source: protocols/twitter/twitter_lib.c @ f85cb0b

/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  Simple module to facilitate twitter functionality.                       *
*                                                                           *
*  Copyright 2009-2010 Geert Mulders <g.c.w.m.mulders@gmail.com>            *
*  Copyright 2010-2013 Wilmer van der Gaast <wilmer@gaast.net>              *
*                                                                           *
*  This library 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, version            *
*  2.1.                                                                     *
*                                                                           *
*  This library 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 this library; if not, write to the Free Software Foundation,  *
*  Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA           *
*                                                                           *
****************************************************************************/

/* For strptime(): */
#if (__sun)
#else
#define _XOPEN_SOURCE
#endif

#include "twitter_http.h"
#include "twitter.h"
#include "bitlbee.h"
#include "url.h"
#include "misc.h"
#include "base64.h"
#include "twitter_lib.h"
#include "parson.h"
#include <ctype.h>
#include <errno.h>

#define TXL_STATUS 1
#define TXL_USER 2
#define TXL_ID 3

struct twitter_xml_list {
        int type;
        gint64 next_cursor;
        GSList *list;
};

struct twitter_xml_user {
        guint64 uid;
        char *name;
        char *screen_name;
};

struct twitter_xml_status {
        time_t created_at;
        char *text;
        struct twitter_xml_user *user;
        guint64 id, rt_id; /* Usually equal, with RTs id == *original* id */
        guint64 reply_to;
        gboolean from_filter;
};

#define JSON_O_FOREACH(o, k, v) \
    const char *k; const JSON_Value *v; int __i; \
    for (__i = 0; json_object_get_tuple(o, __i, &k, &v); __i++)

/**
 * Frees a twitter_xml_user struct.
 */
static void txu_free(struct twitter_xml_user *txu)
{
        if (txu == NULL) {
                return;
        }

        g_free(txu->name);
        g_free(txu->screen_name);
        g_free(txu);
}

/**
 * Frees a twitter_xml_status struct.
 */
static void txs_free(struct twitter_xml_status *txs)
{
        if (txs == NULL) {
                return;
        }

        g_free(txs->text);
        txu_free(txs->user);
        g_free(txs);
}

/**
 * Free a twitter_xml_list struct.
 * type is the type of list the struct holds.
 */
static void txl_free(struct twitter_xml_list *txl)
{
        GSList *l;

        if (txl == NULL) {
                return;
        }

        for (l = txl->list; l; l = g_slist_next(l)) {
                if (txl->type == TXL_STATUS) {
                        txs_free((struct twitter_xml_status *) l->data);
                } else if (txl->type == TXL_ID) {
                        g_free(l->data);
                } else if (txl->type == TXL_USER) {
                        txu_free(l->data);
                }
        }

        g_slist_free(txl->list);
        g_free(txl);
}

/**
 * Compare status elements
 */
static gint twitter_compare_elements(gconstpointer a, gconstpointer b)
{
        struct twitter_xml_status *a_status = (struct twitter_xml_status *) a;
        struct twitter_xml_status *b_status = (struct twitter_xml_status *) b;

        if (a_status->created_at < b_status->created_at) {
                return -1;
        } else if (a_status->created_at > b_status->created_at) {
                return 1;
        } else {
                return 0;
        }
}

/**
 * Add a buddy if it is not already added, set the status to logged in.
 */
static void twitter_add_buddy(struct im_connection *ic, char *name, const char *fullname)
{
        struct twitter_data *td = ic->proto_data;

        // Check if the buddy is already in the buddy list.
        if (!bee_user_by_handle(ic->bee, ic, name)) {
                // The buddy is not in the list, add the buddy and set the status to logged in.
                imcb_add_buddy(ic, name, NULL);
                imcb_rename_buddy(ic, name, fullname);
                if (td->flags & TWITTER_MODE_CHAT) {
                        /* Necessary so that nicks always get translated to the
                           exact Twitter username. */
                        imcb_buddy_nick_hint(ic, name, name);
                        if (td->timeline_gc) {
                                imcb_chat_add_buddy(td->timeline_gc, name);
                        }
                } else if (td->flags & TWITTER_MODE_MANY) {
                        imcb_buddy_status(ic, name, OPT_LOGGED_IN, NULL, NULL);
                }
        }
}

/* Warning: May return a malloc()ed value, which will be free()d on the next
   call. Only for short-term use. NOT THREADSAFE!  */
char *twitter_parse_error(struct http_request *req)
{
        static char *ret = NULL;
        JSON_Value *root, *err;

        g_free(ret);
        ret = NULL;

        if (req->body_size > 0) {
                root = json_parse_string(req->reply_body);
                err = json_object_get_value(json_object(root), "errors");
                if (err && json_type(err) == JSONArray &&
                    (err = json_array_get_value(json_array(err), 0)) &&
                    json_type(err) == JSONObject) {
                        const char *msg = json_object_get_string(json_object(err), "message");
                        if (msg) {
                                ret = g_strdup_printf("%s (%s)", req->status_string, msg);
                        }
                }
                json_value_free(root);
        }

        return ret ? ret : req->status_string;
}

/* WATCH OUT: This function might or might not destroy your connection.
   Sub-optimal indeed, but just be careful when this returns NULL! */
static JSON_Value *twitter_parse_response(struct im_connection *ic, struct http_request *req)
{
        gboolean logging_in = !(ic->flags & OPT_LOGGED_IN);
        gboolean periodic;
        struct twitter_data *td = ic->proto_data;
        JSON_Value *ret;
        char path[64] = "", *s;

        if ((s = strchr(req->request, ' '))) {
                path[sizeof(path) - 1] = '\0';
                strncpy(path, s + 1, sizeof(path) - 1);
                if ((s = strchr(path, '?')) || (s = strchr(path, ' '))) {
                        *s = '\0';
                }
        }

