path: root/main.c

// Compilation command:
// - release: gcc main.c -Wall -O2 -m64 -lncurses -o ttt
// - debug  : gcc main.c -Wall -g3 -m64 -lncurses -o ttt -D DEBUG


#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <ncurses.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define STR_(X) #X				// Convert to string.
#define STR(X) STR_(X)			// Force argument expansions before converting to string.

#define MAX_TASK_NAME		64	// Maximum task name length, including null-terminator.
#define FIRST_DAY_OF_WEEK	1	// (0-6, Sunday = 0)

#define LOG_FILE_NAME "log.txt"
#define DB_BIN_PATH_NAME "./database.bin"
#define DB_CSV_PATH_NAME "./database.csv"


typedef struct /*__attribute__((__packed__))*/ {
	uint32_t	time[7];
	char		name[MAX_TASK_NAME];
} task_t;

typedef struct /*__attribute__((__packed__))*/ {
	uint64_t	modified_on;
	uint32_t	count;
	uint32_t	capacity;
	task_t*		active_task;
	task_t*		tasks;
} database_t;

const char* DB_BIN_FILE_SIGNATURE = "TTT:B:01";
const uint8_t DB_BIN_FILE_SIGNATURE_SIZE = sizeof(DB_BIN_FILE_SIGNATURE);
const size_t SIZEOF_TASK_T = sizeof(task_t);
const size_t SIZEOF_DATABASE_T = sizeof(database_t);
const char* DAYS_OF_WEEK[] = { "sun", "mon", "tue", "wed", "thu", "fri", "sat" };
const uint8_t DAYS_ON_WEEK = sizeof(DAYS_OF_WEEK)/sizeof(char*);

uint32_t selected_task = -1;
database_t database = {
	.tasks = NULL,
	.count = 0,
	.capacity = 0,
};


// Given an UTF8 encoded string, truncate it to length without breaking any UTF8 character.
// The string should have capacity for at least length number of items.
// The terminating null byte ('\0') is included in length.
// The function returns the amount of items that got discarded counting from length.
size_t truncate_string_utf8(char* string, size_t length) {
	
	// Check for special cases where no truncation is required.
	if (length == 0 || string[length-1] == '\0') {
		return 0;
	}
	
	// Search for a non-UTF8-sequence-item so we can truncate the string.
	size_t idx = length - 1;
	while(idx > 0 && ((string[idx] & 0xC0) == 0x80)) {
		idx--;
	}
	string[idx] = '\0';
	return length - idx;
}

// Uses strchr to replace all instances of find by replace.
// Returns string.
char* replace_char(char* string, char find, char replace) {
	char* idx = string;
	while((idx = strchr(idx, find)) != NULL) {
		*idx = replace;
		idx++;
    }
    return string;
}

void print_task(const task_t* task) {
	printf("name: '%s'\n", task->name);
	printf("t[0]: '%" PRIu32 "'\n", task->time[0]);
	printf("t[1]: '%" PRIu32 "'\n", task->time[1]);
	printf("t[2]: '%" PRIu32 "'\n", task->time[2]);
	printf("t[3]: '%" PRIu32 "'\n", task->time[3]);
	printf("t[4]: '%" PRIu32 "'\n", task->time[4]);
	printf("t[5]: '%" PRIu32 "'\n", task->time[5]);
	printf("t[6]: '%" PRIu32 "'\n", task->time[6]);
}


// TODO Maybe inline?
bool add_task(database_t* db, const task_t* task) {
	assert(db != NULL);
	assert(task != NULL);
	
	if (db->count == UINT32_MAX) {
		fprintf(stderr, "Database reached maximum capacity, discarding task '%s'.\n", task->name);
		return false;
	}
	
