/* ------------------------------------------------------------------
 * Asynchorous verification related variables and utilities
 *
 * -----------------------------------------------------------------*/
#include <stdlib.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>

#include "async_veri.h"
#include "test_commands.h"

/* async verification list
 * Note:
 *   1) access to this list must be protected by mutex lock
 */
static struct stm_test_run_node_type *stm_async_veri_node_list = NULL; /* list head for async verification node list */
static struct stm_test_run_node_type *ptr_async_veri_node_last = NULL; /* list tail for async verification node list */
pthread_mutex_t mux_async_list = PTHREAD_MUTEX_INITIALIZER; /* mutex lock, for async node list */

/* async verification thread id */
pthread_t thread_async_id;

/* global const */
#ifdef LOCAL_TEST_STUB
const char *ETB_FILEPATH = "./debug_stm/ETB";
#else
#warning Need to define ETB filepath
const char *ETB_FILEPATH = "/sys/kernel/debug/stm/ETB";
#endif

/* for async verification thread dependencies */
static bool async_verification_finished = false;
pthread_cond_t cond_async_veri = PTHREAD_COND_INITIALIZER;
pthread_mutex_t mux_async_veri = PTHREAD_MUTEX_INITIALIZER;
static bool all_commands_sent = false;

/* set async_verification_finished */
void set_async_verification_finished(bool finished)
{
	async_verification_finished = finished;
}

/* get async_verification_finished */
bool get_async_verification_finished(void)
{
	return async_verification_finished;
}

/* to initialize data and structures related to async verification list
 * Input: none
 * Return: none
 */
inline void INIT_ASYNC_VERI_LIST(void)
{
	/* init of mutex */
	pthread_mutex_init(&mux_async_list, NULL);
	return;
}

/* to append ptr_test_node to async verification list
 * Input:
 *   - ptr_test_node: test node to be appended
 * Return:
 *   - 0: success
 *   - -1: failure
 */
int append_async_verification_node(struct stm_test_run_node_type *ptr_test_node)
{
	/* acquire mutex lock */
	pthread_mutex_lock(&mux_async_list);
	TDBG("ASYNC node append id=0x%08lx.\n", (unsigned long)ptr_test_node);

	/* close off ptr_test_node */
	ptr_test_node->next_async = NULL;

	/* append to list tail */
	/* when not adding the first node */
	if (ptr_async_veri_node_last != NULL)
		ptr_async_veri_node_last->next_async = ptr_test_node;

	ptr_async_veri_node_last = ptr_test_node;

	/* adjust list head when first append */
	if (stm_async_veri_node_list == NULL)
		stm_async_veri_node_list = ptr_async_veri_node_last;

	/* release mutex lock */
	pthread_mutex_unlock(&mux_async_list);

	return 0;
}

/* to wait for async verification to finish or timeout
 * Input: none
 * Return:
 *   - 0: success
 *   - -1: failure
 */
int wait_for_async_verification(void)
{
	int ret = -1;
	struct timespec async_veri_timeout;

	/* set all_commands_sent */
	all_commands_sent = true;

	/* acquire mutex lock */
	pthread_mutex_lock(&mux_async_list);

	/* if async verification list is empty */
	if (stm_async_veri_node_list == NULL) {
		TDBG("Async verification list is empty. No need to wait.\n");
		/* release mutex lock */
		pthread_mutex_unlock(&mux_async_list);
		/* cancel async.veri thread */
		ret = pthread_cancel(thread_async_id);
		if (ret != 0)
			TDBG("Cancellation of thread_async_veri" \
			"fication failed. \n");

		goto thread_async_join;
	}

	/* release mutex lock */
	pthread_mutex_unlock(&mux_async_list);

	/* wait for conditions to join */
	pthread_mutex_lock(&mux_async_veri);

