#include "server.hpp"

#define MAX_CONCURRENCY_LIMIT 40000 // overkill
#define POLL_TIMEOUT 1000           // Milliseconds
#define S2C_SERVICE_FREQ 1.0        // Seconds
#define USER_DATABASE "userDB"
#define FILE_DATABASE "fileDB"
#define FILES_DIR "files"

int nConns; // total # of data sockets
struct pollfd
    peers[MAX_CONCURRENCY_LIMIT + 1]; // sockets to be monitored by poll()
struct CONN_STAT
    connStat[MAX_CONCURRENCY_LIMIT + 1]; // app-layer stats of the sockets
BYTE *buf[MAX_CONCURRENCY_LIMIT + 1];

// Duplicate exists in server and client
void RemoveConnection(int i) {
  close(peers[i].fd);
  if (i < nConns) {
    memmove(peers + i, peers + i + 1, (nConns - i) * sizeof(struct pollfd));
    memmove(connStat + i, connStat + i + 1,
            (nConns - i) * sizeof(struct CONN_STAT));
    free(buf[i]);
    memmove(buf + i, buf + i + 1, (nConns - i) * sizeof(BYTE *));
  }
  nConns--;
  Log("[%s] %d active connections after removal", NAME, nConns);
}

void DoServer(int port) {
  int maxConcurrency = 20; // TODO: Change this to be a #define
  int listenFD = socket(AF_INET, SOCK_STREAM, 0);
  if (listenFD < 0) {
    Error("[%s] Cannot create listening socket.", NAME);
  }
  SetNonBlockIO(listenFD);

  struct sockaddr_in serverAddr;
  memset(&serverAddr, 0, sizeof(struct sockaddr_in));
  serverAddr.sin_family = AF_INET;
  serverAddr.sin_port = htons((unsigned short)port);
  serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);

  int optval = 1;
  int r =
      setsockopt(listenFD, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
  if (r != 0) {
    Error("[%s] Cannot enable SO_REUSEADDR option.", NAME);
  }

  signal(SIGPIPE, SIG_IGN);

  if (bind(listenFD, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) != 0) {
    Error("[%s] Cannot bind to port %d.", NAME, port);
  }

  if (listen(listenFD, 16) != 0) {
    Error("[%s] Cannot listen to port %d.", NAME, port);
  }

  Log("[%s] Listening at 127.0.0.1:%d", NAME, port);

  nConns = 0;
  memset(peers, 0, sizeof(peers));
  peers[0].fd = listenFD;
  peers[0].events = POLLRDNORM;
  memset(connStat, 0, sizeof(connStat));

  int connID = 0;
  while (1) {
    // monitor the listening sock and data socks, nConn+1 in total
    int nReady = poll(peers, nConns + 1, POLL_TIMEOUT);
    if (nReady < 0) {
      Error("[%s] Invalid poll() return value.", NAME);
    }

    struct sockaddr_in clientAddr;
    socklen_t clientAddrLen = sizeof(clientAddr);

    struct timeb currentTime;
    ftime(&currentTime);

    // new incoming connection
    if ((peers[0].revents & POLLRDNORM) && (nConns < maxConcurrency)) {
      int fd = accept(listenFD, (struct sockaddr *)&clientAddr, &clientAddrLen);
      if (fd != -1) {
        SetNonBlockIO(fd);
        nConns++;
        Log("[%s] Accepted connection %d", NAME, nConns);
        peers[nConns].fd = fd;
        peers[nConns].events = POLLRDNORM;
        peers[nConns].revents = 0;

        memset(&connStat[nConns], 0, sizeof(struct CONN_STAT));
        ftime(&connStat[nConns].lastTime);
        connStat[nConns].recInitHeader =
            false; // waiting to recieve initial header
        connStat[nConns].expectingHeader =
            true; // message to be read is a header
        connStat[nConns].nToDo = HEADER_LEN;

        buf[nConns] = (BYTE *)malloc(BUF_LEN);
        memset(buf[nConns], 0, BUF_LEN);
      }