	// If necessary, expand database capacity.
	uint32_t current_capacity = db->capacity;
	if(db->count + 1 > db->capacity) {
		uint32_t new_capacity = current_capacity == 0 ? 2 :
			current_capacity >= UINT32_MAX >> 2 ? UINT32_MAX :
			current_capacity << 1;
		
		task_t* new_database_tasks = realloc(db->tasks, new_capacity * SIZEOF_TASK_T);
		if (new_database_tasks == NULL) {
			fprintf(stderr, "Failed to expand database, discarding task '%s'.\n", task->name);
			return false;
		}
		db->capacity = new_capacity;
		db->tasks = new_database_tasks;
	}
	
	// Store new task.
	memcpy(&(db->tasks[db->count]), task, SIZEOF_TASK_T);
	db->count++;
	
	return true;
}

// TODO Maybe inline?
bool remove_task(database_t* db, uint32_t index) {
	assert(db != NULL);
	assert(index < db->count);
	
	/*
	      | ~ ~		6
	0 1 2 3 4 5		6 - 3 - 1 = 2

			| ~		6
	0 1 2 3 4 5		6 - 4 - 1 = 1
	
			  | ~	6
	0 1 2 3 4 5		6 - 5 - 1 = 0
	*/
	memmove(&db->tasks[index], &db->tasks[index+1], (db->count - index - 1) * SIZEOF_TASK_T);
	db->count--;
	
	if (db->capacity > 16 && db->count < (db->capacity >> 2)) {
		uint32_t new_tasks_capacity = db->capacity << 1;
		task_t* new_tasks = realloc(db->tasks, new_tasks_capacity * SIZEOF_TASK_T);
		if (new_tasks == NULL) {
			fprintf(stderr, "Failed to shrink database memory.\n");
			return false;
		}
		db->tasks = new_tasks;
	}
	return true;
}

void clear_database(database_t* db) {
	free(db->tasks);
	db->tasks = NULL;
	db->count = 0;
	db->capacity = 0;
}

// Stores data from database into binary file.
// Returns success.
bool store_database(const database_t* db, const char* path_name) {
	
	assert(db != NULL);
	assert(path_name != NULL);
	
	// Open file.
	FILE* file = fopen(path_name, "w");
	if (file == NULL) {
		fprintf(stderr, "Failed to open file '%s' while storing database: %s.\n", path_name, strerror(errno));
		return false;
	}
	
	fwrite(DB_BIN_FILE_SIGNATURE, sizeof(char), DB_BIN_FILE_SIGNATURE_SIZE, file);
	fwrite(db, SIZEOF_DATABASE_T, 1, file);
	fwrite(db->tasks, SIZEOF_TASK_T, db->count, file);
	
	fclose(file);
	return true;
}

// Loads data from binary file into database.
// Returns success.
bool load_database(database_t* db, const char* path_name) {
	
	assert(db != NULL);
	assert(path_name != NULL);
	
	// Open file.
	FILE* file = fopen(path_name, "r");
	if (file == NULL) {
		fprintf(stderr, "Failed to open file '%s' while loading database: %s.\n", path_name, strerror(errno));
		return false;
	}
	
	// Validate file signature.
	char file_signature[DB_BIN_FILE_SIGNATURE_SIZE];
	fread(&file_signature, sizeof(char), DB_BIN_FILE_SIGNATURE_SIZE, file);
	if (strncmp(file_signature, DB_BIN_FILE_SIGNATURE, DB_BIN_FILE_SIGNATURE_SIZE) != 0) {
		fprintf(stderr, "Invalid file signature.\n");
		return false;
	}
	
	// Read database structure.
	fread(db, SIZEOF_DATABASE_T, 1, file);
	
	// Keep track of last active task.
	ptrdiff_t active_task_index = db->active_task - db->tasks;
	
	// Restore database capacity.
	db->tasks = calloc(db->capacity, SIZEOF_TASK_T);
	
	// Restore last active task.
	if (db->active_task != NULL) {
		db->active_task = db->tasks + active_task_index;
	}
	
	// Read database entries.
	fread(db->tasks, SIZEOF_TASK_T, db->count, file);
	
