#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>

#include "ecore_file_private.h"

/*
 * TODO:
 *
 * - Listen to these events:
 *   IN_ACCESS, IN_ATTRIB, IN_CLOSE_WRITE, IN_CLOSE_NOWRITE, IN_OPEN
 * - Read all events first, then call the callbacks. This will prevent several
 *   callbacks with the typic save cycle (delete file, new file)
 * - Listen to IN_IGNORED, emitted when the watch is removed
 */

#include <sys/inotify.h>


typedef struct _Ecore_File_Monitor_Inotify Ecore_File_Monitor_Inotify;

#define ECORE_FILE_MONITOR_INOTIFY(x) ((Ecore_File_Monitor_Inotify *)(x))

struct _Ecore_File_Monitor_Inotify
{
   Ecore_File_Monitor  monitor;
   int                 wd;
};

static Ecore_Fd_Handler *_fdh = NULL;
static Ecore_File_Monitor    *_monitors = NULL;
static pid_t             _inotify_fd_pid = -1;

static Eina_Bool           _ecore_file_monitor_inotify_handler(void *data, Ecore_Fd_Handler *fdh);
static Ecore_File_Monitor *_ecore_file_monitor_inotify_monitor_find(int wd);
static void                _ecore_file_monitor_inotify_events(Ecore_File_Monitor *em, char *file, int mask);
static int                 _ecore_file_monitor_inotify_monitor(Ecore_File_Monitor *em, const char *path);
#if 0
static void                _ecore_file_monitor_inotify_print(char *file, int mask);
#endif

int
ecore_file_monitor_backend_init(void)
{
   int fd;
#ifdef HAVE_EXECVP
   int flags;
#endif

   fd = inotify_init();
   if (fd < 0)
     return 0;

#ifdef HAVE_EXECVP
   flags = fcntl(fd, F_GETFD);
   flags |= FD_CLOEXEC;
   fcntl(fd, F_SETFD, flags);
#endif

   _fdh = ecore_main_fd_handler_add(fd, ECORE_FD_READ, _ecore_file_monitor_inotify_handler,
                                    NULL, NULL, NULL);
   if (!_fdh)
     {
        close(fd);
        return 0;
     }

   _inotify_fd_pid = getpid();
   return 1;
}

int
ecore_file_monitor_backend_shutdown(void)
{
   int fd;

   while(_monitors)
        ecore_file_monitor_backend_del(_monitors);

   if (_fdh)
     {
        fd = ecore_main_fd_handler_fd_get(_fdh);
        ecore_main_fd_handler_del(_fdh);
        close(fd);
     }
   _inotify_fd_pid = -1;
   return 1;
}

Ecore_File_Monitor *
ecore_file_monitor_backend_add(const char *path,
                               void (*func) (void *data, Ecore_File_Monitor *em,
                                             Ecore_File_Event event,
                                             const char *path),
                               void *data)
{
   Ecore_File_Monitor *em;
   int len;

   if (_inotify_fd_pid == -1) return NULL;

   if (_inotify_fd_pid != getpid())
     {
        ecore_file_monitor_backend_shutdown();
        ecore_file_monitor_backend_init();
     }

   em = calloc(1, sizeof(Ecore_File_Monitor_Inotify));
   if (!em) return NULL;

   em->func = func;
   em->data = data;

   em->path = strdup(path);
   len = strlen(em->path);
   if (em->path[len - 1] == '/' && strcmp(em->path, "/"))
     em->path[len - 1] = 0;

   _monitors = ECORE_FILE_MONITOR(eina_inlist_append(EINA_INLIST_GET(_monitors), EINA_INLIST_GET(em)));

   if (!_ecore_file_monitor_inotify_monitor(em, em->path))
     return NULL;

   return em;
}

void
ecore_file_monitor_backend_del(Ecore_File_Monitor *em)
{
   int fd;

   if (_monitors)
     _monitors = ECORE_FILE_MONITOR(eina_inlist_remove(EINA_INLIST_GET(_monitors), EINA_INLIST_GET(em)));

   fd = ecore_main_fd_handler_fd_get(_fdh);
   if (ECORE_FILE_MONITOR_INOTIFY(em)->wd)
     inotify_rm_watch(fd, ECORE_FILE_MONITOR_INOTIFY(em)->wd);
   free(em->path);
   free(em);
}

static Eina_Bool
_ecore_file_monitor_inotify_handler(void *data EINA_UNUSED, Ecore_Fd_Handler *fdh)
{
   Ecore_File_Monitor *em;
   char buffer[16384];
   struct inotify_event *event;
   int i = 0;
   int event_size;
   ssize_t size;

   size = read(ecore_main_fd_handler_fd_get(fdh), buffer, sizeof(buffer));
   while (i < size)
     {
        event = (struct inotify_event *)&buffer[i];
        event_size = sizeof(struct inotify_event) + event->len;
        i += event_size;

        em = _ecore_file_monitor_inotify_monitor_find(event->wd);
        if (!em) continue;

        _ecore_file_monitor_inotify_events(em, (event->len ? event->name : NULL), event->mask);
     }

   return ECORE_CALLBACK_RENEW;
}

static Ecore_File_Monitor *
_ecore_file_monitor_inotify_monitor_find(int wd)
{
   Ecore_File_Monitor *l;

