/* diversity-curl.c - DiversityCurl
 *
 * Copyright 2008 OpenMoko, Inc.
 * Authored by Chia-I Wu <olv@openmoko.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <glib.h>
#include <diversity-equipment.h>
#include <diversity-atlas.h>
#include <diversity-curl.h>
#include <curl/curl.h>
#include <sys/stat.h> /* for mode_t flags */

/* TODO remove the limit */
#define TILE_MAX_SIZE	(256 * 1024)

#define JOB_ABORT(job) (((DiversityCurlJobInt *) (job))->abort = TRUE)
#define JOB_ABORTED(job) (((DiversityCurlJobInt *) (job))->abort)

typedef struct _DiversityCurlJobInt DiversityCurlJobInt;
typedef struct _DiversityCurlHandle DiversityCurlHandle;

enum {
	JOB_COMPLETED,
	LAST_SIGNAL
};

enum {
	PROP_0,
	PROP_POOL_SIZE,
	PROP_QUEUE_SIZE,
};

static void diversity_curl_job_free(DiversityCurlJob *job);
static void process_jobs_threaded(gpointer data, gpointer user_data);

#define DIVERSITY_CURL_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE((o), DIVERSITY_TYPE_CURL, DiversityCurlPrivate))
typedef struct _DiversityCurlPrivate DiversityCurlPrivate;

struct _DiversityCurlPrivate {
	gboolean disposed;

	gint pool_size;
	gint queue_size;

	GThreadPool *pool;

	GMutex *mutex;
	GSList *handles;
	GSList *pending_jobs;
	GSList *active_jobs;
	guint active_id;
};

struct _DiversityCurlJobInt {
	DiversityCurlJob pub;

	gboolean processing;
	gboolean abort;
};

struct _DiversityCurlHandle {
	CURL *curl;
	GByteArray *buf;
	DiversityCurlJob *job;
};

static guint curl_signals[LAST_SIGNAL] = { 0 };

G_DEFINE_TYPE(DiversityCurl, diversity_curl, G_TYPE_OBJECT);

static void diversity_curl_dispose(GObject *obj)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(obj);

	priv->disposed = TRUE;

	((GObjectClass *) diversity_curl_parent_class)->dispose(obj);
}

static void diversity_curl_finalize(GObject *obj)
{
	DiversityCurl *curl = DIVERSITY_CURL(obj);
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	GSList *tmp_list;
	gint num_jobs = 0;

	while (priv->pending_jobs)
		diversity_curl_job_cancel(curl, priv->pending_jobs->data);

	g_mutex_lock(priv->mutex);
	tmp_list = priv->active_jobs;
	while (tmp_list) {
		JOB_ABORT(tmp_list->data);
		tmp_list = tmp_list->next;
		num_jobs++;
	}
	g_mutex_unlock(priv->mutex);

	if (priv->pool) {
		if (num_jobs)
			g_debug("waiting for %d download jobs to cancel\n",
					num_jobs);

		g_thread_pool_free(priv->pool, TRUE, TRUE);
	}

	g_mutex_free(priv->mutex);

	g_assert(!priv->pending_jobs);

	if (priv->active_id)
		g_source_remove(priv->active_id);

	g_slist_foreach(priv->active_jobs,
			(GFunc) diversity_curl_job_free, NULL);
	g_slist_free(priv->active_jobs);

	tmp_list = priv->handles;
	while (tmp_list) {
		DiversityCurlHandle *handle = tmp_list->data;

		if (handle) {
			curl_easy_cleanup(handle->curl);
			g_byte_array_free(handle->buf, TRUE);
		}
		tmp_list = tmp_list->next;
	}
	g_slist_free(priv->handles);

	((GObjectClass *) diversity_curl_parent_class)->finalize(obj);
}

static void diversity_curl_set_property(GObject *obj, guint prop_id, const GValue *value, GParamSpec *pspec)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(obj);

	switch (prop_id) {
	case PROP_POOL_SIZE:
		priv->pool_size = g_value_get_int(value);
		break;
	case PROP_QUEUE_SIZE:
		priv->queue_size = g_value_get_int(value);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(obj, prop_id, pspec);
		break;
	}
}

static void diversity_curl_get_property(GObject *obj, guint prop_id, GValue *value, GParamSpec *pspec)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(obj);

	switch (prop_id) {
	case PROP_POOL_SIZE:
		g_value_set_int(value, priv->pool_size);
		break;
	case PROP_QUEUE_SIZE:
		g_value_set_int(value, priv->queue_size);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(obj, prop_id, pspec);
		break;
	}
}

static void diversity_curl_class_init(DiversityCurlClass *klass)
{
	GObjectClass *o_class = (GObjectClass *) klass;

	o_class->dispose = diversity_curl_dispose;
	o_class->finalize = diversity_curl_finalize;
	o_class->set_property = diversity_curl_set_property;
	o_class->get_property = diversity_curl_get_property;

	g_type_class_add_private(klass, sizeof(DiversityCurlPrivate));

