swad-core/swad_forum.c

// swad_forum.c: forums

/*
    SWAD (Shared Workspace At a Distance),
    is a web platform developed at the University of Granada (Spain),
    and used to support university teaching.

    This file is part of SWAD core.
    Copyright (C) 1999-2023 Antonio Ca<EFBFBD>as Vargas

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
/*****************************************************************************/
/********************************* Headers ***********************************/
/*****************************************************************************/

#define _GNU_SOURCE 		// For asprintf
#include <malloc.h>		// For malloc
#include <mysql/mysql.h>	// To access MySQL databases
#include <stddef.h>		// For NULL
#include <stdio.h>		// For asprintf
#include <string.h>
#include <time.h>		// For time_t

#include "swad_action.h"
#include "swad_action_list.h"
#include "swad_box.h"
#include "swad_center_database.h"
#include "swad_config.h"
#include "swad_course_database.h"
#include "swad_database.h"
#include "swad_degree_database.h"
#include "swad_error.h"
#include "swad_figure.h"
#include "swad_form.h"
#include "swad_forum.h"
#include "swad_forum_database.h"
#include "swad_global.h"
#include "swad_hierarchy.h"
#include "swad_HTML.h"
#include "swad_layout.h"
#include "swad_logo.h"
#include "swad_message.h"
#include "swad_notification.h"
#include "swad_notification_database.h"
#include "swad_pagination.h"
#include "swad_parameter.h"
#include "swad_parameter_code.h"
#include "swad_profile.h"
#include "swad_profile_database.h"
#include "swad_program_database.h"
#include "swad_role.h"
#include "swad_timeline.h"
#include "swad_timeline_database.h"

/*****************************************************************************/
/************** External global variables from others modules ****************/
/*****************************************************************************/

extern struct Globals Gbl;

/*****************************************************************************/
/************************ Public constants and types *************************/
/*****************************************************************************/

const Act_Action_t For_ActionsSeeFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActSeeForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActSeeForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActSeeForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActSeeForDegTch,
   [For_FORUM_CENTER_USRS] = ActSeeForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActSeeForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActSeeForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActSeeForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActSeeForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActSeeForGenTch,
   [For_FORUM__SWAD__USRS] = ActSeeForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActSeeForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsSeePstFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActSeePstForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActSeePstForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActSeePstForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActSeePstForDegTch,
   [For_FORUM_CENTER_USRS] = ActSeePstForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActSeePstForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActSeePstForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActSeePstForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActSeePstForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActSeePstForGenTch,
   [For_FORUM__SWAD__USRS] = ActSeePstForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActSeePstForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsRecThrFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActRcvThrForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActRcvThrForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActRcvThrForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActRcvThrForDegTch,
   [For_FORUM_CENTER_USRS] = ActRcvThrForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActRcvThrForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActRcvThrForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActRcvThrForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActRcvThrForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActRcvThrForGenTch,
   [For_FORUM__SWAD__USRS] = ActRcvThrForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActRcvThrForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsRecRepFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActRcvRepForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActRcvRepForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActRcvRepForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActRcvRepForDegTch,
   [For_FORUM_CENTER_USRS] = ActRcvRepForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActRcvRepForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActRcvRepForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActRcvRepForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActRcvRepForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActRcvRepForGenTch,
   [For_FORUM__SWAD__USRS] = ActRcvRepForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActRcvRepForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsReqDelThr[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActReqDelThrCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActReqDelThrCrsTch,
   [For_FORUM_DEGREE_USRS] = ActReqDelThrDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActReqDelThrDegTch,
   [For_FORUM_CENTER_USRS] = ActReqDelThrCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActReqDelThrCtrTch,
   [For_FORUM_INSTIT_USRS] = ActReqDelThrInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActReqDelThrInsTch,
   [For_FORUM_GLOBAL_USRS] = ActReqDelThrGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActReqDelThrGenTch,
   [For_FORUM__SWAD__USRS] = ActReqDelThrSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActReqDelThrSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsDelThrFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActDelThrForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActDelThrForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActDelThrForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActDelThrForDegTch,
   [For_FORUM_CENTER_USRS] = ActDelThrForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActDelThrForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActDelThrForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActDelThrForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActDelThrForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActDelThrForGenTch,
   [For_FORUM__SWAD__USRS] = ActDelThrForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActDelThrForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsCutThrFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActCutThrForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActCutThrForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActCutThrForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActCutThrForDegTch,
   [For_FORUM_CENTER_USRS] = ActCutThrForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActCutThrForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActCutThrForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActCutThrForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActCutThrForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActCutThrForGenTch,
   [For_FORUM__SWAD__USRS] = ActCutThrForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActCutThrForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsPasThrFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActPasThrForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActPasThrForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActPasThrForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActPasThrForDegTch,
   [For_FORUM_CENTER_USRS] = ActPasThrForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActPasThrForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActPasThrForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActPasThrForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActPasThrForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActPasThrForGenTch,
   [For_FORUM__SWAD__USRS] = ActPasThrForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActPasThrForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsDelPstFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActDelPstForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActDelPstForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActDelPstForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActDelPstForDegTch,
   [For_FORUM_CENTER_USRS] = ActDelPstForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActDelPstForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActDelPstForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActDelPstForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActDelPstForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActDelPstForGenTch,
   [For_FORUM__SWAD__USRS] = ActDelPstForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActDelPstForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsEnbPstFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActEnbPstForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActEnbPstForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActEnbPstForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActEnbPstForDegTch,
   [For_FORUM_CENTER_USRS] = ActEnbPstForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActEnbPstForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActEnbPstForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActEnbPstForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActEnbPstForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActEnbPstForGenTch,
   [For_FORUM__SWAD__USRS] = ActEnbPstForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActEnbPstForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

