#include "i2c.h"
#include "lcd.h"
#include <glib.h>
#include <string.h>
#include <stdlib.h>

#define LCD_ENABLE	0x03	/* the 4x40 LCDs have two enable lines - 0x03 enables both at the same time */
#define LCD_DATA_RAM	128		/* display RAM, in the LCD ICs */
#define LCD_CG_RAM	64		/* custom character RAM, in the LCD ICs */

#define LCD_chars_total 160
#define LCD_cols    	40
#define LCD_rows    	4		/* 4x40 LCD */

char LCD_Data[LCD_rows][LCD_cols];	/* shadow copy of LCD display in local RAM, to minimize slow I2C writes */

/*** EndHeader */


static void break_up_string (char *in_string, int N, char **str1, char **str2, char **str3)
{

#define SUBSTRING_CNT 3

	int input_length;
	int j, k, copypos;
	int n;

	char *copy_input;
	char *p;

	j=k=copypos=0;
	input_length=strlen(in_string);
	copy_input = g_strdup(in_string);

	for (j=0; j<SUBSTRING_CNT; j++) {

		gchar *interm_str = g_strnfill (N, 0);

		for (k=0; k<N; k++) {
			copypos++; // next symbol
			if (copypos>input_length) {
				break;
			}
			if ((*(copy_input+k)==' ')&&(copypos<input_length)) { // space found
				//find next space
				p=strchr(copy_input+k+1,' ');
				if (p!=NULL) {
					// next space is beyond N char limit for one line
					if((p-copy_input)/sizeof(char)>=N) {
						break;
					}
				} else {
					// No more spaces. Does the last chunk of text fit?
					if (strlen(copy_input+k+1)>N-k) {
						break;
					}
				}
			}
			// valid character, copy to output string
			*(interm_str+k)=*(copy_input+k);

		}
		// remove processed part from the input
		if (copypos<=input_length) {
			strcpy(copy_input, in_string+copypos);
		}
		n = strlen(interm_str);
		for ((k=n-1); (k=0); k--) { //trim   space
			if (*(interm_str+k)==' ') {
				*(interm_str+k)=0;
			} else {
				break;
			}
		}
		switch (j) {
		case 0:
			*str1 = g_strdup(interm_str);
			break;
		case 1:
			*str2 = g_strdup(interm_str);
			break;
		case 2:
			*str3 = g_strdup(interm_str);
			break;
		}
		g_free(interm_str);

	}

	g_free(copy_input);
}




void LCD_clear()
{
	int i;
	int j;

	I2C_Write(PCF8574A+LCD_Port, 0x00 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x00);
	I2C_Write(PCF8574A+LCD_Port, 0x10 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x10);

	/* wait 1.64ms */
	g_usleep(1640);

	for (i=0; i<4; ++i)
		for (j=0; j<40; ++j) {
			LCD_Data[i][j]=0;
		}

	return;
}


static void LCD_RAM_write(int RAM_start,int row, int col, char *LCD_string)
{
	/* rows: 0-3, cols: 0-39 */

#define data_level 0x04

	int i;
	int cur_row, cur_col;
	int String_length;
	char char_out, enable_one_lcd;
	int ram_location;
	char last_op_a_write;

	if (!LCD_string) {
		return;
	}

	String_length=strlen(LCD_string);
	enable_one_lcd=0x02;

	last_op_a_write=0;
	cur_row=row;
	cur_col=col;

	if (cur_row<2) {
		enable_one_lcd=0x02;
	} else {
		enable_one_lcd=0x01;
	}

	/* write out the string */
	for (i=0; i<String_length; ++i) {
		if (cur_row<2) {
			enable_one_lcd=0x02;
		} else {
			enable_one_lcd=0x01;
		}