	g_object_class_install_property(o_class,
					PROP_POOL_SIZE,
					g_param_spec_int("pool-size",
							 "Pool size",
							 "Size of thread pool",
							 1, 5,
							 2,
							 G_PARAM_WRITABLE |
							 G_PARAM_CONSTRUCT_ONLY));

	g_object_class_install_property(o_class,
					PROP_QUEUE_SIZE,
					g_param_spec_int("queue-size",
							 "Queue size",
							 "Size of queue",
							 1, G_MAXINT,
							 16,
							 G_PARAM_WRITABLE |
							 G_PARAM_CONSTRUCT_ONLY));

	curl_signals[JOB_COMPLETED] =
		g_signal_new("job-completed",
			     G_TYPE_FROM_CLASS(klass),
			     G_SIGNAL_RUN_LAST,
			     G_STRUCT_OFFSET(DiversityCurlClass, job_completed),
			     NULL, NULL,
			     g_cclosure_marshal_VOID__POINTER,
			     G_TYPE_NONE, 1,
			     G_TYPE_POINTER);
}

static void diversity_curl_init(DiversityCurl *curl)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);

	priv->disposed = FALSE;

	priv->pool = NULL;

	priv->mutex = g_mutex_new();
	priv->handles = NULL;
	priv->pending_jobs = NULL;
	priv->active_jobs = NULL;
}

DiversityCurl *diversity_curl_new(gint pool_size, gint queue_size)
{
	DiversityCurl *curl;
	DiversityCurlPrivate *priv;
	GError *error = NULL;
	gint i;

	curl = g_object_new(DIVERSITY_TYPE_CURL,
			    "pool-size", pool_size,
			    "queue-size", queue_size,
			    NULL);

	priv = DIVERSITY_CURL_GET_PRIVATE(curl);

	/* there is pool_size + 1 threads to always allow cancellation */
	priv->pool = g_thread_pool_new(process_jobs_threaded,
			curl, priv->pool_size + 1, TRUE, &error);
	if (!priv->pool) {
		g_warning("failed to create thread pool: %s\n",
				error->message);

		g_error_free(error);

		g_object_unref(curl);

		return NULL;
	}

	for (i = 0; i < priv->pool_size; i++)
		priv->handles = g_slist_prepend(priv->handles, NULL);

	return curl;
}

static DiversityCurlJob *diversity_curl_job_new(void)
{
	DiversityCurlJobInt *job;

	job = g_slice_new0(DiversityCurlJobInt);

	return (DiversityCurlJob *) job;
}

static void diversity_curl_job_free(DiversityCurlJob *job)
{
	g_free(job->uri);
	g_free(job->path);

	g_slice_free(DiversityCurlJobInt, (DiversityCurlJobInt *) job);
}

DiversityCurlJob *diversity_curl_job_get(DiversityCurl *curl)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	DiversityCurlJob *job;

	g_mutex_lock(priv->mutex);
	if (g_slist_length(priv->pending_jobs) +
	    g_slist_length(priv->active_jobs) >= priv->queue_size) {
		g_mutex_unlock(priv->mutex);

		return NULL;
	}
	g_mutex_unlock(priv->mutex);

	job = diversity_curl_job_new();

	return job;
}

void diversity_curl_job_submit(DiversityCurl *curl, DiversityCurlJob *job)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	
	g_mutex_lock(priv->mutex);
	priv->pending_jobs = g_slist_append(priv->pending_jobs, job);
	g_mutex_unlock(priv->mutex);

	g_thread_pool_push(priv->pool, job, NULL);
}

void diversity_curl_job_cancel(DiversityCurl *curl, DiversityCurlJob *job)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	GSList *l;

	g_mutex_lock(priv->mutex);

	l = g_slist_find(priv->pending_jobs, job);
	if (l) {
		DiversityCurlJob *job = l->data;

		job->status = DIVERSITY_ATLAS_TILE_STATUS_CANCELLED;

		priv->pending_jobs =
			g_slist_remove_link(priv->pending_jobs, l);
		priv->active_jobs =
			g_slist_concat(l, priv->active_jobs);
	} else {
		l = g_slist_find(priv->active_jobs, job);

		if (l)
			JOB_ABORT(l->data);
	}

	g_mutex_unlock(priv->mutex);

	if (l)
		g_thread_pool_push(priv->pool, job, NULL);
}

static gboolean diversity_curl_process_active_jobs(DiversityCurl *curl)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);

	g_mutex_lock(priv->mutex);

	while (priv->active_jobs) {
		GSList *tmp_list;
		DiversityCurlJob *job;