      if (--nReady <= 0)
        continue;
    }

    for (int i = 1; i <= nConns; i++) {
      // Log("nConns: %d peers[%d].revents: %02X (POLLRDNORM %02X, POLLWRNORM
      // %02X, POLLERR %02X, POLLHUP %02X)", nConns, i, peers[i].revents,
      // POLLRDNORM, POLLWRNORM, POLLERR, POLLHUP);
      double timeDiff =
          (currentTime.time + currentTime.millitm / (double)1000.0f) -
          (connStat[i].lastTime.time +
           connStat[i].lastTime.millitm / (double)1000.0f);

      if (peers[i].revents &
          (POLLRDNORM | POLLERR |
           POLLHUP)) { // TODO: break out POLLERR and POLLHUP?
        // Log("Servicing connection %d, POLLHUP: %d", i, peers[i].revents &
        // POLLHUP);
        //  Process initial communication
        if (connStat[i].recInitHeader == false) {
          if (Recv_NonBlocking(peers[i].fd, buf[i], &connStat[i], &peers[i]) <
              0) {
            Log("[%s] Line %d: Removing connection %d", NAME, __LINE__, i);
            RemoveConnection(i);
            goto NEXT_CONNECTION;
          }

          if (connStat[i].nToDo == 0) {
            Header header;
            header.decode(buf[i]);
            // Log("Initial communication for connection %d:", i);

            if (!((header.m_command == CONNECT) | (header.m_command == SENDF) |
                  (header.m_command == SENDF2) | (header.m_command == GETF))) {
              Log("[%s] WARN: Unexpected initial connection command %s", NAME,
                  com2str(header.m_command));
            }

            connStat[i].recInitHeader = true;
            connStat[i].expectingHeader =
                true; // flag needed for processing below
            if (processReception(i) != 0) {
              Log("[%s] Line %d: Removing connection %d", NAME, __LINE__, i);
              RemoveConnection(i);
              goto NEXT_CONNECTION;
            }
          }
        }      // End initial communication
        else { // Standard polling recieve
          // Log("Standard polling recieve/send: connStat[i].direction: %02X",
          // connStat[i].direction);
          if (connStat[i].direction == C2S) {
            if (Recv_NonBlocking(peers[i].fd, buf[i], &connStat[i], &peers[i]) <
                0) {
              Log("[%s] Line %d: Removing connection %d", NAME, __LINE__, i);
              RemoveConnection(i);
              goto NEXT_CONNECTION;
            }

            if (connStat[i].nToDo == 0) {
              if (processReception(i) != 0) {
                Log("[%s] Line %d: Removing connection %d", NAME, __LINE__, i);
                RemoveConnection(i);
                goto NEXT_CONNECTION;
              }
            }
          } // end C2S
        }   // End standard recieve
      }     // if POLLRDNORM

      // a data socket is writable
      if (peers[i].revents & POLLWRNORM) {
        // Log("Sending nonblocking!");
        if (Send_NonBlocking(peers[i].fd, buf[i], &connStat[i], &peers[i]) <
            0) {
          Log("[%s] Line %d: Removing connection %d", NAME, __LINE__, i);
          RemoveConnection(i);
          goto NEXT_CONNECTION;
        }
      }

      // a s2c connection hasn't been used in a while? Check that the client is
      // still there with a ping
      if ((connStat[i].direction == S2C) && (timeDiff > S2C_SERVICE_FREQ) &&
          (connStat[i].nToDo == 0) && (connStat[i].messageLen == 0) &&
          (connStat[i].nBuffered == 0)) {
        // Log("[%s] Pinging [%s] on connection %d due to timeout", SERVER_NAME,
        // connStat[i].name, i);
        Header header;
        header.setFlags(S2C, SUCCESS, PRIV, SIGN);
        memcpy(header.m_name, NAME, MAX_USERNAME_LEN);
        header.m_command = PING;
        header.m_size = 0;

        header.encode(&buf[i][connStat[i].messageLen]);
        connStat[i].nBuffered = HEADER_LEN + header.m_size;
        connStat[i].messageLen = HEADER_LEN + header.m_size;
        connStat[i].nToDo = HEADER_LEN + header.m_size;

        peers[i].events |= POLLWRNORM;
      }

    NEXT_CONNECTION:
      asm("nop");
      // if (--nReady <= 0) break;
    } // for
  }   // while
} // do_server