	// Make sure we are reading all the file.
	assert(fgetc(file) == EOF);
	
	fclose(file);
	return true;
}

// Exports data into CSV file.
// Returns success.
bool export_to_csv(const database_t* db, const char* path_name) {
	
	assert(db != NULL);
	assert(path_name != NULL);
	
	FILE* file = fopen(path_name, "w");
	if (file == NULL) {
		fprintf(stderr, "Failed to open file '%s' while exporting to CSV: %s.\n", path_name, strerror(errno));
		return false;
	}
	
	fprintf(file, "%s,%s,%s,%s,%s,%s,%s,%s\n",
		"task",
		DAYS_OF_WEEK[0],
		DAYS_OF_WEEK[1],
		DAYS_OF_WEEK[2],
		DAYS_OF_WEEK[3],
		DAYS_OF_WEEK[4],
		DAYS_OF_WEEK[5],
		DAYS_OF_WEEK[6]
	);
	
	for (uint32_t idx = 0; idx < db->count; idx++) {
		const task_t* task = &db->tasks[idx];
		fprintf(file, "%s,%" PRIu32 ",%" PRIu32 ",%" PRIu32 ",%" PRIu32 ",%" PRIu32 ",%" PRIu32 ",%" PRIu32 "\n",
			task->name,
			task->time[0],
			task->time[1],
			task->time[2],
			task->time[3],
			task->time[4],
			task->time[5],
			task->time[6]
		);
	}
	
	fclose(file);
	return true;
}

// Imports CSV file into database.
// Returns success.
bool import_from_csv(database_t* db, const char* path_name) {
	assert(db != NULL);
	assert(path_name != NULL);
	
	FILE* file = fopen(path_name, "r");
	if (file == NULL) {
		fprintf(stderr, "Failed to open file '%s' while importing from CSV: %s.\n", path_name, strerror(errno));
		return false;
	}
	
	uint32_t number_of_entries = 0;
	task_t task;
	char *line_buffer = NULL;
	size_t line_buffer_size = 0;
	ssize_t read_characters = 0;
	char* name_delimiter;
	
	// Skip header line.
	fscanf(file, "%*[^\n]\n");

	// Parse CSV file.
	while(true) {
		
		read_characters = getline(&line_buffer, &line_buffer_size, file);
		
		// Check if reached EOF.
		if (read_characters == -1) {
			break;
		}
		
		// Clear task struct.
		memset(&task, 0, SIZEOF_TASK_T);
		
		// Find task name string limits.
		name_delimiter = strchr(line_buffer, ',');
		size_t name_length = (name_delimiter - line_buffer) + 1;
		if (name_length > MAX_TASK_NAME) {
			name_length = MAX_TASK_NAME;
		}
		
		// Import task name.
		memcpy(task.name, line_buffer, name_length);
		truncate_string_utf8(task.name, name_length);
		
		// Parse task times.
		if(sscanf(name_delimiter+1, 
			"%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32,
			&task.time[0],
			&task.time[1],
			&task.time[2],
			&task.time[3],
			&task.time[4],
			&task.time[5],
			&task.time[6]
		) != 7) {
			replace_char(line_buffer, '\n', ' ');
			fprintf(stderr, "Discarding invalid line '%s' and continuing.\n", line_buffer);
			continue;
		}
		
		// Add new database entry.
		number_of_entries++;
		add_task(db, &task);
	}
	
	fclose(file);
	free(line_buffer);
	
	return true;
}


enum TEST {
	T_NONE	= 0x00,
	T_UTC	= 0x01,
	T_DAY	= 0x02,
	T_SBIN	= 0x04,
	T_LBIN	= 0x08,
	T_ECSV	= 0x10,
	T_ICSV	= 0x20,
	T_SOS	= 0x40,
	T_ALL	= 0xFF,
};

void prototype(int level) {
	
	const char* done = "# -- done -- -- -- /\n";
	
