#include <stdio.h>
#include <stdlib.h>
#include "sqlite3.h"
#include "x_string.h"
#include "x_curses.h"

#define SQLQUERY_MAX 100
#define ARG_MAX 100
#define TODAY_COL_START -1
#define BACKLOG_COL_START 33
#define BLOCKED_COL_START 66
#define FIXED_WIDTH 19

int checksqlerr(int rc, char *errmsg){
	if( rc!=SQLITE_OK ){
		fprintf(stderr, "rc =  %d\n", rc);
		fprintf(stderr, "SQL error: %s\n", errmsg);
		sqlite3_free(errmsg);
		return -1;
	}
	return 0;
}


int opendb(sqlite3 **db, char* filename){
	int rc = 0;

	rc = sqlite3_open(filename, db);

	if ( rc != 0 ){
		fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(*db));
		sqlite3_close(*db);
		return(rc);
	}

	return(rc);
}

// FOR DEBUG
int callback(void *NotUsed, int argc, char **argv, char **azColName){
	int i;
	for(i=0; i<argc; i++){
		printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
	}
	printf("\n");
	return 0;
}

// FOR DEBUG
int view_all(sqlite3 *db){
	int rc = 0;
	char* errmsg;

	//rc = sqlite3_exec(db, "SELECT * FROM all_info;", print_select, 0, &errmsg);
	rc = sqlite3_exec(db, "SELECT * FROM tasks;", callback, 0, &errmsg);
	//rc = sqlite3_exec(db, "SELECT * FROM entries;", print_select, 0, &errmsg);
	checksqlerr(rc, errmsg);
	return rc;
}

// Print Heading TODO: obvi make this better
void display_heading(){
	printf("\n");
	printf("%s          Today               %s", X_BOLD, X_RST);
	printf("   %s        Backlog                 %s", X_BOLD, X_RST);
	printf("   %s       Blocked                %s", X_BOLD, X_RST);
	printf("\n");

	printf("%s%stitle              due date   %s", X_BOLD, X_UNDL, X_RST);
	printf("   %s%stitle              due date   %s", X_BOLD, X_UNDL, X_RST);
	printf("   %s%stitle              due date   %s", X_BOLD, X_UNDL, X_RST);
	printf("\n");
}

int gen_sql_insert_stmt(sqlite3 *db, sqlite3_stmt** out_stmt, char* table, char* colnames, char* values){
	char sql_query[SQLQUERY_MAX];
	int rc = 0;

	snprintf(sql_query, SQLQUERY_MAX, "INSERT INTO %s %s VALUES %s", table, colnames, values);
	rc = sqlite3_prepare_v2(db, sql_query, -1, out_stmt, NULL);
	if (checksqlerr(rc, "prepare broken in gen_sql_insert_stmt")){
		return -1;
	}
}

// Generate the sql statement by giving the columns, table, and current task list wanted
int gen_sql_select_stmt(sqlite3 *db, sqlite3_stmt** out_stmt, char* colnames, char* table, char* status){
	char sql_query[SQLQUERY_MAX];
	int rc = 0;

	snprintf(sql_query, SQLQUERY_MAX, "SELECT %s FROM %s WHERE status='%s'", colnames, table, status);
	rc = sqlite3_prepare_v2(db, sql_query, -1, out_stmt, NULL);
	if (checksqlerr(rc, "prepare broken in gen_sql_select_stmt")){
		return -1;
	}

	return 0;
}

// Get number of tasks from tasks table give status
int get_num_rows(sqlite3 *db, char* table, char* status){
	sqlite3_stmt *out_stmt;
	int rc = 0;
	char *col_name = "COUNT(*)";

	if ( gen_sql_select_stmt(db, &out_stmt, col_name, table, status) == 1 ){
		return -1;
	}

	while ( rc = sqlite3_step(out_stmt) == SQLITE_ROW ){
		return sqlite3_column_int(out_stmt, 0);
	}

	return -1;
}

// Print with FIXED_WIDTH
int print_fixed_width(const unsigned char* str){
	if (str){
		printf("%-*.*s", FIXED_WIDTH, FIXED_WIDTH, str);
	}else{
		printf("%-*.*s", FIXED_WIDTH, FIXED_WIDTH, "");
	}
}


int display_task_list(int start_col, sqlite3 *db, char* colnames, char* table, char* status){
	static int max_rows = -1;
	int rc = 0;
	int i = 0;
	int num_rows = -1;
	int num_cols = 0;
	char* errmsg;
	const unsigned char* col_val;
	sqlite3_stmt* out_stmt;

