/****************************************************************************
 *
 *   Copyright (c) 2016 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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
 * COPYRIGHT OWNER OR CONTRIBUTORS 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.
 *
 ****************************************************************************/

#include "log_writer_file.h"
#include "messages.h"
#include <fcntl.h>
#include <string.h>

#include <mathlib/mathlib.h>
#include <px4_posix.h>
#ifdef __PX4_NUTTX
#include <systemlib/hardfault_log.h>
#endif /* __PX4_NUTTX */

namespace px4
{
namespace logger
{
constexpr size_t LogWriterFile::_min_write_chunk;


LogWriterFile::LogWriterFile(size_t buffer_size) :
	//We always write larger chunks (orb messages) to the buffer, so the buffer
	//needs to be larger than the minimum write chunk (300 is somewhat arbitrary)
	_buffer_size(math::max(buffer_size, _min_write_chunk + 300))
{
	pthread_mutex_init(&_mtx, nullptr);
	pthread_cond_init(&_cv, nullptr);
	/* allocate write performance counters */
	_perf_write = perf_alloc(PC_ELAPSED, "logger_sd_write");
	_perf_fsync = perf_alloc(PC_ELAPSED, "logger_sd_fsync");
}

bool LogWriterFile::init()
{
	return true;
}

LogWriterFile::~LogWriterFile()
{
	pthread_mutex_destroy(&_mtx);
	pthread_cond_destroy(&_cv);
	perf_free(_perf_write);
	perf_free(_perf_fsync);

	if (_fd >= 0) {
		::close(_fd);
	}

	if (_buffer) {
		delete[] _buffer;
	}
}

void LogWriterFile::start_log(const char *filename)
{
	// register the current file with the hardfault handler: if the system crashes,
	// the hardfault handler will append the crash log to that file on the next reboot.
	// Note that we don't deregister it when closing the log, so that crashes after disarming
	// are appended as well (the same holds for crashes before arming, which can be a bit misleading)
	int ret = hardfault_store_filename(filename);

	if (ret) {
		PX4_ERR("Failed to register ULog file to the hardfault handler (%i)", ret);
	}

	_fd = ::open(filename, O_CREAT | O_WRONLY, PX4_O_MODE_666);

	if (_fd < 0) {
		PX4_ERR("Can't open log file %s, errno: %d", filename, errno);
		_should_run = false;
		return;
	}

	if (_buffer == nullptr) {
		_buffer = new uint8_t[_buffer_size];

		if (_buffer == nullptr) {
			PX4_ERR("Can't create log buffer");
			::close(_fd);
			_fd = -1;
			_should_run = false;
			return;
		}
	}

	PX4_INFO("Opened log file: %s", filename);
	_should_run = true;
	_running = true;

	// Clear buffer and counters
	_head = 0;
	_count = 0;
	_total_written = 0;
	notify();
}

int LogWriterFile::hardfault_store_filename(const char *log_file)
{
#ifdef __PX4_NUTTX
	int fd = open(HARDFAULT_ULOG_PATH, O_TRUNC | O_WRONLY | O_CREAT);

	if (fd < 0) {
		return -errno;
	}

	int n = strlen(log_file);

	if (n >= HARDFAULT_MAX_ULOG_FILE_LEN) {
		PX4_ERR("ULog file name too long (%s, %i>=%i)\n", log_file, n, HARDFAULT_MAX_ULOG_FILE_LEN);
		return -EINVAL;
	}

	if (n + 1 != ::write(fd, log_file, n + 1)) {
		close(fd);
		return -errno;
	}

	int ret = close(fd);

	if (ret != 0) {
		return -errno;
	}

#endif /* __PX4_NUTTX */

	return 0;
}

void LogWriterFile::stop_log()
{
	_should_run = false;
	notify();
}

int LogWriterFile::thread_start()
{
	pthread_attr_t thr_attr;
	pthread_attr_init(&thr_attr);

	sched_param param;
	/* low priority, as this is expensive disk I/O */
	param.sched_priority = SCHED_PRIORITY_DEFAULT - 40;
	(void)pthread_attr_setschedparam(&thr_attr, &param);

	pthread_attr_setstacksize(&thr_attr, PX4_STACK_ADJUSTED(1072));

	int ret = pthread_create(&_thread, &thr_attr, &LogWriterFile::run_helper, this);
	pthread_attr_destroy(&thr_attr);

	return ret;
}

void LogWriterFile::thread_stop()
{
	// this will terminate the main loop of the writer thread
	_exit_thread = true;
	_should_run = false;

	notify();

