<?php
	
/*
	Question2Answer 1.4-beta-2 (c) 2011, Gideon Greenspan

	http://www.question2answer.org/

	
	File: qa-include/qa-app-posts.php
	Version: 1.4-beta-2
	Date: 2011-06-02 08:27:10 GMT
	Description: Higher-level functions to create and manipulate posts


	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.

	More about this license: http://www.question2answer.org/license.php
*/

	if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
		header('Location: ../');
		exit;
	}
	

	require_once QA_INCLUDE_DIR.'qa-db.php';
	require_once QA_INCLUDE_DIR.'qa-db-selects.php';
	require_once QA_INCLUDE_DIR.'qa-app-format.php';
	require_once QA_INCLUDE_DIR.'qa-app-post-create.php';
	require_once QA_INCLUDE_DIR.'qa-app-post-update.php';
	require_once QA_INCLUDE_DIR.'qa-util-string.php';


	function qa_post_create($type, $parentpostid, $title, $content, $format='', $categoryid=null, $tags=null, $userid=null, $notify=null, $email=null)
/*
	Create a new post in the database, and return its postid.
	
	Set $type to 'Q' for a new question, 'A' for an answer, or 'C' for a comment. For questions, set $parentpostid to
	the postid of the answer to which the question is related, or null if (as in most cases) the question is not related
	to an answer. For answers, set $parentpostid to the postid of the question being answered. For comments, set
	$parentpostid to the postid of the question or answer to which the comment relates. The $content and $format
	parameters go together - if $format is '' then $content should be in plain UTF-8 text, and if $format is 'html' then
	$content should be in UTF-8 HTML. Other values of $format may be allowed if an appropriate viewer module is
	installed. The $title, $categoryid and $tags parameters are only relevant when creating a question - $tags can
	either be an array of tags, or a string of tags separated by commas. The new post will be assigned to $userid if it
	is not null, otherwise it will be anonymous. If $notify is true then the author will be sent notifications relating
	to the post - either to $email if it is specified and valid, or to the current email address of $userid if $email is '@'.
*/
	{
		$handle=qa_post_userid_to_handle($userid);
		$text=qa_post_content_to_text($content, $format);

		switch ($type) {
			case 'Q':
				$followanswer=isset($parentpostid) ? qa_post_get_full($parentpostid, 'A') : null;
				$tagstring=qa_post_tags_to_tagstring($tags);
				$postid=qa_question_create($followanswer, $userid, $handle, null, $title, $content, $format, $text, $tagstring, $notify, $email, $categoryid);
				break;
				
			case 'A':
				$question=qa_post_get_full($parentpostid, 'Q');
				$postid=qa_answer_create($userid, $handle, null, $content, $format, $text, $notify, $email, $question);
				break;
				
			case 'C':
				$parentpost=qa_post_get_full($parentpostid, 'QA');
				$commentsfollows=qa_db_single_select(qa_db_full_child_posts_selectspec(null, $parentpostid));
				$question=qa_post_parent_to_question($parentpost);
				$answer=qa_post_parent_to_answer($parentpost);
				$postid=qa_comment_create($userid, $handle, null, $content, $format, $text, $notify, $email, $question, $answer, $commentsfollows);
				break;
				
			default:
				qa_fatal_error('Post type not recognized: '.$type);
				break;
		}
		
		return $postid;
	}
	
	
	function qa_post_set_content($postid, $title, $content, $format=null, $tags=null, $notify=null, $email=null, $byuserid=null)
/*
	Change the data stored for post $postid based on any of the $title, $content, $format, $tags, $notify and $email
	parameters passed which are not null. The meaning of these parameters is the same as for qa_post_create() above.
	Pass the identify of the user making this change in $byuserid (or null for an anonymous change).
*/
	{
		$oldpost=qa_post_get_full($postid, 'QAC');
		
		if (!isset($title))
			$title=$oldpost['title'];
		
		if (!isset($content))
			$content=$oldpost['content'];
			
		if (!isset($format))
			$format=$oldpost['format'];
			
		if (!isset($tags))
			$tags=qa_tagstring_to_tags($oldpost['tags']);
			
		if (isset($notify) || isset($email))
			$setnotify=qa_combine_notify_email($oldpost['userid'], isset($notify) ? $notify : isset($oldpost['notify']),
				isset($email) ? $email : $oldpost['notify']);
		else
			$setnotify=$oldpost['notify'];
	
