/*
 * e-http-request.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-http-request.h"

#define LIBSOUP_USE_UNSTABLE_REQUEST_API
#include <libsoup/soup.h>
#include <libsoup/soup-requester.h>
#include <libsoup/soup-request-http.h>
#include <camel/camel.h>
#include <webkit/webkit.h>

#include <e-util/e-util.h>
#include <mail/em-utils.h>
#include <libemail-engine/e-mail-enumtypes.h>

#include <string.h>

#include <shell/e-shell.h>

#include "e-mail-ui-session.h"

#define d(x)

#define E_HTTP_REQUEST_GET_PRIVATE(obj) \
	(G_TYPE_INSTANCE_GET_PRIVATE \
	((obj), E_TYPE_HTTP_REQUEST, EHTTPRequestPrivate))

struct _EHTTPRequestPrivate {
	gchar *content_type;
	gint content_length;

	EMailPartList *parts_list;
};

G_DEFINE_TYPE (EHTTPRequest, e_http_request, SOUP_TYPE_REQUEST)

static gssize
copy_stream_to_stream (CamelStream *input,
                       GMemoryInputStream *output,
                       GCancellable *cancellable)
{
	gchar *buff;
	gssize read_len = 0;
	gssize total_len = 0;

	g_seekable_seek (G_SEEKABLE (input), 0, G_SEEK_SET, cancellable, NULL);

	buff = g_malloc (4096);
	while ((read_len = camel_stream_read (input, buff, 4096, cancellable, NULL)) > 0) {

		g_memory_input_stream_add_data (output, buff, read_len, g_free);

		total_len += read_len;

		buff = g_malloc (4096);
	}

	/* Free the last unused buffer */
	g_free (buff);

	return total_len;
}

static void
redirect_handler (SoupMessage *msg,
                  gpointer user_data)
{
	if (SOUP_STATUS_IS_REDIRECTION (msg->status_code)) {
		SoupSession *soup_session = user_data;
		SoupURI *new_uri;
		const gchar *new_loc;

		new_loc = soup_message_headers_get_list (msg->response_headers, "Location");
		if (!new_loc)
			return;

		new_uri = soup_uri_new_with_base (soup_message_get_uri (msg), new_loc);
		if (!new_uri) {
			soup_message_set_status_full (
				msg,
				SOUP_STATUS_MALFORMED,
				"Invalid Redirect URL");
			return;
		}

		soup_message_set_uri (msg, new_uri);
		soup_session_requeue_message (soup_session, msg);

		soup_uri_free (new_uri);
	}
}

static void
send_and_handle_redirection (SoupSession *session,
                             SoupMessage *message,
                             gchar **new_location)
{
	gchar *old_uri = NULL;

	g_return_if_fail (message != NULL);

	if (new_location) {
		old_uri = soup_uri_to_string (soup_message_get_uri (message), FALSE);
	}

	soup_message_set_flags (message, SOUP_MESSAGE_NO_REDIRECT);
	soup_message_add_header_handler (
		message, "got_body", "Location",
		G_CALLBACK (redirect_handler), session);
	soup_message_headers_append (message->request_headers, "Connection", "close");
	soup_session_send_message (session, message);

	if (new_location) {
		gchar *new_loc = soup_uri_to_string (soup_message_get_uri (message), FALSE);

		if (new_loc && old_uri && !g_str_equal (new_loc, old_uri)) {
			*new_location = new_loc;
		} else {
			g_free (new_loc);
		}
	}

	g_free (old_uri);
}

static void
handle_http_request (GSimpleAsyncResult *res,
                     GObject *object,
                     GCancellable *cancellable)
{
	EHTTPRequest *request = E_HTTP_REQUEST (object);
	SoupURI *soup_uri;
	gchar *evo_uri, *uri;
	gchar *mail_uri;
	GInputStream *stream;
	gboolean force_load_images = FALSE;
	EMailImageLoadingPolicy image_policy;
	gchar *uri_md5;
	EShell *shell;
	GSettings *settings;
	const gchar *user_cache_dir;
	CamelDataCache *cache;
	CamelStream *cache_stream;
	GHashTable *query;
	gint uri_len;

	if (g_cancellable_is_cancelled (cancellable)) {
		return;
	}

	/* Remove the __evo-mail query */
	soup_uri = soup_request_get_uri (SOUP_REQUEST (request));
	g_return_if_fail (soup_uri_get_query (soup_uri) != NULL);

	query = soup_form_decode (soup_uri_get_query (soup_uri));
	mail_uri = g_hash_table_lookup (query, "__evo-mail");
	if (mail_uri)
		mail_uri = g_strdup (mail_uri);

	g_hash_table_remove (query, "__evo-mail");