// buf has all buffers
// Stat has all stat structs
// i is the index of the link being processed
int processReception(int i) {
  Header header;
  header.decode(buf[i]);
  // header.displayContents(true);

  if (connStat[i]
          .expectingHeader) { // Expecting a header read sequence was completed
    // Log("\nProcessing header reception. header.m_size: %d", header.m_size);
    if (header.m_size > 0) {
      connStat[i].expectingHeader = false;
      connStat[i].nToDo = header.m_size;
    } else if (header.m_size == 0) {
      // printServerCommand(i);
      doServerCommand(i);
      connStat[i].expectingHeader = true;
      connStat[i].nBuffered = 0;
      connStat[i].nToDo = HEADER_LEN;
      memset(buf[i], 0, BUF_LEN);
    } else {
      return -1; // Error, signal to caller to end connection
    }
  } else { // expecting a data read sequence was completed
    // Log("\nProcessing data reception.");
    // printServerCommand(i);
    doServerCommand(i);
    if (connStat[i].direction == C2S) { // CONNECT events for S2C can get here
      connStat[i].expectingHeader = true;
      connStat[i].nBuffered = 0;
      connStat[i].nToDo = HEADER_LEN;
      memset(buf[i], 0, BUF_LEN);
    }
  }

  if (connStat[i].shouldClose) {
    Log("[%s] Line %d: Removing connection %d due to shouldClose", NAME,
        __LINE__, i);
    RemoveConnection(i);
  }

  return 0;
}

void doServerCommand(int i) {
  // Assume the buf[i] has a message at the beginning of the buffers
  Header header;
  header.decode(buf[i]);

  struct timeb currentTime;
  ftime(&currentTime);

  char message[5000] = {0};
  char username[20] = {0};
  char password[20] = {0};
  Header outHeader;
  int numLoggedIn = 0;
  bool foundActiveUser = false;
  int s2cConnNumb = -1;
  char server_filename[5000] = {0};
  char filename[5000] = {0};
  int filenameLen, fileLen, offset, nextFileId, fileId;
  BYTE intbuf[5] = {0};
  FILE *fp;

  switch (header.m_command) {
  case CONNECT:
    buf2i(&buf[i][HEADER_LEN], connStat[i].id);
    connStat[i].direction = header.m_direction;
    connStat[i].linkType = MESSAGE_LINK;
    connStat[i].lastTime = currentTime;
    if (header.m_direction == C2S) {
      Log("[---- : %s] id: %d, direction: C2S, connection number: %d.",
          com2str(header.m_command), connStat[i].id, i);
      connStat[i].expectingHeader = true;
      connStat[i].nBuffered = 0;
      connStat[i].nToDo = HEADER_LEN;
    } else {
      Log("[---- : %s] id: %d, direction: S2C, connection number: %d.",
          com2str(header.m_command), connStat[i].id, i);
      connStat[i].nBuffered = 0;
      connStat[i].messageLen = 0;
      connStat[i].nToDo = 0;
      peers[i].events &= ~POLLRDNORM;
      peers[i].events &= ~POLLWRNORM;
    }
    memset(buf[i], 0, BUF_LEN);
    break;
  case REGISTER:
    memcpy(username, header.m_name, MAX_USERNAME_LEN);
    memcpy(password, &buf[i][HEADER_LEN], header.m_size);
    if (usernameQuery(USER_DATABASE, username) == true) {
      Log("[---- : %s] Registration failed. Username [%s] is already "
          "registered.",
          com2str(header.m_command), username);
      outHeader.setFlags(S2C, FAIL, PUB, SIGN);
      outHeader.m_command = REGISTER;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Cannot register username [");
      strncat(message, username, MAX_USERNAME_LEN);
      strcat(message, "]. Username already registered.\n");
      strcat(message,
             "\tUsernames may only contain characters a-z, A-Z, or 0-9.\n");
      strcat(message, "\tUsernames may be 4 to 8 characters long.");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    } else {
      Log("[---- : %s] Successful registration of user %s",
          com2str(header.m_command), username);
      recordEntry(USER_DATABASE, username, password);
      outHeader.setFlags(S2C, SUCCESS, PUB, SIGN);
      outHeader.m_command = REGISTER;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Successfully registered ");
      strncat(message, username, MAX_USERNAME_LEN);
      strcat(message, ".");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    }
    break;
  case LOGIN:
    memcpy(username, header.m_name, MAX_USERNAME_LEN);
    memcpy(password, &buf[i][HEADER_LEN], header.m_size);
    if (loginQuery(USER_DATABASE, username, password) == true) {
      // Check that user is not currently logged in
      for (int x = 1; x <= nConns; x++) {
        if ((connStat[x].isLoggedIn == true) &&
            (strcmp(username, connStat[x].name) == 0)) {
          Log("[%s : %s] Login failed. User is already logged in.",
              header.m_name, com2str(header.m_command));
          foundActiveUser = true;
          outHeader.setFlags(S2C, FAIL, PUB, SIGN);
          outHeader.m_command = LOGIN;
          memcpy(outHeader.m_name, NAME, strlen(NAME));
          strcat(message, "Login failed. ");
          strncat(message, username, MAX_USERNAME_LEN);
          strcat(message, " is logged in on another device.");
          outHeader.m_size = strlen(message);
          sendMessageToId(connStat[i].id, false, outHeader, message);
          break;
        }
      }