		$byhandle=qa_post_userid_to_handle($byuserid);
		$text=qa_post_content_to_text($content, $format);
		
		switch ($oldpost['basetype']) {
			case 'Q':
				$tagstring=qa_post_tags_to_tagstring($tags);
				qa_question_set_content($oldpost, $title, $content, $format, $text, $tagstring, $setnotify, $byuserid, $byhandle, null);
				break;
				
			case 'A':
				$question=qa_post_get_full($oldpost['parentid'], 'Q');
				qa_answer_set_content($oldpost, $content, $format, $text, $setnotify, $byuserid, $byhandle, null, $question);
				break;
				
			case 'C':
				$parentpost=qa_post_get_full($oldpost['parentid'], 'QA');
				$question=qa_post_parent_to_question($parentpost);
				$answer=qa_post_parent_to_answer($parentpost);		
				qa_comment_set_content($oldpost, $content, $format, $text, $setnotify, $byuserid, $byhandle, null, $question, $answer);
				break;
		}
	}

	
	function qa_post_set_category($postid, $categoryid, $byuserid=null)
/*
	Change the category of $postid to $categoryid. The category of all related posts (shown together on the same
	question page) will also be changed. Pass the identify of the user making this change in $byuserid (or null for an
	anonymous change).
*/
	{
		$oldpost=qa_post_get_full($postid, 'QAC');
		
		if ($oldpost['basetype']=='Q') {
			$byhandle=qa_post_userid_to_handle($byuserid);
			$answers=qa_post_get_question_answers($postid);
			$commentsfollows=qa_post_get_question_commentsfollows($postid);
			qa_question_set_category($oldpost, $categoryid, $byuserid, $byhandle, null, $answers, $commentsfollows);

		} else
			qa_post_set_category($oldpost['parentid'], $categoryid, $byuserid); // keep looking until we find the parent question
	}

	
	function qa_post_set_selchildid($questionid, $answerid, $byuserid=null)
/*
	Set the selected best answer of $questionid to $answerid (or to none if $answerid is null). Pass the identify of the
	user in $byuserid (or null for an anonymous change).
*/
	{
		$oldquestion=qa_post_get_full($questionid, 'Q');
		$byhandle=qa_post_userid_to_handle($byuserid);
		$answers=qa_post_get_question_answers($questionid);
		
		if (isset($answerid) && !isset($answers[$answerid]))
			qa_fatal_error('Answer ID could not be found: '.$answerid);
		
		qa_question_set_selchildid($byuserid, $byuserid, null, $oldquestion, $answerid, $answers);
	}

	
	function qa_post_set_hidden($postid, $hidden=true, $byuserid=null)
/*
	Hide $postid if $hidden is true, show the post. Pass the identify of the user making this change in $byuserid (or
	null for an anonymous change).
*/
	{
		$oldpost=qa_post_get_full($postid, 'QAC');
		$byhandle=qa_post_userid_to_handle($byuserid);
		
		switch ($oldpost['basetype']) {
			case 'Q':
				$answers=qa_post_get_question_answers($postid);
				$commentsfollows=qa_post_get_question_commentsfollows($postid);
				qa_question_set_hidden($oldpost, $hidden, $byuserid, $byhandle, null, $answers, $commentsfollows);
				break;
				
			case 'A':
				$question=qa_post_get_full($oldpost['parentid'], 'Q');
				$commentsfollows=qa_post_get_answer_commentsfollows($postid);
				qa_answer_set_hidden($oldpost, $hidden, $byuserid, $byhandle, null, $question, $commentsfollows);
				break;
				
			case 'C':
				$parentpost=qa_post_get_full($oldpost['parentid'], 'QA');
				$question=qa_post_parent_to_question($parentpost);
				$answer=qa_post_parent_to_answer($parentpost);		
				qa_comment_set_hidden($oldpost, $hidden, $byuserid, $byhandle, null, $question, $answer);
				break;
		}
	}

	
	function qa_post_delete($postid)
/*
	Delete $postid from the database, hiding it first if appropriate.
*/
	{
		$oldpost=qa_post_get_full($postid, 'QAC');
		
		if (!$oldpost['hidden']) {
			qa_post_set_hidden($postid, true, null);
			$oldpost=qa_post_get_full($postid, 'QAC');
		}
		
		switch ($oldpost['basetype']) {
			case 'Q':
				$answers=qa_post_get_question_answers($postid);
				$commentsfollows=qa_post_get_question_commentsfollows($postid);
				
				if (count($answers) || count($commentsfollows))
					qa_fatal_error('Could not delete question ID due to dependents: '.$postid);
					
				qa_question_delete($oldpost, null, null, null);
				break;
				
			case 'A':
				$question=qa_post_get_full($oldpost['parentid'], 'Q');
				$commentsfollows=qa_post_get_answer_commentsfollows($postid);