	///////////////////////////////////////////////////////////////////////////
	// Get current UTC time.
	if (level & T_UTC) {
		fprintf(stderr, "# current UTC time --------------------------- \\\n");
		time_t x = time(NULL);
		printf("%s", ctime(&x));
		fprintf(stderr, done);
	}
	
	///////////////////////////////////////////////////////////////////////////
	// Get current day of the week.
	if (level & T_DAY) {
		fprintf(stderr, "# current day of the week --------------------- \\\n");
		time_t now_ut = time(NULL);
		uint8_t week_day = localtime(&now_ut)->tm_wday;
		fprintf(stderr, "%d\n", week_day);
		fprintf(stderr, done);
	}
	
	///////////////////////////////////////////////////////////////////////////
	// Prepare some data for testing.
	/*
	task_t tmp[] = {
		{
			.name = "ALPHA-TASK",
			.time = { 0, 0, 0, 0, 0, 0, 0 },
		},
		{
			.name = "BETA-TASK",
			.time = { 1, 1, 1, 1, 1, 1, 1 },
		},
		{
			.name = "DELTA-TASK",
			.time = { 2, 2, 2, 2, 2, 2, 2 },
		}
	};
	
	uint32_t number_of_items = sizeof(tmp) / sizeof(task_t);
	database.tasks = calloc(number_of_items, SIZEOF_TASK_T);
	database.capacity = number_of_items;
	database.count = number_of_items;
	memcpy(database.tasks, &tmp, SIZEOF_TASK_T * number_of_items);
	*/
	
	///////////////////////////////////////////////////////////////////////////
	// Store database from memory to binary file.
	if (level & T_SBIN) {
		fprintf(stderr, "# store database ------------------------------ \\\n");
		store_database(&database, DB_BIN_PATH_NAME);
		fprintf(stderr, done);
	}
	
	///////////////////////////////////////////////////////////////////////////
	// Load database from binary file to memory.
	if (level & T_LBIN) {
		fprintf(stderr, "# load database ------------------------------- \\\n");
		database_t db_load;
		memset(&db_load, 0, SIZEOF_DATABASE_T);
		
		load_database(&db_load, DB_BIN_PATH_NAME);
		fprintf(stderr, "loaded %" PRIu32 " entries.\n", db_load.count);
		
		for (uint32_t idx = 0; idx < db_load.count; idx++) {
			print_task(&db_load.tasks[idx]);
		}
		clear_database(&db_load);
		fprintf(stderr, done);
	}
	
	///////////////////////////////////////////////////////////////////////////
	// Export database to CSV file.
	if (level & T_ECSV) {
		fprintf(stderr, "# export to CSV ------------------------------- \\\n");
		export_to_csv(&database, DB_CSV_PATH_NAME);
		fprintf(stderr, done);
	}
	
	///////////////////////////////////////////////////////////////////////////
	// Import database from CSV file.
	if (level & T_ICSV) {
		fprintf(stderr, "# import from CSV ----------------------------- \\\n");
		database_t db_import;
		memset(&db_import, 0, SIZEOF_DATABASE_T);
		
		import_from_csv(&db_import, DB_CSV_PATH_NAME);
		fprintf(stderr, "imported %" PRIu32 " entries.\n", db_import.count);
		
		for (uint32_t idx = 0; idx < db_import.count; idx++) {
			print_task(&db_import.tasks[idx]);
		}
		clear_database(&db_import);
		fprintf(stderr, done);
	}	
	
	///////////////////////////////////////////////////////////////////////////
	// Check size of structs
	if (level & T_SOS) {
		size_t size;
		char* name;
		fprintf(stderr, "# check structs sizes ------------------------- \\\n");
		
		name = "database_t";
		size = sizeof(database_t);
		fprintf(stderr, "sizeof(%s) = %zu bytes (%zu bits : %6.3f W64b)\n", name, size, size*8, ((double)size)*8.0/64.0);
		
		name = "task_t";
		size = sizeof(task_t);
		fprintf(stderr, "sizeof(%s) = %zu bytes (%zu bits : %6.3f W64b)\n", name, size, size*8, ((double)size)*8.0/64.0);
		
		fprintf(stderr, done);
	}
}


char* line_buffer;
int size_x, size_y, pos_x, pos_y;
uint8_t selected_layout = 0;

