<?php

/**
 * @file mod/dfrn_request.php
 * @brief Module: dfrn_request
 *
 * Purpose: Handles communication associated with the issuance of
 * friend requests.
 *
 * @see PDF with dfrn specs: https://github.com/friendica/friendica/blob/master/spec/dfrn2.pdf
 *    You also find a graphic which describes the confirmation process at
 *    https://github.com/friendica/friendica/blob/master/spec/dfrn2_contact_request.png
 */
use Friendica\App;
use Friendica\Core\Config;
use Friendica\Core\PConfig;
use Friendica\Core\System;
use Friendica\Database\DBM;
use Friendica\Model\Contact;
use Friendica\Model\Group;
use Friendica\Model\User;
use Friendica\Model\Profile;
use Friendica\Module\Login;
use Friendica\Network\Probe;

require_once 'include/enotify.php';

function dfrn_request_init(App $a)
{
	if ($a->argc > 1) {
		$which = $a->argv[1];
	}

	Profile::load($a, $which);
	return;
}

/**
 * Function: dfrn_request_post
 *
 * Purpose:
 * Handles multiple scenarios.
 *
 * Scenario 1:
 * Clicking 'submit' on a friend request page.
 *
 * Scenario 2:
 * Following Scenario 1, we are brought back to our home site
 * in order to link our friend request with our own server cell.
 * After logging in, we click 'submit' to approve the linkage.
 *
 */
function dfrn_request_post(App $a)
{
	if (($a->argc != 2) || (!count($a->profile))) {
		logger('Wrong count of argc or profiles: argc=' . $a->argc . ',profile()=' . count($a->profile));
		return;
	}

	if (x($_POST, 'cancel')) {
		goaway(System::baseUrl());
	}

	/*
	 * Scenario 2: We've introduced ourself to another cell, then have been returned to our own cell
	 * to confirm the request, and then we've clicked submit (perhaps after logging in).
	 * That brings us here:
	 */
	if ((x($_POST, 'localconfirm')) && ($_POST['localconfirm'] == 1)) {
		// Ensure this is a valid request
		if (local_user() && ($a->user['nickname'] == $a->argv[1]) && (x($_POST, 'dfrn_url'))) {
			$dfrn_url = notags(trim($_POST['dfrn_url']));
			$aes_allow = (((x($_POST, 'aes_allow')) && ($_POST['aes_allow'] == 1)) ? 1 : 0);
			$confirm_key = ((x($_POST, 'confirm_key')) ? $_POST['confirm_key'] : "");
			$hidden = ((x($_POST, 'hidden-contact')) ? intval($_POST['hidden-contact']) : 0);
			$contact_record = null;
			$blocked = 1;
			$pending = 1;

			if (x($dfrn_url)) {
				// Lookup the contact based on their URL (which is the only unique thing we have at the moment)
				$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND `nurl` = '%s' AND NOT `self` LIMIT 1",
					intval(local_user()),
					dbesc(normalise_link($dfrn_url))
				);

				if (DBM::is_result($r)) {
					if (strlen($r[0]['dfrn-id'])) {
						// We don't need to be here. It has already happened.
						notice(t("This introduction has already been accepted.") . EOL);
						return;
					} else {
						$contact_record = $r[0];
					}
				}

				if (is_array($contact_record)) {
					$r = q("UPDATE `contact` SET `ret-aes` = %d, hidden = %d WHERE `id` = %d",
						intval($aes_allow),
						intval($hidden),
						intval($contact_record['id'])
					);
				} else {
					// Scrape the other site's profile page to pick up the dfrn links, key, fn, and photo
					$parms = Probe::profile($dfrn_url);

					if (!count($parms)) {
						notice(t('Profile location is not valid or does not contain profile information.') . EOL);
						return;
					} else {
						if (!x($parms, 'fn')) {
							notice(t('Warning: profile location has no identifiable owner name.') . EOL);
						}
						if (!x($parms, 'photo')) {
							notice(t('Warning: profile location has no profile photo.') . EOL);
						}
						$invalid = Probe::validDfrn($parms);
						if ($invalid) {
							notice(sprintf(tt("%d required parameter was not found at the given location", "%d required parameters were not found at the given location", $invalid), $invalid) . EOL);
							return;
						}
					}