				if (count($commentsfollows))
					qa_fatal_error('Could not delete answer ID due to dependents: '.$postid);

				qa_answer_delete($oldpost, $question, null, null, null);
				break;
				
			case 'C':
				$parentpost=qa_post_get_full($oldpost['parentid'], 'QA');
				$question=qa_post_parent_to_question($parentpost);
				$answer=qa_post_parent_to_answer($parentpost);		
				qa_comment_delete($oldpost, $question, $answer, null, null, null);
				break;
		}
	}


	function qa_post_get_full($postid, $requiredbasetypes=null)
/*
	Return the full information from the database for $postid in an array.
*/
	{
		$post=qa_db_single_select(qa_db_full_post_selectspec(null, $postid));
			
		if (!is_array($post))
			qa_fatal_error('Post ID could not be found: '.$postid);
		
		if (isset($requiredbasetypes) && !is_numeric(strpos($requiredbasetypes, $post['basetype'])))
			qa_fatal_error('Post of wrong type: '.$post['basetype']);
		
		return $post;
	}

	
	function qa_post_userid_to_handle($userid)
/*
	Return the handle corresponding to $userid, unless it is null in which case return null.
*/
	{
		if (isset($userid)) {
			$user=qa_db_single_select(qa_db_user_account_selectspec($userid, true));
			
			if (!is_array($user))
				qa_fatal_error('User ID could not be found: '.$userid);
			
			return $user['handle'];
		}
		
		return null;
	}


	function qa_post_content_to_text($content, $format)
/*
	Return the textual rendition of $content in $format (used for indexing).
*/
	{
		$viewer=qa_load_viewer($content, $format);
		
		if (!isset($viewer))
			qa_fatal_error('Content could not be parsed in format: '.$format);
			
		return $viewer->get_text($content, $format, array());
	}

	
	function qa_post_tags_to_tagstring($tags)
/*
	Return tagstring to store in the database based on $tags as an array or a comma-separated string.
*/
	{
		if (is_array($tags))
			$tags=implode(',', $tags);
		
		return qa_tags_to_tagstring(array_unique(preg_split('/\s*,\s*/', qa_strtolower(strtr($tags, '/', ' ')), -1, PREG_SPLIT_NO_EMPTY)));
	}

	
	function qa_post_get_question_answers($questionid)
/*
	Return the full database records for all answers to question $questionid
*/
	{
		$answers=array();
		
		$childposts=qa_db_single_select(qa_db_full_child_posts_selectspec(null, $questionid));
		
		foreach ($childposts as $postid => $post)
			if ($post['basetype']=='A')
				$answers[$postid]=$post;
		
		return $answers;
	}

	
	function qa_post_get_question_commentsfollows($questionid)
/*
	Return the full database records for all comments or follow-on questions for question $questionid or its answers
*/
	{
		$commentsfollows=array();
		
		list($childposts, $achildposts)=qa_db_multi_select(array(
			qa_db_full_child_posts_selectspec(null, $questionid),
			qa_db_full_a_child_posts_selectspec(null, $questionid),
		));

		foreach ($childposts as $postid => $post)
			if ($post['basetype']=='C')
				$commentsfollows[$postid]=$post;
		
		foreach ($achildposts as $postid => $post)
			if ( ($post['basetype']=='Q') || ($post['basetype']=='C') )
				$commentsfollows[$postid]=$post;
		
		return $commentsfollows;
	}

	
	function qa_post_get_answer_commentsfollows($answerid)
/*
	Return the full database records for all comments or follow-on questions for answer $answerid
*/
	{
		$commentsfollows=array();
		
		$childposts=qa_db_single_select(qa_db_full_child_posts_selectspec(null, $answerid));

		foreach ($childposts as $postid => $post)
			if ( ($post['basetype']=='Q') || ($post['basetype']=='C') )
				$commentsfollows[$postid]=$post;
				
		return $commentsfollows;
	}
	

	function qa_post_parent_to_question($parentpost)
/*
	Return $parentpost if it's the database record for a question, otherwise return the database record for its parent
*/
	{
		if ($parentpost['basetype']=='Q')
			$question=$parentpost;
		else
			$question=qa_post_get_full($parentpost['parentid'], 'Q');
		
		return $question;
	}

	
	function qa_post_parent_to_answer($parentpost)
/*
	Return $parentpost if it's the database record for an answer, otherwise return null
*/
	{
		if ($parentpost['basetype']=='A')
			$answer=$parentpost;
		else
			$answer=null;
			
		return $answer;
	}
	

/*
	Omit PHP closing tag to help avoid accidental output
*/