#include "node.h"
#include "platform.h"

#include <sys/param.h> // for MAXPATHLEN
#include <unistd.h> // getpagesize
#include <windows.h>


namespace node {

static char buf[MAXPATHLEN + 1];
static char *process_title = NULL;


// Does the about the same as perror(), but for windows api functions
static void _winapi_perror(const char* prefix = NULL) {
  DWORD errno = GetLastError();
  char *errmsg;

  FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                NULL, errno, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&errmsg, 0, NULL);

  // FormatMessage messages include a newline character

  if (prefix) {
    fprintf(stderr, "%s: %s", prefix, errmsg);
  } else {
    fputs(errmsg, stderr);
  }
}


char** OS::SetupArgs(int argc, char *argv[]) {
  return argv;
}


void OS::SetProcessTitle(char *title) {
  // We need to convert _title_ to UTF-16 first, because that's what windows uses internally.
  // It would be more efficient to use the UTF-16 value that we can obtain from v8,
  // but it's not accessible from here.

  // Max title length; according to the specs it should be 64K but in practice it's a little over 30000,
  // but who needs titles that long anyway?
  const int MAX_TITLE_LENGTH = 30001;

  int length;
  WCHAR *title_w;

  // Find out how big the buffer for the wide-char title must be
  length = MultiByteToWideChar(CP_UTF8, 0, title, -1, NULL, 0);
  if (!length) {
    _winapi_perror("MultiByteToWideChar");
    return;
  }

  // Convert to wide-char string
  title_w = new WCHAR[length];
  length = MultiByteToWideChar(CP_UTF8, 0, title, -1, title_w, length);
  if (!length) {
    _winapi_perror("MultiByteToWideChar");
    delete title_w;
    return;
  };

  // If the title must be truncated insert a \0 terminator there
  if (length > MAX_TITLE_LENGTH) {
    title_w[MAX_TITLE_LENGTH - 1] = *L"\0";
  }

  if (!SetConsoleTitleW(title_w)) {
    _winapi_perror("SetConsoleTitleW");
  }

  free(process_title);
  process_title = strdup(title);

  delete title_w;
}


static inline char* _getProcessTitle() {
  WCHAR *title_w;
  char *title;
  int length, length_w;

  length_w = GetConsoleTitleW(L"\0", sizeof(WCHAR));

  // If length is zero, there may be an error or the title may be empty
  if (!length_w) {
    if (GetLastError()) {
      _winapi_perror("GetConsoleTitleW");
      return NULL;
    }
    else {
      // The title is empty, so return empty string
      process_title = strdup("\0");
      return process_title;
    }
  }

  // Room for \0 terminator
  length_w++;

  title_w = new WCHAR[length_w];

  if (!GetConsoleTitleW(title_w, length_w * sizeof(WCHAR))) {
    _winapi_perror("GetConsoleTitleW");
    delete title_w;
    return NULL;
  }

  // Find out what the size of the buffer is that we need
  length = WideCharToMultiByte(CP_UTF8, 0, title_w, length_w, NULL, 0, NULL, NULL);
  if (!length) {
    _winapi_perror("WideCharToMultiByte");
    delete title_w;
    return NULL;
  }

  title = (char *) malloc(length);
  if (!title) {
    perror("malloc");
    delete title_w;
    return NULL;
  }

  // Do utf16 -> utf8 conversion here
  if (!WideCharToMultiByte(CP_UTF8, 0, title_w, -1, title, length, NULL, NULL)) {
    _winapi_perror("WideCharToMultiByte");
    delete title_w;
    free(title);
    return NULL;
  }

  delete title_w;

  return title;
}


const char* OS::GetProcessTitle(int *len) {
  // If the process_title was never read before nor explicitly set,
  // we must query it with getConsoleTitleW
  if (!process_title) {
    process_title = _getProcessTitle();
  }

  if (process_title) {
    *len = strlen(process_title);
    return process_title;
  } else {
    *len = 0;
    return NULL;
  }
}


int OS::GetMemory(size_t *rss, size_t *vsize) {
  FILE *f = fopen("/proc/self/stat", "r");
  if (!f) return -1;

  int itmp;
  char ctmp;
  size_t page_size = getpagesize();

  /* PID */
  if (fscanf(f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Exec file */
  if (fscanf (f, "%s ", buf) == 0) goto error; /* coverity[secure_coding] */
  /* State */
  if (fscanf (f, "%c ", &ctmp) == 0) goto error; /* coverity[secure_coding] */
  /* Parent process */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Process group */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Session id */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* TTY */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* TTY owner process group */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Flags */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Minor faults (no memory page) */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Minor faults, children */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Major faults (memory page faults) */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Major faults, children */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* utime */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* stime */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* utime, children */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* stime, children */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* jiffies remaining in current time slice */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* 'nice' value */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* jiffies until next timeout */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* jiffies until next SIGALRM */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* start time (jiffies since system boot) */
  if (fscanf (f, "%d ", &itmp) == 0) goto error; /* coverity[secure_coding] */

  /* Virtual memory size */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  *vsize = (size_t) itmp;

  /* Resident set size */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  *rss = (size_t) itmp * page_size;

  /* rlim */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Start of text */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* End of text */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */
  /* Start of stack */
  if (fscanf (f, "%u ", &itmp) == 0) goto error; /* coverity[secure_coding] */

  fclose (f);

  return 0;

error:
  fclose (f);
  return -1;
}


int OS::GetExecutablePath(char* buffer, size_t* size) {
  *size = readlink("/proc/self/exe", buffer, *size - 1);
  if (*size <= 0) return -1;
  buffer[*size] = '\0';
  return 0;
}

}  // namespace node