// Compilation command:
// - release: gcc task_tracker.c -Wall -O2 -m64 -lncurses -o task_tracker.x64
// - debug  : gcc task_tracker.c -Wall -g3 -m64 -lncurses -o task_tracker.x64


#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <ncurses.h>
#include <stdbool.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 127
#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"


// TODO The hash is overkill... right? And I could decouple it from the task_t.

struct task_event {
	char*		name;
	time_t		start;
	time_t		end;
};

typedef struct {
	char		name[MAX_TASK_NAME+1]; // Allow space for null termination char.
	uint32_t	time[7];
	uint32_t	hash;
// 	uint32_t	time[sizeof(DAYS_OF_WEEK)];
// #define DAYS_ON_WEEK sizeof(DAYS_OF_WEEK)
// 	uint32_t	time[DAYS_ON_WEEK];
} task_t;


const char* DB_BIN_FILE_SIGNATURE = "TTBF:1.0";
const uint8_t DB_BIN_FILE_SIGNATURE_SIZE = sizeof(DB_BIN_FILE_SIGNATURE);
const size_t SIZEOF_TASK_T = sizeof(task_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*);

task_t* tasks = NULL;
uint32_t tasks_count = 0;
uint32_t tasks_capacity = 0;

int selected_task = -1;
char** tasks_names = NULL;
uint32_t tasks_names_size = 0;
uint32_t tasks_names_capacity = 0;


char* replace_char(char* string, char find, char replace){
	char *idx = string;
	while((idx = strchr(idx, find)) != NULL) {
		*idx = replace;
		*idx++;
    }
    return string;
}

uint32_t CRC32(const uint8_t data[], size_t data_length) {
	
	static const uint32_t crc32_table[] = {
		0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
		0xe963a535, 0x9e6495a3,	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
		0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
		0xf3b97148, 0x84be41de,	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
		0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,	0x14015c4f, 0x63066cd9,
		0xfa0f3d63, 0x8d080df5,	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
		0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,	0x35b5a8fa, 0x42b2986c,
		0xdbbbc9d6, 0xacbcf940,	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
		0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
		0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
		0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,	0x76dc4190, 0x01db7106,
		0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
		0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
		0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
		0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
		0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
		0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
		0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
		0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
		0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
		0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
		0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
		0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
		0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
		0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
		0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
		0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
		0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
		0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
		0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
		0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
		0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
		0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
		0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
		0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
		0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
		0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
		0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
		0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
		0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
		0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
		0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
		0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
	};
	
	uint32_t crc32 = 0xFFFFFFFFu;
	
	for (size_t i = 0; i < data_length; i++) {
		const uint32_t lookupIndex = (crc32 ^ data[i]) & 0xff;
		crc32 = (crc32 >> 8) ^ crc32_table[lookupIndex];
	}
	
	// Finalize the CRC-32 value by inverting all the bits
	crc32 ^= 0xFFFFFFFFu;
	return crc32;
}

uint32_t hash_string(const char* string) {
	size_t data_length = strlen(string);
	uint8_t* data = (uint8_t*)string;
	return CRC32(data, data_length);
}

void print_task(const task_t* task) {
	printf("name: '%s'\n", task->name);
	printf("hash: '%" PRIu32 "'\n", task->hash);
	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]);
}

void store_database(const task_t* database, uint32_t number_of_entries, const char* path_name) {
	
	assert(database != NULL);
	assert(path_name != NULL);
	
	// Open file.
	FILE* file = fopen(path_name, "w");
	if (file == NULL) {
		fprintf(stderr, "Failed to open database file: %s.\n", strerror(errno)); // TODO Fix message.
		return;
	}
	
	fwrite(DB_BIN_FILE_SIGNATURE, sizeof(char), DB_BIN_FILE_SIGNATURE_SIZE, file);
	fwrite(&number_of_entries, sizeof(number_of_entries), 1, file);
	fwrite(database, SIZEOF_TASK_T, number_of_entries, file);
	
	fclose(file);
}

uint32_t load_database(task_t** database, const char* path_name) {
	
	assert(database != NULL);
	assert(path_name != NULL);
	