const Act_Action_t For_ActionsDisPstFor[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = ActDisPstForCrsUsr,
   [For_FORUM_COURSE_TCHS] = ActDisPstForCrsTch,
   [For_FORUM_DEGREE_USRS] = ActDisPstForDegUsr,
   [For_FORUM_DEGREE_TCHS] = ActDisPstForDegTch,
   [For_FORUM_CENTER_USRS] = ActDisPstForCtrUsr,
   [For_FORUM_CENTER_TCHS] = ActDisPstForCtrTch,
   [For_FORUM_INSTIT_USRS] = ActDisPstForInsUsr,
   [For_FORUM_INSTIT_TCHS] = ActDisPstForInsTch,
   [For_FORUM_GLOBAL_USRS] = ActDisPstForGenUsr,
   [For_FORUM_GLOBAL_TCHS] = ActDisPstForGenTch,
   [For_FORUM__SWAD__USRS] = ActDisPstForSWAUsr,
   [For_FORUM__SWAD__TCHS] = ActDisPstForSWATch,
   [For_FORUM_UNKNOWN    ] = ActSeeFor,
  };

/*****************************************************************************/
/*********************** Private constants and types *************************/
/*****************************************************************************/

#define For_FORUM_MAX_LEVELS 5

static const unsigned PermissionThreadDeletion[For_NUM_TYPES_FORUM] =
  {
   [For_FORUM_COURSE_USRS] = 0x3F0,
   [For_FORUM_COURSE_TCHS] = 0x3F0,
   [For_FORUM_DEGREE_USRS] = 0x3E0,
   [For_FORUM_DEGREE_TCHS] = 0x3E0,
   [For_FORUM_CENTER_USRS] = 0x3C0,
   [For_FORUM_CENTER_TCHS] = 0x3C0,
   [For_FORUM_INSTIT_USRS] = 0x380,
   [For_FORUM_INSTIT_TCHS] = 0x380,
   [For_FORUM_GLOBAL_USRS] = 0x300,
   [For_FORUM_GLOBAL_TCHS] = 0x300,
   [For_FORUM__SWAD__USRS] = 0x300,
   [For_FORUM__SWAD__TCHS] = 0x300,
   [For_FORUM_UNKNOWN    ] = 0x000,
  };

