/*
 * Copyright (c) 2013-2014 Hugh Bailey <obs.jim@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define _FILE_OFFSET_BITS 64

#include <errno.h>
#include <stdlib.h>
#include "c99defs.h"
#include "platform.h"
#include "bmem.h"
#include "utf8.h"
#include "dstr.h"

FILE *os_wfopen(const wchar_t *path, const char *mode)
{
	FILE *file = NULL;

	if (path) {
#ifdef _MSC_VER
		wchar_t *wcs_mode;

		os_utf8_to_wcs_ptr(mode, 0, &wcs_mode);
		file = _wfopen(path, wcs_mode);
		bfree(wcs_mode);
#else
		char *mbs_path;

		os_wcs_to_utf8_ptr(path, 0, &mbs_path);
		file = fopen(mbs_path, mode);
		bfree(mbs_path);
#endif
	}

	return file;
}

FILE *os_fopen(const char *path, const char *mode)
{
#ifdef _WIN32
	wchar_t *wpath = NULL;
	FILE *file = NULL;

	if (path) {
		os_utf8_to_wcs_ptr(path, 0, &wpath);
		file = os_wfopen(wpath, mode);
		bfree(wpath);
	}

	return file;
#else
	return path ? fopen(path, mode) : NULL;
#endif
}

int64_t os_fgetsize(FILE *file)
{
	int64_t cur_offset = os_ftelli64(file);
	int64_t size;
	int errval = 0;

	if (fseek(file, 0, SEEK_END) == -1)
		return -1;

	size = os_ftelli64(file);
	if (size == -1)
		errval = errno;

	if (os_fseeki64(file, cur_offset, SEEK_SET) != 0 && errval != 0)
		errno = errval;

	return size;
}

int os_fseeki64(FILE *file, int64_t offset, int origin)
{
#ifdef _MSC_VER
	return _fseeki64(file, offset, origin);
#else
	return fseeko(file, offset, origin);
#endif
}

int64_t os_ftelli64(FILE *file)
{
#ifdef _MSC_VER
	return _ftelli64(file);
#else
	return ftello(file);
#endif
}

size_t os_fread_mbs(FILE *file, char **pstr)
{
	size_t size = 0;
	size_t len = 0;

	fseek(file, 0, SEEK_END);
	size = (size_t)os_ftelli64(file);
	*pstr = NULL;

	if (size > 0) {
		char *mbstr = bmalloc(size+1);

		fseek(file, 0, SEEK_SET);
		size = fread(mbstr, 1, size, file);
		if (size == 0) {
			bfree(mbstr);
			return 0;
		}

		mbstr[size] = 0;
		len = os_mbs_to_utf8_ptr(mbstr, size, pstr);
		bfree(mbstr);
	}

	return len;
}

size_t os_fread_utf8(FILE *file, char **pstr)
{
	size_t size = 0;
	size_t size_read;
	size_t len = 0;

	*pstr = NULL;

	fseek(file, 0, SEEK_END);
	size = (size_t)os_ftelli64(file);

	if (size > 0) {
		char bom[3];
		char *utf8str;
		off_t offset;

		/* remove the ghastly BOM if present */
		fseek(file, 0, SEEK_SET);
		size_read = fread(bom, 1, 3, file);
		if (size_read != 3)
			return 0;

		offset = (astrcmp_n(bom, "\xEF\xBB\xBF", 3) == 0) ? 3 : 0;

		size -= offset;
		if (size == 0)
			return 0;

		utf8str = bmalloc(size+1);
		fseek(file, offset, SEEK_SET);

		size = fread(utf8str, 1, size, file);
		if (size == 0) {
			bfree(utf8str);
			return 0;
		}

		utf8str[size] = 0;

		*pstr = utf8str;
	}

	return len;
}

char *os_quick_read_mbs_file(const char *path)
{
	FILE *f = os_fopen(path, "rb");
	char *file_string = NULL;

	if (!f)
		return NULL;

	os_fread_mbs(f, &file_string);
	fclose(f);

	return file_string;
}

char *os_quick_read_utf8_file(const char *path)
{
	FILE *f = os_fopen(path, "rb");
	char *file_string = NULL;

	if (!f)
		return NULL;

	os_fread_utf8(f, &file_string);
	fclose(f);

	return file_string;
}

bool os_quick_write_mbs_file(const char *path, const char *str, size_t len)
{
	FILE *f = os_fopen(path, "wb");
	char *mbs = NULL;
	size_t mbs_len = 0;
	if (!f)
		return false;

	mbs_len = os_utf8_to_mbs_ptr(str, len, &mbs);
	if (mbs_len)
		fwrite(mbs, 1, mbs_len, f);
	bfree(mbs);
	fclose(f);

	return true;
}

bool os_quick_write_utf8_file(const char *path, const char *str, size_t len,
		bool marker)
{
	FILE *f = os_fopen(path, "wb");
	if (!f)
		return false;

