cs228/PG5/server/server.cc

// Ben Harris

// Multiplayer command-line shooter server

#include <iostream>
#include <fstream>
#include <sstream>
#include <cstdlib>
#include <string>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <fdstream/fdstream.h>
#include <poll.h>
#include <fcntl.h>
#include "server.h"

using namespace std;

ppos pos[26];
Board board;
struct pollfd fds[26];

int main(int argc, char **argv) {
    for (int r = 1; r < 26; r++) fds[r].fd = -1;
    fds[0].fd = socket(AF_INET, SOCK_STREAM, 0);
    sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(12421);
    sin.sin_addr.s_addr = INADDR_ANY;
    int b = bind(fds[0].fd, (sockaddr * ) & sin, sizeof(sockaddr_in));
    if (b < 0) {
        perror("bind");
        exit(1);
    }
    fds[0].events = POLLIN;
    listen(fds[0].fd, 26);
    string line;

    while (1) {
        if (poll(fds, 26, -1) < 0) {
            perror("poll");
            exit(1);
        }
        if (fds[0].revents & POLLIN) {
            int f = 1;
            for (; f <= 25; f++) if (fds[f].fd == -1) break;
            new_player(f);
        }
        for (int i = 1; i <= 25; i++) {
            if (fds[i].revents & POLLIN && fds[i].fd != -1) {
                if (getline(pos[i].read, line)) {
                    do_line(line, i);
                } else {
                    ostringstream msg;
                    msg << "Player " << i << "'s client disconnected";
                    kill_player(i);
                    alert(msg.str());
                }
                update();
            }
        }
    }
    return 0;
}

// METHODS  ////////////////////////////////////////////////////////////////////
void do_line(string line, int player) {
    if (line == "MOVE") { pos[player].move_forward(); }
    else if (line == "LEFT") { pos[player].turn_left(); }
    else if (line == "RIGHT") { pos[player].turn_right(); }
    else if (line == "FIRE") { shoot(player); }
    else if (line == "SCAN") { scan(player); }
    else if (line == "EXIT") {
        kill_player(player);
        ostringstream msg;
        msg << "Player " << player << " threw in the towel";
        alert(msg.str());
    } else if (line == "HELP" || line == "help") {
        pos[player].write
                << "Commands are: MOVE, LEFT, RIGHT, SCAN, FIRE, and EXIT. Kill other players. Join and leave at any time."
                << endl;
    } else { pos[player].write << "invalid command. type HELP for more info." << endl; }
    // cout << "Player " << player << " at (" << pos[player].row << ", " << pos[player].col << ") facing " << pos[player].dr << "dr and " << pos[player].dc << "dc" <<endl;
}

void new_player(int player) {
    if (player > 25) return;
    srand(time(NULL));
    ostringstream msg; // need ostringstream to concatenate int with strings
    msg << "Player " << player << " joined the game";
    alert(msg.str());
    fds[player].fd = accept(fds[0].fd, NULL, NULL);
    int i = rand() % 10, j = rand() % 10;
    while (board[i][j]) {
        i = rand() % 10;
        j = rand() % 10;
    }
    pos[player].row = i;
    pos[player].col = j;
    pos[player].dr = rand() % 3 - 1;
    pos[player].dc = pos[player].dr == 0 ? rand() % 2 ? 1 : -1 : 0;
    fds[player].events = POLLIN;
    fds[player].revents = 0;
    pos[player].read.clear();
    pos[player].read.attach(fds[player].fd);
    pos[player].write.clear();
    pos[player].write.attach(fds[player].fd);
    pos[player].write << "You are player " << player << endl;
    update();
}

void kill_player(int player) {
    pos[player].read.close();
    pos[player].write.close();
    fds[player].events = 0;
    fds[player].revents = 0;
    fds[player].fd = -1;
}

void alert(string msg) {
    for (int i = 1; i <= 25; i++) if (fds[i].fd != -1) pos[i].write << msg << endl;
}

void shoot(int player) {
    update();
    int curr;
    for (int i = 1; i <= 5; i++) {
        curr = board[(pos[player].row + i * pos[player].dr + 10) % 10][(pos[player].col + i * pos[player].dc + 10) %
                                                                       10];
        if (curr == 0) continue;
        else {
            pos[player].write << "You shot player " << curr << endl;
            pos[curr].write << "You were shot by player " << player << endl;
            ostringstream msg;
            msg << "Player " << player << " shot " << curr;
            kill_player(curr);
            alert(msg.str());
            break;
        }
    }
    update();
}

void update() {
    for (int i = 0; i < 10; i++) for (int j = 0; j < 10; j++) board[i][j] = 0;
    for (int i = 1; i <= 25; i++) {
        if (fds[i].fd == -1) continue;
        if (!board[pos[i].row][pos[i].col]) {
            board[pos[i].row][pos[i].col] = i;
        } else {
            int other_player = board[pos[i].row][pos[i].col];
            ostringstream msg;
            msg << "Players " << i << " and " << other_player << " died in a collision";
            pos[i].write << "You died in a collision with player " << other_player << endl;
            kill_player(i);
            pos[other_player].write << "You died in a collision with player " << i << endl;
            kill_player(other_player);
            alert(msg.str());
        }
    }
    // for(int i = 0 ; i < 10; i++){ // debug
    //   for(int j = 0; j < 10; j++)
    //     cout << board[i][j] << " ";
    //   cout << endl;
    // }
}

void scan(int player) {
    update();
    pos[player].write << "printscan" << endl;
    for (int i = 5; i >= 1; i--) {
        for (int j = 2; j >= -2; j--)
            pos[player].write << board[(pos[player].row - j * pos[player].dc + i * pos[player].dr + 10) % 10][
                    (pos[player].col + i * pos[player].dc + j * pos[player].dr + 10) % 10] << " ";
        pos[player].write << "\n_ _ _ _ _\n";
    }
    pos[player].write.flush();
}