// Forum images will be saved with:
// - maximum width of For_IMAGE_SAVED_MAX_HEIGHT
// - maximum height of For_IMAGE_SAVED_MAX_HEIGHT
// - maintaining the original aspect ratio (aspect ratio recommended: 3:2)
#define For_IMAGE_SAVED_MAX_WIDTH	768
#define For_IMAGE_SAVED_MAX_HEIGHT	768
#define For_IMAGE_SAVED_QUALITY		 90	// 1 to 100

struct For_FiguresForum
  {
   unsigned NumForums;
   unsigned NumThreads;
   unsigned NumPosts;
   unsigned NumUsrsToBeNotifiedByEMail;
  };

/*****************************************************************************/
/****************************** Private prototypes ***************************/
/*****************************************************************************/

static long For_InsertForumPst (long ThrCod,long UsrCod,
                                const char *Subject,const char *Content,
                                struct Med_Media *Media);
static bool For_RemoveForumPst (long PstCod,long MedCod);
static unsigned For_NumPstsInThrWithPstCod (long PstCod,long *ThrCod);

static void For_RemoveThreadOnly (long ThrCod);
static void For_RemoveThreadAndItsPsts (long ThrCod);

static time_t For_GetThrReadTime (long ThrCod);

static void For_PutIconsOneThread (void *Forums);

static void For_PutParsNewPost (void *Forums);

static void For_ShowAForumPost (struct For_Forums *Forums,
	                        unsigned PstNum,
                                bool LastPst,char LastSubject[Cns_MAX_BYTES_SUBJECT + 1],
                                bool NewPst,bool ICanModerateForum);
static void For_GetPstData (long PstCod,long *UsrCod,time_t *CreatTimeUTC,
                            char Subject[Cns_MAX_BYTES_SUBJECT   + 1],
                            char Content[Cns_MAX_BYTES_LONG_TEXT + 1],
                            struct Med_Media *Media);
static void For_WriteNumberOfPosts (const struct For_Forums *Forums,long UsrCod);

static void For_PutParsForum (void *Forums);

static void For_PutParForumSet (For_ForumSet_t ForumSet);

static void For_PutIconsForums (__attribute__((unused)) void *Args);
static void For_PutFormWhichForums (const struct For_Forums *Forums);

static void For_WriteLinksToGblForums (const struct For_Forums *Forums,
                                       bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static void For_WriteLinksToPlatformForums (const struct For_Forums *Forums,
					    bool IsLastForum,
                                            bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static long For_WriteLinksToInsForums (const struct For_Forums *Forums,
				       long InsCod,bool IsLastIns,
                                       bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static long For_WriteLinksToCtrForums (const struct For_Forums *Forums,
				       long CtrCod,bool IsLastCtr,
                                       bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static long For_WriteLinksToDegForums (const struct For_Forums *Forums,
				       long DegCod,bool IsLastDeg,
                                       bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static long For_WriteLinksToCrsForums (const struct For_Forums *Forums,
				       long CrsCod,bool IsLastCrs,
                                       bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static void For_WriteLinkToForum (const struct For_Forums *Forums,
	                          const struct For_Forum *Forum,
                                  bool Highlight,
                                  unsigned Level,
                                  bool IsLastItemInLevel[1 + For_FORUM_MAX_LEVELS]);
static unsigned For_GetNumThrsWithNewPstsInForum (const struct For_Forum *Forum,
                                                  unsigned NumThreads);
static unsigned For_GetNumOfUnreadPostsInThr (long ThrCod,unsigned NumPostsInThr);

static void For_WriteNumberOfThrs (unsigned NumThrs);