	if (marker)
		fwrite("\xEF\xBB\xBF", 1, 3, f);
	if (len)
		fwrite(str, 1, len, f);
	fclose(f);

	return true;
}

size_t os_mbs_to_wcs(const char *str, size_t len, wchar_t *dst, size_t dst_size)
{
	size_t out_len;

	if (!str)
		return 0;

	out_len = dst ? (dst_size - 1) : mbstowcs(NULL, str, len);

	if (len && dst) {
		if (!dst_size)
			return 0;

		if (out_len)
			out_len = mbstowcs(dst, str, out_len + 1);

		dst[out_len] = 0;
	}

	return out_len;
}

size_t os_utf8_to_wcs(const char *str, size_t len, wchar_t *dst,
		size_t dst_size)
{
	size_t in_len;
	size_t out_len;

	if (!str)
		return 0;

	in_len = len ? len : strlen(str);
	out_len = dst ? (dst_size - 1) : utf8_to_wchar(str, in_len, NULL, 0, 0);

	if (out_len && dst) {
		if (!dst_size)
			return 0;

		if (out_len)
			out_len = utf8_to_wchar(str, in_len,
					dst, out_len + 1, 0);

		dst[out_len] = 0;
	}

	return out_len;
}

size_t os_wcs_to_mbs(const wchar_t *str, size_t len, char *dst, size_t dst_size)
{
	size_t out_len;

	if (!str)
		return 0;

	out_len = dst ? (dst_size - 1) : wcstombs(NULL, str, len);

	if (len && dst) {
		if (!dst_size)
			return 0;

		if (out_len)
			out_len = wcstombs(dst, str, out_len + 1);

		dst[out_len] = 0;
	}

	return out_len;
}

size_t os_wcs_to_utf8(const wchar_t *str, size_t len, char *dst,
		size_t dst_size)
{
	size_t in_len;
	size_t out_len;

	if (!str)
		return 0;

	in_len = (len != 0) ? len : wcslen(str);
	out_len = dst ? (dst_size - 1) : wchar_to_utf8(str, in_len, NULL, 0, 0);

	if (out_len && dst) {
		if (!dst_size)
			return 0;

		if (out_len)
			out_len = wchar_to_utf8(str, in_len,
					dst, out_len + 1, 0);

		dst[out_len] = 0;
	}

	return out_len;
}

size_t os_mbs_to_wcs_ptr(const char *str, size_t len, wchar_t **pstr)
{
	if (str) {
		size_t out_len = os_mbs_to_wcs(str, len, NULL, 0);

		*pstr = bmalloc((out_len + 1) * sizeof(wchar_t));
		return os_mbs_to_wcs(str, len, *pstr, out_len + 1);
	} else {
		*pstr = NULL;
		return 0;
	}
}

size_t os_utf8_to_wcs_ptr(const char *str, size_t len, wchar_t **pstr)
{
	if (str) {
		size_t out_len = os_utf8_to_wcs(str, len, NULL, 0);

		*pstr = bmalloc((out_len + 1) * sizeof(wchar_t));
		return os_utf8_to_wcs(str, len, *pstr, out_len + 1);
	} else {
		*pstr = NULL;
		return 0;
	}
}

size_t os_wcs_to_mbs_ptr(const wchar_t *str, size_t len, char **pstr)
{
	if (str) {
		size_t out_len = os_wcs_to_mbs(str, len, NULL, 0);

		*pstr = bmalloc((out_len + 1) * sizeof(char));
		return os_wcs_to_mbs(str, len, *pstr, out_len + 1);
	} else {
		*pstr = NULL;
		return 0;
	}
}

size_t os_wcs_to_utf8_ptr(const wchar_t *str, size_t len, char **pstr)
{
	if (str) {
		size_t out_len = os_wcs_to_utf8(str, len, NULL, 0);

		*pstr = bmalloc((out_len + 1) * sizeof(char));
		return os_wcs_to_utf8(str, len, *pstr, out_len + 1);
	} else {
		*pstr = NULL;
		return 0;
	}
}

size_t os_utf8_to_mbs_ptr(const char *str, size_t len, char **pstr)
{
	char    *dst    = NULL;
	size_t  out_len = 0;

	if (str) {
		wchar_t *wstr = NULL;
		size_t  wlen  = os_utf8_to_wcs_ptr(str, len, &wstr);
		out_len = os_wcs_to_mbs_ptr(wstr, wlen, &dst);
		bfree(wstr);
	}
	*pstr = dst;

	return out_len;
}

size_t os_mbs_to_utf8_ptr(const char *str, size_t len, char **pstr)
{
	char    *dst    = NULL;
	size_t  out_len = 0;

	if (str) {
		wchar_t *wstr = NULL;
		size_t  wlen  = os_mbs_to_wcs_ptr(str, len, &wstr);
		out_len = os_wcs_to_utf8_ptr(wstr, wlen, &dst);
		bfree(wstr);
	}

	*pstr = dst;
	return out_len;
}