#include "entry.h"

#include "utils.h"
#include "disk.h"

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

bool is_entry_id_valid(const char* entry_id) {
	if (entry_id == NULL)
		return false;

	size_t length = strlen(entry_id);

	// Check that the length is valid
	if (length == 0 || length > MAX_ENTRY_LENGTH)
		return false;

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

	// Check that the entry id is not a reserved name
	if (strcmp(entry_id, ".") == 0 || strcmp(entry_id, "..") == 0)
		return false;

	return true;
}

Result get_entry_path(const char* entry_id, char** out_path) {
	*out_path = NULL;

	// Check that the entry id is valid
	if (!is_entry_id_valid(entry_id)) {
		log_message(LOG_LEVEL_ERROR, "Invalid entry id '%s'.", entry_id);
		return FAILURE;
	}

	return format(out_path, "%s/%s", ENTRY_POOL_DIR, entry_id);
}

Result get_entry_disk_path(const char* entry_id, char** out_path) {
	*out_path = NULL;

	// Get the path of the entry
	char* entry_path;
	Result result = get_entry_path(entry_id, &entry_path);
	if (result != SUCCESS)
		return result;

	// Get the path of the disk
	result = format(out_path, "%s/disk", entry_path);

	// Free the entry path
	free(entry_path);

	return result;
}

Result get_entry_type_path(const char* entry_id, char** out_path) {
	*out_path = NULL;

	// Get the path of the entry
	char* entry_path;
	Result result = get_entry_path(entry_id, &entry_path);
	if (result != SUCCESS)
		return result;

	// Get the path of the type file
	result = format(out_path, "%s/type", entry_path);

	// Free the entry path
	free(entry_path);

	return result;
}

Result entry_exists(const char* entry_id, bool* out_exists) {
	*out_exists = false;

	// Get the path of the entry
	char* path;
	Result result = get_entry_path(entry_id, &path);
	if (result != SUCCESS)
		return result;

	// Check if the entry exists and is a directory
	struct stat st;
	bool exists = stat(path, &st) == 0 && S_ISDIR(st.st_mode);

	// Free the path
	free(path);

	// Output the result
	*out_exists = exists;

	return SUCCESS;
}

Result add_entry(const char* entry_id, EntryType type) {
	// Check that it does not exist
	bool exists;
	Result result = entry_exists(entry_id, &exists);
	if (result != SUCCESS)
		return result;

	if (exists) {
		log_message(LOG_LEVEL_ERROR, "The entry '%s' already exists.", entry_id);
		return FAILURE;
	}

	// Get the path of the entry
	char* entry_path;
	result = get_entry_path(entry_id, &entry_path);
	if (result != SUCCESS)
		return result;

	// Create the directory
	if (mkdir(entry_path, 0755) == -1) {
		log_message(LOG_LEVEL_ERROR, "Failed to create the directory '%s' (%s).", entry_path, strerror(errno));

		free(entry_path);
		return FAILURE;
	}

	// Free the entry path
	free(entry_path);

	// Get the path of the type file
	char* type_path;
	result = get_entry_type_path(entry_id, &type_path);
	if (result != SUCCESS) {
		remove_entry(entry_id);
		return result;
	}

	// Write the type file
	const char* type_string;
	switch (type) {
	case ENTRY_TYPE_ROOT:
		type_string = ENTRY_TYPE_ROOT_STRING;
		break;
	case ENTRY_TYPE_BACKED:
		type_string = ENTRY_TYPE_BACKED_STRING;
		break;
	case ENTRY_TYPE_AUTOMATIC:
		type_string = ENTRY_TYPE_AUTOMATIC_STRING;
		break;
	default:
		log_message(LOG_LEVEL_ERROR, "Invalid entry type.");
		remove_entry(entry_id);
		return FAILURE;
	}

	result = write_file(type_path, type_string);