        /* Kinda nasty. :-( Trying to suppress error messages, but only
           for periodic (i.e. mentions/timeline) queries. */
        periodic = strstr(path, "timeline") || strstr(path, "mentions");

        if (req->status_code == 401 && logging_in) {
                /* IIRC Twitter once had an outage where they were randomly
                   throwing 401s so I'll keep treating this one as fatal
                   only during login. */
                imcb_error(ic, "Authentication failure (%s)",
                           twitter_parse_error(req));
                imc_logout(ic, FALSE);
                return NULL;
        } else if (req->status_code != 200) {
                // It didn't go well, output the error and return.
                if (!periodic || logging_in || ++td->http_fails >= 5) {
                        twitter_log(ic, "Error: Could not retrieve %s: %s",
                                    path, twitter_parse_error(req));
                }

                if (logging_in) {
                        imc_logout(ic, TRUE);
                }
                return NULL;
        } else {
                td->http_fails = 0;
        }

        if ((ret = json_parse_string(req->reply_body)) == NULL) {
                imcb_error(ic, "Could not retrieve %s: %s",
                           path, "XML parse error");
        }
        return ret;
}

static void twitter_http_get_friends_ids(struct http_request *req);

/**
 * Get the friends ids.
 */
void twitter_get_friends_ids(struct im_connection *ic, gint64 next_cursor)
{
        // Primitive, but hey! It works...
        char *args[2];

        args[0] = "cursor";
        args[1] = g_strdup_printf("%" G_GINT64_FORMAT, next_cursor);
        twitter_http(ic, TWITTER_FRIENDS_IDS_URL, twitter_http_get_friends_ids, ic, 0, args, 2);

        g_free(args[1]);
}

/**
 * Fill a list of ids.
 */
static gboolean twitter_xt_get_friends_id_list(JSON_Value *node, struct twitter_xml_list *txl)
{
        JSON_Array *c;
        int i;

        // Set the list type.
        txl->type = TXL_ID;

        if (!(c = json_object_get_array(json_object(node), "ids"))) {
                return FALSE;
        }

        for (i = 0; i < json_array_get_count(c); i++) {
                jint id = json_array_get_integer(c, i);

                txl->list = g_slist_prepend(txl->list,
                                            g_strdup_printf("%lld", id));
        }

        JSON_Value *next = json_object_get_value(json_object(node), "next_cursor");
        if (next && json_type(next) == JSONInteger) {
                txl->next_cursor = json_integer(next);
        } else {
                txl->next_cursor = -1;
        }

        return TRUE;
}

static void twitter_get_users_lookup(struct im_connection *ic);

/**
 * Callback for getting the friends ids.
 */
static void twitter_http_get_friends_ids(struct http_request *req)
{
        struct im_connection *ic;
        JSON_Value *parsed;
        struct twitter_xml_list *txl;
        struct twitter_data *td;

        ic = req->data;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td = ic->proto_data;

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = td->follow_ids;

        // Parse the data.
        if (!(parsed = twitter_parse_response(ic, req))) {
                return;
        }

        twitter_xt_get_friends_id_list(parsed, txl);
        json_value_free(parsed);

        td->follow_ids = txl->list;
        if (txl->next_cursor) {
                /* These were just numbers. Up to 4000 in a response AFAIK so if we get here
                   we may be using a spammer account. \o/ */
                twitter_get_friends_ids(ic, txl->next_cursor);
        } else {
                /* Now to convert all those numbers into names.. */
                twitter_get_users_lookup(ic);
        }

        txl->list = NULL;
        txl_free(txl);
}

static gboolean twitter_xt_get_users(JSON_Value *node, struct twitter_xml_list *txl);
static void twitter_http_get_users_lookup(struct http_request *req);

static void twitter_get_users_lookup(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        char *args[2] = {
                "user_id",
                NULL,
        };
        GString *ids = g_string_new("");
        int i;

        /* We can request up to 100 users at a time. */
        for (i = 0; i < 100 && td->follow_ids; i++) {
                g_string_append_printf(ids, ",%s", (char *) td->follow_ids->data);
                g_free(td->follow_ids->data);
                td->follow_ids = g_slist_remove(td->follow_ids, td->follow_ids->data);
        }
        if (ids->len > 0) {
                args[1] = ids->str + 1;
                /* POST, because I think ids can be up to 1KB long. */
                twitter_http(ic, TWITTER_USERS_LOOKUP_URL, twitter_http_get_users_lookup, ic, 1, args, 2);
        } else {
                /* We have all users. Continue with login. (Get statuses.) */
                td->flags |= TWITTER_HAVE_FRIENDS;
                twitter_login_finish(ic);
        }
        g_string_free(ids, TRUE);
}

/**
 * Callback for getting (twitter)friends...
 *
 * Be afraid, be very afraid! This function will potentially add hundreds of "friends". "Who has
 * hundreds of friends?" you wonder? You probably not, since you are reading the source of
 * BitlBee... Get a life and meet new people!
 */
static void twitter_http_get_users_lookup(struct http_request *req)
{
        struct im_connection *ic = req->data;
        JSON_Value *parsed;
        struct twitter_xml_list *txl;
        GSList *l = NULL;
        struct twitter_xml_user *user;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // Get the user list from the parsed xml feed.
        if (!(parsed = twitter_parse_response(ic, req))) {
                return;
        }
        twitter_xt_get_users(parsed, txl);
        json_value_free(parsed);

        // Add the users as buddies.
        for (l = txl->list; l; l = g_slist_next(l)) {
                user = l->data;
                twitter_add_buddy(ic, user->screen_name, user->name);
        }