					$dfrn_request = $parms['dfrn-request'];

					$photo = $parms["photo"];

					// Escape the entire array
					DBM::esc_array($parms);

					// Create a contact record on our site for the other person
					$r = q("INSERT INTO `contact` ( `uid`, `created`,`url`, `nurl`, `addr`, `name`, `nick`, `photo`, `site-pubkey`,
						`request`, `confirm`, `notify`, `poll`, `poco`, `network`, `aes_allow`, `hidden`, `blocked`, `pending`)
						VALUES ( %d, '%s', '%s', '%s', '%s', '%s' , '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', %d, %d, %d, %d)",
						intval(local_user()),
						datetime_convert(),
						dbesc($dfrn_url),
						dbesc(normalise_link($dfrn_url)),
						$parms['addr'],
						$parms['fn'],
						$parms['nick'],
						$parms['photo'],
						$parms['key'],
						$parms['dfrn-request'],
						$parms['dfrn-confirm'],
						$parms['dfrn-notify'],
						$parms['dfrn-poll'],
						$parms['dfrn-poco'],
						dbesc(NETWORK_DFRN),
						intval($aes_allow),
						intval($hidden),
						intval($blocked),
						intval($pending)
					);
				}

				if ($r) {
					info(t("Introduction complete.") . EOL);
				}

				$r = q("SELECT `id`, `network` FROM `contact` WHERE `uid` = %d AND `url` = '%s' AND `site-pubkey` = '%s' LIMIT 1",
					intval(local_user()),
					dbesc($dfrn_url),
					$parms['key'] // this was already escaped
				);
				if (DBM::is_result($r)) {
					Group::addMember(User::getDefaultGroup($uid, $r[0]["network"]), $r[0]['id']);

					if (isset($photo)) {
						Contact::updateAvatar($photo, local_user(), $r[0]["id"], true);
					}

					$forwardurl = System::baseUrl() . "/contacts/" . $r[0]['id'];
				} else {
					$forwardurl = System::baseUrl() . "/contacts";
				}

				// Allow the blocked remote notification to complete
				if (is_array($contact_record)) {
					$dfrn_request = $contact_record['request'];
				}

				if (strlen($dfrn_request) && strlen($confirm_key)) {
					$s = fetch_url($dfrn_request . '?confirm_key=' . $confirm_key);
				}

				// (ignore reply, nothing we can do it failed)
				// Old: goaway(Profile::zrl($dfrn_url));
				goaway($forwardurl);
				return; // NOTREACHED
			}
		}

		// invalid/bogus request
		notice(t('Unrecoverable protocol error.') . EOL);
		goaway(System::baseUrl());
		return; // NOTREACHED
	}

	/*
	 * Otherwise:
	 *
	 * Scenario 1:
	 * We are the requestee. A person from a remote cell has made an introduction
	 * on our profile web page and clicked submit. We will use their DFRN-URL to
	 * figure out how to contact their cell.
	 *
	 * Scrape the originating DFRN-URL for everything we need. Create a contact record
	 * and an introduction to show our user next time he/she logs in.
	 * Finally redirect back to the requestor so that their site can record the request.
	 * If our user (the requestee) later confirms this request, a record of it will need
	 * to exist on the requestor's cell in order for the confirmation process to complete..
	 *
	 * It's possible that neither the requestor or the requestee are logged in at the moment,
	 * and the requestor does not yet have any credentials to the requestee profile.
	 *
	 * Who is the requestee? We've already loaded their profile which means their nickname should be
	 * in $a->argv[1] and we should have their complete info in $a->profile.
	 *
	 */
	if (!(is_array($a->profile) && count($a->profile))) {
		notice(t('Profile unavailable.') . EOL);
		return;
	}

