/***********************************************************
*               Calendar database rutines.                 *
************************************************************
* Description:                                             *
*                                                          *
* Created by: Avrami Tzur                                  *
* At: Sat Nov  7 20:52:24 1992                             *
***********************************************************/

/* INCLUDES */
# include <signal.h>
# include <stdio.h>			/* for printing error messages */
# include <sys/types.h>
# include <sys/stat.h>			/* for stat() ** needs types.h ***/
# include <sys/time.h>
# include <fcntl.h>
# include <errno.h>
# include "AOPcalendar.h" 


/* DECLARATIONS */
int apiDbInitilizeDb(char *file_name);
int apiDbInsertAppointment(dayAppP rec, int year, int month, int day);
dayAppP apiDbGetDateAppointments(int year, int month, int day, int *counter);
dayAppP apiDbGetAppointment(int year, int month, int day, int start_time);
int apiDbDeleteAppointment(int year, int month, int day, int start_time);
int apiDbUpdateAppointment(int year, int month, int day, int start_time, dayAppP rec);

static int calOpenFile(char *file_name, char *status);
static int calCloseFile();
static void calFreeStruct();
static int calLoadApp(calListP day_rec);
static int calStoreInfo(char *file_name);
static appListP calGetAppointment(long date, int start_time);
static calListP calGetDateRecord(long date, int create_new);
static appListP calInsertAppRecord(calListP day_rec, dayAppP app_rec);
static void calDeleteAppRecord(appListP app_rec);
static void calDeleteDayRecord(calListP day_rec);
static int calDateCmp(long date1, long date2);
static void calSysError(char *message);
static long intToDate(int year, int month, int day);
static void dateToInt(long date, int *year, int *month, int *day);

static FILE *db_file = NULL ;
static calListP cal_list = NULL;
static char *db_name ;



/*
============================================================
|                       apiDbInitilizeDb()                 |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 12:35:50 1992                             |
|==========================================================|
*/
int apiDbInitilizeDb(char *file_name)
{
   int ret;
   int i ;
   calListP temp_list = NULL;
   char buffer[sizeof(struct dayStruct)];

   /* Store the file name. */
   /* You might want to play with directory and stuff ... */
   if(file_name == NULL) {
      file_name = ".AOPcal";
   }
   
   db_name = (char *)malloc(strlen(file_name)+1);
   strcpy(db_name, file_name);
      
   /* Open the file */
   if((ret = calOpenFile(db_name, CAL_READ)) == CAL_ERROR)
      return(ret);

   if(cal_list != NULL) {
      /* Free the previus read list */
      calFreeStruct();
   }

   /* Load the table. The file format is
      Date year + month + day + Number of appointment records  
      Record 1 + Record2 + ... Record
      The days are sorted and the appointment records are sorted by
      the appointment start time.
   */

   while(!feof(db_file)) {
      /* Get the date */
      if(fread(buffer,sizeof(struct dayStruct),1,db_file) != 1) {
         if(!feof(db_file)){
            calSysError("Error in reading");
            return(CAL_ERROR);
         } else break;
      }
      /* Store in record */
      if(temp_list == NULL) {
         /* First element */
         cal_list = (calListP)malloc(sizeof(struct calList));
         temp_list = cal_list;
         temp_list->previous = NULL;
      }
      else {
         temp_list->next = (calListP)malloc(sizeof(struct calList));
         temp_list->next->previous = temp_list;
         temp_list = temp_list->next;
         }
      temp_list->next = NULL;
      /* Strore the day structure. */
      memcpy((char *)&(temp_list->day_struct),buffer, sizeof(struct dayStruct));

      /* Store the appointment records. */
      if((ret = calLoadApp(temp_list)) == CAL_ERROR)
         return(ret);
   }

   /* Close the file. */
   if((ret = calCloseFile()) == CAL_ERROR)
      return(ret);

   return(CAL_OK);
}

/*
============================================================
|                  apiDbInsertAppointment()                |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:15:41 1992                             |
|==========================================================|
*/
int apiDbInsertAppointment(dayAppP rec, int year, int month, int day)
{
   int found = 0;
   calListP day_rec;
   appListP  app_rec;
   long date = intToDate(year, month, day);

   /* Find the day record. */
   day_rec = calGetDateRecord(date, CAL_CREATE);
   