		if (LCD_string[i]!=LCD_Data[cur_row][cur_col]) {
			if (!last_op_a_write) {
				/* move to new position */
				ram_location = (cur_row & 1) * 64 + cur_col + RAM_start;
				char_out=ram_location & 0xf0;
				I2C_Write(PCF8574A+LCD_Port, char_out | enable_one_lcd);
				I2C_Write(PCF8574A+LCD_Port, char_out);
				char_out=ram_location << 4;
				I2C_Write(PCF8574A+LCD_Port, char_out | enable_one_lcd);
				I2C_Write(PCF8574A+LCD_Port, char_out);
			}
			LCD_Data[cur_row][cur_col]=LCD_string[i];
			char_out=LCD_string[i] & 0xf0;
			I2C_Write(PCF8574A+LCD_Port, char_out | enable_one_lcd | data_level);
			I2C_Write(PCF8574A+LCD_Port, char_out | data_level);
			char_out=LCD_string[i] << 4;
			I2C_Write(PCF8574A+LCD_Port, char_out | enable_one_lcd | data_level);
			I2C_Write(PCF8574A+LCD_Port, char_out | data_level);
			last_op_a_write=1;
		} else {
			last_op_a_write=0;
		}

		++cur_col;
		if (cur_col==40) {
			cur_col=0;
			++cur_row;
		}
	}
	return;
}


void LCD_write(int row, int col, char *LCD_string)
{
	LCD_RAM_write(LCD_DATA_RAM, row, col, LCD_string);
	return;
}


static void LCD_make_custom_chars()
{
	/* define custom LCD characters 2 and 3 (up arrow and down arrow).*/
	/* The up arrow is stored in one LCD controller (for rows 0 and 1) */
	/* The down arrow is stored in the other LCD controller (for rows 2 and 3) */
	LCD_RAM_write(LCD_CG_RAM,0,16,"\x4");
	LCD_RAM_write(LCD_CG_RAM,0,17,"\xe");
	LCD_RAM_write(LCD_CG_RAM,0,18,"\x15");
	LCD_RAM_write(LCD_CG_RAM,0,19,"\x4");
	LCD_RAM_write(LCD_CG_RAM,0,20,"\x4");
	LCD_RAM_write(LCD_CG_RAM,0,21,"\x4");
	LCD_RAM_write(LCD_CG_RAM,0,22,"\x4");
	LCD_RAM_write(LCD_CG_RAM,0,23,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,24,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,25,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,26,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,27,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,28,"\x4");
	LCD_RAM_write(LCD_CG_RAM,2,29,"\x15");
	LCD_RAM_write(LCD_CG_RAM,2,30,"\xe");
	LCD_RAM_write(LCD_CG_RAM,2,31,"\x4");
// prove that it works - debug only
//	LCD_RAM_write(LCD_DATA_RAM,0,39,"\x2");
//	LCD_RAM_write(LCD_DATA_RAM,3,39,"\x3");

	return;
}


void LCD_initialize(void)
{
	/* Wait 15ms */
	g_usleep(15000);

	I2C_Write(PCF8574A+LCD_Port, 0x30 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x30);

	/* wait 4.1ms */
	g_usleep(4100);

	I2C_Write(PCF8574A+LCD_Port, 0x30 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x30);

	/* wait 100us */
	g_usleep(100);

	I2C_Write(PCF8574A+LCD_Port, 0x30 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x30);

	/* wait 4.1ms */
	g_usleep(4100);

	I2C_Write(PCF8574A+LCD_Port, 0x20 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x20);

	/*wait 40us */
	g_usleep(40);

	I2C_Write(PCF8574A+LCD_Port, 0x20 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x20);
	I2C_Write(PCF8574A+LCD_Port, 0x80 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x80);

	/* wait 40us */
	g_usleep(40);

	LCD_clear();

	I2C_Write(PCF8574A+LCD_Port, 0x00 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x00);
	I2C_Write(PCF8574A+LCD_Port, 0x60 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x60);

	/* wait 40us */
	g_usleep(40);

	I2C_Write(PCF8574A+LCD_Port, 0x00 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0x00);
	I2C_Write(PCF8574A+LCD_Port, 0xc0 | LCD_ENABLE);
	I2C_Write(PCF8574A+LCD_Port, 0xc0);

	LCD_make_custom_chars();

	return;
}


void LCD_display_error_message(char *response)
{
	char *row0 = NULL;
	char *row1 = NULL;
	char *row2 = NULL;

//	Error_Screen=1;  //FIXME

	break_up_string (response, LCD_cols, &row0, &row1, &row2);

	LCD_clear();
	LCD_write(0,0,row0);
	LCD_write(1,0,row1);
	LCD_write(2,0,row2);
	LCD_write(3,0,Press_Change_Message);

	g_free (row0);
	g_free (row1);
	g_free (row2);

	return;
}