/* Copyright 2005 alexeyt at freeshell dot org
 * released under GPL version 2.0 or later
 * A simplistic ASCII-art aquarium. Build with:
 * cc -o aquarium aquarium.c -lcurses
 * You can give the number of fish as an argument. Have fun.
 */


#include <curses.h>
#include <signal.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

struct fish {
	int x;
	int y;
	int color;
	int right;
};

void finish ( int sig ) {
	endwin();
	exit ( sig );
}

void spawn ( struct fish *f ) {
	f->y = random() % LINES;
	f->color = random() % 7 + 1;
	if ( random() % 2 ) {
		f->right = 1;
		f->x = -1;
	} else {
		f->right = 0;
		f->x = COLS;
	}
}

void swim ( struct fish *f ) {
	int x;

	attrset ( COLOR_PAIR ( f->color ) | A_BOLD );
	if ( f->right ) {
		if ( ++f->x > COLS ) {
			move ( f->y, COLS - 1 );
			addch ( ' ' );
			spawn ( f );
		}
		x = ( f->x - 2 );
		if ( x >= 0 ) {
			move ( f->y, x );
			addch ( ' ' );
		}
		x++;
		if ( x >= 0 ) {
			if ( !x ) move ( f->y, 0 );
			addch ( '>' );
		}
		x++;
		if ( ( x >= 0 ) && ( x < COLS ) ) {
			if ( !x ) move ( f->y, 0 );
			addch ( '<' );
		}
		x++;
		if ( x < COLS ) {
			if ( !x ) move ( f->y, 0 );
			addch ( '>' );
		}
	} else {
		if ( f->x-- < 0 ) {
			move ( f->y, 0 );
			addch ( ' ' );
			spawn ( f );
		}
		x = ( f->x - 1 );
		if ( x >= 0 ) {
			move ( f->y, x );
			addch ( '<' );
		}
		x++;
		if ( ( x >= 0 ) && ( x < COLS ) ) {
			if ( !x ) move ( f->y, 0 );
			addch ( '>' );
		}
		x++;
		if ( x < COLS ) {
			if ( !x ) move ( f->y, 0 );
			addch ( '<' );
		}
		x++;
		if ( x < COLS ) addch ( ' ' );
	}
	move ( 0, 0 );
	refresh();
}

void curses_init() {
	initscr();
	noecho();
 	nonl();
	cbreak();
	intrflush ( stdscr, 0 );
	keypad ( stdscr, 0 );

	start_color();
	if ( has_colors() && ( COLOR_PAIRS > 7 ) ) {
		init_pair ( 1, COLOR_GREEN, COLOR_BLACK );
		init_pair ( 2, COLOR_RED, COLOR_BLACK );
		init_pair ( 3, COLOR_YELLOW, COLOR_BLACK );
		init_pair ( 4, COLOR_BLUE, COLOR_BLACK );
		init_pair ( 5, COLOR_MAGENTA, COLOR_BLACK );
		init_pair ( 6, COLOR_CYAN, COLOR_BLACK );
		init_pair ( 7, COLOR_WHITE, COLOR_BLACK );
		bkgd ( COLOR_PAIR(7) );
	} else {
		endwin();
		exit ( 1 );
	}
}

int main ( int argc, char **argv ) {
	int nfish, i;
	struct fish *school;

	if ( ( argc < 2 ) || ( ( nfish = atoi ( argv[1] ) ) <= 0 ) )
		nfish = 10;

	if ( ! ( school = calloc ( nfish, sizeof ( struct fish ) ) ) )
		exit ( 1 );

	srandom ( time ( 0 ) );
	signal ( SIGINT, finish );

	curses_init();

	for ( i = 0; i < nfish; i++ ) {
		spawn ( &( school[i] ) );
		school[i].x = random() % COLS;
	}

	while ( 1 ) {
		for ( i = 0; i < nfish; i++ )
			swim ( &( school[i] ) );
		usleep ( 100000 );
	}

	endwin();
	exit ( 0 );
}