		/* find the first completed job */
		tmp_list = priv->active_jobs;
		while (tmp_list) {
			job = tmp_list->data;
			if (!((DiversityCurlJobInt *) job)->processing)
				break;

			tmp_list = tmp_list->next;
		}

		if (!tmp_list)
			break;

		priv->active_jobs = g_slist_delete_link(priv->active_jobs, tmp_list);

		g_mutex_unlock(priv->mutex);

		if (!priv->disposed)
			g_signal_emit(curl, curl_signals[JOB_COMPLETED],
					0, job);
		diversity_curl_job_free(job);

		g_mutex_lock(priv->mutex);
	}

	priv->active_id = 0;

	g_mutex_unlock(priv->mutex);

	return FALSE;
}

static gboolean write_file(const gchar *path, const guint8 *buf, gssize len)
{
	GError *error = NULL;

	g_file_set_contents(path, (gchar *) buf, len, &error);

	if (error && error->code == G_FILE_ERROR_NOENT) {
		char *dir;
		mode_t mode;

		g_error_free(error);

		dir = g_path_get_dirname(path);
		mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;

		if (g_mkdir_with_parents(dir, mode) == 0) {
			error = NULL;

			g_file_set_contents(path,
					(gchar *) buf, len, &error);
			if (error)
				g_error_free(error);
		}

		g_free(dir);
	}

	return (error == NULL);
}

static size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp)
{
	DiversityCurlHandle *handle = userp;
	size_t total;

	if (JOB_ABORTED(handle->job))
		return 0;

	total = size * nmemb;
	if (handle->buf->len + total > TILE_MAX_SIZE)
		return 0;

	g_byte_array_append(handle->buf, buffer, total);

	return total;
}

static CURLcode _process_pending_job(DiversityCurlHandle *handle, DiversityCurlJob *job)
{
	CURLcode ret;
	gboolean saved = FALSE;

	handle->job = job;

	curl_easy_setopt(handle->curl, CURLOPT_URL, job->uri);
	curl_easy_setopt(handle->curl, CURLOPT_WRITEDATA, handle);

	//printf("curl url: %s\n", job->uri);
	//curl_easy_setopt(handle, CURLOPT_VERBOSE, 1);

	ret = curl_easy_perform(handle->curl);
	if (ret == CURLE_OK)
		saved = write_file(job->path,
				handle->buf->data, handle->buf->len);

	if (JOB_ABORTED(job))
		job->status = DIVERSITY_ATLAS_TILE_STATUS_CANCELLED;
	else if (saved)
		job->status = DIVERSITY_ATLAS_TILE_STATUS_DONE;
	else if (ret == CURLE_OPERATION_TIMEDOUT)
		job->status = DIVERSITY_ATLAS_TILE_STATUS_TIMEOUT;
	else
		job->status = DIVERSITY_ATLAS_TILE_STATUS_FAILED;

	if (handle->buf->len)
		g_byte_array_remove_range(handle->buf, 0,
				handle->buf->len);

	handle->job = NULL;

	return ret;
}

inline static GSList *_pop_handle(DiversityCurl *curl)
{
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	DiversityCurlHandle *handle;
	GSList *head;

	if (!priv->handles)
		return NULL;

	head = priv->handles;
	priv->handles = g_slist_remove_link(priv->handles, head);

	handle = head->data;
	if (!handle) {
		g_mutex_unlock(priv->mutex);

		handle = g_slice_new(DiversityCurlHandle);

		handle->curl = curl_easy_init();
		curl_easy_setopt(handle->curl, CURLOPT_NOSIGNAL, 1);
		curl_easy_setopt(handle->curl, CURLOPT_TIMEOUT, 120);
		curl_easy_setopt(handle->curl,
				CURLOPT_WRITEFUNCTION, write_data);
		curl_easy_setopt(handle->curl,
				CURLOPT_USERAGENT, "diversity/0.0");

		handle->buf = g_byte_array_new();
		handle->job = NULL;

		head->data = handle;

		g_mutex_lock(priv->mutex);
	}

	return head;
}

static void process_jobs_threaded(gpointer data, gpointer user_data)
{
	DiversityCurl *curl = user_data;
	DiversityCurlPrivate *priv = DIVERSITY_CURL_GET_PRIVATE(curl);
	GSList *handle;

	g_mutex_lock(priv->mutex);

	handle = _pop_handle(curl);

	while (priv->pending_jobs) {
		GSList *tmp;
		DiversityCurlJob *job;

		if (!handle)
			break;

		tmp = priv->pending_jobs;
		job = tmp->data;

		priv->pending_jobs =
			g_slist_remove_link(priv->pending_jobs, tmp);
		priv->active_jobs = g_slist_concat(tmp, priv->active_jobs);

		((DiversityCurlJobInt *) job)->processing = TRUE;

		g_mutex_unlock(priv->mutex);
		_process_pending_job(handle->data, job);
		g_mutex_lock(priv->mutex);

		((DiversityCurlJobInt *) job)->processing = FALSE;
		if (!priv->active_id)
			priv->active_id =
				g_idle_add((GSourceFunc)
					   diversity_curl_process_active_jobs,
					   curl);
	}

	if (priv->active_jobs && !priv->active_id)
		priv->active_id =
			g_idle_add((GSourceFunc)
				   diversity_curl_process_active_jobs,
				   curl);

	if (handle)
		priv->handles = g_slist_concat(handle, priv->handles);

	g_mutex_unlock(priv->mutex);
}