#define TABLE_HEADERS_SIZE 9

typedef struct {
	int table_size;
	int table_headers_size;
	char* table_headers[TABLE_HEADERS_SIZE];
} layout_t;

layout_t* layouts = NULL;


void initialize_layouts() {
	layout_t* layout = NULL;
	
	layouts = calloc(2, sizeof(layout_t));
	
	// Layout : 0 : normal.
	layout = &layouts[0];
	layout->table_size = 8;
	layout->table_headers_size = TABLE_HEADERS_SIZE;
	// TODO Headers must be dynamic according to FIRST_DAY_OF_WEEK
	layout->table_headers[0] = " Task ";
	layout->table_headers[1] = " Mon ";
	layout->table_headers[2] = " Tue ";
	layout->table_headers[3] = " Wed ";
	layout->table_headers[4] = " Thu ";
	layout->table_headers[5] = " Fri ";
	layout->table_headers[6] = " Sat ";
	layout->table_headers[7] = " Sun ";
	layout->table_headers[8] = " Total ";
// 	layout->table_headers = { " Task ", " Mon ", " Tue ", " Wed ", " Thu ", " Fri ", " Sat ", " Sun ", " Total " };
	
	// Layout : 1 : compact.
	layout = &layouts[1];
	layout->table_size = 6;
	layout->table_headers_size = TABLE_HEADERS_SIZE;
	// TODO Headers must be dynamic according to FIRST_DAY_OF_WEEK
	layout->table_headers[0] = " Task ";
	layout->table_headers[1] = " M ";
	layout->table_headers[2] = " T ";
	layout->table_headers[3] = " W ";
	layout->table_headers[4] = " T ";
	layout->table_headers[5] = " F ";
	layout->table_headers[6] = " S ";
	layout->table_headers[7] = " S ";
	layout->table_headers[8] = "  #  ";
// 	layout->table_headers = { " T ", " M ", " T ", " W ", " T ", " F ", " S ", " S ", "  #  " };
}

void initialization() {
	// Make sure architecture uses 8bits per char.
	assert(CHAR_BIT == 8);
	
	// TODO May use the memset or set the properties during instancing.
	// Prepare memory.
	memset(&database, 0, SIZEOF_DATABASE_T);
}

void free_memory() {
	clear_database(&database);
	
	free(line_buffer);
	line_buffer = NULL;
	
	free(layouts);
	layouts = NULL;
}

void draw_header() {
	
	layout_t* layout = &layouts[selected_layout];
	int table_size = layout->table_size;
	char** table_headers = layout->table_headers;
	
	mvaddch(0, 0, ACS_ULCORNER);
	for (int idx = 1; idx < size_x-1; idx++) {
		addch(ACS_HLINE);
	}
	addch(ACS_URCORNER);
	
	int start_columns = size_x - 1 - 8*table_size - 2;
	int columns[] = {
		0,
		start_columns+(table_size*0),
		start_columns+(table_size*1),
		start_columns+(table_size*2),
		start_columns+(table_size*3),
		start_columns+(table_size*4),
		start_columns+(table_size*5),
		start_columns+(table_size*6),
		start_columns+(table_size*7),
	};
	
	mvaddstr(0, columns[0]+2, table_headers[0]);
	for (int idx = 1; idx < 9; idx++) {
		mvaddch(0, columns[idx], ACS_TTEE);
		mvaddstr(0, columns[idx]+2, table_headers[idx]);
	}
}

void draw_table() {
	task_t* task;
	
	layout_t* layout = &layouts[selected_layout];
	int table_size = layout->table_size;
// 	char** table_headers = layout->table_headers;
	