        // Free the structure.
        txl_free(txl);

        twitter_get_users_lookup(ic);
}

struct twitter_xml_user *twitter_xt_get_user(const JSON_Object *node)
{
        struct twitter_xml_user *txu;
        
        if (!node)
                return NULL;

        txu = g_new0(struct twitter_xml_user, 1);
        txu->name = g_strdup(json_object_get_string(node, "name"));
        txu->screen_name = g_strdup(json_object_get_string(node, "screen_name"));
        txu->uid = json_object_get_integer(node, "id");

        return txu;
}

/**
 * Function to fill a twitter_xml_list struct.
 * It sets:
 *  - all <user>s from the <users> element.
 */
static gboolean twitter_xt_get_users(JSON_Value *node, struct twitter_xml_list *txl)
{
        struct twitter_xml_user *txu;
        int i;

        // Set the type of the list.
        txl->type = TXL_USER;

        if (json_type(node) != JSONArray) {
                return FALSE;
        }
        
        // The root <users> node should hold the list of users <user>
        // Walk over the nodes children.
        JSON_Array *arr = json_array(node);
        for (i = 0; i < json_array_get_count(arr); i++) {
                JSON_Object *o = json_array_get_object(arr, i);
                if (!o)
                        continue;
                txu = twitter_xt_get_user(o);
                if (txu) {
                        txl->list = g_slist_prepend(txl->list, txu);
                }
        }

        return TRUE;
}

#ifdef __GLIBC__
#define TWITTER_TIME_FORMAT "%a %b %d %H:%M:%S %z %Y"
#else
#define TWITTER_TIME_FORMAT "%a %b %d %H:%M:%S +0000 %Y"
#endif

static void expand_entities(char **text, const JSON_Object *node);

/**
 * Function to fill a twitter_xml_status struct.
 * It sets:
 *  - the status text and
 *  - the created_at timestamp and
 *  - the status id and
 *  - the user in a twitter_xml_user struct.
 */
static struct twitter_xml_status *twitter_xt_get_status(const JSON_Object *node)
{
        struct twitter_xml_status *txs;
        const JSON_Object *rt = NULL;

        if (!node) {
                return FALSE;
        }
        txs = g_new0(struct twitter_xml_status, 1);

        JSON_O_FOREACH(node, k, v) {
                if (strcmp("text", k) == 0 && (txs->text = g_strdup(json_string(v)))) {
                        // TODO: Huh strip html? In json? Not sure whether I have to..
                        strip_html(txs->text);
                } else if (strcmp("retweeted_status", k) == 0 && (rt = json_object(v))) {
                        // Handling below.
                } else if (strcmp("created_at", k) == 0 && json_type(v) == JSONString) {
                        struct tm parsed;

                        /* Very sensitive to changes to the formatting of
                           this field. :-( Also assumes the timezone used
                           is UTC since C time handling functions suck. */
                        if (strptime(json_string(v), TWITTER_TIME_FORMAT, &parsed) != NULL) {
                                txs->created_at = mktime_utc(&parsed);
                        }
                } else if (strcmp("user", k) == 0 && json_type(v) == JSONObject) {
                        txs->user = twitter_xt_get_user(json_object(v));
                } else if (strcmp("id", k) == 0 && json_type(v) == JSONInteger) {
                        txs->rt_id = txs->id = json_integer(v);
                } else if (strcmp("in_reply_to_status_id", k) == 0 && json_type(v) == JSONInteger) {
                        txs->reply_to = json_integer(v);
                }
        }

        /* If it's a (truncated) retweet, get the original. Even if the API claims it
           wasn't truncated because it may be lying. */
        if (rt) {
                struct twitter_xml_status *rtxs = twitter_xt_get_status(rt);
                if (rtxs) {
                        g_free(txs->text);
                        txs->text = g_strdup_printf("RT @%s: %s", rtxs->user->screen_name, rtxs->text);
                        txs->id = rtxs->id;
                        txs_free(rtxs);
                }
        } else {
                expand_entities(&txs->text, node);
        }

        if (txs->text && txs->user && txs->id) {
                return txs;
        }

        txs_free(txs);
        return NULL;
}

/**
 * Function to fill a twitter_xml_status struct (DM variant).
 */
static struct twitter_xml_status *twitter_xt_get_dm(const JSON_Object *node)
{
        struct twitter_xml_status *txs;

        if (!node) {
                return FALSE;
        }
        txs = g_new0(struct twitter_xml_status, 1);

        JSON_O_FOREACH(node, k, v) {
                if (strcmp("text", k) == 0 && (txs->text = g_strdup(json_string(v)))) {
                        strip_html(txs->text);
                } else if (strcmp("created_at", k) == 0 && json_type(v) == JSONString) {
                        struct tm parsed;

                        /* Very sensitive to changes to the formatting of
                           this field. :-( Also assumes the timezone used
                           is UTC since C time handling functions suck. */
                        if (strptime(json_string(v), TWITTER_TIME_FORMAT, &parsed) != NULL) {
                                txs->created_at = mktime_utc(&parsed);
                        }
                } else if (strcmp("sender", k) == 0 && json_type(v) == JSONObject) {
                        txs->user = twitter_xt_get_user(json_object(v));
                } else if (strcmp("id", k) == 0 && json_type(v) == JSONInteger) {
                        txs->id = json_integer(v);
                }
        }

        expand_entities(&txs->text, node);

        if (txs->text && txs->user && txs->id) {
                return txs;
        }

        txs_free(txs);
        return NULL;
}

static void expand_entities(char **text, const JSON_Object *node)
{
        JSON_Object *entities, *quoted;
        char *quote_url = NULL, *quote_text = NULL;

        if (!(entities = json_object_get_object(node, "entities")))
                return;
        if ((quoted = json_object_get_object(node, "quoted_status"))) {
                /* New "retweets with comments" feature. Note that this info
                 * seems to be included in the streaming API only! Grab the
                 * full message and try to insert it when we run into the
                 * Tweet entity. */
                struct twitter_xml_status *txs = twitter_xt_get_status(quoted);
                quote_text = g_strdup_printf("@%s: %s", txs->user->screen_name, txs->text);
                quote_url = g_strdup_printf("%s/status/%" G_GUINT64_FORMAT, txs->user->screen_name, txs->id);
                txs_free(txs);
        } else {
                quoted = NULL;
        }