	// Start col for the current task list
	X_goright(start_col);

	// Get the number of rows in current task list
	num_rows = get_num_rows(db, table, status);
	// Then keep track of the furthest down we go
	if (num_rows > max_rows){
		max_rows = num_rows;
	}

	// Generate the sql statement by giving the columns, table, and current task list wanted
	if ( gen_sql_select_stmt(db, &out_stmt, colnames, table, status) ){
		return -1;
	}

	// TODO: prob should be a func begin
	// while there is still rows available
	while ( rc = sqlite3_step(out_stmt) == SQLITE_ROW ){
		// for each column print the column
		num_cols = sqlite3_column_count(out_stmt); 
		for (i = 0; i < num_cols; i++){
			col_val = sqlite3_column_text(out_stmt, i);
			print_fixed_width(col_val);
		}
		// move down one and over to the start of the current task column
		printf("\n");
	// end
		X_goright(start_col);
	}

	// if while loop broke and rc returned an error
	if ( rc == SQLITE_ERROR ){
		X_godown(max_rows);
		checksqlerr(rc, "step broken in display_task_list");
		return -1;
	}

	// Once the task list is completely printed
	// reset to the top of the task lists
	if (num_rows > 0){
		X_goup(num_rows);
	}

	// if it is the last task list move down one past the longest list
	if ( status == "blocked"){
		X_godown(max_rows);
	}
	return 0;
}

// pass in the args and return the title and due date
// due date passed as NULL if for delete
// TODO input validation for strings implement in strings!
int parse_args(int argc, char** argv, char** title, char** due_date){
	if ( argc > 1 ){
		*title = argv[2];
	}

	if ( argc > 2 ){
		*due_date = argv[3];
	}

}

// TODO: the way this ensures that we are only passing in
//       valid inputs is stupid and ugly FIX
int add_task(sqlite3 *db, int argc, char** argv){
	int rc = 0;
	char* table = "tasks";
	char* title;
	char* due_date;
	char* colnames = "(title, due_date)";
	char values[100];
	sqlite3_stmt* out_stmt;

	parse_args(argc, argv, &title, &due_date);

	if ( due_date != NULL ){
		snprintf(values, 100, "('%s', '%s')", title, due_date);
	}else{
		colnames = "(title)";
		snprintf(values, 100, "('%s')", title);
	}

	if ( gen_sql_insert_stmt(db, &out_stmt, table, colnames, values) ){
		return -1;
	}
	if ( ( rc = sqlite3_step(out_stmt) ) == SQLITE_DONE){
		return 0;
	}

	checksqlerr(rc, "broken in add_task");
	return 1;
}

// Print kanban table
// All lists with task name and due date
int view(sqlite3 *db){
	char* table = "tasks";
	char* status = "today";
	char* colnames = "title,due_date";
	
	// Print Heading
	display_heading();

	// Print "today" tasks
	if ( display_task_list(TODAY_COL_START, db, colnames, table, status) ){
		return -1;
	}

	// Print "backlog" tasks
	status = "backlog";
	if ( display_task_list(BACKLOG_COL_START, db, colnames, table, status) ){
		return -1;
	}

	// Print "blocked" tasks
	status = "blocked";
	if ( display_task_list(BLOCKED_COL_START, db, colnames, table, status) ){
		return -1;
	}

	return 0;
}

int main( int argc, char **argv ){
	sqlite3 *db;
	int rc = 0;
	char* home_dir = getenv("HOME");
	char* filename = x_strconcat(home_dir, DB_PATH);

	rc = opendb(&db, filename);
	if ( argv[1] ){
		if (argv[1][0] == 'b'){
			rc = view(db);
		}
		else if ( argv[1][0] == 'a'){
			rc = add_task(db,argc,argv);
		}
		else if ( argv[1][0] == 'v'){
			rc = view_all(db);
		}
	}
	else{
		rc = view(db);
	}

	sqlite3_close(db);


	return 0;
}