/*
 * libdivecomputer
 *
 * Copyright (C) 2012 Jef Driesen
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA
 */

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

#ifdef _WIN32
#include <windows.h>
#endif

#include "context-private.h"

struct dc_context_t {
	dc_loglevel_t loglevel;
	dc_logfunc_t logfunc;
	void *userdata;
#ifdef ENABLE_LOGGING
	char msg[4096];
#endif
};

#ifdef ENABLE_LOGGING
static void
logfunc (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *msg, void *userdata)
{
	const char *loglevels[] = {"NONE", "ERROR", "WARNING", "INFO", "DEBUG", "ALL"};

	fprintf (stderr, "%s: %s [in %s:%d (%s)]\n", loglevels[loglevel], msg, file, line, function);
}
#endif

dc_status_t
dc_context_new (dc_context_t **out)
{
	dc_context_t *context = NULL;

	if (out == NULL)
		return DC_STATUS_INVALIDARGS;

	context = (dc_context_t *) malloc (sizeof (dc_context_t));
	if (context == NULL)
		return DC_STATUS_NOMEMORY;

#ifdef ENABLE_LOGGING
	context->loglevel = DC_LOGLEVEL_WARNING;
	context->logfunc = logfunc;
#else
	context->loglevel = DC_LOGLEVEL_NONE;
	context->logfunc = NULL;
#endif
	context->userdata = NULL;

#ifdef ENABLE_LOGGING
	memset (context->msg, 0, sizeof (context->msg));
#endif

	*out = context;

	return DC_STATUS_SUCCESS;
}

dc_status_t
dc_context_free (dc_context_t *context)
{
	free (context);

	return DC_STATUS_SUCCESS;
}

dc_status_t
dc_context_set_loglevel (dc_context_t *context, dc_loglevel_t loglevel)
{
	if (context == NULL)
		return DC_STATUS_INVALIDARGS;

#ifdef ENABLE_LOGGING
	context->loglevel = loglevel;
#endif

	return DC_STATUS_SUCCESS;
}

dc_status_t
dc_context_set_logfunc (dc_context_t *context, dc_logfunc_t logfunc, void *userdata)
{
	if (context == NULL)
		return DC_STATUS_INVALIDARGS;

#ifdef ENABLE_LOGGING
	context->logfunc = logfunc;
	context->userdata = userdata;
#endif

	return DC_STATUS_SUCCESS;
}

dc_status_t
dc_context_log (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, const char *format, ...)
{
#ifdef ENABLE_LOGGING
	va_list ap;
#endif

	if (context == NULL)
		return DC_STATUS_INVALIDARGS;

#ifdef ENABLE_LOGGING
	if (loglevel > context->loglevel)
		return DC_STATUS_SUCCESS;

	if (context->logfunc == NULL)
		return DC_STATUS_SUCCESS;

	va_start (ap, format);
	vsnprintf (context->msg, sizeof (context->msg), format, ap);
	va_end (ap);

	context->logfunc (context, loglevel, file, line, function, context->msg, context->userdata);
#endif

	return DC_STATUS_SUCCESS;
}

dc_status_t
dc_context_syserror (dc_context_t *context, dc_loglevel_t loglevel, const char *file, unsigned int line, const char *function, int errcode)
{
	const char *errmsg = NULL;

#ifdef _WIN32
	char buffer[256];

	DWORD rc = FormatMessageA (FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
			NULL, errcode, 0, buffer, sizeof (buffer), NULL);

	/* Remove the CRLF and period at the end of the error message. */
	while (rc > 0 && (
		buffer[rc - 1] == '\n' ||
		buffer[rc - 1] == '\r' ||
		buffer[rc - 1] == '.'))
	{
		buffer[rc - 1] = '\0';
		rc--;
	}

	if (rc > 0)
		errmsg = buffer;
#elif defined (HAVE_STRERROR_R)
	char buffer[256];

	int rc = strerror_r (errcode, buffer, sizeof (buffer));
	if (rc == 0)
		errmsg = buffer;
#else
	/* Fallback to the non-threadsafe function. */
	errmsg = strerror (errcode);
#endif

	if (errmsg == NULL)
		errmsg = "Unknown system error";

	return dc_context_log (context, loglevel, file, line, function, "%s (%d)", errmsg, errcode);
}