	// Open file.
	FILE* file = fopen(path_name, "r");
	if (file == NULL) {
		fprintf(stderr, "Failed to open database file '%s': %s.\n", path_name, strerror(errno)); // TODO Fix message.
		return 0;
	}
	
	// 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 0;
	}
	
	// Read number of entries.
	uint32_t number_of_entries;
	fread(&number_of_entries, sizeof(number_of_entries), 1, file);
	
	// Read database entries.
	*database = calloc(number_of_entries, SIZEOF_TASK_T);
	fread(*database, SIZEOF_TASK_T, number_of_entries, file);
	
	// Make sure we are reading all the file.
	assert(fgetc(file) == EOF);
	
	fclose(file);
	
	return number_of_entries;
}

void export_database(const task_t* database, uint32_t number_of_entries, const char* path_name) {
	
	assert(database != NULL);
	assert(path_name != NULL);
	
	FILE* file = fopen(path_name, "w");
	if (file == NULL) {
		fprintf(stderr, "Failed to open database file '%s': %s.\n", path_name, strerror(errno)); // TODO Fix message.
		return;
	}
	
	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 < number_of_entries; idx++) {
		const task_t* task = &database[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);
}

uint32_t import_database(task_t** database, const char* path_name) {
	
	assert(database != NULL);
	assert(path_name != NULL);
	
	FILE* file = fopen(path_name, "r");
	if (file == NULL) {
		fprintf(stderr, "Failed to open database file '%s': %s.\n", path_name, strerror(errno)); // TODO Fix message.
		return 0;
	}
	
	uint32_t number_of_entries = 0;
	uint32_t capacity = 0;
	task_t task;
	int error;
	
	fscanf(file, "%*[^\n]\n"); // Skip header line.
	scan_csv: {
		
		error = fscanf(file,
			"%" STR(MAX_TASK_NAME) "[^,],%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 ",%" SCNu32 "\n",
			task.name,
			&task.time[0],
			&task.time[1],
			&task.time[2],
			&task.time[3],
			&task.time[4],
			&task.time[5],
			&task.time[6]
		);
		
		if (error != EOF)
		{
			task.hash = hash_string(task.name);
			number_of_entries++;
			
			// Expand tasks capacity if required.
			if (number_of_entries > capacity) {
				capacity = capacity == 0 ? 16 : capacity << 1;
				*database = reallocarray(*database, capacity, SIZEOF_TASK_T);
				if (errno != 0 || errno == ENOMEM) {
					; // TODO reallocarray failed
				}
			}
			memcpy(&((*database)[number_of_entries-1]), &task, SIZEOF_TASK_T);
			
			goto scan_csv;
		}
	}
	
	assert(number_of_entries == 3);
	*database = reallocarray(*database, number_of_entries, SIZEOF_TASK_T);
	// TODO check for allocation errors.
// 	if (error != EOF) {
// 		fprintf(stderr, "Failed to parse database file: %s.\n", strerror(errno));
// 	}
	
	
	fclose(file);
	
	return number_of_entries;
}

void add_task(char* name) {
	
	// Exit if task has already been added.
	uint32_t name_hash = CRC32((uint8_t*)name, sizeof(name));
	for (uint32_t idx = 0; idx < tasks_count; idx++)
	{
		if (name_hash == tasks[idx].hash && strcmp(name, tasks[idx].name) == 0)
		{
			return;
		}
	}
	
	// Expand tasks capacity if required.
	if (tasks_count >= tasks_capacity)
	{
		tasks_capacity = tasks_capacity == 0 ? 16 : tasks_capacity << 1;
		tasks = realloc(tasks, SIZEOF_TASK_T * tasks_capacity);
	}
	
	// Add new task entry.
	task_t* new_task = &tasks[tasks_count];
	memset(new_task, '0', SIZEOF_TASK_T);
	strncpy(new_task->name, name, MAX_TASK_NAME);
	new_task->name[MAX_TASK_NAME] = '\0';
	printf(">>> %s\n", new_task->name); // TODO debug
	new_task->hash = name_hash;
	tasks_count++;
}

void prototype() {
	
	const char* done = "# -- done -- -- -- /\n";
	
	///////////////////////////////////////////////////////////////////////////
	// Get current UTC time.
	
	fprintf(stderr, "# current UTC time --------------------------- \\\n");
	time_t x = time(NULL);
	printf("%s", ctime(&x));
	fprintf(stderr, done);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Get current day of the week.
	