	// wait for thread to complete
	int ret = pthread_join(_thread, nullptr);

	if (ret) {
		PX4_WARN("join failed: %d", ret);
	}

}

void *LogWriterFile::run_helper(void *context)
{
	px4_prctl(PR_SET_NAME, "log_writer_file", px4_getpid());

	reinterpret_cast<LogWriterFile *>(context)->run();
	return nullptr;
}

void LogWriterFile::run()
{
	while (!_exit_thread) {
		// Outer endless loop
		// Wait for _should_run flag
		while (!_exit_thread) {
			bool start = false;
			pthread_mutex_lock(&_mtx);
			pthread_cond_wait(&_cv, &_mtx);
			start = _should_run;
			pthread_mutex_unlock(&_mtx);

			if (start) {
				break;
			}
		}

		if (_exit_thread) {
			break;
		}

		int poll_count = 0;
		int written = 0;

		while (true) {
			size_t available = 0;
			void *read_ptr = nullptr;
			bool is_part = false;

			/* lock _buffer
			 * wait for sufficient data, cycle on notify()
			 */
			pthread_mutex_lock(&_mtx);

			while (true) {
				available = get_read_ptr(&read_ptr, &is_part);

				/* if sufficient data available or partial read or terminating, exit this wait loop */
				if ((available >= _min_write_chunk) || is_part || !_should_run) {
					/* GOTO end of block */
					break;
				}

				/* wait for a call to notify()
				 * this call unlocks the mutex while waiting, and returns with the mutex locked
				 */
				pthread_cond_wait(&_cv, &_mtx);
			}

			pthread_mutex_unlock(&_mtx);
			written = 0;

			if (available > 0) {
				perf_begin(_perf_write);
				written = ::write(_fd, read_ptr, available);
				perf_end(_perf_write);

				/* call fsync periodically to minimize potential loss of data */
				if (++poll_count >= 100) {
					perf_begin(_perf_fsync);
					::fsync(_fd);
					perf_end(_perf_fsync);
					poll_count = 0;
				}

				if (written < 0) {
					PX4_WARN("error writing log file");
					_should_run = false;
					/* GOTO end of block */
					break;
				}

				pthread_mutex_lock(&_mtx);
				/* subtract bytes written from number in _buffer (_count -= written) */
				mark_read(written);
				pthread_mutex_unlock(&_mtx);

				_total_written += written;
			}

			if (!_should_run && written == static_cast<int>(available) && !is_part) {
				// Stop only when all data written
				_running = false;
				_head = 0;
				_count = 0;

				if (_fd >= 0) {
					int res = ::close(_fd);
					_fd = -1;

					if (res) {
						PX4_WARN("error closing log file");

					} else {
						PX4_INFO("closed logfile, bytes written: %zu", _total_written);
					}
				}

				break;
			}
		}
	}
}

int LogWriterFile::write_message(void *ptr, size_t size, uint64_t dropout_start)
{
	if (_need_reliable_transfer) {
		int ret;

		while ((ret = write(ptr, size, dropout_start)) == -1) {
			unlock();
			notify();
			usleep(3000);
			lock();
		}

		return ret;
	}

	return write(ptr, size, dropout_start);
}

int LogWriterFile::write(void *ptr, size_t size, uint64_t dropout_start)
{
	if (!is_started()) {
		return 0;
	}

	// Bytes available to write
	size_t available = _buffer_size - _count;
	size_t dropout_size = 0;

	if (dropout_start) {
		dropout_size = sizeof(ulog_message_dropout_s);
	}

	if (size + dropout_size > available) {
		// buffer overflow
		return -1;
	}

	if (dropout_start) {
		//write dropout msg
		ulog_message_dropout_s dropout_msg;
		dropout_msg.duration = (uint16_t)(hrt_elapsed_time(&dropout_start) / 1000);
		write_no_check(&dropout_msg, sizeof(dropout_msg));
	}

	write_no_check(ptr, size);
	return 0;
}

void LogWriterFile::write_no_check(void *ptr, size_t size)
{
	size_t n = _buffer_size - _head;	// bytes to end of the buffer

	uint8_t *buffer_c = reinterpret_cast<uint8_t *>(ptr);

	if (size > n) {
		// Message goes over the end of the buffer
		memcpy(&(_buffer[_head]), buffer_c, n);
		_head = 0;

	} else {
		n = 0;
	}

	// now: n = bytes already written
	size_t p = size - n;	// number of bytes to write
	memcpy(&(_buffer[_head]), &(buffer_c[n]), p);
	_head = (_head + p) % _buffer_size;
	_count += size;
}

size_t LogWriterFile::get_read_ptr(void **ptr, bool *is_part)
{
	// bytes available to read
	int read_ptr = _head - _count;

	if (read_ptr < 0) {
		read_ptr += _buffer_size;
		*ptr = &_buffer[read_ptr];
		*is_part = true;
		return _buffer_size - read_ptr;

	} else {
		*ptr = &_buffer[read_ptr];
		*is_part = false;
		return _count;
	}
}

}
}