static void For_PutIconsThreads (void *Forums);
static void For_PutParsNewThread (void *Forums);
static void For_ListForumThrs (struct For_Forums *Forums,
	                       long ThrCods[Pag_ITEMS_PER_PAGE],
                               long ThrCodHighlighted,
                               struct Pag_Pagination *PaginationThrs);

static void For_SetForumType (struct For_Forums *Forums);
static void For_RestrictAccess (const struct For_Forums *Forums);

static void For_WriteFormForumPst (struct For_Forums *Forums,
                                   bool IsReply,const char *Subject);

static void For_PutParsRemThread (void *Forums);

static bool For_CheckIfICanMoveThreads (void);
static void For_InsertThrInClipboard (long ThrCod);

static void For_ShowStatOfAForumType (For_ForumType_t ForumType,
				      long HieCod[Hie_NUM_LEVELS],
                                      struct For_FiguresForum *FiguresForum);
static void For_WriteForumTitleAndStats (For_ForumType_t ForumType,
					 long HieCod[Hie_NUM_LEVELS],
                                         const char *Icon,struct For_FiguresForum *FiguresForum,
                                         const char *ForumName1,const char *ForumName2);
static void For_WriteForumTotalStats (struct For_FiguresForum *FiguresForum);

/*****************************************************************************/
/********************************** Reset forum ******************************/
/*****************************************************************************/

void For_ResetForums (struct For_Forums *Forums)
  {
   Forums->ForumSet        = For_DEFAULT_FORUM_SET;
   Forums->ThreadsOrder    = For_DEFAULT_ORDER;
   Forums->CurrentPageThrs = 0;
   Forums->CurrentPagePsts = 0;

   Forums->Forum.Type      = For_FORUM_UNKNOWN;
   Forums->Forum.HieCod  = -1L;

   Forums->Thread.Selected =
   Forums->Thread.Current  =
   Forums->Thread.ToMove   = -1L;

   Forums->PstCod          = -1L;
  }

/*****************************************************************************/
/****************************** Enable a forum post **************************/
/*****************************************************************************/

void For_EnablePost (void)
  {
   extern const char *Txt_FORUM_Post_unbanned;
   struct For_Forums Forums;

   /***** Reset forum *****/
   For_ResetForums (&Forums);

   /***** Get parameters related to forum *****/
   For_GetParsForums (&Forums);

   /***** Delete post from table of disabled posts *****/
   For_DB_RemovePstFromDisabled (Forums.PstCod);

   /***** Show forum list again *****/
   For_ShowForumList (&Forums);

   /***** Show threads again *****/
   For_ShowForumThreadsHighlightingOneThread (&Forums,Ale_SUCCESS,NULL);

   /***** Show the posts again *****/
   For_ShowPostsOfAThread (&Forums,Ale_SUCCESS,Txt_FORUM_Post_unbanned);
  }

/*****************************************************************************/
/***************************** Disable a forum post **************************/
/*****************************************************************************/

void For_DisablePost (void)
  {
   extern const char *Txt_FORUM_Post_banned;
   struct For_Forums Forums;

   /***** Get parameters related to forums *****/
   For_GetParsForums (&Forums);

   /***** Check if post really exists, if it has not been removed *****/
   if (For_DB_CheckIfForumPstExists (Forums.PstCod))
     {
      /***** Insert post into table of banned posts *****/
      For_DB_InsertPstIntoDisabled (Forums.PstCod);

      /***** Show forum list again *****/
      For_ShowForumList (&Forums);

      /***** Show threads again *****/
      For_ShowForumThreadsHighlightingOneThread (&Forums,Ale_SUCCESS,NULL);

      /***** Show the posts again *****/
      For_ShowPostsOfAThread (&Forums,Ale_SUCCESS,Txt_FORUM_Post_banned);
     }
   else
      Err_WrongPostExit ();
  }

/*****************************************************************************/
/************** Insert a post new in the table of posts of forums ************/
/*****************************************************************************/

static long For_InsertForumPst (long ThrCod,long UsrCod,
                                const char *Subject,const char *Content,
                                struct Med_Media *Media)
  {
   /***** Store media in filesystem and database *****/
   Med_RemoveKeepOrStoreMedia (-1L,Media);

