/***************************************************************************
 *   Copyright (C) 2007 by Dominic Rath                                    *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "log.h"
#include "configuration.h"
#include "fileio.h"

struct fileio {
	char *url;
	size_t size;
	enum fileio_type type;
	enum fileio_access access;
	FILE *file;
};

static inline int fileio_close_local(struct fileio *fileio)
{
	int retval = fclose(fileio->file);
	if (retval != 0) {
		if (retval == EBADF)
			LOG_ERROR("BUG: fileio->file not a valid file descriptor");
		else
			LOG_ERROR("couldn't close %s: %s", fileio->url, strerror(errno));

		return ERROR_FILEIO_OPERATION_FAILED;
	}

	return ERROR_OK;
}

static inline int fileio_open_local(struct fileio *fileio)
{
	char file_access[4];
	ssize_t file_size;

	switch (fileio->access) {
		case FILEIO_READ:
			strcpy(file_access, "r");
			break;
		case FILEIO_WRITE:
			strcpy(file_access, "w");
			break;
		case FILEIO_READWRITE:
			strcpy(file_access, "w+");
			break;
		case FILEIO_APPEND:
			strcpy(file_access, "a");
			break;
		case FILEIO_APPENDREAD:
			strcpy(file_access, "a+");
			break;
		default:
			LOG_ERROR("BUG: access neither read, write nor readwrite");
			return ERROR_COMMAND_SYNTAX_ERROR;
	}

	/* win32 always opens in binary mode */
#ifndef _WIN32
	if (fileio->type == FILEIO_BINARY)
#endif
		strcat(file_access, "b");

	fileio->file = open_file_from_path(fileio->url, file_access);
	if (!fileio->file) {
		LOG_ERROR("couldn't open %s", fileio->url);
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	file_size = 0;

	if ((fileio->access != FILEIO_WRITE) || (fileio->access == FILEIO_READWRITE)) {
		/* NB! Here we use fseek() instead of stat(), since stat is a
		 * more advanced operation that might not apply to e.g. a disk path
		 * that refers to e.g. a tftp client */
		int result, result2;

		result = fseek(fileio->file, 0, SEEK_END);

		file_size = ftell(fileio->file);

		result2 = fseek(fileio->file, 0, SEEK_SET);

		if ((file_size < 0) || (result < 0) || (result2 < 0)) {
			fileio_close_local(fileio);
			return ERROR_FILEIO_OPERATION_FAILED;
		}
	}

	fileio->size = file_size;

	return ERROR_OK;
}

int fileio_open(struct fileio **fileio, const char *url,
		enum fileio_access access_type, enum fileio_type type)
{
	int retval;
	struct fileio *tmp;

	tmp = malloc(sizeof(struct fileio));

	tmp->type = type;
	tmp->access = access_type;
	tmp->url = strdup(url);

	retval = fileio_open_local(tmp);

	if (retval != ERROR_OK) {
		free(tmp->url);
		free(tmp);
		return retval;
	}

	*fileio = tmp;

	return ERROR_OK;
}

int fileio_close(struct fileio *fileio)
{
	int retval;

	retval = fileio_close_local(fileio);

	free(fileio->url);
	free(fileio);

	return retval;
}

int fileio_seek(struct fileio *fileio, size_t position)
{
	int retval;

	retval = fseek(fileio->file, position, SEEK_SET);

	if (retval != 0) {
		LOG_ERROR("couldn't seek file %s: %s", fileio->url, strerror(errno));
		return ERROR_FILEIO_OPERATION_FAILED;
	}

	return ERROR_OK;
}

static int fileio_local_read(struct fileio *fileio, size_t size, void *buffer,
		size_t *size_read)
{
	ssize_t retval;

	retval = fread(buffer, 1, size, fileio->file);
	*size_read = (retval >= 0) ? retval : 0;

	return (retval < 0) ? retval : ERROR_OK;
}

int fileio_read(struct fileio *fileio, size_t size, void *buffer,
		size_t *size_read)
{
	return fileio_local_read(fileio, size, buffer, size_read);
}

int fileio_read_u32(struct fileio *fileio, uint32_t *data)
{
	int retval;
	uint8_t buf[4];
	size_t size_read;

	retval = fileio_local_read(fileio, sizeof(uint32_t), buf, &size_read);

	if (ERROR_OK == retval && sizeof(uint32_t) != size_read)
		retval = -EIO;
	if (ERROR_OK == retval)
		*data = be_to_h_u32(buf);

	return retval;
}

static int fileio_local_fgets(struct fileio *fileio, size_t size, void *buffer)
{
	if (fgets(buffer, size, fileio->file) == NULL)
		return ERROR_FILEIO_OPERATION_FAILED;

	return ERROR_OK;
}

int fileio_fgets(struct fileio *fileio, size_t size, void *buffer)
{
	return fileio_local_fgets(fileio, size, buffer);
}

static int fileio_local_write(struct fileio *fileio, size_t size,
		const void *buffer, size_t *size_written)
{
	ssize_t retval;

	retval = fwrite(buffer, 1, size, fileio->file);
	*size_written = (retval >= 0) ? retval : 0;

	return (retval < 0) ? retval : ERROR_OK;
}

int fileio_write(struct fileio *fileio, size_t size, const void *buffer,
		size_t *size_written)
{
	int retval;

	retval = fileio_local_write(fileio, size, buffer, size_written);

	if (retval == ERROR_OK)
		fileio->size += *size_written;

	return retval;
}

int fileio_write_u32(struct fileio *fileio, uint32_t data)
{
	int retval;
	uint8_t buf[4];
	h_u32_to_be(buf, data);
	size_t size_written;

	retval = fileio_write(fileio, 4, buf, &size_written);

	if (ERROR_OK == retval && size_written != sizeof(uint32_t))
		retval = -EIO;

	return retval;
}

/**
 * FIX!!!!
 *
 * For now this can not fail, but that's because a seek was executed
 * on startup.
 *
 * Avoiding the seek on startup opens up for using streams.
 *
 */
int fileio_size(struct fileio *fileio, size_t *size)
{
	*size = fileio->size;

	return ERROR_OK;
}
