/*
Copyright 2014 Grady Moran

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <ncurses.h> //http://ftp.gnu.org/pub/gnu/ncurses/ncurses-5.9.tar.gz
//#include <unistd.h>
     
#define SIDELEN 7 //SIDELEN * SIDELEN sized board
#define DELAY 3 //tenths of seconds, higher is easier
    
typedef struct _coord{
        int x, y;
} coord;
     
void placeFood(int board[SIDELEN][SIDELEN]);
void makeChanges(char dir, int * snakelen, coord * head, int board[SIDELEN][SIDELEN]); //maybe make this return a boolean/char to indicate when the game is over
void displayBoard(int board[SIDELEN][SIDELEN]);
char getInput(char dir); //if no valid input (wasd) is pressed after DELAY tenths of seconds, dir is returned.
     
int main()
{
        int board[SIDELEN][SIDELEN]; //board is a 2D array of ints with 0 for nothing, a positive int for part of the snake, and -1 for a food thing
        int i, j;
        for (i = 0; i < SIDELEN; i++){
                for (j = 0; j < SIDELEN; j++){
                        board[i][j] = 0;
                }
        }
        int snakelen;
        snakelen = 1;
        char dir = 'w';
        coord head;
        head.x = SIDELEN/2;
        head.y = SIDELEN/2;
        board[head.y][head.x] = snakelen;
              //ncurses intialization stuff  
        initscr();
        noecho();
        placeFood(board);
        displayBoard(board);
     
        while(1){//while the game is running
                dir = getInput(dir);
                makeChanges(dir, &snakelen, &head, board);
                displayBoard(board);
        }
        endwin();
}    
void placeFood(int board[SIDELEN][SIDELEN])
{
        srandom(time(NULL));
        coord my_try;
        my_try.x = random() % SIDELEN;
        my_try.y = random() % SIDELEN;
        while (board[my_try.y][my_try.x] != 0){ //placing the food on the snake
                my_try.x = random() % SIDELEN;
                my_try.y = random() % SIDELEN; 
        }
        board[my_try.y][my_try.x] = -1;
}
 
void makeChanges(char dir, int * snakelen, coord * head, int board[SIDELEN][SIDELEN])
{
        int i, j, emptyspots = 0;
        //win
        for (i = 0; i < SIDELEN; i++){
                for (j = 0; j < SIDELEN; j++){
                        if (board[j][i] == 0) emptyspots++;
                }
        }
        if (emptyspots == 0){
                clear();
                printw("You win! Get a life!");
                refresh();
                flushinp();
                getch();
                endwin();
                exit(0);
        }
 
        switch (dir){ //change variables to represent moves
                case 'a':
                        if (head->y != 0) head->y--;
                        else head->y = SIDELEN -1;//the elses are when it is at the edge and needs to wrap around the other side of the screen
                        break;
                case 'd':
                        if (head->y < SIDELEN-1) head->y++;
                        else head->y = 0;
                        break;
                case 's':
                        if (head->x < SIDELEN-1) head->x++;
                        else head->x = 0;
                        break;
                case 'w':
                        if (head->x != 0) head->x--;
                        else head->x = SIDELEN -1;
                        break;
        }
        if (board[head->y][head->x] == 0 || board[head->y][head->x] == 1){ //move normally
                board[head->y][head->x] = *snakelen + 1;
        } else if (board[head->y][head->x] < 0){ //gets the food
                *snakelen+=1;
                board[head->y][head->x] = *snakelen;
                int i, j;
                for (i = 0; i < SIDELEN; i++){
                       for (j = 0; j < SIDELEN; j++){
                               if (board[i][j] >= 1) board [i][j]++;
                        }
                }
                placeFood(board);
        } else { //lose
                clear();
                printw("You lose! Ha ha!");
                refresh();
               
                getch();
                endwin();
                exit(0);
        }
 
        //making the changes
        for (i = 0; i < SIDELEN; i++){
                for (j = 0; j < SIDELEN; j++){
                        if (board[i][j] >= 1) board [i][j]--;
                }
        }
}
 
void displayBoard(int board[SIDELEN][SIDELEN])
{
        clear();
        char snake[] = "[#] ";
        char food[] = "[X] ";
        char nothing[] = "[ ] ";
        int i,j;
        char thisline[SIDELEN * 4];
        for (i = 0; i < SIDELEN; i++){
                strcpy(thisline, "");
                for (j = 0; j < SIDELEN; j++){
                        if (board[j][i] > 0){
                                strcat(thisline, snake);
                        } if (board[j][i] < 0){
                                strcat(thisline, food);
                        } if (board[j][i] == 0){
                                strcat(thisline, nothing);             
                        }
                }
                printw("%s\n", thisline);
        }
        refresh();
}
 
char getInput(char dir)
{
           
        flushinp();
        halfdelay(DELAY);
       
        struct timeval t1, t2;
        gettimeofday(&t1, NULL);
        char x = getch();
        gettimeofday(&t2, NULL);
        cbreak();
	flushinp();
  
        unsigned long long elapsed = 1000 * (t2.tv_sec - t1.tv_sec) + (t2.tv_usec - t1.tv_usec) / 1000;
        long leftOverDelay = (long) (DELAY * 100 - elapsed)*1000000;
        //convert seconds to nanoseconds and make sure seconds is actually in long form
    
        struct timespec t;
        t.tv_sec = 0;
        t.tv_nsec = leftOverDelay;
        nanosleep(&t, NULL);
   
        if (x == 'w' || x == 'a' || x == 's' || x == 'd') return x;
        return dir;
}