      if (!foundActiveUser) {
        for (int x = 1; x <= nConns; x++) {
          if (connStat[i].id == connStat[x].id) {
            memcpy(connStat[x].name, username, MAX_USERNAME_LEN);
            // Log("Connection %d (%s) is loggin in.", x, connStat[x].name);
            connStat[x].isLoggedIn = true;
          }
        }
        Log("[%s : %s] Successful login", connStat[i].name,
            com2str(header.m_command));
        outHeader.setFlags(S2C, SUCCESS, PUB, SIGN);
        outHeader.m_command = LOGIN;
        memcpy(outHeader.m_name, NAME, strlen(NAME));
        strcat(message, "Welcome ");
        strncat(message, username, MAX_USERNAME_LEN);
        strcat(message, ".");
        outHeader.m_size = strlen(message);
        sendMessageToId(connStat[i].id, true, outHeader, message);
      }
    } else {
      Log("[---- : %s] Login failed: %s", com2str(header.m_command), username);
      outHeader.setFlags(S2C, FAIL, PUB, SIGN);
      outHeader.m_command = LOGIN;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Login failed: Invalid username or password.");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    }
    break;
  case LOGOUT:
    if (connStat[i].isLoggedIn) {
      for (int x = 1; x <= nConns; x++) {
        if (connStat[i].id == connStat[x].id) {
          // Log("Connection %d (user %s) is logging off.", x,
          // connStat[x].name);
          connStat[x].isLoggedIn = false;
          foundActiveUser = true;
        }
      }
      Log("[%s : %s] Successful logout.", connStat[i].name,
          com2str(header.m_command));
      outHeader.setFlags(S2C, SUCCESS, PUB, SIGN);
      outHeader.m_command = LOGOUT;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Goodbye ");
      strcat(message, connStat[i].name);
      strcat(message, ".");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    } else {
      Log("[---- : %s] Failed: Connection %d is not logged in.",
          com2str(header.m_command), i);
      outHeader.setFlags(S2C, FAIL, PUB, SIGN);
      outHeader.m_command = LOGOUT;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Logout failed. You are not logged in.");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    }
    break;
  case SEND:
  case SENDA:
  case SEND2:
  case SENDA2:
    if (connStat[i].isLoggedIn) {
      outHeader.setFlags(S2C, SUCCESS, PUB, header.m_trace);
      outHeader.m_command = header.m_command;
      if (header.m_trace == SIGN)
        memcpy(outHeader.m_name, connStat[i].name, strlen(connStat[i].name));
      else
        memcpy(outHeader.m_name, ANON, strlen(ANON));
      memcpy(message, &buf[i][HEADER_LEN], header.m_size);
      outHeader.m_size = strlen(message);
      if ((header.m_command == SEND) || (header.m_command == SENDA)) {
        Log("[%s : %s] %s", connStat[i].name, com2str(header.m_command),
            message);
        sendMessageToAllLoggedIn(outHeader, message);
      } else {
        memcpy(username, header.m_name, MAX_USERNAME_LEN);
        Log("[%s : %s %s] %s", connStat[i].name, com2str(header.m_command),
            username, message);
        sendMessageToName(username, outHeader, message);
      }
    } else {
      Log("[%s : %s] Failed: Connection %d is not logged in.", connStat[i].name,
          com2str(header.m_command), i);
      outHeader.setFlags(S2C, FAIL, PUB, SIGN);
      outHeader.m_command = header.m_command;
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Users must be logged in to '");
      strcat(message, com2str(header.m_command));
      strcat(message, "'. Login with '");
      strcat(message, com2str(LOGIN));
      strcat(message, " [username] [password]'.");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    }
    break;
  case SENDF:  // Initial connection
  case SENDF2: // Initial connection
    buf2i(&buf[i][HEADER_LEN], connStat[i].id);
    // Log("This connection's id: %d", connStat[i].id);
    connStat[i].direction = header.m_direction;
    connStat[i].linkType = FILE_LINK;
    connStat[i].lastTime = currentTime;
    connStat[i].expectingHeader = true;
    connStat[i].nBuffered = 0;
    connStat[i].nToDo = HEADER_LEN;
    connStat[i].shouldClose =
        true; // flag to close this connection once it's processed

