#include <iostream>
#include <unistd.h> // pipe, fork.
#include <stdio.h>  // perror
#include <cstdlib>
#include <fstream>

using namespace std;

void DoParent(int readfd, int writefd);
void DoChild(int readfd, int writefd);
string EightBall();

const char EOM = '\n';

int main() {
    int pipe1[2];
    int pipe2[2];
    pid_t pid;
    string message;

    if(-1 == pipe(pipe1)) {
        perror("Pipe1 failed");
	exit(-1);
    }

    if(-1 == pipe(pipe2)) {
        perror("Pipe2 failed");
	exit(-1);
    }

    pid = fork();
    if (-1 == pid) {
        perror("Fork Faild");
        exit(-1);
    }
 
    // in this case, the parent will send messages to the child.
    if (pid) {
        // parent, writer
	close(pipe1[0]);
	close(pipe2[1]);

	DoParent(pipe2[0], pipe1[1]);

    } else {
        // child
	close(pipe1[1]);
	close(pipe2[0]);

	DoChild(pipe1[0], pipe2[1]);

    }

    return 0;
}

void DoParent(int readfd, int writefd){
    string question, answer;
    char letter;

    while (question != "EXIT") {
        // get a question from the user
	cout << "Enter a question for the 8-ball => ";
        getline(cin, question);
	cout << endl;


        // send the question to the child
        write(writefd, question.c_str(), question.size());	
	write(writefd, &EOM, 1);

        // read the answer from the child
	if (question != "EXIT") {
	    answer = "";
	    do {
	        read(readfd, &letter, 1);
	        if (letter != EOM) {
	            answer += letter;
	        }
	    } while (letter != EOM);

            // write the answer to the user
	    cout << "The 8-ball answers \"" << answer << '"' << endl;
	}
    }

    return;
}

void DoChild(int readfd, int writefd){
    string question, answer;
    char letter =' ';
    srand(time(NULL));
    ofstream logFile;

    logFile.open("EightBall.log");

    while (question != "EXIT") {
       // read the question
       question = "";

       read(readfd, &letter, 1);
       while (letter != EOM) {
           question += letter;
           read(readfd, &letter, 1);
       }

       if (question != "EXIT") {
           // generate the answer
	   answer = EightBall();

           // send the answer
	   write(writefd,answer.c_str(), answer.size());
	   write(writefd, &EOM, 1);

           // log the question and the answer.
	   logFile << question << endl;
	   logFile << answer << endl;
	   logFile << endl;
       }
    }

    logFile.close();
    return ;
}

string EightBall() {
    int answer = rand() % 20;

    switch(answer) {
	case 0: return "It is certain.";
	case 1: return "It is decidedly so.";
	case 2: return "Without a doubt.";
	case 3: return "Yes, definitely.";
	case 4: return "You may rely on it.";
	case 5: return "As I see it, yes.";
	case 6: return "Most likely.";
	case 7: return "Outlook good.";
	case 8: return "Yes.";
	case 9: return "Signs point to yes.";
	case 10: return "Reply hazy try again.";
	case 11: return "Ask again later.";
	case 12: return "Better not tell you now.";
	case 13: return "Cannot predict now.";
	case 14: return "Concentrate and ask again.";
	case 15: return "Don't count on it.";
	case 16: return "My reply is no.";
	case 17: return "My sources say no.";
	case 18: return "Outlook not so good.";
	case 19: return "Very doubtful.";
    }
    return "Program error, conuslt your systems administrator!";
}