        JSON_O_FOREACH(entities, k, v) {
                int i;

                if (json_type(v) != JSONArray) {
                        continue;
                }
                if (strcmp(k, "urls") != 0 && strcmp(k, "media") != 0) {
                        continue;
                }

                for (i = 0; i < json_array_get_count(json_array(v)); i++) {
                        const char *format = "%s%s <%s>%s";
                        JSON_Object *r = json_array_get_object(json_array(v), i);

                        if (!r) {
                                continue;
                        }

                        const char *kort = json_object_get_string(r, "url");
                        const char *disp = json_object_get_string(r, "display_url");
                        const char *full = json_object_get_string(r, "expanded_url");
                        char *pos, *new;

                        if (!kort || !disp || !(pos = strstr(*text, kort))) {
                                continue;
                        }
                        if (quote_url && strstr(full, quote_url)) {
                                format = "%s<%s> [%s]%s";
                                disp = quote_text;
                        }

                        *pos = '\0';
                        new = g_strdup_printf(format, *text, kort,
                                              disp, pos + strlen(kort));

                        g_free(*text);
                        *text = new;
                }
        }
        g_free(quote_text);
        g_free(quote_url);
}

/**
 * Function to fill a twitter_xml_list struct.
 * It sets:
 *  - all <status>es within the <status> element and
 *  - the next_cursor.
 */
static gboolean twitter_xt_get_status_list(struct im_connection *ic, const JSON_Value *node,
                                           struct twitter_xml_list *txl)
{
        struct twitter_xml_status *txs;
        int i;

        // Set the type of the list.
        txl->type = TXL_STATUS;

        if (json_type(node) != JSONArray) {
                return FALSE;
        }

        // The root <statuses> node should hold the list of statuses <status>
        // Walk over the nodes children.
        for (i = 0; i < json_array_get_count(json_array(node)); i++) {
                txs = twitter_xt_get_status(json_array_get_object(json_array(node), i));
                if (!txs) {
                        continue;
                }

                txl->list = g_slist_prepend(txl->list, txs);
        }

        return TRUE;
}

/* Will log messages either way. Need to keep track of IDs for stream deduping.
   Plus, show_ids is on by default and I don't see why anyone would disable it. */
static char *twitter_msg_add_id(struct im_connection *ic,
                                struct twitter_xml_status *txs, const char *prefix)
{
        struct twitter_data *td = ic->proto_data;
        int reply_to = -1;
        bee_user_t *bu;

        if (txs->reply_to) {
                int i;
                for (i = 0; i < TWITTER_LOG_LENGTH; i++) {
                        if (td->log[i].id == txs->reply_to) {
                                reply_to = i;
                                break;
                        }
                }
        }

        if (txs->user && txs->user->screen_name &&
            (bu = bee_user_by_handle(ic->bee, ic, txs->user->screen_name))) {
                struct twitter_user_data *tud = bu->data;

                if (txs->id > tud->last_id) {
                        tud->last_id = txs->id;
                        tud->last_time = txs->created_at;
                }
        }

        td->log_id = (td->log_id + 1) % TWITTER_LOG_LENGTH;
        td->log[td->log_id].id = txs->id;
        td->log[td->log_id].bu = bee_user_by_handle(ic->bee, ic, txs->user->screen_name);

        /* This is all getting hairy. :-( If we RT'ed something ourselves,
           remember OUR id instead so undo will work. In other cases, the
           original tweet's id should be remembered for deduplicating. */
        if (g_strcasecmp(txs->user->screen_name, td->user) == 0) {
                td->log[td->log_id].id = txs->rt_id;
                /* More useful than NULL. */
                td->log[td->log_id].bu = &twitter_log_local_user;
        }

        if (set_getbool(&ic->acc->set, "show_ids")) {
                if (reply_to != -1) {
                        return g_strdup_printf("\002[\002%02x->%02x\002]\002 %s%s",
                                               td->log_id, reply_to, prefix, txs->text);
                } else {
                        return g_strdup_printf("\002[\002%02x\002]\002 %s%s",
                                               td->log_id, prefix, txs->text);
                }
        } else {
                if (*prefix) {
                        return g_strconcat(prefix, txs->text, NULL);
                } else {
                        return NULL;
                }
        }
}

/**
 * Function that is called to see the filter statuses in groupchat windows.
 */
static void twitter_status_show_filter(struct im_connection *ic, struct twitter_xml_status *status)
{
        struct twitter_data *td = ic->proto_data;
        char *msg = twitter_msg_add_id(ic, status, "");
        struct twitter_filter *tf;
        GSList *f;
        GSList *l;

        for (f = td->filters; f; f = g_slist_next(f)) {
                tf = f->data;

                switch (tf->type) {
                case TWITTER_FILTER_TYPE_FOLLOW:
                        if (status->user->uid != tf->uid) {
                                continue;
                        }
                        break;

                case TWITTER_FILTER_TYPE_TRACK:
                        if (strcasestr(status->text, tf->text) == NULL) {
                                continue;
                        }
                        break;

                default:
                        continue;
                }

                for (l = tf->groupchats; l; l = g_slist_next(l)) {
                        imcb_chat_msg(l->data, status->user->screen_name,
                                      msg ? msg : status->text, 0, 0);
                }
        }

        g_free(msg);
}

/**
 * Function that is called to see the statuses in a groupchat window.
 */
static void twitter_status_show_chat(struct im_connection *ic, struct twitter_xml_status *status)
{
        struct twitter_data *td = ic->proto_data;
        struct groupchat *gc;
        gboolean me = g_strcasecmp(td->user, status->user->screen_name) == 0;
        char *msg;