	// TODO Colors
	start_color();
	init_pair(1, COLOR_BLACK, COLOR_CYAN);
	
	
	int start_columns = size_x - 1 - 8*table_size - 2;
	int columns[] = {
		0,
		start_columns+(table_size*0),
		start_columns+(table_size*1),
		start_columns+(table_size*2),
		start_columns+(table_size*3),
		start_columns+(table_size*4),
		start_columns+(table_size*5),
		start_columns+(table_size*6),
		start_columns+(table_size*7),
		size_x-1,
	};
	
	move(1, 0);
	for (uint32_t idx = 0; idx < database.count; idx++){
		
		task = &database.tasks[idx];
		
		// Enable highlight color on selected entry.
		if (idx == selected_task) {
			attron(COLOR_PAIR(1));
		}
		
		// Clear line_buffer and add string termination.
		memset(line_buffer, ' ', size_x * sizeof(char));
		line_buffer[size_x-1] = '\0';
		
		// Check maximum available space for task name and print it accordingly.
		size_t task_name_length = strlen(task->name)*sizeof(char);
		size_t max_column_length = start_columns - 2;
		size_t copy_length = task_name_length < max_column_length ? task_name_length : max_column_length;
		memcpy(line_buffer+2, task->name, copy_length);
		addstr(line_buffer);

		// Disable highlight color on selected entry.
		if (idx == selected_task) {
			attroff(COLOR_PAIR(1));
		}
		
		// Print columns separators.
		pos_y = getcury(stdscr);
		for (int c_idx = 0; c_idx < sizeof(columns)/sizeof(int); c_idx++) {
			mvaddch(pos_y, columns[c_idx], ACS_VLINE);
		}
		
		// Go to next line.
		pos_y++;
		move(pos_y, 0);
	}
}

void draw_footer() {
	const char *app_name = "Task Tracker";
	const char *app_version = "v1.0";
	
	int row, col;                        /* to store the number of rows and the number of colums of the screen */
	initscr();							/* start the curses mode */
	getmaxyx(stdscr,row,col);			/* get the number of rows and columns */
	
	mvaddch(row-1, 0, ACS_LLCORNER);
	addch(' ');
	printw(app_name);
	addch(' ');
	for (int idx = strlen(app_name) + 3; idx < col - strlen(app_version) - 3; idx ++) {
		addch(ACS_HLINE);
	}
	addch(' ');
	printw(app_version);
	addch(' ');
	addch(ACS_LRCORNER);
}

WINDOW *create_newwin(int height, int width, int starty, int startx);
void destroy_win(WINDOW *local_win);

int main(int argc, char *argv[]) {
	initialization();
	
	// TODO Parse commands using: https://stackoverflow.com/questions/9642732/parsing-command-line-arguments-in-c
	if (argc > 1) {
		
		char* action;
		bool do_action = false;
		for (int idx = 1; idx < argc; idx++) {
			
			action = "--version";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			action = "-v";
			do_action |= strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				fprintf(stdout, "Task Time Tracker v1.0\n");
				return EXIT_SUCCESS;
			}
			
			action = "--fake_bin";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				prototype(T_SBIN);
				return EXIT_SUCCESS;
			}
			
			action = "--t_sos";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				prototype(T_SOS);
				return EXIT_SUCCESS;
			}
			
			action = "--t_icsv";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				prototype(T_ICSV);
				return EXIT_SUCCESS;
			}
			
			action = "--t_lbin";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				prototype(T_LBIN);
				return EXIT_SUCCESS;
			}
			
			action = "--t_csv2bin";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				clear_database(&database);
				import_from_csv(&database, DB_CSV_PATH_NAME);
				store_database(&database, DB_BIN_PATH_NAME);
				return EXIT_SUCCESS;
			}
			
			action = "--test";
			do_action = strncmp(argv[idx], action, strlen(action)) == 0;
			if (do_action) {
				prototype(T_ALL);
				return EXIT_SUCCESS;
			}
		}

	
		fprintf(stdout, "Unkown command '%s'.\nUse '%s --help' for list of commands.\n", argv[1], argv[0]);
		return EXIT_FAILURE;
	}
	
	load_database(&database, DB_BIN_PATH_NAME);
	
	initialize_layouts();
	