	$nickname       = $a->profile['nickname'];
	$notify_flags   = $a->profile['notify-flags'];
	$uid            = $a->profile['uid'];
	$maxreq         = intval($a->profile['maxreq']);
	$contact_record = null;
	$failed         = false;
	$parms          = null;
	$blocked = 1;
	$pending = 1;

	if (x($_POST, 'dfrn_url')) {
		// Block friend request spam
		if ($maxreq) {
			$r = q("SELECT * FROM `intro` WHERE `datetime` > '%s' AND `uid` = %d",
				dbesc(datetime_convert('UTC', 'UTC', 'now - 24 hours')),
				intval($uid)
			);
			if (DBM::is_result($r) && count($r) > $maxreq) {
				notice(sprintf(t('%s has received too many connection requests today.'), $a->profile['name']) . EOL);
				notice(t('Spam protection measures have been invoked.') . EOL);
				notice(t('Friends are advised to please try again in 24 hours.') . EOL);
				return;
			}
		}

		/* Cleanup old introductions that remain blocked.
		 * Also remove the contact record, but only if there is no existing relationship
		 */
		$r = q("SELECT `intro`.*, `intro`.`id` AS `iid`, `contact`.`id` AS `cid`, `contact`.`rel`
			FROM `intro` LEFT JOIN `contact` on `intro`.`contact-id` = `contact`.`id`
			WHERE `intro`.`blocked` = 1 AND `contact`.`self` = 0
			AND `intro`.`datetime` < UTC_TIMESTAMP() - INTERVAL 30 MINUTE "
		);
		if (DBM::is_result($r)) {
			foreach ($r as $rr) {
				if (!$rr['rel']) {
					q("DELETE FROM `contact` WHERE `id` = %d AND NOT `self`",
						intval($rr['cid'])
					);
				}
				q("DELETE FROM `intro` WHERE `id` = %d",
					intval($rr['iid'])
				);
			}
		}

		$real_name = x($_POST, 'realname') ? notags(trim($_POST['realname'])) : '';

		$url = trim($_POST['dfrn_url']);
		if (!strlen($url)) {
			notice(t("Invalid locator") . EOL);
			return;
		}

		$hcard = '';

		// Detect the network
		$data = Probe::uri($url);
		$network = $data["network"];

		// Canonicalise email-style profile locator
		$url = Probe::webfingerDfrn($url, $hcard);

		if (substr($url, 0, 5) === 'stat:') {
			// Every time we detect the remote subscription we define this as OStatus.
			// We do this even if it is not OStatus.
			// we only need to pass this through another section of the code.
			if ($network != NETWORK_DIASPORA) {
				$network = NETWORK_OSTATUS;
			}

			$url = substr($url, 5);
		} else {
			$network = NETWORK_DFRN;
		}

		logger('dfrn_request: url: ' . $url . ',network=' . $network, LOGGER_DEBUG);

		if ($network === NETWORK_DFRN) {
			$ret = q("SELECT * FROM `contact` WHERE `uid` = %d AND `url` = '%s' AND `self` = 0 LIMIT 1",
				intval($uid),
				dbesc($url)
			);

			if (DBM::is_result($ret)) {
				if (strlen($ret[0]['issued-id'])) {
					notice(t('You have already introduced yourself here.') . EOL);
					return;
				} elseif ($ret[0]['rel'] == CONTACT_IS_FRIEND) {
					notice(sprintf(t('Apparently you are already friends with %s.'), $a->profile['name']) . EOL);
					return;
				} else {
					$contact_record = $ret[0];
					$parms = ['dfrn-request' => $ret[0]['request']];
				}
			}

			$issued_id = random_string();

			if (is_array($contact_record)) {
				// There is a contact record but no issued-id, so this
				// is a reciprocal introduction from a known contact
				$r = q("UPDATE `contact` SET `issued-id` = '%s' WHERE `id` = %d",
					dbesc($issued_id),
					intval($contact_record['id'])
				);
			} else {
				$url = validate_url($url);
				if (!$url) {
					notice(t('Invalid profile URL.') . EOL);
					goaway(System::baseUrl() . '/' . $a->cmd);
					return; // NOTREACHED
				}

				if (!allowed_url($url)) {
					notice(t('Disallowed profile URL.') . EOL);
					goaway(System::baseUrl() . '/' . $a->cmd);
					return; // NOTREACHED
				}

				if (blocked_url($url)) {
					notice(t('Blocked domain') . EOL);
					goaway(System::baseUrl() . '/' . $a->cmd);
					return; // NOTREACHED
				}