	/* Remove __evo-load-images if present (and in such case set
	 * force_load_images to TRUE) */
	force_load_images = g_hash_table_remove (query, "__evo-load-images");

	soup_uri_set_query_from_form (soup_uri, query);
	g_hash_table_unref (query);

	evo_uri = soup_uri_to_string (soup_uri, FALSE);

	/* Remove the "evo-" prefix from scheme */
	uri_len = strlen (evo_uri);
	uri = NULL;
	if (evo_uri && (uri_len > 5)) {

		/* Remove trailing "?" if there is no URI query */
		if (evo_uri[uri_len - 1] == '?') {
			uri = g_strndup (evo_uri + 4, uri_len - 5);
		} else {
			uri = g_strdup (evo_uri + 4);
		}
		g_free (evo_uri);
	}

	g_return_if_fail (uri && *uri);

	/* Use MD5 hash of the URI as a filname of the resourec cache file.
	 * We were previously using the URI as a filename but the URI is
	 * sometimes too long for a filename. */
	uri_md5 = g_compute_checksum_for_string (G_CHECKSUM_MD5, uri, -1);

	/* Open Evolution's cache */
	user_cache_dir = e_get_user_cache_dir ();
	cache = camel_data_cache_new (user_cache_dir, NULL);
	if (cache) {
		camel_data_cache_set_expire_age (cache, 24 * 60 * 60);
		camel_data_cache_set_expire_access (cache, 2 * 60 * 60);
	}

	/* Found item in cache! */
	cache_stream = camel_data_cache_get (cache, "http", uri_md5, NULL);
	if (cache_stream) {

		gssize len;

		stream = g_memory_input_stream_new ();

		len = copy_stream_to_stream (
			cache_stream,
			G_MEMORY_INPUT_STREAM (stream), cancellable);
		request->priv->content_length = len;

		g_object_unref (cache_stream);

		/* When succesfully read some data from cache then
		 * get mimetype and return the stream to WebKit.
		 * Otherwise try to fetch the resource again from the network. */
		if ((len != -1) && (request->priv->content_length > 0)) {
			GFile *file;
			GFileInfo *info;
			gchar *path;

			path = camel_data_cache_get_filename (cache, "http", uri_md5);
			file = g_file_new_for_path (path);
			info = g_file_query_info (
				file, G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
				0, cancellable, NULL);

			request->priv->content_type = g_strdup (
				g_file_info_get_content_type (info));

			d (
				printf ("'%s' found in cache (%d bytes, %s)\n",
				uri, request->priv->content_length,
				request->priv->content_type));

			g_object_unref (info);
			g_object_unref (file);
			g_free (path);

			/* Set result and quit the thread */
			g_simple_async_result_set_op_res_gpointer (res, stream, NULL);

			goto cleanup;
		} else {
			d (printf ("Failed to load '%s' from cache.\n", uri));
		}
	}

	/* If the item is not in the cache and Evolution is in offline mode then
	 * quit regardless any image loading policy */
	shell = e_shell_get_default ();
	if (!e_shell_get_online (shell)) {
		goto cleanup;
	}

	settings = g_settings_new ("org.gnome.evolution.mail");
	image_policy = g_settings_get_enum (settings, "image-loading-policy");
	g_object_unref (settings);