   EINA_INLIST_FOREACH(_monitors, l)
     {
        if (ECORE_FILE_MONITOR_INOTIFY(l)->wd == wd)
          return l;
     }
   return NULL;
}

static void
_ecore_file_monitor_inotify_events(Ecore_File_Monitor *em, char *file, int mask)
{
   char buf[PATH_MAX];
   int isdir;

   if ((file) && (file[0]))
     snprintf(buf, sizeof(buf), "%s/%s", em->path, file);
   else
     strcpy(buf, em->path);
   isdir = mask & IN_ISDIR;

#if 0
   _ecore_file_monitor_inotify_print(buf, mask);
#endif

   if (mask & IN_ATTRIB)
     {
        em->func(em->data, em, ECORE_FILE_EVENT_MODIFIED, buf);
     }
   if (mask & IN_CLOSE_WRITE)
     {
        if (!isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_CLOSED, buf);
     }
   if (mask & IN_MODIFY)
     {
        if (!isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_MODIFIED, buf);
     }
   if (mask & IN_MOVED_FROM)
     {
        if (isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_DELETED_DIRECTORY, buf);
        else
          em->func(em->data, em, ECORE_FILE_EVENT_DELETED_FILE, buf);
     }
   if (mask & IN_MOVED_TO)
     {
        if (isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_CREATED_DIRECTORY, buf);
        else
          em->func(em->data, em, ECORE_FILE_EVENT_CREATED_FILE, buf);
     }
   if (mask & IN_DELETE)
     {
        if (isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_DELETED_DIRECTORY, buf);
        else
          em->func(em->data, em, ECORE_FILE_EVENT_DELETED_FILE, buf);
     }
   if (mask & IN_CREATE)
     {
        if (isdir)
          em->func(em->data, em, ECORE_FILE_EVENT_CREATED_DIRECTORY, buf);
        else
          em->func(em->data, em, ECORE_FILE_EVENT_CREATED_FILE, buf);
     }
   if (mask & IN_DELETE_SELF)
     {
        em->func(em->data, em, ECORE_FILE_EVENT_DELETED_SELF, em->path);
     }
   if (mask & IN_MOVE_SELF)
     {
        /* We just call delete. The dir is gone... */
        em->func(em->data, em, ECORE_FILE_EVENT_DELETED_SELF, em->path);
     }
   if (mask & IN_UNMOUNT)
     {
        /* We just call delete. The dir is gone... */
        em->func(em->data, em, ECORE_FILE_EVENT_DELETED_SELF, em->path);
     }
   if (mask & IN_IGNORED)
     {
        /* The watch is removed. If the file name still exists monitor the new one,
         * else delete it */
        if (ecore_file_exists(em->path))
          {
             if (_ecore_file_monitor_inotify_monitor(em, em->path))
               em->func(em->data, em, ECORE_FILE_EVENT_DELETED_SELF, em->path);
          }
        else
          em->func(em->data, em, ECORE_FILE_EVENT_DELETED_SELF, em->path);
     }
}

static int
_ecore_file_monitor_inotify_monitor(Ecore_File_Monitor *em, const char *path)
{
   int mask =
      IN_ATTRIB |
      IN_CLOSE_WRITE |
      IN_MOVED_FROM |
      IN_MOVED_TO |
      IN_DELETE |
      IN_CREATE |
      IN_MODIFY |
      IN_DELETE_SELF |
      IN_MOVE_SELF |
      IN_UNMOUNT;

   ECORE_FILE_MONITOR_INOTIFY(em)->wd =
      inotify_add_watch(ecore_main_fd_handler_fd_get(_fdh), path, mask);
   if (ECORE_FILE_MONITOR_INOTIFY(em)->wd < 0)
     {
        INF("inotify_add_watch failed, file was deleted");
        ecore_file_monitor_backend_del(em);
        return 0;
     }
   return 1;
}

#if 0
static void
_ecore_file_monitor_inotify_print(char *file, int mask)
{
   const char *type;

   if (mask & IN_ISDIR)
     type = "dir";
   else
     type = "file";

   if (mask & IN_ACCESS)
     INF("Inotify accessed %s: %s", type, file);
   if (mask & IN_MODIFY)
     INF("Inotify modified %s: %s", type, file);
   if (mask & IN_ATTRIB)
     INF("Inotify attributes %s: %s", type, file);
   if (mask & IN_CLOSE_WRITE)
     INF("Inotify close write %s: %s", type, file);
   if (mask & IN_CLOSE_NOWRITE)
     INF("Inotify close write %s: %s", type, file);
   if (mask & IN_OPEN)
     INF("Inotify open %s: %s", type, file);
   if (mask & IN_MOVED_FROM)
     INF("Inotify moved from %s: %s", type, file);
   if (mask & IN_MOVED_TO)
     INF("Inotify moved to %s: %s", type, file);
   if (mask & IN_DELETE)
     INF("Inotify delete %s: %s", type, file);
   if (mask & IN_CREATE)
     INF("Inotify create %s: %s", type, file);
   if (mask & IN_DELETE_SELF)
     INF("Inotify delete self %s: %s", type, file);
   if (mask & IN_MOVE_SELF)
     INF("Inotify move self %s: %s", type, file);
   if (mask & IN_UNMOUNT)
     INF("Inotify unmount %s: %s", type, file);
}
#endif