				$parms = Probe::profile(($hcard) ? $hcard : $url);

				if (!count($parms)) {
					notice(t('Profile location is not valid or does not contain profile information.') . EOL);
					goaway(System::baseUrl() . '/' . $a->cmd);
				} else {
					if (!x($parms, 'fn')) {
						notice(t('Warning: profile location has no identifiable owner name.') . EOL);
					}
					if (!x($parms, 'photo')) {
						notice(t('Warning: profile location has no profile photo.') . EOL);
					}
					$invalid = Probe::validDfrn($parms);
					if ($invalid) {
						notice(sprintf(tt("%d required parameter was not found at the given location", "%d required parameters were not found at the given location", $invalid), $invalid) . EOL);

						return;
					}
				}

				$parms['url'] = $url;
				$parms['issued-id'] = $issued_id;
				$photo = $parms["photo"];

				DBM::esc_array($parms);
				$r = q("INSERT INTO `contact` ( `uid`, `created`, `url`, `nurl`, `addr`, `name`, `nick`, `issued-id`, `photo`, `site-pubkey`,
					`request`, `confirm`, `notify`, `poll`, `poco`, `network`, `blocked`, `pending` )
					VALUES ( %d, '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', %d, %d )",
					intval($uid),
					dbesc(datetime_convert()),
					$parms['url'],
					dbesc(normalise_link($url)),
					$parms['addr'],
					$parms['fn'],
					$parms['nick'],
					$parms['issued-id'],
					$parms['photo'],
					$parms['key'],
					$parms['dfrn-request'],
					$parms['dfrn-confirm'],
					$parms['dfrn-notify'],
					$parms['dfrn-poll'],
					$parms['dfrn-poco'],
					dbesc(NETWORK_DFRN),
					intval($blocked),
					intval($pending)
				);

				// find the contact record we just created
				if ($r) {
					$r = q("SELECT `id` FROM `contact`
						WHERE `uid` = %d AND `url` = '%s' AND `issued-id` = '%s' LIMIT 1",
						intval($uid),
						$parms['url'],
						$parms['issued-id']
					);
					if (DBM::is_result($r)) {
						$contact_record = $r[0];
						Contact::updateAvatar($photo, $uid, $contact_record["id"], true);
					}
				}
			}
			if ($r === false) {
				notice(t('Failed to update contact record.') . EOL);
				return;
			}

			$hash = random_string() . (string) time();   // Generate a confirm_key

			if (is_array($contact_record)) {
				$ret = q("INSERT INTO `intro` ( `uid`, `contact-id`, `blocked`, `knowyou`, `note`, `hash`, `datetime`)
					VALUES ( %d, %d, 1, %d, '%s', '%s', '%s' )",
					intval($uid),
					intval($contact_record['id']),
					((x($_POST,'knowyou') && ($_POST['knowyou'] == 1)) ? 1 : 0),
					dbesc(notags(trim($_POST['dfrn-request-message']))),
					dbesc($hash),
					dbesc(datetime_convert())
				);
			}

			// This notice will only be seen by the requestor if the requestor and requestee are on the same server.
			if (!$failed) {
				info(t('Your introduction has been sent.') . EOL);
			}

			// "Homecoming" - send the requestor back to their site to record the introduction.
			$dfrn_url = bin2hex(System::baseUrl() . '/profile/' . $nickname);
			$aes_allow = ((function_exists('openssl_encrypt')) ? 1 : 0);

			goaway($parms['dfrn-request'] . "?dfrn_url=$dfrn_url"
				. '&dfrn_version=' . DFRN_PROTOCOL_VERSION
				. '&confirm_key=' . $hash
				. (($aes_allow) ? "&aes_allow=1" : "")
			);
			// NOTREACHED
			// END $network === NETWORK_DFRN
		} elseif (($network != NETWORK_PHANTOM) && ($url != "")) {

			/* Substitute our user's feed URL into $url template
			 * Send the subscriber home to subscribe
			 */
			// Diaspora needs the uri in the format user@domain.tld
			// Diaspora will support the remote subscription in a future version
			if ($network == NETWORK_DIASPORA) {
				$uri = $nickname . '@' . $a->get_hostname();

				if ($a->get_path()) {
					$uri .= '/' . $a->get_path();
				}

				$uri = urlencode($uri);
			} else {
				$uri = System::baseUrl() . '/profile/' . $nickname;
			}