   /***** Insert forum post in the database *****/
   return For_DB_InsertForumPst (ThrCod,UsrCod,Subject,Content,Media->MedCod);
  }

/*****************************************************************************/
/***************** Delete a post from the forum post table *******************/
/*****************************************************************************/
// Return true if the post thread is deleted

static bool For_RemoveForumPst (long PstCod,long MedCod)
  {
   long ThrCod;
   bool ThreadDeleted = false;

   /***** Remove media file attached to forum post *****/
   Med_RemoveMedia (MedCod);

   /***** If the post is the only one in its thread, delete that thread *****/
   if (For_NumPstsInThrWithPstCod (PstCod,&ThrCod) < 2)
     {
      For_RemoveThreadOnly (ThrCod);
      ThreadDeleted = true;
     }

   /***** Delete the post from the table of disabled forum posts *****/
   For_DB_RemovePstFromDisabled (PstCod);

   /***** Delete post from forum post table *****/
   For_DB_RemovePst (PstCod);

   /***** Update the last post of the thread *****/
   if (!ThreadDeleted)
      For_DB_UpdateThrLastPst (ThrCod,For_DB_GetThrLastPst (ThrCod));

   return ThreadDeleted;
  }

/*****************************************************************************/
/*********** Get the number of posts in the thread than holds a post *********/
/*****************************************************************************/

static unsigned For_NumPstsInThrWithPstCod (long PstCod,long *ThrCod)
  {
   MYSQL_RES *mysql_res;
   MYSQL_ROW row;
   unsigned NumPsts;

   /***** Initialize default values *****/
   *ThrCod = -1L;
   NumPsts = 0;

   /***** Trivial check: PstCod should be > 0 *****/
   if (PstCod <= 0)
      return NumPsts;

   /***** Get number of posts in the thread that holds a post from database *****/
   if (For_DB_GetThreadAndNumPostsGivenPstCod (&mysql_res,PstCod) == 1)	// Result should have one row
     {
      row = mysql_fetch_row (mysql_res);
      /*
      row[0]: ThrCod
      row[1]: COUNT(PstCod)
      */
      if (sscanf (row[0],"%ld",ThrCod) != 1)
	 Err_ShowErrorAndExit ("Error when getting number of posts in a thread.");
      if (sscanf (row[1],"%u",&NumPsts) != 1)
	 Err_ShowErrorAndExit ("Error when getting number of posts in a thread.");
     }
   DB_FreeMySQLResult (&mysql_res);

   return NumPsts;
  }

/*****************************************************************************/
/*************** Delete a thread from the forum thread table *****************/
/*****************************************************************************/

static void For_RemoveThreadOnly (long ThrCod)
  {
   /***** Indicate that this thread has not been read by anyone *****/
   For_DB_RemoveThrFromReadThrs (ThrCod);

   /***** Remove thread code from thread clipboard *****/
   For_DB_RemoveThrFromClipboard (ThrCod);

   /***** Delete thread from forum thread table *****/
   For_DB_RemoveThread (ThrCod);
  }

/*****************************************************************************/
/*************** Delete a thread from the forum thread table *****************/
/*****************************************************************************/

static void For_RemoveThreadAndItsPsts (long ThrCod)
  {
   /***** Delete disabled posts in thread *****/
   For_DB_RemoveDisabledPstsInThread (ThrCod);

   /***** Delete thread posts *****/
   For_DB_RemoveThreadPsts (ThrCod);

   /***** Delete thread from forum thread table *****/
   For_RemoveThreadOnly (ThrCod);
  }

/*****************************************************************************/
/*********** Get thread, forum type and hierarchy code of a post *************/
/*****************************************************************************/
// Return thread to which the post belongs

long For_GetThreadForumTypeAndHieCodOfAPost (long PstCod,struct For_Forum *Forum)
  {
   MYSQL_RES *mysql_res;
   MYSQL_ROW row;
   unsigned UnsignedNum;
   long ThrCod;

   /***** Set defaults *****/
   Forum->Type = For_FORUM_UNKNOWN;
   Forum->HieCod = -1L;
   ThrCod = -1L;