    for (int x = 1; x <= nConns; x++) {
      if ((connStat[x].direction == C2S) &&
          (connStat[x].linkType == MESSAGE_LINK) &&
          (connStat[x].id == connStat[i].id)) {
        strncat(connStat[i].name, connStat[x].name, MAX_USERNAME_LEN);
        connStat[i].isLoggedIn = connStat[x].isLoggedIn;
        foundActiveUser = true;
        s2cConnNumb = x;
        break;
      }
    }

    if (s2cConnNumb == -1) {
      Log("Unexpected state. Received %s on new connection without S2C "
          "connection for messages.",
          com2str(header.m_command));
    } else if (!connStat[i].isLoggedIn) {
      Log("[%s : %s] Failed: Connection %d is not logged in.", connStat[i].name,
          com2str(header.m_command), i);
      outHeader.setFlags(S2C, FAIL, PUB, SIGN);
      outHeader.m_command = SEND; // avoid file transfer logic on client side
      memcpy(outHeader.m_name, NAME, strlen(NAME));
      strcat(message, "Users must be logged in to '");
      strcat(message, com2str(header.m_command));
      strcat(message, "'. Login with '");
      strcat(message, com2str(LOGIN));
      strcat(message, " [username] [password]'.");
      outHeader.m_size = strlen(message);
      sendMessageToId(connStat[i].id, false, outHeader, message);
    } else {
      // Save the file
      nextFileId = getNumEntries(FILE_DATABASE);
      if (nextFileId == -1) {
        Log("Enexpected state. %s next File Id of -1.", FILE_DATABASE);
      } else {
        snprintf(server_filename, sizeof(server_filename), "%s/%d_", FILES_DIR,
                 nextFileId);
        offset = HEADER_LEN + 4;
        buf2i(&buf[i][offset], filenameLen); // first 4 bytes is client id
        offset += 4;
        memcpy(&server_filename[strlen(server_filename)], &buf[i][offset],
               filenameLen);
        memcpy(filename, &buf[i][offset], filenameLen);
        offset += filenameLen;
        buf2i(&buf[i][offset], fileLen);
        offset += 4;
        fp = fopen(FILE_DATABASE, "a");
        if (fp == NULL) {
          Log("Failed to open %s for writing.", FILE_DATABASE);
        } else {
          fputs(server_filename, fp);
          fputs("\n", fp);
          fclose(fp);
        }
        buf2file(&buf[i][offset], fileLen, server_filename);

        // Send SENDF/SENDF2 message to interested parties
        outHeader.setFlags(S2C, SUCCESS, header.m_recipient,
                           SIGN); // will update recipient as necessary
        outHeader.m_command = header.m_command;
        memcpy(outHeader.m_name, connStat[i].name, strlen(connStat[i].name));
        i2buf(nextFileId, intbuf);
        memcpy(message, intbuf, 4);
        offset = 4;
        memcpy(&message[offset], &buf[i][HEADER_LEN + 8], filenameLen);
        offset += filenameLen;
        outHeader.m_size = offset;