	/* set timeout value, absolute time */
	clock_gettime(CLOCK_REALTIME, &async_veri_timeout);
	async_veri_timeout.tv_sec += ASYNC_VERIFICATION_TIMEOUT_SECONDS;

	while (get_async_verification_finished() == false) {
		TDBG("Async verification not finished yet!\n");
		ret = pthread_cond_timedwait(&cond_async_veri, \
			&mux_async_veri, &async_veri_timeout);
		/* if timeout, cancel thread_async_verification */
		if (ret == ETIMEDOUT) {
			ret = pthread_cancel(thread_async_id);
			if (ret != 0)
				TDBG("Cancellation of thread_async_veri" \
					"fication failed. \n");
			TDBG("Pthread_cond_timedwait TIMEOUT.\n");
			break;
		}
	}

	pthread_mutex_unlock(&mux_async_veri);

thread_async_join:
	ret = pthread_join(thread_async_id, NULL);
           if (ret != 0)
               TDBG("Failure in pthread_join(thread_async_id)\n");

	return 0;
}

/* TODO: decode message as STPv2
 * Input:
 * Return:
 */
static int stp_decoding(char *buf, int length)
{
	TDBG("Decoding of message in %s().\n", __FUNCTION__);
	return 0;
}

/* TODO:to match ETB buf content against async.veri list
 * Input:
 * Return:
 */
static bool match_async_node(struct stm_test_run_node_type *this, \
			const char *buf)
{
	TDBG("Match ETB buf against asnyn.veri list.\n");
	TDBG("Fake, match found! \n");
	return true;
}

/* remove this node from async verification list
 * Input:
 *   - pre: pointer to the previous node
 *   - this: pointer to this node, which will be removed from the list
 * Return:
 *   - 0: success
 *   - -1: failure
 * Assumption:
 *   - mutex_async_list must be acquired before calling this API.
 */
static int remove_async_verification_node(struct stm_test_run_node_type *pre, \
				struct stm_test_run_node_type *this)
{
	TDBG("ASYNC node remove id=0x%08lx.\n", (unsigned long)this);
	if (pre == NULL) { /* if this points to list head */
		stm_async_veri_node_list = this->next_async;
		this->next_async = NULL;
		if (stm_async_veri_node_list == NULL) /* empty */
			ptr_async_veri_node_last = NULL;
		return 0;
	}

	pre->next_async = this->next_async;
	this->next_async = NULL;
	/* are we removing the last node? */
	if (ptr_async_veri_node_last == this)
		ptr_async_veri_node_last = pre; /* adjust last node pointer */
	return 0;
}

/* Entry function of async verifcation thread */
void *thread_async_verification(void *param)
{
	int ret = -1;
	int fd_ETB = -1;
	int fdmax = -1;
	fd_set fds;
	struct timeval tv;
	char buf[MAX_ETB_LINE_BUF_SIZE] = "";
	struct stm_test_run_node_type *ptr_async_veri_current = NULL;
	struct stm_test_run_node_type *ptr_pre = NULL;

	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
	TDBG("Thread Entry Point, %s()\n", __FUNCTION__);

	/* open ETB file for readonly */
	fd_ETB = open(ETB_FILEPATH, O_RDONLY | O_SYNC);
	if (fd_ETB == -1) {
		printf("Failed to open ETB file for readonly.\n");
		TDBG("Exit Thread %s()\n", __FUNCTION__);
		/* thread exit */
		pthread_exit(NULL);
		return NULL;
	}

	/* acquire async.list mutex lock */
	pthread_mutex_lock(&mux_async_list);

	while (true) {
		/* if async verification list is empty and test commands sent */
		if ((stm_async_veri_node_list == NULL) && \
			(all_commands_sent == true)) {
			TDBG("Async verification list is empty, and all test" \
				"commands were sent.\n");
			TDBG("No new async verification is expected.\n");
			TDBG("Async verification thread exit.\n");
			/* release async.list mutex lock */
			pthread_mutex_unlock(&mux_async_list);

			/* broadcast a condition met */
			pthread_mutex_lock(&mux_async_veri);
			set_async_verification_finished(true);
			pthread_cond_signal(&cond_async_veri);
			pthread_mutex_unlock(&mux_async_veri);

			break;
		}

		TDBG("Thread: %s, Line: %d\n", __FUNCTION__, __LINE__);
		/* release async.list mutex lock */
		pthread_mutex_unlock(&mux_async_list);