			$url = str_replace('{uri}', $uri, $url);
			goaway($url);
			// NOTREACHED
			// END $network != NETWORK_PHANTOM
		} else {
			notice(t("Remote subscription can't be done for your network. Please subscribe directly on your system.") . EOL);
			return;
		}
	} return;
}

function dfrn_request_content(App $a)
{
	if (($a->argc != 2) || (!count($a->profile))) {
		return "";
	}

	// "Homecoming". Make sure we're logged in to this site as the correct user. Then offer a confirm button
	// to send us to the post section to record the introduction.
	if (x($_GET, 'dfrn_url')) {
		if (!local_user()) {
			info(t("Please login to confirm introduction.") . EOL);
			/* setup the return URL to come back to this page if they use openid */
			return Login::form();
		}

		// Edge case, but can easily happen in the wild. This person is authenticated,
		// but not as the person who needs to deal with this request.
		if ($a->user['nickname'] != $a->argv[1]) {
			notice(t("Incorrect identity currently logged in. Please login to <strong>this</strong> profile.") . EOL);
			return Login::form();
		}

		$dfrn_url = notags(trim(hex2bin($_GET['dfrn_url'])));
		$aes_allow = x($_GET, 'aes_allow') && $_GET['aes_allow'] == 1 ? 1 : 0;
		$confirm_key = x($_GET, 'confirm_key') ? $_GET['confirm_key'] : "";

		// Checking fastlane for validity
		if (x($_SESSION, "fastlane") && (normalise_link($_SESSION["fastlane"]) == normalise_link($dfrn_url))) {
			$_POST["dfrn_url"] = $dfrn_url;
			$_POST["confirm_key"] = $confirm_key;
			$_POST["localconfirm"] = 1;
			$_POST["hidden-contact"] = 0;
			$_POST["submit"] = t('Confirm');

			dfrn_request_post($a);

			killme();
			return; // NOTREACHED
		}

		$tpl = get_markup_template("dfrn_req_confirm.tpl");
		$o = replace_macros($tpl, [
			'$dfrn_url' => $dfrn_url,
			'$aes_allow' => (($aes_allow) ? '<input type="hidden" name="aes_allow" value="1" />' : "" ),
			'$hidethem' => t('Hide this contact'),
			'$hidechecked' => '',
			'$confirm_key' => $confirm_key,
			'$welcome' => sprintf(t('Welcome home %s.'), $a->user['username']),
			'$please' => sprintf(t('Please confirm your introduction/connection request to %s.'), $dfrn_url),
			'$submit' => t('Confirm'),
			'$uid' => $_SESSION['uid'],
			'$nickname' => $a->user['nickname'],
			'dfrn_rawurl' => $_GET['dfrn_url']
		]);
		return $o;
	} elseif ((x($_GET, 'confirm_key')) && strlen($_GET['confirm_key'])) {
		// we are the requestee and it is now safe to send our user their introduction,
		// We could just unblock it, but first we have to jump through a few hoops to
		// send an email, or even to find out if we need to send an email.
		$intro = q("SELECT * FROM `intro` WHERE `hash` = '%s' LIMIT 1",
			dbesc($_GET['confirm_key'])
		);

		if (DBM::is_result($intro)) {
			$r = q("SELECT `contact`.*, `user`.* FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
				WHERE `contact`.`id` = %d LIMIT 1",
				intval($intro[0]['contact-id'])
			);

			$auto_confirm = false;

			if (DBM::is_result($r)) {
				if ($r[0]['page-flags'] != PAGE_NORMAL && $r[0]['page-flags'] != PAGE_PRVGROUP) {
					$auto_confirm = true;
				}

				if (!$auto_confirm) {
					notification([
						'type'         => NOTIFY_INTRO,
						'notify_flags' => $r[0]['notify-flags'],
						'language'     => $r[0]['language'],
						'to_name'      => $r[0]['username'],
						'to_email'     => $r[0]['email'],
						'uid'          => $r[0]['uid'],
						'link'         => System::baseUrl() . '/notifications/intros',
						'source_name'  => ((strlen(stripslashes($r[0]['name']))) ? stripslashes($r[0]['name']) : t('[Name Withheld]')),
						'source_link'  => $r[0]['url'],
						'source_photo' => $r[0]['photo'],
						'verb'         => ACTIVITY_REQ_FRIEND,
						'otype'        => 'intro'
					]);
				}

