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

#include <xmlmemory.h>
#include <parser.h>
#include <tree.h>

#include <thread/thread.h>
#include <avl/avl.h>
#include <httpp/httpp.h>
#include <net/sock.h>

#include "connection.h"

#include "global.h"
#include "refbuf.h"
#include "client.h"
#include "stats.h"

#ifdef _WIN32
#define vsnprintf _vsnprintf
#endif

typedef struct _event_listener_tag
{
	stats_event_t **queue;
	mutex_t *mutex;

	struct _event_listener_tag *next;
} event_listener_t;

int _stats_running = 1;
long _stats_thread_id;
int _stats_threads = 0;

stats_t _stats;
mutex_t _stats_mutex;

stats_event_t *_global_event_queue;
mutex_t _global_event_mutex;

cond_t _event_signal_cond;

event_listener_t *_event_listeners;



static void *_stats_thread(void *arg);
static int _compare_stats(void *a, void *b, void *arg);
static int _compare_source_stats(void *a, void *b, void *arg);
static int _free_stats(void *key);
static int _free_source_stats(void *key);
static void _add_event_to_queue(stats_event_t *event, stats_event_t **queue);
static stats_node_t *_find_node(avl_tree *tree, char *name);
static stats_source_t *_find_source(avl_tree *tree, char *source);
static void _free_event(stats_event_t *event);

void stats_initialize()
{
	_event_listeners = NULL;

	/* set up global struct */
	_stats.global_tree = avl_tree_new(_compare_stats, NULL);
	_stats.source_tree = avl_tree_new(_compare_source_stats, NULL);

	/* set up global mutex */
	thread_mutex_create(&_stats_mutex);

	/* set up event signaler */
	thread_cond_create(&_event_signal_cond);

	/* set up stats queues */
	_global_event_queue = NULL;
	thread_mutex_create(&_global_event_mutex);

	/* fire off the stats thread */
	_stats_running = 1;
	_stats_thread_id = thread_create("Stats Thread", _stats_thread, NULL, THREAD_ATTACHED);
}

void stats_shutdown()
{
	int n;

    if(!_stats_running) /* We can't shutdown if we're not running. */
        return;

	/* wait for thread to exit */
	_stats_running = 0;
	thread_join(_stats_thread_id);

	/* wait for other threads to shut down */
	do {
		thread_sleep(300000);
		thread_mutex_lock(&_stats_mutex);
		n = _stats_threads;
		thread_mutex_unlock(&_stats_mutex);
	} while (n > 0);

	/* free the queues */

	/* destroy the queue mutexes */
	thread_mutex_destroy(&_global_event_mutex);

	/* tear it all down */
	thread_cond_destroy(&_event_signal_cond);
	thread_mutex_destroy(&_stats_mutex);
	avl_tree_free(_stats.source_tree, _free_source_stats);
	avl_tree_free(_stats.global_tree, _free_stats);
}

stats_t *stats_get_stats()
{
	// lock global stats
	
	// copy stats

	// unlock global stats

	// return copied stats

	return NULL;
}

void stats_event(char *source, char *name, char *value)
{
	stats_event_t *node;
	stats_event_t *event;

	if (name == NULL || strcmp(name, "") == 0) return;

	/* build event */
	event = (stats_event_t *)malloc(sizeof(stats_event_t));
	event->source = NULL;
	if (source != NULL) event->source = (char *)strdup(source);
	event->name = (char *)strdup(name);
	event->value = NULL;
	event->next = NULL;
	if (value != NULL) event->value = (char *)strdup(value);

	/* queue event */
	thread_mutex_lock(&_global_event_mutex);
	if (_global_event_queue == NULL) {
		_global_event_queue = event;
	} else {
		node = _global_event_queue;
		while (node->next) node = node->next;
		node->next = event;
	}
	thread_mutex_unlock(&_global_event_mutex);
}

void stats_event_args(char *source, char *name, char *format, ...)
{
	char buf[1024];
	va_list val;
	
	va_start(val, format);
	vsnprintf(buf, 1024, format, val);
	va_end(val);

	stats_event(source, name, buf);
}

static char *_get_stats(char *source, char *name)
{
	stats_node_t *stats = NULL;
	stats_source_t *src = NULL;
	char *value = NULL;

	thread_mutex_lock(&_stats_mutex);