	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.
	
	uint32_t tasks_count = 3;
	task_t* tasks = calloc(SIZEOF_TASK_T, 3);
	
	task_t tmp[3] = {
		{
			.name = "TASK-00 : Sample task name.",
			.time = { 3,2,1,0,1,2,3 },
			.hash = hash_string("TASK-00 : Sample task name.")
		},
		{
			.name = "TASK-01 : A wild task appears",
			.time = { 1,2,3,4,5,6,7 },
			.hash = hash_string("TASK-01 : A wild task appears")
		},
		{
			.name = "BAZINGA : Not a task!",
			.time = { 11,22,33,44,55,66,77 },
			.hash = hash_string("BAZINGA : Not a task!")
		}
	};	
	memcpy(tasks, &tmp, SIZEOF_TASK_T * 3);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Store database from memory to binary file.
	
	fprintf(stderr, "# store database ------------------------------ \\\n");
	store_database(tasks, tasks_count, DB_BIN_PATH_NAME);
	fprintf(stderr, done);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Load database from binary file to memory.
	
	fprintf(stderr, "# load database ------------------------------- \\\n");
	task_t* task_load = NULL;
	uint32_t number_of_entries_load = load_database(&task_load, DB_BIN_PATH_NAME);
	
	fprintf(stderr, "loaded %" PRIu32 " entries.\n", number_of_entries_load);
	for (uint32_t idx = 0; idx < number_of_entries_load; idx++) {
		print_task(&task_load[idx]);
	}
	free(task_load);
	fprintf(stderr, done);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Export database to CSV file.
	
	fprintf(stderr, "# export to CSV ------------------------------- \\\n");
	export_database(tasks, tasks_count, DB_CSV_PATH_NAME);
	fprintf(stderr, done);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Import database from CSV file.
	
	fprintf(stderr, "# import from CSV ----------------------------- \\\n");
	task_t* task_import = NULL;
	uint32_t number_of_entries_import = import_database(&task_import, DB_CSV_PATH_NAME);
	
	fprintf(stderr, "imported %" PRIu32 " entries.\n", number_of_entries_import);
	for (uint32_t idx = 0; idx < number_of_entries_import; idx++) {
		print_task(&task_import[idx]);
	}
	free(task_import);
	fprintf(stderr, done);
	
	
	///////////////////////////////////////////////////////////////////////////
	// Release memory and exit.
	
	free(tasks);
	return;
}


void draw_table() {
	task_t asd;
}

void draw_header() {
	const char *table_headers[] = { "Task", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun", "Total" };
	const int table_headers_size = sizeof(table_headers)/sizeof(char*);
	
	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(0, 0, ACS_ULCORNER);
	for (int idx = 0; idx < table_headers_size; idx++) {
		if (idx > 0) {
			addch(ACS_TTEE);
// 			printw(" %c", ACS_PLUS);
		}
		addch(ACS_HLINE);
		printw(" %s ", table_headers[idx]);
		addch(ACS_HLINE);
		
	}
	
	int cursor_y, cursor_x;
	getyx(stdscr, cursor_y, cursor_x);
	for (int idx = cursor_x; idx < col-1; idx++) {
		addch(ACS_HLINE);
	}
	addch(ACS_URCORNER);
}

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 */
	
	printw("Row %d", row);
	
	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[]) {
	prototype();
	return 0;
	
	
	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);
    
	int rows;
	int colums;
	
	ch = KEY_RESIZE;
	do {
        switch(ch)
		{
			case KEY_RESIZE:
				erase();
				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:
				destroy_win(my_win);
				my_win = create_newwin(height, width, --starty,startx);
				break;
			
			case KEY_DOWN:
				destroy_win(my_win);
				my_win = create_newwin(height, width, ++starty,startx);
				break;	
		}
		
		draw_header();
		draw_table();
		draw_footer();
	
	} while((ch = getch()) != KEY_F(1));
	
	endwin();
	return 0;
}

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);
}