        // Create a new groupchat if it does not exsist.
        gc = twitter_groupchat_init(ic);

        if (!me) {
                /* MUST be done before twitter_msg_add_id() to avoid #872. */
                twitter_add_buddy(ic, status->user->screen_name, status->user->name);
        }
        msg = twitter_msg_add_id(ic, status, "");

        // Say it!
        if (me) {
                imcb_chat_log(gc, "You: %s", msg ? msg : status->text);
        } else {
                imcb_chat_msg(gc, status->user->screen_name,
                              msg ? msg : status->text, 0, status->created_at);
        }

        g_free(msg);
}

/**
 * Function that is called to see statuses as private messages.
 */
static void twitter_status_show_msg(struct im_connection *ic, struct twitter_xml_status *status)
{
        struct twitter_data *td = ic->proto_data;
        char from[MAX_STRING] = "";
        char *prefix = NULL, *text = NULL;
        gboolean me = g_strcasecmp(td->user, status->user->screen_name) == 0;

        if (td->flags & TWITTER_MODE_ONE) {
                g_snprintf(from, sizeof(from) - 1, "%s_%s", td->prefix, ic->acc->user);
                from[MAX_STRING - 1] = '\0';
        }

        if (td->flags & TWITTER_MODE_ONE) {
                prefix = g_strdup_printf("\002<\002%s\002>\002 ",
                                         status->user->screen_name);
        } else if (!me) {
                twitter_add_buddy(ic, status->user->screen_name, status->user->name);
        } else {
                prefix = g_strdup("You: ");
        }

        text = twitter_msg_add_id(ic, status, prefix ? prefix : "");

        imcb_buddy_msg(ic,
                       *from ? from : status->user->screen_name,
                       text ? text : status->text, 0, status->created_at);

        g_free(text);
        g_free(prefix);
}

static void twitter_status_show(struct im_connection *ic, struct twitter_xml_status *status)
{
        struct twitter_data *td = ic->proto_data;
        char *last_id_str;

        if (status->user == NULL || status->text == NULL) {
                return;
        }

        /* Grrrr. Would like to do this during parsing, but can't access
           settings from there. */
        if (set_getbool(&ic->acc->set, "strip_newlines")) {
                strip_newlines(status->text);
        }

        if (status->from_filter) {
                twitter_status_show_filter(ic, status);
        } else if (td->flags & TWITTER_MODE_CHAT) {
                twitter_status_show_chat(ic, status);
        } else {
                twitter_status_show_msg(ic, status);
        }

        // Update the timeline_id to hold the highest id, so that by the next request
        // we won't pick up the updates already in the list.
        td->timeline_id = MAX(td->timeline_id, status->rt_id);

        last_id_str = g_strdup_printf("%" G_GUINT64_FORMAT, td->timeline_id);
        set_setstr(&ic->acc->set, "_last_tweet", last_id_str);
        g_free(last_id_str);
}

static gboolean twitter_stream_handle_object(struct im_connection *ic, JSON_Object *o, gboolean from_filter);

static void twitter_http_stream(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        JSON_Value *parsed;
        int len = 0;
        char c, *nl;
        gboolean from_filter;

        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        ic->flags |= OPT_PONGED;
        td = ic->proto_data;

        if ((req->flags & HTTPC_EOF) || !req->reply_body) {
                if (req == td->stream) {
                        td->stream = NULL;
                } else if (req == td->filter_stream) {
                        td->filter_stream = NULL;
                }

                imcb_error(ic, "Stream closed (%s)", req->status_string);
                if (req->status_code == 401) {
                        imcb_error(ic, "Check your system clock.");
                }
                imc_logout(ic, TRUE);
                return;
        }

        /* MUST search for CRLF, not just LF:
           https://dev.twitter.com/docs/streaming-apis/processing#Parsing_responses */
        if (!(nl = strstr(req->reply_body, "\r\n"))) {
                return;
        }

        len = nl - req->reply_body;
        if (len > 0) {
                c = req->reply_body[len];
                req->reply_body[len] = '\0';

                if ((parsed = json_parse_string(req->reply_body))) {
                        from_filter = (req == td->filter_stream);
                        twitter_stream_handle_object(ic, json_object(parsed), from_filter);
                }
                json_value_free(parsed);
                req->reply_body[len] = c;
        }

        http_flush_bytes(req, len + 2);

        /* One notification might bring multiple events! */
        if (req->body_size > 0) {
                twitter_http_stream(req);
        }
}

static gboolean twitter_stream_handle_event(struct im_connection *ic, JSON_Object *o);
static gboolean twitter_stream_handle_status(struct im_connection *ic, struct twitter_xml_status *txs);

static gboolean twitter_stream_handle_object(struct im_connection *ic, JSON_Object *o, gboolean from_filter)
{
        struct twitter_data *td = ic->proto_data;
        struct twitter_xml_status *txs;
        JSON_Object *c;

        if ((txs = twitter_xt_get_status(o))) {
                txs->from_filter = from_filter;
                gboolean ret = twitter_stream_handle_status(ic, txs);
                txs_free(txs);
                return ret;
        } else if ((c = json_object_get_object(o, "direct_message")) &&
                   (txs = twitter_xt_get_dm(c))) {
                if (g_strcasecmp(txs->user->screen_name, td->user) != 0) {
                        imcb_buddy_msg(ic, txs->user->screen_name,
                                       txs->text, 0, txs->created_at);
                }
                txs_free(txs);
                return TRUE;
        } else if (json_object_get_string(o, "event")) {
                twitter_stream_handle_event(ic, o);
                return TRUE;
        } else if ((c = json_object_get_object(o, "disconnect"))) {
                /* HACK: Because we're inside an event handler, we can't just
                   disconnect here. Instead, just change the HTTP status string
                   into a Twitter status string. */
                char *reason = g_strdup(json_object_get_string(c, "reason"));
                if (reason) {
                        g_free(td->stream->status_string);
                        td->stream->status_string = reason;
                }
                return TRUE;
        }
        return FALSE;
}