	if (source == NULL) {
		stats = _find_node(_stats.global_tree, name);
	} else {
		src = _find_source(_stats.source_tree, source);
		if (src) {
			stats = _find_node(src->stats_tree, name);
		}
	}

	if (stats) value = (char *)strdup(stats->value);

	thread_mutex_unlock(&_stats_mutex);

	return value;
}

void stats_event_inc(char *source, char *name)
{
	char *old_value;
	int new_value;
	
	old_value = _get_stats(source, name);
	if (old_value != NULL) {
		new_value = atoi(old_value);
		free(old_value);
		new_value++;
	} else {
		new_value = 1;
	}

	stats_event_args(source, name, "%d", new_value);
}

void stats_event_add(char *source, char *name, unsigned long value)
{
	char *old_value;
	unsigned long new_value;

	old_value = _get_stats(source, name);
	if (old_value != NULL) {
		new_value = atol(old_value);
		free(old_value);
		new_value += value;
	} else {
		new_value = value;
	}

	stats_event_args(source, name, "%ld", new_value);
}

void stats_event_dec(char *source, char *name)
{
	char *old_value;
	int new_value;

	old_value = _get_stats(source, name);
	if (old_value != NULL) {
		new_value = atoi(old_value);
		free(old_value);
		new_value--;
		if (new_value < 0) new_value = 0;
	} else {
		new_value = 0;
	}

	stats_event_args(source, name, "%d", new_value);
}

/* note: you must call this function only when you have exclusive access
** to the avl_tree
*/
static stats_node_t *_find_node(avl_tree *stats_tree, char *name)
{
	stats_node_t *stats;
	avl_node *node;
	int cmp;

	/* get the root node */
	node = stats_tree->root->right;
	
	while (node) {
		stats = (stats_node_t *)node->key;
		cmp = strcmp(name, stats->name);
		if (cmp < 0) 
			node = node->left;
		else if (cmp > 0)
			node = node->right;
		else
			return stats;
	}
	
	/* didn't find it */
	return NULL;
}

/* note: you must call this function only when you have exclusive access
** to the avl_tree
*/
static stats_source_t *_find_source(avl_tree *source_tree, char *source)
{
	stats_source_t *stats;
	avl_node *node;
	int cmp;

	/* get the root node */
	node = source_tree->root->right;
	while (node) {
		stats = (stats_source_t *)node->key;
		cmp = strcmp(source, stats->source);
		if (cmp < 0)
			node = node->left;
		else if (cmp > 0)
			node = node->right;
		else
			return stats;
	}

	/* didn't find it */
	return NULL;
}

static stats_event_t *_copy_event(stats_event_t *event)
{
	stats_event_t *copy = (stats_event_t *)malloc(sizeof(stats_event_t));
	if (event->source) 
		copy->source = (char *)strdup(event->source);
	else
		copy->source = NULL;
	copy->name = (char *)strdup(event->name);
	if (event->value)
		copy->value = (char *)strdup(event->value);
	else
		copy->value = NULL;
	copy->next = NULL;

	return copy;
}

static void *_stats_thread(void *arg)
{
	stats_event_t *event;
	stats_event_t *copy;
	stats_node_t *node;
	stats_node_t *anode;
	stats_source_t *snode;
	stats_source_t *asnode;
	event_listener_t *listener;
	avl_node *avlnode;

	while (_stats_running) {
		thread_mutex_lock(&_global_event_mutex);
		if (_global_event_queue != NULL) {
			/* grab the next event from the queue */
			event = _global_event_queue;
			_global_event_queue = event->next;
			event->next = NULL;
			thread_mutex_unlock(&_global_event_mutex);

			thread_mutex_lock(&_stats_mutex);
			if (event->source == NULL) {
				/* we have a global event */
				if (event->value != NULL) {
					/* adding/updating */
					node = _find_node(_stats.global_tree, event->name);
					if (node == NULL) {
						/* add node */
						anode = (stats_node_t *)malloc(sizeof(stats_node_t));
						anode->name = (char *)strdup(event->name);
						anode->value = (char *)strdup(event->value);

						avl_insert(_stats.global_tree, (void *)anode);
					} else {
						/* update node */
						free(node->value);
						node->value = (char *)strdup(event->value);
					}