				if ($auto_confirm) {
					require_once 'mod/dfrn_confirm.php';
					$handsfree = [
						'uid'      => $r[0]['uid'],
						'node'     => $r[0]['nickname'],
						'dfrn_id'  => $r[0]['issued-id'],
						'intro_id' => $intro[0]['id'],
						'duplex'   => (($r[0]['page-flags'] == PAGE_FREELOVE) ? 1 : 0),
						'activity' => intval(PConfig::get($r[0]['uid'], 'system', 'post_newfriend'))
					];
					dfrn_confirm_post($a, $handsfree);
				}
			}

			if (!$auto_confirm) {

				// If we are auto_confirming, this record will have already been nuked
				// in dfrn_confirm_post()

				$r = q("UPDATE `intro` SET `blocked` = 0 WHERE `hash` = '%s'",
					dbesc($_GET['confirm_key'])
				);
			}
		}

		killme();
		return; // NOTREACHED
	} else {
		// Normal web request. Display our user's introduction form.
		if ((Config::get('system', 'block_public')) && (!local_user()) && (!remote_user())) {
			if (!Config::get('system', 'local_block')) {
				notice(t('Public access denied.') . EOL);
				return;
			}
		}

		// Try to auto-fill the profile address
		// At first look if an address was provided
		// Otherwise take the local address
		if (x($_GET, 'addr') && ($_GET['addr'] != "")) {
			$myaddr = hex2bin($_GET['addr']);
		} elseif (x($_GET, 'address') && ($_GET['address'] != "")) {
			$myaddr = $_GET['address'];
		} elseif (local_user()) {
			if (strlen($a->path)) {
				$myaddr = System::baseUrl() . '/profile/' . $a->user['nickname'];
			} else {
				$myaddr = $a->user['nickname'] . '@' . substr(System::baseUrl(), strpos(System::baseUrl(), '://') + 3);
			}
		} else {
			// last, try a zrl
			$myaddr = Profile::getMyURL();
		}

		$target_addr = $a->profile['nickname'] . '@' . substr(System::baseUrl(), strpos(System::baseUrl(), '://') + 3);

		/* The auto_request form only has the profile address
		 * because nobody is going to read the comments and
		 * it doesn't matter if they know you or not.
		 */
		if ($a->profile['page-flags'] == PAGE_NORMAL) {
			$tpl = get_markup_template('dfrn_request.tpl');
		} else {
			$tpl = get_markup_template('auto_request.tpl');
		}

		$page_desc = t("Please enter your 'Identity Address' from one of the following supported communications networks:");

		$invite_desc = sprintf(
			t('If you are not yet a member of the free social web, <a href="%s/siteinfo">follow this link to find a public Friendica site and join us today</a>.'),
			get_server()
		);

		$o = replace_macros($tpl, [
			'$header' => t('Friend/Connection Request'),
			'$desc' => t('Examples: jojo@demo.friendica.com, http://demo.friendica.com/profile/jojo, testuser@gnusocial.de'),
			'$pls_answer' => t('Please answer the following:'),
			'$does_know_you' => ['knowyou', sprintf(t('Does %s know you?'), $a->profile['name']), false, '', [t('No'), t('Yes')]],
			'$add_note' => t('Add a personal note:'),
			'$page_desc' => $page_desc,
			'$friendica' => t('Friendica'),
			'$statusnet' => t('GNU Social (Pleroma, Mastodon)'),
			'$diaspora' => t('Diaspora (Socialhome, Hubzilla)'),
			'$diasnote' => sprintf(t(' - please do not use this form.  Instead, enter %s into your Diaspora search bar.'), $target_addr),
			'$your_address' => t('Your Identity Address:'),
			'$invite_desc' => $invite_desc,
			'$submit' => t('Submit Request'),
			'$cancel' => t('Cancel'),
			'$nickname' => $a->argv[1],
			'$name' => $a->profile['name'],
			'$myaddr' => $myaddr
		]);
		return $o;
	}

	return; // Somebody is fishing.
}