   /* Increase the appointmnt counter. */
   (day_rec->day_struct.app_counter)++;
   
   /* Add the appointment to the appointment list */
   app_rec = calInsertAppRecord(day_rec,rec);
   
   /* Update the file on disk. */
   return(calStoreInfo(NULL));
}

/*
============================================================
|                 apiDbGetDateAppointments()               |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Tue Nov 10 10:41:16 1992                             |
|==========================================================|
*/
dayAppP apiDbGetDateAppointments(int year, int month, int day, int *counter)
{
   long date = intToDate(year, month, day);
   calListP day_rec = calGetDateRecord(date, CAL_CHECK );
   dayAppP app_array;
   appListP temp;
   int i;

   if(day_rec == NULL) {
      *counter = 0;
      return(NULL);
   } else {
      *counter = day_rec->day_struct.app_counter;
      app_array = (dayAppP)malloc(sizeof(struct dayApp)*day_rec->day_struct.app_counter);
      temp = day_rec->app_list;
      for(i=0; i< *counter; i++) {
         memcpy((char *)&(app_array[i]), (char *)&(temp->app), sizeof(struct dayApp));
         temp = temp->next;
      }
      return(app_array);
   }
}

/*
============================================================
|                   apiDbGetAppointment()                  |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Tue Nov 17 13:03:44 1992                             |
|==========================================================|
*/
dayAppP apiDbGetAppointment(int year, int month, int day, int start_time)
{
   long date = intToDate(year, month, day);
   appListP temp = calGetAppointment(date, start_time);
   dayAppP app;

   if(temp == NULL) return(NULL);
   else {
      app = (dayAppP)malloc(sizeof(struct dayApp));
      memcpy((char *)app, (char *)&(temp->app), sizeof(struct dayApp));
      return(app);
   } 
}

/*
============================================================
|                  apiDbDeleteAppointment()                |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:07:25 1992                             |
|==========================================================|
*/
int apiDbDeleteAppointment(int year, int month, int day, int start_time)
{
   long date = intToDate(year, month, day);
   appListP app_rec = calGetAppointment(date, start_time);

   if(app_rec == NULL) return(CAL_ERROR);
   else {
      /* Delete the record. */
      calDeleteAppRecord(app_rec);
      
      /* Decrement the appointment counter. */
      (app_rec->day_rec->day_struct.app_counter)--;
      
      if(app_rec->day_rec->day_struct.app_counter == 0) {
         /* The last appointment. Delete the day record*/
         calDeleteDayRecord(app_rec->day_rec);
      }
      
      /* Update the file on disk. */
      return(calStoreInfo(NULL));
   }
}

/*
============================================================
|                  apiDbUpdateAppointment()                |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:17:08 1992                             |
|==========================================================|
*/
int apiDbUpdateAppointment(int year, int month, int day, int start_time, dayAppP rec)
{
   long date = intToDate(year, month, day);
   appListP app_rec = calGetAppointment(date, start_time);
   calListP day_rec;

   if(app_rec == NULL) return(CAL_ERROR);
   else {
      day_rec = app_rec->day_rec;
      
      /* Delete the old record. */
      calDeleteAppRecord(app_rec);
      
      /* Insert the new record. */
      calInsertAppRecord(day_rec, rec);

      /* Update the file on disk. */
      return(calStoreInfo(NULL));
   }
}



/*
============================================================
|                       calOpenFile()                      |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   : Open the db file.                               |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Sat Nov  7 22:35:07 1992                             |
|==========================================================|
*/
static int calOpenFile(char *file_name, char *status)
{
   
   db_file = fopen(file_name,status);
   if(db_file == NULL) {
      calSysError("Can not open db file");
      return(CAL_ERROR);
   } else return(CAL_OK);
}


/*
============================================================
|                      calCloseFile()                      |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Sun Nov  8 00:14:11 1992                             |
|==========================================================|
*/
static int calCloseFile()
{
   /* Check that the file is open. */
   if(db_file == NULL) {
      calSysError("db file not open");
      return(CAL_ERROR);
   }
   fclose(db_file);
   return(CAL_OK);
}


/*
============================================================
|                      calFreeStruct()                     |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:52:51 1992                             |
|==========================================================|
*/
static void calFreeStruct()
{
   calListP temp12, temp11 = cal_list;
   appListP temp21, temp22;