static gboolean twitter_stream_handle_status(struct im_connection *ic, struct twitter_xml_status *txs)
{
        struct twitter_data *td = ic->proto_data;
        int i;

        for (i = 0; i < TWITTER_LOG_LENGTH; i++) {
                if (td->log[i].id == txs->id) {
                        /* Got a duplicate (RT, probably). Drop it. */
                        return TRUE;
                }
        }

        if (!(g_strcasecmp(txs->user->screen_name, td->user) == 0 ||
              set_getbool(&ic->acc->set, "fetch_mentions") ||
              bee_user_by_handle(ic->bee, ic, txs->user->screen_name))) {
                /* Tweet is from an unknown person and the user does not want
                   to see @mentions, so drop it. twitter_stream_handle_event()
                   picks up new follows so this simple filter should be safe. */
                /* TODO: The streaming API seems to do poor @mention matching.
                   I.e. I'm getting mentions for @WilmerSomething, not just for
                   @Wilmer. But meh. You want spam, you get spam. */
                return TRUE;
        }

        twitter_status_show(ic, txs);

        return TRUE;
}

static gboolean twitter_stream_handle_event(struct im_connection *ic, JSON_Object *o)
{
        struct twitter_data *td = ic->proto_data;
        JSON_Object *source = json_object_get_object(o, "source");
        JSON_Object *target = json_object_get_object(o, "target");
        const char *type = json_object_get_string(o, "event");

        if (!type || !source || !target) {
                return FALSE;
        }

        if (strcmp(type, "follow") == 0) {
                struct twitter_xml_user *us = twitter_xt_get_user(source);
                struct twitter_xml_user *ut = twitter_xt_get_user(target);
                if (g_strcasecmp(us->screen_name, td->user) == 0) {
                        twitter_add_buddy(ic, ut->screen_name, ut->name);
                }
                txu_free(us);
                txu_free(ut);
        }

        return TRUE;
}

gboolean twitter_open_stream(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        char *args[2] = { "with", "followings" };

        if ((td->stream = twitter_http(ic, TWITTER_USER_STREAM_URL,
                                       twitter_http_stream, ic, 0, args, 2))) {
                /* This flag must be enabled or we'll get no data until EOF
                   (which err, kind of, defeats the purpose of a streaming API). */
                td->stream->flags |= HTTPC_STREAMING;
                return TRUE;
        }

        return FALSE;
}

static gboolean twitter_filter_stream(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        char *args[4] = { "follow", NULL, "track", NULL };
        GString *followstr = g_string_new("");
        GString *trackstr = g_string_new("");
        gboolean ret = FALSE;
        struct twitter_filter *tf;
        GSList *l;

        for (l = td->filters; l; l = g_slist_next(l)) {
                tf = l->data;

                switch (tf->type) {
                case TWITTER_FILTER_TYPE_FOLLOW:
                        if (followstr->len > 0) {
                                g_string_append_c(followstr, ',');
                        }

                        g_string_append_printf(followstr, "%" G_GUINT64_FORMAT,
                                               tf->uid);
                        break;

                case TWITTER_FILTER_TYPE_TRACK:
                        if (trackstr->len > 0) {
                                g_string_append_c(trackstr, ',');
                        }

                        g_string_append(trackstr, tf->text);
                        break;

                default:
                        continue;
                }
        }

        args[1] = followstr->str;
        args[3] = trackstr->str;

        if (td->filter_stream) {
                http_close(td->filter_stream);
        }

        if ((td->filter_stream = twitter_http(ic, TWITTER_FILTER_STREAM_URL,
                                              twitter_http_stream, ic, 0,
                                              args, 4))) {
                /* This flag must be enabled or we'll get no data until EOF
                   (which err, kind of, defeats the purpose of a streaming API). */
                td->filter_stream->flags |= HTTPC_STREAMING;
                ret = TRUE;
        }

        g_string_free(followstr, TRUE);
        g_string_free(trackstr, TRUE);

        return ret;
}

static void twitter_filter_users_post(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        struct twitter_filter *tf;
        GList *users = NULL;
        JSON_Value *parsed;
        GString *fstr;
        GSList *l;
        GList *u;
        int i;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td = ic->proto_data;

        if (!(parsed = twitter_parse_response(ic, req))) {
                return;
        }

        for (l = td->filters; l; l = g_slist_next(l)) {
                tf = l->data;

                if (tf->type == TWITTER_FILTER_TYPE_FOLLOW) {
                        users = g_list_prepend(users, tf);
                }
        }

        if (json_type(parsed) != JSONArray) {
                goto finish;
        }

        for (i = 0; i < json_array_get_count(json_array(parsed)); i++) {
                JSON_Object *o = json_array_get_object(json_array(parsed), i);
                jint id = json_object_get_integer(o, "id");
                const char *name = json_object_get_string(o, "screen_name");

                if (!name || !id) {
                        continue;
                }

                for (u = users; u; u = g_list_next(u)) {
                        tf = u->data;

                        if (g_strcasecmp(tf->text, name) == 0) {
                                tf->uid = id;
                                users = g_list_delete_link(users, u);
                                break;
                        }
                }
        }

finish:
        json_value_free(parsed);
        twitter_filter_stream(ic);

        if (!users) {
                return;
        }

        fstr = g_string_new("");

        for (u = users; u; u = g_list_next(u)) {
                if (fstr->len > 0) {
                        g_string_append(fstr, ", ");
                }

                g_string_append(fstr, tf->text);
        }

        imcb_error(ic, "Failed UID acquisitions: %s", fstr->str);

        g_string_free(fstr, TRUE);
        g_list_free(users);
}

gboolean twitter_open_filter_stream(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        char *args[2] = { "screen_name", NULL };
        GString *ustr = g_string_new("");
        struct twitter_filter *tf;
        struct http_request *req;
        GSList *l;

        for (l = td->filters; l; l = g_slist_next(l)) {
                tf = l->data;

                if (tf->type != TWITTER_FILTER_TYPE_FOLLOW || tf->uid != 0) {
                        continue;
                }

                if (ustr->len > 0) {
                        g_string_append_c(ustr, ',');
                }

                g_string_append(ustr, tf->text);
        }

        if (ustr->len == 0) {
                g_string_free(ustr, TRUE);
                return twitter_filter_stream(ic);
        }

        args[1] = ustr->str;
        req = twitter_http(ic, TWITTER_USERS_LOOKUP_URL,
                           twitter_filter_users_post,
                           ic, 0, args, 2);

        g_string_free(ustr, TRUE);
        return req != NULL;
}

static void twitter_get_home_timeline(struct im_connection *ic, gint64 next_cursor);
static void twitter_get_mentions(struct im_connection *ic, gint64 next_cursor);