		/* select, wait on ETB device */
		FD_ZERO(&fds);
		FD_SET(fd_ETB, &fds);
		fdmax = fd_ETB + 1;
		tv.tv_sec = 1; /* * ASYNC_VERIFICATION_TIMEOUT_SECONDS; */
		tv.tv_usec = 0;
		ret = select(fdmax, &fds, NULL, &fds, &tv);
#ifdef LOCAL_TEST_STUB
		/* We don't want the loop run too fase when locally */
		{
			struct timespec delay = {1, 0}; /* {sec, usec} */
			nanosleep(&delay, NULL);
		}
#endif /* LOCAL_TEST_STUB */
		if (ret == -1) {
			printf("Error select(), %s\n", __FUNCTION__);
			/* acquire async.list mutex lock */
			pthread_mutex_lock(&mux_async_list);
			continue;
		} else if (ret == 0) {
			printf("Timeout happend in waiting ETB select().\n");
			/* acquire async.list mutex lock */
			pthread_mutex_lock(&mux_async_list);
			continue;
		}
		/* read ETB */
		if (FD_ISSET(fd_ETB, &fds)) {
			ret = read(fd_ETB, buf, MAX_ETB_LINE_BUF_SIZE);
			if (ret >= 0) {
				/* decode message as STPv2 */
				stp_decoding(buf, ret);
			}
#ifdef LOCAL_TEST_STUB
			buf[ret] = '\0';
			TDBG("ETB read: %s<\n", buf);
			/* for local debugging purpose */
			/* rewind fd_ETB to its beginning */
			lseek(fd_ETB, 0, SEEK_SET);
#endif /* LOCAL_TEST_STUB */
		}
		/* acquire async.list mutex lock */
		pthread_mutex_lock(&mux_async_list);

		/* go through async.list to find a match */
		ptr_async_veri_current = stm_async_veri_node_list;
		while (ptr_async_veri_current != NULL) {
			/* TODO: should we call async verification API here? */
			/* if a match is found */
			if (match_async_node(ptr_async_veri_current, buf) == \
				true) {
				/* update the related node */
				ptr_async_veri_current->command_result->async_veri_result = ASYNC_VERIFICATION_SUCCESS;
				/* record time of async_verified */
				ret = clock_gettime(CLOCK_REALTIME, &(ptr_async_veri_current->command_result->time_async_verified));
				if (ret == -1) /* failure */
					TDBG("Failed to read clock time.\n");
				/* and remove it from the list */
				remove_async_verification_node(ptr_pre, \
					ptr_async_veri_current);
				break;
			}
			/* move to next async node */
			ptr_pre = ptr_async_veri_current;
			ptr_async_veri_current = \
				ptr_async_veri_current->next_async;
		}
		/* loop again */
	}

	TDBG("Thread Exit, %s()\n", __FUNCTION__);
	/* close ETB file */
	if (fd_ETB != -1)
		close(fd_ETB);

	/* thread exit */
	pthread_exit(NULL);
	return NULL;
}

/* free resources usded by async verification */
void async_free_resources(void)
{
	pthread_cond_destroy(&cond_async_veri);
	pthread_mutex_destroy(&mux_async_veri);
	pthread_mutex_destroy(&mux_async_list);
	return;
}

#ifdef ASYNC_VERI_TEST_STUB
int loop = 3000;
struct timespec ten_us = {0, 10000};

void thread(void)
{
	int i, j;

/*	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
 */
	pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
	printf("Sub before.\n");

	for(i = 0; i < loop * 3; i++) {
		/* printf("Sub  thread. i=%5d\n", i);
		 */
		for(j = 0; j < 100000; j ++);
/*		pthread_testcancel();
 */
	}

/*	printf("Sub after.\n");
 */
	return;
}

int main(void)
{
	pthread_t id;
	int i,ret;
	int fd_ETB;
	fd_set fds;
	int fdmax;
	struct timeval tv;
	char buf[MAX_ETB_LINE_BUF_SIZE] = "";

