#include "backing.h"

#include "disk.h"
#include "entry.h"

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <libgen.h>
#include <sys/stat.h>

bool IsBackingIdentifierValid(const char* backing_identifier) {
	if (backing_identifier == NULL)
		return false;

	// Check that the identifier is not empty or too long
	size_t length = strlen(backing_identifier);
	if (length == 0 || length > 64)
		return false;

	// Check that the identifier does not contain any slashes
	for (size_t i = 0; i < length; i++)
		if (backing_identifier[i] == '/')
			return false;

	// Check that the identifier is not "." or ".."
	if (strcmp(backing_identifier, ".") == 0 || strcmp(backing_identifier, "..") == 0)
		return false;

	// Check that the identifier starts with a number
	if (backing_identifier[0] < '0' || backing_identifier[0] > '9')
		return false;

	return true;
}

int GetBackingIndex(const char* backing_identifier) {
	// Check that the identifier is valid
	if (!IsBackingIdentifierValid(backing_identifier))
		return -1;

	// Get the index
	return atoi(backing_identifier);
}

Status GetBackingPoolPath(char** _backing_pool_path) {
	return Format(_backing_pool_path, "/var/lib/sandbox/backings");
}

Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path) {
	// Check that the identifier is valid, as it will be used in a path
	if (!IsBackingIdentifierValid(backing_identifier)) {
		Log(LOG_LEVEL_ERROR, "Invalid backing identifier '%s'.", backing_identifier);
		return FAILURE;
	}

	// Get the backing pool path
	char* backing_pool_path = NULL;
	Status status = GetBackingPoolPath(&backing_pool_path);
	if (status != SUCCESS)
		return status;

	// Format the backing path
	status = Format(_backing_path, "%s/%s", backing_pool_path, backing_identifier);
	free(backing_pool_path);

	return status;
}