   /***** Check if there is a row with forum type *****/
   if (For_DB_GetThreadForumTypeAndHieCodOfAPost (&mysql_res,PstCod))
     {
      row = mysql_fetch_row (mysql_res);

      /* Get forum thread (row[0]) */
      if (sscanf (row[0],"%ld",&ThrCod) != 1)
	 Err_WrongThreadExit ();

      /* Get forum type (row[1]) */
      if (sscanf (row[1],"%u",&UnsignedNum) == 1)
	 if (UnsignedNum < For_NUM_TYPES_FORUM)
	    Forum->Type = (For_ForumType_t) UnsignedNum;

      /* Get forum hierarchy code (row[2]) */
      if (sscanf (row[2],"%ld",&Forum->HieCod) != 1)
	 Err_WrongForumExit ();
     }

   /***** Free structure that stores the query result *****/
   DB_FreeMySQLResult (&mysql_res);

   return ThrCod;
  }

/*****************************************************************************/
/*************** Get forum type and hierarchy code of a post *****************/
/*****************************************************************************/

void For_GetForumTypeAndHieCodOfAThread (long ThrCod,struct For_Forum *Forum)
  {
   MYSQL_RES *mysql_res;
   MYSQL_ROW row;
   unsigned UnsignedNum;

   /***** Set defaults *****/
   Forum->Type = For_FORUM_UNKNOWN;
   Forum->HieCod = -1L;

   /***** Check if there is a row with forum type *****/
   if (For_DB_GetForumTypeAndHieCodOfAThread (&mysql_res,ThrCod))
     {
      row = mysql_fetch_row (mysql_res);

      /* Get forum type (row[0]) */
      if (sscanf (row[0],"%u",&UnsignedNum) == 1)
	 if (UnsignedNum < For_NUM_TYPES_FORUM)
	    Forum->Type = (For_ForumType_t) UnsignedNum;

      /* Get forum hierarchy code (row[1]) */
      if (sscanf (row[1],"%ld",&Forum->HieCod) != 1)
	 Err_WrongForumExit ();
     }

   /***** Free structure that stores the query result *****/
   DB_FreeMySQLResult (&mysql_res);
  }

/*****************************************************************************/
/****************** Get thread read time for the current user ****************/
/*****************************************************************************/

static time_t For_GetThrReadTime (long ThrCod)
  {
   MYSQL_RES *mysql_res;
   MYSQL_ROW row;
   time_t ReadTimeUTC;

   /***** Get read time of a thread from database *****/
   if (For_DB_GetThrReadTime (&mysql_res,ThrCod))
     {
      /***** There is a row ==> get read time *****/
      row = mysql_fetch_row (mysql_res);

      ReadTimeUTC = Dat_GetUNIXTimeFromStr (row[0]);
     }
   else
      ReadTimeUTC = (time_t) 0;	// If there is no row for this thread and current user,
				// then current user has not read this thread

   /***** Free structure that stores the query result *****/
   DB_FreeMySQLResult (&mysql_res);

   return ReadTimeUTC;
  }

/*****************************************************************************/
/************************ Show posts in a thread *****************************/
/*****************************************************************************/

void For_ShowPostsOfAThread (struct For_Forums *Forums,
			     Ale_AlertType_t AlertType,const char *Message)
  {
   extern const char *Hlp_COMMUNICATION_Forums_posts;
   extern const char *Txt_Thread;
   struct For_Thread Thread;
   char LastSubject[Cns_MAX_BYTES_SUBJECT + 1];
   char FrameTitle[128 + Cns_MAX_BYTES_SUBJECT];
   MYSQL_RES *mysql_res;
   MYSQL_ROW row;
   unsigned NumRow;
   unsigned NumPst = 0;		// Initialized to avoid warning
   unsigned NumPsts;
   time_t ReadTimeUTC;		// Read time of thread for the current user
   time_t CreatTimeUTC;		// Creation time of post
   struct Pag_Pagination PaginationPsts;
   bool NewPst = false;
   bool ICanModerateForum = false;