				} else {
					/* we're deleting */
					node = _find_node(_stats.global_tree, event->name);
					if (node != NULL)
						avl_delete(_stats.global_tree, (void *)node, _free_stats);
				}
			} else {
				/* we have a source event */

				snode = _find_source(_stats.source_tree, event->source);
				if (snode != NULL) {
					/* this is a source we already have a tree for */
					if (event->value != NULL) {
						/* we're add/updating */
						node = _find_node(snode->stats_tree, event->name);
						if (node == NULL) {
							/* adding node */
							anode = (stats_node_t *)malloc(sizeof(stats_node_t));
							anode->name = (char *)strdup(event->name);
							anode->value = (char *)strdup(event->value);

							avl_insert(snode->stats_tree, (void *)anode);
						} else {
							/* updating node */
							free(node->value);
							node->value = (char *)strdup(event->value);
						}
					} else {
						/* we're deleting */
						node = _find_node(snode->stats_tree, event->name);
						if (node != NULL) {
							avl_delete(snode->stats_tree, (void *)node, _free_stats);

						        avlnode = avl_get_first(snode->stats_tree);
							if (avlnode == NULL) {
								avl_delete(_stats.source_tree, (void *)snode, _free_source_stats);
							}
						}
					}
				} else {
					/* this is a new source */
					asnode = (stats_source_t *)malloc(sizeof(stats_source_t));
					asnode->source = (char *)strdup(event->source);
					asnode->stats_tree = avl_tree_new(_compare_stats, NULL);

					anode = (stats_node_t *)malloc(sizeof(stats_node_t));
					anode->name = (char *)strdup(event->name);
					anode->value = (char *)strdup(event->value);
					
					avl_insert(asnode->stats_tree, (void *)anode);

					avl_insert(_stats.source_tree, (void *)asnode);
				}
			}
			
			/* now we have an event that's been processed into the running stats */
			/* this event should get copied to event listeners' queues */
			listener = _event_listeners;
			while (listener) {
				copy = _copy_event(event);
				thread_mutex_lock(listener->mutex);
				_add_event_to_queue(copy, listener->queue);
				thread_mutex_unlock(listener->mutex);

				listener = listener->next;
			}
			thread_cond_broadcast(&_event_signal_cond);

			/* now we need to destroy the event */
			_free_event(event);

			thread_mutex_unlock(&_stats_mutex);
		} else {
			thread_mutex_unlock(&_global_event_mutex);
		}

		thread_sleep(300000);
	}

	/* wake the other threads so they can shut down cleanly */
	thread_cond_broadcast(&_event_signal_cond);

	thread_exit(0);

	return NULL;
}

/* you must have the _stats_mutex locked here */
static void _register_listener(stats_event_t **queue, mutex_t *mutex)
{
	event_listener_t *node;
	event_listener_t *evli = (event_listener_t *)malloc(sizeof(event_listener_t));

	evli->queue = queue;
	evli->mutex = mutex;
	evli->next = NULL;

	if (_event_listeners == NULL) {
		_event_listeners = evli;
	} else {
		node = _event_listeners;
		while (node->next) node = node->next;
		node->next = evli;
	}
}

static stats_event_t *_make_event_from_node(stats_node_t *node, char *source)
{
	stats_event_t *event = (stats_event_t *)malloc(sizeof(stats_event_t));
	
	if (source != NULL)
		event->source = (char *)strdup(source);
	else
		event->source = NULL;
	event->name = (char *)strdup(node->name);
	event->value = (char *)strdup(node->value);
	event->next = NULL;

	return event;
}

static void _add_event_to_queue(stats_event_t *event, stats_event_t **queue)
{
	stats_event_t *node;

	if (*queue == NULL) {
		*queue = event;
	} else {
		node = *queue;
		while (node->next) node = node->next;
		node->next = event;
	}
}

static stats_event_t *_get_event_from_queue(stats_event_t **queue)
{
	stats_event_t *event;

	if (*queue == NULL) return NULL;

	event = *queue;
	*queue = (*queue)->next;
	event->next = NULL;

	return event;
}

static int _send_event_to_client(stats_event_t *event, connection_t *con)
{
	int ret;