	/* Item not found in cache, but image loading policy allows us to fetch
	 * it from the interwebs */
	if (!force_load_images && mail_uri &&
	    (image_policy == E_MAIL_IMAGE_LOADING_POLICY_SOMETIMES)) {
		CamelObjectBag *registry;
		gchar *decoded_uri;
		EMailPartList *part_list;

		registry = e_mail_part_list_get_registry ();
		decoded_uri = soup_uri_decode (mail_uri);

		part_list = camel_object_bag_get (registry, decoded_uri);
		if (part_list) {
			EShellBackend *shell_backend;
			EMailBackend *backend;
			EMailSession *session;
			CamelInternetAddress *addr;
			CamelMimeMessage *message;
			gboolean known_address = FALSE;
			GError *error = NULL;

			shell_backend =
				e_shell_get_backend_by_name (shell, "mail");
			backend = E_MAIL_BACKEND (shell_backend);
			session = e_mail_backend_get_session (backend);

			message = e_mail_part_list_get_message (part_list);
			addr = camel_mime_message_get_from (message);

			e_mail_ui_session_check_known_address_sync (
				E_MAIL_UI_SESSION (session),
				addr, FALSE, cancellable,
				&known_address, &error);

			if (error != NULL) {
				g_warning ("%s: %s", G_STRFUNC, error->message);
				g_error_free (error);
			}

			if (known_address)
				force_load_images = TRUE;

			g_object_unref (part_list);
		}

		g_free (decoded_uri);
	}

	if ((image_policy == E_MAIL_IMAGE_LOADING_POLICY_ALWAYS) ||
	    force_load_images) {

		SoupSession *session;
		SoupMessage *message;
		CamelStream *cache_stream;
		GError *error;
		GMainContext *context;
		EProxy *proxy;

		context = g_main_context_new ();
		g_main_context_push_thread_default (context);

		session = soup_session_sync_new_with_options (
				SOUP_SESSION_TIMEOUT, 90,
				NULL);

		proxy = e_proxy_new ();
		e_proxy_setup_proxy (proxy);

		if (e_proxy_require_proxy_for_uri (proxy, uri)) {
			SoupURI *proxy_uri;

			proxy_uri = e_proxy_peek_uri_for (proxy, uri);

			g_object_set (session, SOUP_SESSION_PROXY_URI, proxy_uri, NULL);
		}

		g_clear_object (&proxy);

		message = soup_message_new (SOUP_METHOD_GET, uri);
		soup_message_headers_append (
			message->request_headers, "User-Agent", "Evolution/" VERSION);

		send_and_handle_redirection (session, message, NULL);

		if (!SOUP_STATUS_IS_SUCCESSFUL (message->status_code)) {
			g_warning ("Failed to request %s (code %d)", uri, message->status_code);
			goto cleanup;
		}

		/* Write the response body to cache */
		error = NULL;
		cache_stream = camel_data_cache_add (cache, "http", uri_md5, &error);
		if (error != NULL) {
			g_warning (
				"Failed to create cache file for '%s': %s",
				uri, error->message);
			g_clear_error (&error);
		} else {
			camel_stream_write (
				cache_stream, message->response_body->data,
				message->response_body->length, cancellable, &error);

			camel_stream_close (cache_stream, cancellable, NULL);
			g_object_unref (cache_stream);

			if (error != NULL) {
				if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
					g_warning (
						"Failed to write data to cache stream: %s",
						error->message);
				g_clear_error (&error);
				goto cleanup;
			}
		}

		/* Send the response body to WebKit */
		stream = g_memory_input_stream_new_from_data (
			g_memdup (message->response_body->data, message->response_body->length),
			message->response_body->length,
			(GDestroyNotify) g_free);

		request->priv->content_length = message->response_body->length;
		request->priv->content_type =
			g_strdup (
				soup_message_headers_get_content_type (
					message->response_headers, NULL));

		g_object_unref (message);
		g_object_unref (session);
		g_main_context_unref (context);

		d (printf ("Received image from %s\n"
			"Content-Type: %s\n"
			"Content-Length: %d bytes\n"
			"URI MD5: %s:\n",
			uri, request->priv->content_type,
			request->priv->content_length, uri_md5));

		g_simple_async_result_set_op_res_gpointer (res, stream, NULL);
		goto cleanup;
	}

 cleanup:
	if (cache) {
		g_object_unref (cache);
	}
	g_free (uri);
	g_free (uri_md5);
	g_free (mail_uri);
}

static void
http_request_finalize (GObject *object)
{
	EHTTPRequest *request = E_HTTP_REQUEST (object);

	if (request->priv->content_type) {
		g_free (request->priv->content_type);
		request->priv->content_type = NULL;
	}

	if (request->priv->parts_list) {
		g_object_unref (request->priv->parts_list);
		request->priv->parts_list = NULL;
	}

