/*
 * Copyright (c) 2010-2011 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libusb
 * @{
 */
/** @file
 * @brief Debugging support.
 */
#include <adt/list.h>
#include <fibril_synch.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <usb/debug.h>

/** Debugging tag. */
typedef struct {
	/** Linked list member. */
	link_t link;
	/** Tag name.
	 * We always have a private copy of the name.
	 */
	char *tag;
	/** Enabled level of debugging. */
	int level;
} usb_debug_tag_t;

/** Get instance of usb_debug_tag_t from link_t. */
#define USB_DEBUG_TAG_INSTANCE(iterator) \
	list_get_instance(iterator, usb_debug_tag_t, link)

/** List of all known tags. */
static LIST_INITIALIZE(tag_list);
/** Mutex guard for the list of all tags. */
static FIBRIL_MUTEX_INITIALIZE(tag_list_guard);

/** Level of logging messages. */
static usb_log_level_t log_level = USB_LOG_LEVEL_WARNING;
/** Prefix for logging messages. */
static const char *log_prefix = "usb";
/** Serialization mutex for logging functions. */
static FIBRIL_MUTEX_INITIALIZE(log_serializer);
static FILE *log_stream = NULL;

/** Find or create new tag with given name.
 *
 * @param tagname Tag name.
 * @return Debug tag structure.
 * @retval NULL Out of memory.
 */
static usb_debug_tag_t *get_tag(const char *tagname)
{
	link_t *link;
	for (link = tag_list.next; \
	    link != &tag_list; \
	    link = link->next) {
		usb_debug_tag_t *tag = USB_DEBUG_TAG_INSTANCE(link);
		if (str_cmp(tag->tag, tagname) == 0) {
			return tag;
		}
	}

	/*
	 * Tag not found, we will create a new one.
	 */
	usb_debug_tag_t *new_tag = malloc(sizeof(usb_debug_tag_t));
	int rc = asprintf(&new_tag->tag, "%s", tagname);
	if (rc < 0) {
		free(new_tag);
		return NULL;
	}
	list_initialize(&new_tag->link);
	new_tag->level = 1;

	/*
	 * Append it to the end of known tags.
	 */
	list_append(&new_tag->link, &tag_list);

	return new_tag;
}

/** Print debugging information.
 * If the tag is used for the first time, its structures are automatically
 * created and initial verbosity level is set to 1.
 *
 * @param tagname Tag name.
 * @param level Level (verbosity) of the message.
 * @param format Formatting string for printf().
 */
void usb_dprintf(const char *tagname, int level, const char *format, ...)
{
	fibril_mutex_lock(&tag_list_guard);
	usb_debug_tag_t *tag = get_tag(tagname);
	if (tag == NULL) {
		printf("USB debug: FATAL ERROR - failed to create tag.\n");
		goto leave;
	}

	if (tag->level < level) {
		goto leave;
	}

	va_list args;
	va_start(args, format);

	printf("[%s:%d]: ", tagname, level);
	vprintf(format, args);

	va_end(args);

leave:
	fibril_mutex_unlock(&tag_list_guard);
}

/** Enable debugging prints for given tag.
 *
 * Setting level to <i>n</i> will cause that only printing messages
 * with level lower or equal to <i>n</i> will be printed.
 *
 * @param tagname Tag name.
 * @param level Enabled level.
 */
void usb_dprintf_enable(const char *tagname, int level)
{
	fibril_mutex_lock(&tag_list_guard);
	usb_debug_tag_t *tag = get_tag(tagname);
	if (tag == NULL) {
		printf("USB debug: FATAL ERROR - failed to create tag.\n");
		goto leave;
	}

	tag->level = level;

leave:
	fibril_mutex_unlock(&tag_list_guard);
}

/** Enable logging.
 *
 * @param level Maximal enabled level (including this one).
 * @param message_prefix Prefix for each printed message.
 */
void usb_log_enable(usb_log_level_t level, const char *message_prefix)
{
	log_prefix = message_prefix;
	log_level = level;
	if (log_stream == NULL) {
		char *fname;
		int rc = asprintf(&fname, "/log/%s", message_prefix);
		if (rc > 0) {
			log_stream = fopen(fname, "w");
			free(fname);
		}
	}
}


static const char *log_level_name(usb_log_level_t level)
{
	switch (level) {
		case USB_LOG_LEVEL_FATAL:
			return " FATAL";
		case USB_LOG_LEVEL_ERROR:
			return " ERROR";
		case USB_LOG_LEVEL_WARNING:
			return " WARN";
		case USB_LOG_LEVEL_INFO:
			return " info";
		default:
			return "";
	}
}