   /* Go over all the days. */
   while(temp11 != NULL) {
      temp21 = temp11->app_list;
      /* Go over all the appointments. */
      while(temp21 != NULL){
         temp22 = temp21->next;
         free(temp21);
         temp21 = temp22;
      }
      temp12 = temp11->next;
      free(temp11);
      temp11 = temp12;
   }
   cal_list = NULL;
         
}



/*
============================================================
|                       calLoadApp()                       |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 13:22:55 1992                             |
|==========================================================|
*/
static int calLoadApp(calListP day_rec)
{
   appListP temp = NULL;
   int i;

   for(i=0; i<day_rec->day_struct.app_counter; i++) {
      /* Allocate a record */
      if(temp == NULL) {
         /* First record. */
         day_rec->app_list = (appListP)malloc(sizeof(struct appList));
         temp = day_rec->app_list;
         temp->previous = NULL;
      } else {
         temp->next = (appListP)malloc(sizeof(struct appList));
         temp->next->previous = temp;
         temp = temp->next;
      }
      temp->day_rec = day_rec;
      temp->next = NULL;
      /* Read a record */
      if(fread((char *)&(temp->app),sizeof(struct dayApp),1,db_file) != 1) {
         calSysError("Error in reading");
         return(CAL_ERROR); 
      }
   }
   return(CAL_OK);
}


/*
============================================================
|                      calStoreInfo()                      |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 13:35:16 1992                             |
|==========================================================|
*/
static int calStoreInfo(char *file_name)
{
   int ret, i, items;
   calListP temp_list = NULL;
   appListP app_list;
   
   
   /* Open the file */
   if(file_name == NULL) file_name = db_name;
   
   if((ret = calOpenFile(file_name, CAL_WRITE)) == CAL_ERROR)
      return(ret);

   /* Store the info */
   temp_list = cal_list;
   while(temp_list != NULL) {
      if(temp_list->day_struct.app_counter != 0)
      {
         /* Write the day record. */
         if((items = fwrite((char *)&(temp_list->day_struct),
                         sizeof(struct dayStruct), 1, db_file)) != 1) {
            calSysError("Unable to write to db file");
            return(CAL_ERROR);
         }
         /* Write the appointments. */
         app_list = temp_list->app_list; 
         for(i=0; i<temp_list->day_struct.app_counter; i++)
         {
            if((items = fwrite((char *)&(app_list->app),
                sizeof(struct dayApp), 1, db_file)) != 1) {
               calSysError("Unable to write to db file");
               return(CAL_ERROR);
            }
            app_list = app_list->next;
         }
      }
      temp_list = temp_list->next;
   }

    /* Close the file. */
   if((ret = calCloseFile()) == CAL_ERROR)
      return(ret);
   
   return(CAL_OK);
}


/*
============================================================
|                    calGetAppointment()                   |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Tue Nov 17 13:58:53 1992                             |
|==========================================================|
*/
static appListP calGetAppointment(long date, int start_time)
{
   calListP day_rec = calGetDateRecord(date, CAL_CHECK );
   appListP temp;
   int i;

   if(day_rec == NULL) {
      return(NULL);
   } else {
      temp = day_rec->app_list;
      for(i=0; i<day_rec->day_struct.app_counter; i++) {
         if(temp->app.start >= start_time) break;
         else temp = temp->next;
      }
      if(temp == NULL) return(NULL);
      else {
         if(temp->app.start == start_time) return(temp);
         else return(NULL);
      }
   }
}


/*
============================================================
|                    calGetDateRecord()                    |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 16:12:35 1992                             |
|==========================================================|
*/
static calListP calGetDateRecord(long date, int create_new)
{
   int found = 0;
   calListP day_nex, day_pre, day_rec;
   appListP app_list;
   int day_comp;

   /* Find the date. */
   day_pre = NULL;   
   day_nex = cal_list;
   while(day_nex != NULL) {
      day_comp = calDateCmp(day_nex->day_struct.date,date);
      if(day_comp != DAY_COMPARE_BEFORE) {
         found = (day_comp == DAY_COMPARE_EQUAL);
         break;
      } else {
         day_pre = day_nex;
         day_nex = day_nex->next;
      }
   }
   
   if(!create_new) return((found) ? day_nex: NULL);

   if(!found) {
      /* Date record not found. Create a new one. */
      day_rec = (calListP)malloc(sizeof(struct calList));
      day_rec->day_struct.date = date;
      day_rec->day_struct.app_counter = 0;
      day_rec->app_list = NULL;