	WINDOW *my_win;
	int startx, starty, width, height;
	int ch;

	initscr();			/* Start curses mode 		*/
	cbreak();			/* Line buffering disabled, Pass on
					 * everty thing to me 		*/
	keypad(stdscr, TRUE);		/* I need that nifty F1 	*/
    curs_set(0);        // Set cursor invisible.

	height = 3;
	width = 10;
	starty = (LINES - height) / 2;	/* Calculating for a center placement */
	startx = (COLS - width) / 2;	/* of the window		*/
	printw("Press F1 to exit");
	refresh();
	my_win = create_newwin(height, width, starty, startx);
    
	ch = KEY_RESIZE;
	do {
        switch(ch)
		{
			case KEY_RESIZE:
				erase();
				if (line_buffer != NULL) {
					free(line_buffer);
				}
				getmaxyx(stdscr, size_y, size_x);
				line_buffer = malloc(size_x * sizeof(char));
				break;
			
			case KEY_LEFT:
				destroy_win(my_win);
				my_win = create_newwin(height, width, starty,--startx);
				break;
			
			case KEY_RIGHT:
				destroy_win(my_win);
				my_win = create_newwin(height, width, starty,++startx);
				break;
			
			case KEY_UP:
				selected_task = selected_task == 0 ? 0 : selected_task - 1;
				destroy_win(my_win);
				my_win = create_newwin(height, width, --starty,startx);
				break;
			
			case KEY_DOWN:
				selected_task = (selected_task+1) == database.count ? selected_task : selected_task + 1;
				destroy_win(my_win);
				my_win = create_newwin(height, width, ++starty,startx);
				break;	
		}
		
		selected_layout = size_x > 100 ? 0 : 1;

		if (size_x >= 60 && size_y > 2) {
			draw_header();
			draw_table();
			draw_footer();
		}
		else {
			const char* INVALID_WINDOW_MESSAGE = "Please expand window.";
			mvaddstr(size_y / 2, (size_x - strlen(INVALID_WINDOW_MESSAGE)) / 2, INVALID_WINDOW_MESSAGE);
		}
	
	} while((ch = getch()) != KEY_F(1));
	
	free_memory();
	endwin();
	return EXIT_SUCCESS;
}

WINDOW *create_newwin(int height, int width, int starty, int startx) {
	WINDOW *local_win;

	local_win = newwin(height, width, starty, startx);
	box(local_win, 0 , 0);		/* 0, 0 gives default characters 
					 * for the vertical and horizontal
					 * lines			*/
	wrefresh(local_win);		/* Show that box 		*/

	return local_win;
}

void destroy_win(WINDOW *local_win) {
	/* box(local_win, ' ', ' '); : This won't produce the desired
	 * result of erasing the window. It will leave it's four corners 
	 * and so an ugly remnant of window. 
	 */
	wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
	/* The parameters taken are 
	 * 1. win: the window on which to operate
	 * 2. ls: character to be used for the left side of the window 
	 * 3. rs: character to be used for the right side of the window 
	 * 4. ts: character to be used for the top side of the window 
	 * 5. bs: character to be used for the bottom side of the window 
	 * 6. tl: character to be used for the top left corner of the window 
	 * 7. tr: character to be used for the top right corner of the window 
	 * 8. bl: character to be used for the bottom left corner of the window 
	 * 9. br: character to be used for the bottom right corner of the window
	 */
	wrefresh(local_win);
	delwin(local_win);
}