/*
 * This file is part of firk's window manager for x11 (fwm)
 * Copyright (C) 2022 firk <firk@cantconnect.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include "fwm-menu.h"
#include "xdg_parser.h"

static void fix_command(char *s) {
  size_t j, k;
  char c;
  for(j=k=0; c=s[j]; j++) {
    if(c!='%') { s[k++] = c; continue; }
    c = s[++j];
    if(!c) break;
    if(c=='%') s[k++] = '%';
  }
  s[k] = 0;
}

extern int parse_desktop_file(t_desktop_file *rr, int dirfd, char const *name) {
  int fd;
  char title[256], command[4096], path[4096];

  char buf[4096], c, *b;
  unsigned int sz, p, p0, ln;
  int r, skip, in_section, use_term;
  size_t jj;

  /* TODO: distinguish between errors and not-shown entry */
  while((fd = openat(dirfd, name, O_RDONLY|O_NOCTTY))<0) if(errno!=EINTR) { logprint("can't open file \"%s\"", name); return -1; }
  sz = 0;
  r = 1;
  skip = 0;
  ln = 1;
  in_section = 0;
  use_term = 0;
  title[0] = command[0] = path[0] = 0;
  while(r) {
    if(sz>=sizeof(buf)) break;
    while((r = read(fd, buf+sz, sizeof(buf)-sz))<0) if(errno!=EINTR) return -1;
    for(p=sz,p0=0,sz+=r; p<sz; p++) {
      c = buf[p];
      if(c=='\n') {
        buf[p] = 0;
        if(skip) skip=0; else {
          b = buf+p0;
          if(*b=='[') in_section = !strcasecmp(b,"[Desktop Entry]");
          else if(in_section) {
            if(!strcasecmp(b,"Terminal=true")) use_term = 1;
            else if(!strncasecmp(b,"Exec=",5)) { strncpy(command, b+5, sizeof(command)); if(command[sizeof(command)-1]) { logprint("file \"%s\" line %u command too long, skipping entry", name, ln); close(fd); return -1; } }
            else if(!strncasecmp(b,"Path=",5)) { strncpy(path, b+5, sizeof(path)); if(path[sizeof(path)-1]) { logprint("file \"%s\" line %u path too long, skipping entry", name, ln); close(fd); return -1; } }
            else if(!strncasecmp(b,"Name=",5)) { strncpy(title, b+5, sizeof(title)); title[sizeof(title)-1] = 0; }
            else if(!strncasecmp(b,"Type=",5) && strcasecmp(b+5,"Application")) { close(fd); return -1; }
            else if(!strcasecmp(b,"NoDisplay=true")) { close(fd); return -1; }
            else if(!strcasecmp(b,"Hidden=true")) { close(fd); return -1; }
          }
        }
        p0 = p+1;
        ln++;
      } else if(!skip && (c>=0 && c!=9 && c<32 || c==127)) { logprint("file \"%s\" line %u contains invalid symbols, skipping it", name, ln); skip = 1; }
    }
    if(p0) if(sz-=p0) bcopy(buf+p0, buf, sz);
  }
  close(fd);
  if(sz>=sizeof(buf)) logprint("file \"%s\" line %u too long, skipping all below", name, ln);
  else if(sz) logprint("file \"%s\" line %u (last) non-terminated, skipping it", name, ln);
  fix_command(command);
  if(!command[0]) return -1;
  if(!title[0]) {
    jj = strlen(name);
    if(jj<=8 || strcmp(name+(jj-8),".desktop")) return -1;
    if(jj>=sizeof(title)) jj = sizeof(title)-1;
    bcopy(name, title, jj);
    title[jj] = 0;
  }
  if(!(rr->title = strdup(title))) { logprint("out of memory"); return -1; }
  if(!(rr->command = strdup(command))) { free((void*)rr->title); logprint("out of memory"); return -1; }
  if(*path && !(rr->path = strdup(path))) { free((void*)rr->command); free((void*)rr->title); logprint("out of memory"); return -1; }
  rr->use_term = use_term;
  return 0;
}