	/* send data to the client!!!! */
	ret = sock_write(con->sock, "EVENT %s %s %s\n", (event->source != NULL) ? event->source : "global", event->name, event->value ? event->value : "null");

	return (ret == -1) ? 0 : 1;
}

void _dump_stats_to_queue(stats_event_t **queue)
{
	avl_node *node;
	avl_node *node2;
	stats_event_t *event;
	stats_source_t *source;

	thread_mutex_lock(&_stats_mutex);
	/* first we fill our queue with the current stats */
	/* start with the global stats */
	node = avl_get_first(_stats.global_tree);
	while (node) {
		event = _make_event_from_node((stats_node_t *)node->key, NULL);
		_add_event_to_queue(event, queue);

		node = avl_get_next(node);
	}

	/* now the stats for each source */
	node = avl_get_first(_stats.source_tree);
	while (node) {
		source = (stats_source_t *)node->key;
		node2 = avl_get_first(source->stats_tree);
		while (node2) {
			event = _make_event_from_node((stats_node_t *)node2->key, source->source);
			_add_event_to_queue(event, queue);

			node2 = avl_get_next(node2);
		}
		
		node = avl_get_next(node);
	}
	thread_mutex_unlock(&_stats_mutex);
}

/* factoring out code for stats loops
** this function copies all stats to queue, and registers 
** the queue for all new events atomically.
** note: mutex must already be created!
*/
static void _atomic_get_and_register(stats_event_t **queue, mutex_t *mutex)
{
	avl_node *node;
	avl_node *node2;
	stats_event_t *event;
	stats_source_t *source;

	thread_mutex_lock(&_stats_mutex);

	/* first we fill our queue with the current stats */
	
	/* start with the global stats */
	node = avl_get_first(_stats.global_tree);
	while (node) {
		event = _make_event_from_node((stats_node_t *)node->key, NULL);
		_add_event_to_queue(event, queue);

		node = avl_get_next(node);
	}

	/* now the stats for each source */
	node = avl_get_first(_stats.source_tree);
	while (node) {
		source = (stats_source_t *)node->key;
		node2 = avl_get_first(source->stats_tree);
		while (node2) {
			event = _make_event_from_node((stats_node_t *)node2->key, source->source);
			_add_event_to_queue(event, queue);

			node2 = avl_get_next(node2);
		}
		
		node = avl_get_next(node);
	}

	/* now we register to receive future event notices */
	_register_listener(queue, mutex);

	thread_mutex_unlock(&_stats_mutex);
}

void *stats_connection(void *arg)
{
	stats_connection_t *statcon = (stats_connection_t *)arg;
	stats_event_t *local_event_queue = NULL;
	mutex_t local_event_mutex;
	stats_event_t *event;

	/* increment the thread count */
	thread_mutex_lock(&_stats_mutex);
	_stats_threads++;
	thread_mutex_unlock(&_stats_mutex);

	thread_mutex_create(&local_event_mutex);

	_atomic_get_and_register(&local_event_queue, &local_event_mutex);

	while (_stats_running) {
		thread_mutex_lock(&local_event_mutex);
		event = _get_event_from_queue(&local_event_queue);
		if (event != NULL) {
			if (!_send_event_to_client(event, statcon->con)) {
				_free_event(event);
				thread_mutex_unlock(&local_event_mutex);
				break;
			}
			_free_event(event);
		} else {
			thread_mutex_unlock(&local_event_mutex);
			thread_cond_wait(&_event_signal_cond);
			continue;
		}
			       
		thread_mutex_unlock(&local_event_mutex);
	}

	thread_mutex_destroy(&local_event_mutex);

	thread_mutex_lock(&_stats_mutex);
	_stats_threads--;
	thread_mutex_unlock(&_stats_mutex);

	thread_exit(0);
	
	return NULL;
}

/* this function is primarily to support gui code needing to get stats updates
** create a thread with this as the start proc with an arg of the callback function
** on each stats event the callback will be called with the event
** and the callback is responsible for copying the data if it needs it after returning
*/
void *stats_callback(void *arg)
{
	void (*callback)(stats_event_t *event);

	stats_event_t *local_event_queue = NULL;
	mutex_t local_event_mutex;

	stats_event_t *event;

	callback = arg;

	thread_mutex_lock(&_stats_mutex);
	_stats_threads++;
	thread_mutex_unlock(&_stats_mutex);

	thread_mutex_create(&local_event_mutex);