        if (header.m_command == SENDF) {
          Log("[%s : %s] %s", connStat[i].name, com2str(header.m_command),
              filename);
          sendMessageToAllLoggedInExceptSender(connStat[i].id, outHeader,
                                               message);
        } else {
          memcpy(username, header.m_name, MAX_USERNAME_LEN);
          Log("[%s : %s %s] %s", connStat[i].name, com2str(header.m_command),
              username, filename);
          sendMessageToName(username, outHeader, message);
        }
      }
    }
    break;
  case GETF:
    buf2i(&buf[i][HEADER_LEN], connStat[i].id);
    // header name is origional sender. Find client's name with client id
    for (int x = 1; x <= nConns; x++) {
      if ((connStat[i].id == connStat[x].id) &&
          (connStat[x].direction == C2S) &&
          (connStat[x].linkType == MESSAGE_LINK)) {
        memcpy(connStat[i].name, connStat[x].name, MAX_USERNAME_LEN);
        break;
      }
    }
    buf2i(&buf[i][HEADER_LEN + 4], fileId);
    connStat[i].direction = S2C;
    connStat[i].linkType = FILE_LINK;
    connStat[i].lastTime = currentTime;
    // no need for shouldClose. Client will close connection and periodic ping
    // will detect closure

    snprintf(server_filename, sizeof(server_filename), "%s/%d_", FILES_DIR,
             fileId);
    memcpy(&server_filename[strlen(server_filename)], &buf[i][HEADER_LEN + 8],
           header.m_size - 8);

    memcpy(filename, &buf[i][HEADER_LEN + 8], header.m_size - 8);
    filenameLen = strlen(filename);

    // Log("Getting file %s", server_filename);
    memset(buf[i], 0, BUF_LEN);

    // Check that the file exists
    fp = fopen(server_filename, "r");
    if (fp) {
      fclose(fp);
      outHeader.setFlags(S2C, SUCCESS, header.m_recipient,
                         SIGN); // will update recipient as necessary
      if (header.m_command == SENDF2)
        outHeader.m_recipient = PRIV;
      outHeader.m_command = header.m_command;
      memcpy(outHeader.m_name, header.m_name,
             MAX_USERNAME_LEN); // pass along origional sender
      offset = HEADER_LEN;
      i2buf(filenameLen, &buf[i][offset]); // encode filename length
      offset += 4;
      memcpy(&buf[i][offset], filename,
             strlen(filename)); // encode the filename
      offset += strlen(filename);
      fileLen = file2buf(server_filename, &buf[i][offset + 4]);
      i2buf(fileLen, &buf[i][offset]);
      offset += 4 + fileLen;
      outHeader.m_size = offset - HEADER_LEN;
      outHeader.encode(buf[i]);

      connStat[i].nBuffered = offset;
      connStat[i].messageLen = offset;
      connStat[i].nToDo = offset;
      peers[i].events &= ~POLLRDNORM;
      peers[i].events |= POLLWRNORM;

      Log("[%s : %s] %s", connStat[i].name, com2str(header.m_command),
          filename);
    } else {
      Log("File not found: %s", filename);
      // TODO: Send message if file is not found
    }
    break;
  case LIST:
    Log("[%s : %s]", connStat[i].name, com2str(header.m_command));
    outHeader.setFlags(S2C, SUCCESS, PUB, SIGN);
    outHeader.m_command = LIST;
    memcpy(outHeader.m_name, NAME, strlen(NAME));
    for (int x = 1; x <= nConns; x++) {
      if ((connStat[x].direction == C2S) &&
          (connStat[x].linkType == MESSAGE_LINK) && (connStat[x].isLoggedIn)) {
        numLoggedIn++;
      }
    }
    snprintf(message, sizeof(message), "%d", numLoggedIn);
    strcat(message, " user(s) currently logged in:");
    for (int x = 1; x <= nConns; x++) {
      if ((connStat[x].direction == C2S) &&
          (connStat[x].linkType == MESSAGE_LINK) && (connStat[x].isLoggedIn)) {
        strcat(message, "\n\t");
        strncat(message, connStat[x].name, MAX_USERNAME_LEN);
      }
    }
    outHeader.m_size = strlen(message);
    sendMessageToId(connStat[i].id, false, outHeader, message);
    break;
  case PING:
    // PONG
    break;
  default:
    Log("No doServerCommand() for command %s", com2str(header.m_command));
  }
}