/**
 * Get the timeline with optionally mentions
 */
gboolean twitter_get_timeline(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;
        gboolean include_mentions = set_getbool(&ic->acc->set, "fetch_mentions");

        if (td->flags & TWITTER_DOING_TIMELINE) {
                if (++td->http_fails >= 5) {
                        imcb_error(ic, "Fetch timeout (%d)", td->flags);
                        imc_logout(ic, TRUE);
                        return FALSE;
                }
        }

        td->flags |= TWITTER_DOING_TIMELINE;

        twitter_get_home_timeline(ic, next_cursor);

        if (include_mentions) {
                twitter_get_mentions(ic, next_cursor);
        }

        return TRUE;
}

/**
 * Call this one after receiving timeline/mentions. Show to user once we have
 * both.
 */
void twitter_flush_timeline(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        gboolean include_mentions = set_getbool(&ic->acc->set, "fetch_mentions");
        int show_old_mentions = set_getint(&ic->acc->set, "show_old_mentions");
        struct twitter_xml_list *home_timeline = td->home_timeline_obj;
        struct twitter_xml_list *mentions = td->mentions_obj;
        guint64 last_id = 0;
        GSList *output = NULL;
        GSList *l;

        imcb_connected(ic);

        if (!(td->flags & TWITTER_GOT_TIMELINE)) {
                return;
        }

        if (include_mentions && !(td->flags & TWITTER_GOT_MENTIONS)) {
                return;
        }

        if (home_timeline && home_timeline->list) {
                for (l = home_timeline->list; l; l = g_slist_next(l)) {
                        output = g_slist_insert_sorted(output, l->data, twitter_compare_elements);
                }
        }

        if (include_mentions && mentions && mentions->list) {
                for (l = mentions->list; l; l = g_slist_next(l)) {
                        if (show_old_mentions < 1 && output && twitter_compare_elements(l->data, output->data) < 0) {
                                continue;
                        }

                        output = g_slist_insert_sorted(output, l->data, twitter_compare_elements);
                }
        }

        // See if the user wants to see the messages in a groupchat window or as private messages.
        while (output) {
                struct twitter_xml_status *txs = output->data;
                if (txs->id != last_id) {
                        twitter_status_show(ic, txs);
                }
                last_id = txs->id;
                output = g_slist_remove(output, txs);
        }

        txl_free(home_timeline);
        txl_free(mentions);

        td->flags &= ~(TWITTER_DOING_TIMELINE | TWITTER_GOT_TIMELINE | TWITTER_GOT_MENTIONS);
        td->home_timeline_obj = td->mentions_obj = NULL;
}

static void twitter_http_get_home_timeline(struct http_request *req);
static void twitter_http_get_mentions(struct http_request *req);

/**
 * Get the timeline.
 */
static void twitter_get_home_timeline(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;

        txl_free(td->home_timeline_obj);
        td->home_timeline_obj = NULL;
        td->flags &= ~TWITTER_GOT_TIMELINE;

        char *args[6];
        args[0] = "cursor";
        args[1] = g_strdup_printf("%" G_GINT64_FORMAT, next_cursor);
        args[2] = "include_entities";
        args[3] = "true";
        if (td->timeline_id) {
                args[4] = "since_id";
                args[5] = g_strdup_printf("%" G_GUINT64_FORMAT, td->timeline_id);
        }

        if (twitter_http(ic, TWITTER_HOME_TIMELINE_URL, twitter_http_get_home_timeline, ic, 0, args,
                         td->timeline_id ? 6 : 4) == NULL) {
                if (++td->http_fails >= 5) {
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_HOME_TIMELINE_URL, "connection failed");
                }
                td->flags |= TWITTER_GOT_TIMELINE;
                twitter_flush_timeline(ic);
        }

        g_free(args[1]);
        if (td->timeline_id) {
                g_free(args[5]);
        }
}

/**
 * Get mentions.
 */
static void twitter_get_mentions(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;

        txl_free(td->mentions_obj);
        td->mentions_obj = NULL;
        td->flags &= ~TWITTER_GOT_MENTIONS;

        char *args[6];
        args[0] = "cursor";
        args[1] = g_strdup_printf("%" G_GINT64_FORMAT, next_cursor);
        args[2] = "include_entities";
        args[3] = "true";
        if (td->timeline_id) {
                args[4] = "since_id";
                args[5] = g_strdup_printf("%" G_GUINT64_FORMAT, td->timeline_id);
        } else {
                args[4] = "count";
                args[5] = g_strdup_printf("%d", set_getint(&ic->acc->set, "show_old_mentions"));
        }

        if (twitter_http(ic, TWITTER_MENTIONS_URL, twitter_http_get_mentions,
                         ic, 0, args, 6) == NULL) {
                if (++td->http_fails >= 5) {
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_MENTIONS_URL, "connection failed");
                }
                td->flags |= TWITTER_GOT_MENTIONS;
                twitter_flush_timeline(ic);
        }

        g_free(args[1]);
        g_free(args[5]);
}

/**
 * Callback for getting the home timeline.
 */
static void twitter_http_get_home_timeline(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        JSON_Value *parsed;
        struct twitter_xml_list *txl;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td = ic->proto_data;

