if (i >= 128/fwidth)
			break; // no text wrap
		memcpy(disp->buffer[line] + i*fwidth + fspacing, &disp->font.data[(a-foffset) * fwidth], fwidth);
	}
}

// put one pixel at xy, on=1|0 (turn on|off pixel)
void oled_putpixel(struct display_info *disp, uint8_t x, uint8_t y, uint8_t on) {
	uint8_t pageId = y / 8;
	uint8_t bitOffset = y % 8;
	if (x < 128-2) {
		if (on == 1)
			disp->buffer[pageId][x] |= (1<<bitOffset);
		else
			disp->buffer[pageId][x] &= ~(1<<bitOffset);
	}
}

// put string to the buffer at xy
void oled_putstrto(struct display_info *disp, uint8_t x, uint8_t y, char *str) {
	uint8_t a;
	int slen = strlen(str);
	uint8_t fwidth = disp->font.width;
	uint8_t fheight = disp->font.height;
	uint8_t foffset = disp->font.offset;
	uint8_t fspacing = disp->font.spacing;
	int i=0;
	int j=0;
	int k=0;

	for (k=0; k<slen; k++) {
		a=(uint8_t)str[k];
		for (i=0; i<fwidth; i++) {
			for (j=0; j<fheight; j++) {
				if (((disp->font.data[(a-foffset)*fwidth + i] >> j) & 0x01))
					oled_putpixel(disp, x+i, y+j, 1);
				else
					oled_putpixel(disp, x+i, y+j, 0);
			}
		}
		x+=fwidth+fspacing;
	}
}