// copyright 2012–2020 nick black
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/swap.h>

#include "swap.h"
#include "popen.h"
#include "growlight.h"

int mkswap(device *d){
  if(d->mnttype && strcmp(d->mnttype, "swap")){
    diag("Won't create swap on %s filesystem at %s\n",
        d->mnttype, d->name);
    return -1;
  }
  if(d->swapprio >= SWAP_MAXPRIO){
    diag("Already swapping on %s\n", d->name);
    return -1;
  }
  if(vspopen_drain("mkswap -L SprezzaSwap /dev/%s", d->name)){
    return -1;
  }
  return 0;
}

// Create swap on the device, and use it
int swapondev(device *d){
  char fn[PATH_MAX], *mt;

  if(mkswap(d)){
    return -1;
  }
  snprintf(fn, sizeof(fn), "/dev/%s", d->name);
  if((mt = strdup("swap")) == NULL){
    return -1;
  }
  if(swapon(fn, 0)){
    diag("Couldn't swap on %s (%s?)\n", fn, strerror(errno));
    free(mt);
    return -1;
  }
  free(d->mnttype);
  d->mnttype = mt;
  d->swapprio = SWAP_MAXPRIO; // FIXME take as param
  return 0;
}

// Deactive the swap on this partition (if applicable)
int swapoffdev(device *d){
  char fn[PATH_MAX];

  snprintf(fn, sizeof(fn), "/dev/%s", d->name);
  if(swapoff(fn)){
    diag("Couldn't stop swapping on %s (%s?)\n", fn, strerror(errno));
    return -1;
  }
  d->swapprio = SWAP_INACTIVE;
  return 0;
}

// Parse /proc/swaps to detect active swap devices
int parse_swaps(const glightui *gui, const char *name){
  char buf[BUFSIZ];
  int line = 0;
  FILE *fp;

  if((fp = fopen(name, "re")) == NULL){
    diag("Couldn't open %s (%s?)\n", name, strerror(errno));
    return -1;
  }
  // First line is a legend
  while(fgets(buf, sizeof(buf), fp)){
    char *toke = buf, *type, *size, *e;
    device *d;

    if(++line == 1){
      continue;
    }
    while(isgraph(*toke)){ // First field: "Filename"
      ++toke;
    }
    *toke++ = '\0';
    while(isspace(*toke)){
      ++toke;
    }
    type = toke++;    // Second field: "Type". "block"/"file"
    while(isgraph(*toke)){
      ++toke;
    }
    *toke++ = '\0';
    if(strcmp(type, "file") == 0){
      continue;
    }
    if((d = lookup_device(buf)) == NULL){
      goto err;
    }
    size = toke++;    // Third field: "Size".
    while(isgraph(*toke)){
      ++toke;
    }
    *toke++ = '\0';
    errno = 0;
    if(((d->mntsize = strtoull(size, &e, 0)) == ULLONG_MAX && errno == ERANGE) ||
        d->mntsize == 0 || *e){
      goto err;
    }
    d->mntsize *= 1024;
    if(d->swapprio == SWAP_INVALID){
      if(!d->mnttype || strcmp(d->mnttype, "swap")){
        if(d->mnttype){
          diag("Warning: %s went from %s to swap\n", d->name, d->mnttype);
          free(d->mnttype);
          d->mnttype = NULL;
        }
        if((d->mnttype = strdup("swap")) == NULL){
          goto err;
        }
      }
      // FIXME we can get the real priority from the last field
      d->swapprio = SWAP_MAXPRIO; // FIXME
      if(d->layout == LAYOUT_PARTITION){
        d = d->partdev.parent;
      }
      d->uistate = gui->block_event(d, d->uistate);
    }
  }
  fclose(fp);
  return 0;

err:
  diag("Error parsing %s\n", name);
  fclose(fp);
  return -1;
}
