/*
 * obidms.c
 *
 *  @date 23 May 2015
 *  @Author: coissac
 */

#include <obidms.h>


/***********************************************************************
 *
 * D E C L A R A T I O N   O F   T H E  P R I V A T E   F U N C T I O N S
 *
 ***********************************************************************/


/**
 * Internal function building the directory name from a OBIDMS name.
 *
 * The function build the directory name corresponding to a OBIDMS.
 * It checks also that the name is not too long.
 *
 * @warning The returned pointer has to be freed by the caller.
 *
 * @param name the name of the OBIDMS
 *
 * @return a pointer to the directory name
 * @retvalue <dirdbname> if everything is ok
 * @retvalue NULL if an error occurs
 *
 * ###Error values
 * 		- OBIDMS_MEMORY_ERROR    : something wrong occurs during memory allocation.
 * 		- OBIDMS_LONG_NAME_ERROR : the database name exceeds the limit.
 *
 * @since May 2015
 * @author Eric Coissac (eric.coissac@metabarcoding.org)
 */
static char *build_directory_name(const char *name) {

	char *dirdbname;

	// Build the database directory name
	if (asprintf(&dirdbname,"%s.obidms",name) < 0)
	{
		obi_set_errno(OBIDMS_MEMORY_ERROR);
		return NULL;
	}

	// Test if the database name is not too long
	if (strlen(dirdbname) >= OBIDMS_MAX_NAME)
	{
		obi_set_errno(OBIDMS_LONG_NAME_ERROR);
		free(dirdbname);
		return NULL;
	}

	return dirdbname;
}

/***********************************************************************
 *
 * D E F I N I T I O N   O F   T H E  P R I V A T E   F U N C T I O N S
 *
 ***********************************************************************/

int obi_dms_exists(const char* name) {
    struct stat buffer;
	char *dirdbname;
    int exist;

	// Build and check the directory name
	dirdbname = build_directory_name(name);
	if (dirdbname==NULL)
		return -1;

	exist = stat(dirdbname,&buffer);

	free(dirdbname);

    if(exist == 0)
        return 1;
    else // -1
        return 0;
}


OBIDMS_p obi_create_dms(const char *name) {
	char *dirdbname;

	// Build and check the directory name
	dirdbname = build_directory_name(name);
	if (dirdbname==NULL)
		return NULL;


	// Try to create the directory
	if (mkdir(dirdbname,0x777) < 0)
	{
		if (errno==EEXIST)
			obi_set_errno(OBIDMS_EXIST_ERROR);
		else
			obi_set_errno(OBIDMS_UNKNOWN_ERROR);

		free(dirdbname);
		return NULL;
	}

	free(dirdbname);

	return obi_open_dms(name);
}

OBIDMS_p obi_open_dms(const char *name) {
	OBIDMS_p dms=NULL;
	char *dirdbname;
	DIR  *directory;

	// Build and check the directory name
	dirdbname = build_directory_name(name);
	if (dirdbname==NULL)
		return NULL;

	// try to open the directory
	directory = opendir(dirdbname);
	if (directory==NULL) {
		switch (errno) {
		case ENOENT:
			obi_set_errno(OBIDMS_NOT_EXIST_ERROR);
			break;

		case EACCES:
			obi_set_errno(OBIDMS_ACCESS_ERROR);
			break;

		case ENOMEM:
			obi_set_errno(OBIDMS_MEMORY_ERROR);
			break;

		default:
			obi_set_errno(OBIDMS_UNKNOWN_ERROR);
		}
		free(dirdbname);
		return NULL;
	}

	// Allocate the data structure
	dms = (OBIDMS_p) malloc(sizeof(OBIDMS_t));

	if (dms==NULL)
	{
		obi_set_errno(OBIDMS_MEMORY_ERROR);
		free(dirdbname);
		return NULL;
	}

	// Initialise the data structure
	strcpy(dms->dirname,dirdbname);
	dms->directory=directory;

	free(dirdbname);
	return dms;
}

OBIDMS_p obi_dms(const char *name) {
	int exist = obi_dms_exists(name);

	switch (exist) {
		case 0:
			return obi_create_dms(name);
		case 1:
			return obi_open_dms(name);
	};

	return NULL;

}


int obi_close_dms(OBIDMS_p dms) {

	if (dms != NULL)
	{
		if (closedir(dms->directory) < 0)
		{
			obi_set_errno(OBIDMS_MEMORY_ERROR);
			free(dms);
			return -1;
		}

		free(dms);

	}

	return 0;
}