/** Print logging message.
 *
 * @param level Verbosity level of the message.
 * @param format Formatting directive.
 */
void usb_log_printf(usb_log_level_t level, const char *format, ...)
{
	FILE *screen_stream = NULL;
	switch (level) {
		case USB_LOG_LEVEL_FATAL:
		case USB_LOG_LEVEL_ERROR:
			screen_stream = stderr;
			break;
		default:
			screen_stream = stdout;
			break;
	}
	assert(screen_stream != NULL);

	va_list args;

	/*
	 * Serialize access to log files.
	 * Always print to log file, to screen print only when the enabled
	 * log level is high enough.
	 */
	fibril_mutex_lock(&log_serializer);

	const char *level_name = log_level_name(level);

	if (log_stream != NULL) {
		va_start(args, format);

		fprintf(log_stream, "[%s]%s: ", log_prefix, level_name);
		vfprintf(log_stream, format, args);
		fflush(log_stream);

		va_end(args);
	}

	if (level <= log_level) {
		va_start(args, format);

		fprintf(screen_stream, "[%s]%s: ", log_prefix, level_name);
		vfprintf(screen_stream, format, args);
		fflush(screen_stream);

		va_end(args);
	}

	fibril_mutex_unlock(&log_serializer);
}


#define REMAINDER_STR_FMT " (%zu)..."
/* string + terminator + number width (enough for 4GB)*/
#define REMAINDER_STR_LEN (5 + 1 + 10)
#define BUFFER_DUMP_GROUP_SIZE 4
#define BUFFER_DUMP_LEN 240 /* Ought to be enough for everybody ;-). */
static fibril_local char buffer_dump[BUFFER_DUMP_LEN];

/** Dump buffer into string.
 *
 * The function dumps given buffer into hexadecimal format and stores it
 * in a static fibril local string.
 * That means that you do not have to deallocate the string (actually, you
 * can not do that) and you do not have to guard it against concurrent
 * calls to it.
 * The only limitation is that each call rewrites the buffer again.
 * Thus, it is necessary to copy the buffer elsewhere (that includes printing
 * to screen or writing to file).
 * Since this function is expected to be used for debugging prints only,
 * that is not a big limitation.
 *
 * @warning You cannot use this function twice in the same printf
 * (see detailed explanation).
 *
 * @param buffer Buffer to be printed (can be NULL).
 * @param size Size of the buffer in bytes (can be zero).
 * @param dumped_size How many bytes to actually dump (zero means all).
 * @return Dumped buffer as a static (but fibril local) string.
 */
const char *usb_debug_str_buffer(uint8_t *buffer, size_t size,
    size_t dumped_size)
{
	/*
	 * Remove previous string (that might also reveal double usage of
	 * this function).
	 */
	bzero(buffer_dump, BUFFER_DUMP_LEN);

	if (buffer == NULL) {
		return "(null)";
	}
	if (size == 0) {
		return "(empty)";
	}
	if ((dumped_size == 0) || (dumped_size > size)) {
		dumped_size = size;
	}

	/* How many bytes are available in the output buffer. */
	size_t buffer_remaining_size = BUFFER_DUMP_LEN - 1 - REMAINDER_STR_LEN;
	char *it = buffer_dump;

	size_t index = 0;

	while (index < size) {
		/* Determine space before the number. */
		const char *space_before;
		if (index == 0) {
			space_before = "";
		} else if ((index % BUFFER_DUMP_GROUP_SIZE) == 0) {
			space_before = "  ";
		} else {
			space_before = " ";
		}

		/*
		 * Add the byte as a hexadecimal number plus the space.
		 * We do it into temporary buffer to ensure that always
		 * the whole byte is printed.
		 */
		int val = buffer[index];
		char current_byte[16];
		int printed = snprintf(current_byte, 16,
		    "%s%02x", space_before, val);
		if (printed < 0) {
			break;
		}

		if ((size_t) printed > buffer_remaining_size) {
			break;
		}

		/* We can safely add 1, because space for end 0 is reserved. */
		str_append(it, buffer_remaining_size + 1, current_byte);

		buffer_remaining_size -= printed;
		/* Point at the terminator 0. */
		it += printed;
		index++;

		if (index >= dumped_size) {
			break;
		}
	}

	/* Add how many bytes were not printed. */
	if (index < size) {
		snprintf(it, REMAINDER_STR_LEN,
		    REMAINDER_STR_FMT, size - index);
	}

	return buffer_dump;
}


/**
 * @}
 */