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

#include <stdlib.h>
#include <stdio.h>

#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 an OBIDMS name.
 *
 * The function builds the directory name corresponding to an OBIDMS.
 * It checks also that the name is not too long.
 *
 * @warning The returned pointer has to be freed by the caller.
 *
 * @param dms_name the name of the OBIDMS
 *
 * @return a pointer to the directory name
 * @retvalue <directory_name> if everything is ok
 * @retvalue NULL if an error occurs
 *
 * ###Error values
 * 		- OBIDMS_MEMORY_ERROR    : something wrong occured 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 *dms_name);


/***********************************************************************
 *
 * 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
 *
 ***********************************************************************/

static char *build_directory_name(const char *dms_name)
{
	char *directory_name;

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

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

	return directory_name;
}


/*********************************************************************
 *
 * D E F I N I T I O N   O F   T H E  P U B L I C   F U N C T I O N S
 *
 *********************************************************************/

int obi_dms_exists(const char* dms_name)
{
    struct stat buffer;
	char *directory_name;
    int exists;

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

	exists = stat(directory_name, &buffer);

	free(directory_name);

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


OBIDMS_p obi_create_dms(const char* dms_name)
{
	char *directory_name;

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


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

		free(directory_name);
		return NULL;
	}

	free(directory_name);

	return obi_open_dms(dms_name);
}


OBIDMS_p obi_open_dms(const char* dms_name)
{
	OBIDMS_p	dms;
	char*	 	directory_name;
	DIR*		directory;

	dms = NULL;

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

	// try to open the directory
	directory = opendir(directory_name);
	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(directory_name);
		return NULL;
	}

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

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

	// Initialize the data structure
	strcpy(dms->directory_name, directory_name);
	dms->directory = directory;

	free(directory_name);
	return dms;
}


OBIDMS_p obi_dms(const char* dms_name)
{
	int exists = obi_dms_exists(dms_name);

	switch (exists) {
		case 0:
			return obi_create_dms(dms_name);
		case 1:
			return obi_open_dms(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;
}