      /* Conect the new record to the previous record */
      day_rec->previous = day_pre;
      if(day_pre == NULL) {
         /* The new is the first. */
         cal_list = day_rec;
      } else {
         day_pre->next = day_rec;
      }
      
      /* Conect the new record to the next record. */
      day_rec->next = day_nex;
      if(day_nex != NULL) {
         /* Conect the next backwards. */
         day_nex->previous = day_rec;
      }
   } else day_rec = day_nex;

   return(day_rec);
}



/*
============================================================
|                   calInsertAppRecord()                   |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 16:22:26 1992                             |
|==========================================================|
*/
static appListP calInsertAppRecord(calListP day_rec, dayAppP app_rec)
{
   appListP nex_rec, new_rec, pre_rec;

   /* Find the insertion point. */
   pre_rec = NULL;
   nex_rec = day_rec->app_list;
   while(nex_rec != NULL) {
      if(nex_rec->app.start <= app_rec->start) {
         pre_rec = nex_rec;
         nex_rec = nex_rec->next;
      } else break;
   }

   /* Create a new record. */
   new_rec = (appListP)malloc(sizeof(struct appList));
   memcpy((char *)&(new_rec->app), (char *)app_rec, sizeof(struct dayApp));
   new_rec->day_rec = day_rec;
   
   /* Connect backwards. */
   new_rec->previous = pre_rec;
   if(pre_rec == NULL) {
      /* The first in the list. */
      day_rec->app_list = new_rec;
   } else {
      pre_rec->next = new_rec;
   }

   /* Conect forward. */
   new_rec->next = nex_rec;
   if(nex_rec != NULL) nex_rec->previous = new_rec;

   return(new_rec);
      
}



/*
============================================================
|                   calDeleteAppRecord()                   |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:08:06 1992                             |
|==========================================================|
*/
static void calDeleteAppRecord(appListP app_rec)
{
   if(app_rec->previous == NULL) {
      /* It was the first one. */
      app_rec->day_rec->app_list = app_rec->next;
   } else app_rec->previous->next = app_rec->next;
   if(app_rec->next != NULL) {
      app_rec->next->previous = app_rec->previous;
   }
   /* Free the memory. */
   free(app_rec);

}


/*
============================================================
|                   calDeleteDayRecord()                   |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:22:38 1992                             |
|==========================================================|
*/
static void calDeleteDayRecord(calListP day_rec)
{
   if(day_rec->previous == NULL) {
      /* It was the first one. */
      cal_list = day_rec->next;
   } else day_rec->previous->next = day_rec->next;
   if(day_rec->next != NULL) {
      day_rec->next->previous = day_rec->previous;
   }

   /* Free the memory. */
   free(day_rec);
}


/*
============================================================
|                       calDateComp()                      |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Mon Nov  9 17:57:51 1992                             |
|==========================================================|
*/
static int calDateCmp(long date1, long date2)
{
   return((date1 == date2)? DAY_COMPARE_EQUAL :
          ((date1 > date2)?DAY_COMPARE_BEFORE : DAY_COMPARE_AFTER));
}

/*
============================================================
|                       calSysError()                      |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Sun Nov  8 00:12:30 1992                             |
|==========================================================|
*/
static void calSysError(char *message)
{
   printf("\n\n\nERROR\n%s\n\n\n",message);
}



/*
============================================================
|                        intToDate()                       |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Tue Nov 17 13:25:59 1992                             |
|==========================================================|
*/
static long intToDate(int year, int month, int day)
{
   return(year*10000 + month*100 + day);
}

/*
============================================================
|                        dateToInt()                       |
|----------------------------------------------------------|
| Params : 1)                                              |
|          2)                                              |
|          3)                                              |
| Desc   :                                                 |
|                                                          |
| Returns:                                                 |
| Created by: Avrami Tzur                                  |
| At: Tue Nov 17 13:27:56 1992                             |
|==========================================================|
*/
static void dateToInt(long date, int *year, int *month, int *day)
{
   *year  = date / 10000;
   date   = date % 10000;
   *month = date / 100;
   *day   = date % 100;
}