	_atomic_get_and_register(&local_event_queue, &local_event_mutex);

	while (_stats_running) {
		thread_mutex_lock(&local_event_mutex);
		event = _get_event_from_queue(&local_event_queue);
		if (event != NULL) {
			callback(event);
			_free_event(event);
		} else {
			thread_mutex_unlock(&local_event_mutex);
			thread_cond_wait(&_event_signal_cond);
			continue;
		}
		
		thread_mutex_unlock(&local_event_mutex);
	}

	thread_mutex_destroy(&local_event_mutex);

	thread_mutex_lock(&_stats_mutex);
	_stats_threads--;
	thread_mutex_unlock(&_stats_mutex);

	thread_exit(0);

	return NULL;
}

typedef struct _source_xml_tag {
	char *mount;
	xmlNodePtr node;

	struct _source_xml_tag *next;
} source_xml_t;

static xmlNodePtr _find_xml_node(char *mount, source_xml_t **list, xmlNodePtr root)
{
	source_xml_t *node, *node2;
	int found = 0;

	/* search for existing node */
	node = *list;
	while (node) {
		if (strcmp(node->mount, mount) == 0) {
			found = 1;
			break;
		}
		node = node->next;
	}

	if (found) return node->node;

	/* if we didn't find it, we must build it and add it to the list */

	/* build node */
	node = (source_xml_t *)malloc(sizeof(source_xml_t));
	node->mount = strdup(mount);
	node->node = xmlNewChild(root, NULL, "source", NULL);
	xmlSetProp(node->node, "mount", mount);
	node->next = NULL;

	/* add node */
	if (*list == NULL) {
		*list = node;
	} else {
		node2 = *list;
		while (node2->next) node2 = node2->next;
		node2->next = node;
	}

	return node->node;
}

void stats_sendxml(client_t *client)
{
	int bytes;
	stats_event_t *event;
	stats_event_t *queue;
	xmlDocPtr doc;
	xmlNodePtr node, srcnode;
	int len;
	char *buff = NULL;
	source_xml_t *snd;
	source_xml_t *src_nodes = NULL;

	queue = NULL;
	_dump_stats_to_queue(&queue);

	doc = xmlNewDoc("1.0");
	node = xmlNewDocNode(doc, NULL, "icestats", NULL);
	xmlDocSetRootElement(doc, node);


	event = _get_event_from_queue(&queue);
	while (event) {
		if (event->source == NULL) {
			xmlNewChild(node, NULL, event->name, event->value);
		} else {
			srcnode = _find_xml_node(event->source, &src_nodes, node);
			xmlNewChild(srcnode, NULL, event->name, event->value);
		}

		_free_event(event);
		event = _get_event_from_queue(&queue);
	}

	xmlDocDumpMemory(doc, (xmlChar **)&buff, &len);
	xmlFreeDoc(doc);
	
	client->respcode = 200;
	bytes = sock_write(client->con->sock, "HTTP/1.0 200 OK\r\n"
			   "Content-Length: %d\r\n"
			   "Content-Type: text/xml\r\n"
			   "\r\n", len);
	if (bytes > 0) client->con->sent_bytes += bytes;
	else goto send_error;

	bytes = sock_write_bytes(client->con->sock, buff, len);
	if (bytes > 0) client->con->sent_bytes += bytes;

 send_error:
	while (src_nodes) {
		snd = src_nodes->next;
		free(src_nodes->mount);
		free(src_nodes);
		src_nodes = snd;
	}
	if (buff) free(buff);
	client_destroy(client);
}

static int _compare_stats(void *arg, void *a, void *b)
{
	stats_node_t *nodea = (stats_node_t *)a;
	stats_node_t *nodeb = (stats_node_t *)b;

	return strcmp(nodea->name, nodeb->name);
}

static int _compare_source_stats(void *arg, void *a, void *b)
{
	stats_source_t *nodea = (stats_source_t *)a;
	stats_source_t *nodeb = (stats_source_t *)b;

	return strcmp(nodea->source, nodeb->source);
}

static int _free_stats(void *key)
{
	stats_node_t *node = (stats_node_t *)key;
	free(node->value);
	free(node->name);
	free(node);
	
	return 1;
}

static int _free_source_stats(void *key)
{
	stats_source_t *node = (stats_source_t *)key;
	avl_tree_free(node->stats_tree, _free_stats);
	free(node->source);
    free(node);

	return 1;
}

static void _free_event(stats_event_t *event)
{
	if (event->source) free(event->source);
	if (event->name) free(event->name);
	if (event->value) free(event->value);
	free(event);
}