	// Free the type path
	free(type_path);

	if (result != SUCCESS) {
		remove_entry(entry_id);
		return result;
	}

	return SUCCESS;
}

Result add_root_entry(const char* entry_id, uint64_t size) {
	// Add the entry
	Result result = add_entry(entry_id, ENTRY_TYPE_ROOT);
	if (result != SUCCESS)
		return result;

	// Get the path of the disk
	char* disk_path;
	result = get_entry_disk_path(entry_id, &disk_path);
	if (result != SUCCESS) {
		remove_entry(entry_id);
		return result;
	}

	// Create the disk
	result = create_root_disk(disk_path, size, 0644);

	// Free the disk path
	free(disk_path);

	if (result != SUCCESS) {
		remove_entry(entry_id);
		return result;
	}

	return SUCCESS;
}

Result remove_entry(const char* entry_id) {
	// Check that it exists
	bool exists;
	Result result = entry_exists(entry_id, &exists);
	if (result != SUCCESS)
		return result;

	if (!exists) {
		log_message(LOG_LEVEL_ERROR, "The entry '%s' does not exist.", entry_id);
		return FAILURE;
	}

	// Get the path of the entry
	char* entry_path;
	result = get_entry_path(entry_id, &entry_path);
	if (result != SUCCESS)
		return result;

	// Remove the directory
	if (rmdir(entry_path) == -1) {
		log_message(LOG_LEVEL_ERROR, "Failed to remove the directory '%s' (%s).", entry_path, strerror(errno));

		free(entry_path);
		return FAILURE;
	}

	// Free the entry path
	free(entry_path);

	return SUCCESS;
}

Result reset_entry(const char* entry_id) {
	// Check that it exists
	bool exists;
	Result result = entry_exists(entry_id, &exists);
	if (result != SUCCESS)
		return result;

	if (!exists) {
		log_message(LOG_LEVEL_ERROR, "The entry '%s' does not exist.", entry_id);
		return FAILURE;
	}

	// Get the path of the disk
	char* disk_path;
	result = get_entry_disk_path(entry_id, &disk_path);
	if (result != SUCCESS)
		return result;

	// Reset the disk
	result = reset_disk(disk_path);

	// Free the disk path
	free(disk_path);

	return result;
}

Result get_entry_info(const char* entry_id, EntryInfo* out_info) {
	out_info->backing_id = NULL;
	out_info->type = ENTRY_TYPE_UNKNOWN;

	// Get the path of the type file
	char* type_path;
	Result result = get_entry_type_path(entry_id, &type_path);
	if (result != SUCCESS)
		return result;

	// Read the type file
	char* type;
	result = read_file(type_path, &type);
	if (result != SUCCESS) {
		free(type_path);
		return result;
	}

	// Free the type path
	free(type_path);

	// Check the type
	if (strcmp(type, ENTRY_TYPE_ROOT_STRING) == 0)
		out_info->type = ENTRY_TYPE_ROOT;
	else if (strcmp(type, ENTRY_TYPE_BACKED_STRING) == 0)
		out_info->type = ENTRY_TYPE_BACKED;
	else if (strcmp(type, ENTRY_TYPE_AUTOMATIC_STRING) == 0)
		out_info->type = ENTRY_TYPE_AUTOMATIC;

	// Free the type
	free(type);

	// Get the path of the entry disk
	char* disk_path;
	result = get_entry_disk_path(entry_id, &disk_path);
	if (result != SUCCESS)
		return result;

	// Get the information about the disk
	result = get_disk_info(disk_path, &out_info->disk_info);

	// Free the disk path
	free(disk_path);

	if (result != SUCCESS)
		return result;

	// Check if the disk is backed
	if (out_info->disk_info.backing_file != NULL) {
		out_info->backing_id = strdup(basename(out_info->disk_info.backing_file));
		if (out_info->backing_id == NULL) {
			free_disk_info(&out_info->disk_info);
			return OUT_OF_MEMORY;
		}
	}

	return SUCCESS;
}

void free_entry_info(EntryInfo* info) {
	free(info->backing_id);
	free_disk_info(&info->disk_info);
}