	/* open ETB file for readonly */
	fd_ETB = open(ETB_FILEPATH, O_RDONLY | O_SYNC);
	if (fd_ETB == -1) {
		printf("Failed to open ETB file for readonly.\n");
		TDBG("Exit Thread %s()\n", __FUNCTION__);
		return -1;
	}
#if 0
	ret = read(fd_ETB, buf, MAX_ETB_LINE_BUF_SIZE);
	if (ret >= 0) {
		/* decode message as STPv2 */
		stp_decoding(buf, ret);
	}
#ifdef LOCAL_TEST_STUB
	buf[ret] = '\0';
	TDBG("ETB read: %s<\n", buf);
	/* for local debugging purpose */
	/* rewind fd_ETB to its beginning */
	lseek(fd_ETB, 0, SEEK_SET);
#endif /* LOCAL_TEST_STUB */

	ret = read(fd_ETB, buf, MAX_ETB_LINE_BUF_SIZE);
	if (ret >= 0) {
		/* decode message as STPv2 */
		stp_decoding(buf, ret);
	}
#ifdef LOCAL_TEST_STUB
	buf[ret] = '\0';
	TDBG("ETB read: %s<\n", buf);
	/* for local debugging purpose */
	/* rewind fd_ETB to its beginning */
	lseek(fd_ETB, 0, SEEK_SET);
#endif /* LOCAL_TEST_STUB */

	FD_ZERO(&fds);
	FD_SET(fd_ETB, &fds);
	fdmax = fd_ETB + 1;
#endif
	i = 0;
	while (i < 10) {
		i ++;
		/* select, wait on ETB device */
		FD_ZERO(&fds);
		FD_SET(fd_ETB, &fds);
		fdmax = fd_ETB + 1;
		tv.tv_sec = 1; /* * ASYNC_VERIFICATION_TIMEOUT_SECONDS; */
		tv.tv_usec = 0;
		ret = select(fdmax, &fds, NULL, NULL, &tv);
		if (ret == -1) {
			printf("Error select(), %s\n", __FUNCTION__);
			continue;
		} else if (ret == 0) {
			printf("Timeout happend in waiting ETB select().\n");
			continue;
		}
		/* read ETB */
		if (FD_ISSET(fd_ETB, &fds)) {
			ret = read(fd_ETB, buf, MAX_ETB_LINE_BUF_SIZE);
			if (ret >= 0) {
				/* decode message as STPv2 */
				stp_decoding(buf, ret);
			}
#ifdef LOCAL_TEST_STUB
			buf[ret] = '\0';
			TDBG("ETB read: %s<\n", buf);
			/* for local debugging purpose */
			/* rewind fd_ETB to its beginning */
			lseek(fd_ETB, 0, SEEK_SET);
#endif /* LOCAL_TEST_STUB */
		}
	}

	ret = pthread_create(&id, NULL, (void *)thread, NULL);
	pthread_cancel(id);
	pthread_join(id,NULL);

	printf("Main joined.\n");

	return 0;

	if (ret != 0){
		printf("Create pthread error!\n");
		exit(1);
	}

	for(i = 0; i < loop; i++) {
		printf("Main thread. i=%5d\n", i);
		nanosleep(&ten_us, NULL);
	}

	pthread_cancel(id);

	pthread_join(id,NULL);

	return (0);
}

#if 0
/* to calculate difference between two timespec
 * Input:
 *   - start: start of timespec
 *   - end: end of timespec
 * Return:
 *   - diff between start and end in 'struct timespec' format
 */
/* TODO: double check return a struct, good? */
static struct timespec time_diff(const struct timespec start, \
	const struct timespec end)
{
	struct timespec temp;

	if ((end.tv_nsec - start.tv_nsec) < 0) {
		temp.tv_sec = end.tv_sec - start.tv_sec - 1;
		temp.tv_nsec = 1000000000 + end.tv_nsec - start.tv_nsec;
	} else {
		temp.tv_sec = end.tv_sec - start.tv_sec;
		temp.tv_nsec = end.tv_nsec - start.tv_nsec;
	}

	return temp;
}

int main()
{
	pthread_mutex_init(&mux, NULL);
	pthread_mutex_lock(&mux);
	TDBG("pthread_mutex testing.\n");
	pthread_mutex_unlock(&mux);

	return 0;
}
#endif
#endif /* ASYNC_VERI_TEST_STUB */