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // The root <statuses> node should hold the list of statuses <status>
        if (!(parsed = twitter_parse_response(ic, req))) {
                goto end;
        }
        twitter_xt_get_status_list(ic, parsed, txl);
        json_value_free(parsed);

        td->home_timeline_obj = txl;

end:
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td->flags |= TWITTER_GOT_TIMELINE;

        twitter_flush_timeline(ic);
}

/**
 * Callback for getting mentions.
 */
static void twitter_http_get_mentions(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        JSON_Value *parsed;
        struct twitter_xml_list *txl;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td = ic->proto_data;

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // The root <statuses> node should hold the list of statuses <status>
        if (!(parsed = twitter_parse_response(ic, req))) {
                goto end;
        }
        twitter_xt_get_status_list(ic, parsed, txl);
        json_value_free(parsed);

        td->mentions_obj = txl;

end:
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td->flags |= TWITTER_GOT_MENTIONS;

        twitter_flush_timeline(ic);
}

/**
 * Callback to use after sending a POST request to twitter.
 * (Generic, used for a few kinds of queries.)
 */
static void twitter_http_post(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        JSON_Value *parsed;
        jint id;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        td = ic->proto_data;
        td->last_status_id = 0;

        if (!(parsed = twitter_parse_response(ic, req))) {
                return;
        }

        if ((id = json_object_get_integer(json_object(parsed), "id"))) {
                td->last_status_id = id;
        }

        json_value_free(parsed);

        if (req->flags & TWITTER_HTTP_USER_ACK) {
                twitter_log(ic, "Command processed successfully");
        }
}

/**
 * Function to POST a new status to twitter.
 */
void twitter_post_status(struct im_connection *ic, char *msg, guint64 in_reply_to)
{
        char *args[4] = {
                "status", msg,
                "in_reply_to_status_id",
                g_strdup_printf("%" G_GUINT64_FORMAT, in_reply_to)
        };

        twitter_http(ic, TWITTER_STATUS_UPDATE_URL, twitter_http_post, ic, 1,
                     args, in_reply_to ? 4 : 2);
        g_free(args[3]);
}


/**
 * Function to POST a new message to twitter.
 */
void twitter_direct_messages_new(struct im_connection *ic, char *who, char *msg)
{
        char *args[4];

        args[0] = "screen_name";
        args[1] = who;
        args[2] = "text";
        args[3] = msg;
        // Use the same callback as for twitter_post_status, since it does basically the same.
        twitter_http(ic, TWITTER_DIRECT_MESSAGES_NEW_URL, twitter_http_post, ic, 1, args, 4);
}

void twitter_friendships_create_destroy(struct im_connection *ic, char *who, int create)
{
        char *args[2];

        args[0] = "screen_name";
        args[1] = who;
        twitter_http(ic, create ? TWITTER_FRIENDSHIPS_CREATE_URL : TWITTER_FRIENDSHIPS_DESTROY_URL,
                     twitter_http_post, ic, 1, args, 2);
}

void twitter_status_destroy(struct im_connection *ic, guint64 id)
{
        char *url;

        url = g_strdup_printf("%s%" G_GUINT64_FORMAT "%s",
                              TWITTER_STATUS_DESTROY_URL, id, ".json");
        twitter_http_f(ic, url, twitter_http_post, ic, 1, NULL, 0,
                       TWITTER_HTTP_USER_ACK);
        g_free(url);
}

void twitter_status_retweet(struct im_connection *ic, guint64 id)
{
        char *url;

        url = g_strdup_printf("%s%" G_GUINT64_FORMAT "%s",
                              TWITTER_STATUS_RETWEET_URL, id, ".json");
        twitter_http_f(ic, url, twitter_http_post, ic, 1, NULL, 0,
                       TWITTER_HTTP_USER_ACK);
        g_free(url);
}

/**
 * Report a user for sending spam.
 */
void twitter_report_spam(struct im_connection *ic, char *screen_name)
{
        char *args[2] = {
                "screen_name",
                NULL,
        };

        args[1] = screen_name;
        twitter_http_f(ic, TWITTER_REPORT_SPAM_URL, twitter_http_post,
                       ic, 1, args, 2, TWITTER_HTTP_USER_ACK);
}

/**
 * Favourite a tweet.
 */
void twitter_favourite_tweet(struct im_connection *ic, guint64 id)
{
        char *args[2] = {
                "id",
                NULL,
        };

        args[1] = g_strdup_printf("%" G_GUINT64_FORMAT, id);
        twitter_http_f(ic, TWITTER_FAVORITE_CREATE_URL, twitter_http_post,
                       ic, 1, args, 2, TWITTER_HTTP_USER_ACK);
        g_free(args[1]);
}

static void twitter_http_status_show_url(struct http_request *req)
{
        struct im_connection *ic = req->data;
        JSON_Value *parsed;
        uint64_t id;
        const char *name;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic)) {
                return;
        }

        if (!(parsed = twitter_parse_response(ic, req))) {
                return;
        }

        name = json_object_dotget_string(json_object(parsed), "user.screen_name");
        id = json_object_get_integer(json_object(parsed), "id");

        if (name && id) {
                twitter_log(ic, "https://twitter.com/%s/status/%" G_GUINT64_FORMAT, name, id);
        } else {
                twitter_log(ic, "Error: could not fetch tweet url.");
        }

        json_value_free(parsed);
}

void twitter_status_show_url(struct im_connection *ic, guint64 id)
{
        char *url = g_strdup_printf("%s%" G_GUINT64_FORMAT "%s", TWITTER_STATUS_SHOW_URL, id, ".json");
        twitter_http(ic, url, twitter_http_status_show_url, ic, 0, NULL, 0);
        g_free(url);
}