	G_OBJECT_CLASS (e_http_request_parent_class)->finalize (object);
}

static gboolean
http_request_check_uri (SoupRequest *request,
                        SoupURI *uri,
                        GError **error)
{
	return ((strcmp (uri->scheme, "evo-http") == 0) ||
		(strcmp (uri->scheme, "evo-https") == 0));
}

static void
http_request_send_async (SoupRequest *request,
                         GCancellable *cancellable,
                         GAsyncReadyCallback callback,
                         gpointer user_data)
{
	EHTTPRequest *ehr;
	GSimpleAsyncResult *simple;
	gchar *mail_uri;
	SoupURI *uri;
	const gchar *enc;
	CamelObjectBag *registry;
	GHashTable *query;

	ehr = E_HTTP_REQUEST (request);
	uri = soup_request_get_uri (request);
	g_return_if_fail (soup_uri_get_query (uri) != NULL);

	query = soup_form_decode (soup_uri_get_query (uri));

	d ({
		gchar *uri_str = soup_uri_to_string (uri, FALSE);
		printf ("received request for %s\n", uri_str);
		g_free (uri_str);
	});

	enc = g_hash_table_lookup (query, "__evo-mail");

	if (!enc || !*enc) {
		g_hash_table_destroy (query);
		return;
	}

	mail_uri = soup_uri_decode (enc);

	registry = e_mail_part_list_get_registry ();
	ehr->priv->parts_list = camel_object_bag_get (registry, mail_uri);
	g_free (mail_uri);

	g_return_if_fail (ehr->priv->parts_list);

	simple = g_simple_async_result_new (
		G_OBJECT (request), callback,
		user_data, http_request_send_async);

	g_simple_async_result_set_check_cancellable (simple, cancellable);

	g_simple_async_result_run_in_thread (
		simple, handle_http_request,
		G_PRIORITY_DEFAULT, cancellable);

	g_object_unref (simple);

	g_hash_table_destroy (query);
}

static GInputStream *
http_request_send_finish (SoupRequest *request,
                          GAsyncResult *result,
                          GError **error)
{
	GInputStream *stream;

	stream = g_simple_async_result_get_op_res_gpointer (G_SIMPLE_ASYNC_RESULT (result));

	/* Reset the stream before passing it back to webkit */
	if (stream && G_IS_SEEKABLE (stream))
		g_seekable_seek (G_SEEKABLE (stream), 0, G_SEEK_SET, NULL, NULL);

	if (!stream) /* We must always return something */
		stream = g_memory_input_stream_new ();

	return stream;
}

static goffset
http_request_get_content_length (SoupRequest *request)
{
	EHTTPRequest *efr = E_HTTP_REQUEST (request);

	d (printf ("Content-Length: %d bytes\n", efr->priv->content_length));
	return efr->priv->content_length;
}

static const gchar *
http_request_get_content_type (SoupRequest *request)
{
	EHTTPRequest *efr = E_HTTP_REQUEST (request);

	d (printf ("Content-Type: %s\n", efr->priv->content_type));

	return efr->priv->content_type;
}

static const gchar *data_schemes[] = { "evo-http", "evo-https", NULL };

static void
e_http_request_class_init (EHTTPRequestClass *class)
{
	GObjectClass *object_class;
	SoupRequestClass *request_class;

	g_type_class_add_private (class, sizeof (EHTTPRequestPrivate));

	object_class = G_OBJECT_CLASS (class);
	object_class->finalize = http_request_finalize;

	request_class = SOUP_REQUEST_CLASS (class);
	request_class->schemes = data_schemes;
	request_class->send_async = http_request_send_async;
	request_class->send_finish = http_request_send_finish;
	request_class->get_content_type = http_request_get_content_type;
	request_class->get_content_length = http_request_get_content_length;
	request_class->check_uri = http_request_check_uri;
}

static void
e_http_request_init (EHTTPRequest *request)
{
	request->priv = E_HTTP_REQUEST_GET_PRIVATE (request);
}