// Send the message to every S2C with the specified id. If the reqLoggedIn
// flag is set, require that the connection is logged in.
void sendMessageToId(int id, bool reqLoggedIn, Header header, char *message) {
  for (int i = 1; i <= nConns; i++) {
    if ((connStat[i].direction == S2C) && (id == connStat[i].id)) {
      if (reqLoggedIn) {
        if (connStat[i].isLoggedIn) {
          prepareMessage(i, header, message);
        }
      } else {
        prepareMessage(i, header, message);
      }
    }
  }
}

// Send the message to every S2C which is logged in.
void sendMessageToAllLoggedIn(Header header, char *message) {
  for (int i = 1; i <= nConns; i++) {
    if ((connStat[i].direction == S2C) && connStat[i].isLoggedIn) {
      prepareMessage(i, header, message);
    }
  }
}

// Send the message to every s2cConnNumb
void sendMessageToAllLoggedInExceptSender(int senderID, Header header,
                                          char *message) {
  for (int i = 1; i <= nConns; i++) {
    if ((connStat[i].direction == S2C) && connStat[i].isLoggedIn &&
        (connStat[i].id != senderID)) {
      prepareMessage(i, header, message);
    }
  }
}

// Send the message to all loged in users with the specified name.
void sendMessageToName(char *name, Header header, char *message) {
  for (int i = 1; i <= nConns; i++) {
    if ((connStat[i].direction == S2C) && connStat[i].isLoggedIn &&
        (strcmp(name, connStat[i].name) == 0)) {
      prepareMessage(i, header, message);
    }
  }
}

// Load a message into a connection
void prepareMessage(int i, Header header, char *message) {
  if (connStat[i].direction == S2C) {
    int offset = connStat[i].nBuffered;

    // Log("Preparing message for connection %d", i);
    // header.displayContents(true);
    // Log("Message: |%s|", message);
    // Log("offset: %d, nBuffered: %d, nToDo: %d: messageLen: %d", offset,
    // connStat[i].nBuffered, connStat[i].nToDo, connStat[i].messageLen);

    header.encode(&buf[i][offset]);
    memcpy(&buf[i][offset + HEADER_LEN], message, header.m_size);

    connStat[i].nBuffered += HEADER_LEN + header.m_size;
    if (connStat[i].nToDo == 0) {
      connStat[i].messageLen = HEADER_LEN + header.m_size;
      connStat[i].nToDo = HEADER_LEN + header.m_size;
    }

    peers[i].events |= POLLWRNORM;
  } else {
    Log("[%s] WARN: attempted to write to C2S connection %d", NAME, i);
  }
}

void printServerCommand(int i) {
  Header h;
  h.decode(buf[i]);

  Log("[%s]: [%s, %s, %s, %s] [%s]  [%s]  [%d]", connStat[i].name,
      !h.m_direction ? "C2S" : "S2C", !h.m_flag ? "SUCCESS" : "FAIL",
      !h.m_recipient ? "PUB" : "PRIV", !h.m_trace ? "SIGN" : "ANNON",
      com2str(h.m_command), h.m_name, h.m_size);

  if (h.m_size > 0)
    Log("\tData: [%s]", buf[i] + HEADER_LEN);
}

int main(int argc, char **argv) {
  if (argc != 2) {
    Log("Usage: %s reset", argv[0]);
    Log("Usage: %s [server Port]", argv[0]);
    return -1;
  }

  if (strcmp("reset", argv[1]) == 0) {
    Log("Clearing databases");
    if (remove(USER_DATABASE) != 0)
      Error("Error deleting %s", USER_DATABASE);
    if (remove(FILE_DATABASE) != 0)
      Error("Error deleting %s", FILE_DATABASE);
    exit(EXIT_SUCCESS);
  }

  // Make directory if it doesn't exist
  struct stat s;

  if (stat("files", &s) != 0) {
    if (mkdir("files", S_IRWXU | S_IRWXG | S_IRWXO) != 0) {
      perror("mkdir");
      return -1;
    }
  }

  int port = atoi(argv[1]);
  DoServer(port);

  return 0;
}