#
# Original Markdown  
# Copyright (c) 2004-2006 John Gruber  
# 
s around # "paragraphs" that are wrapped in non-block-level tags, such as anchors, # phrase emphasis, and spans. The list of tags we're looking for is # hard-coded: # # * List "a" is made of tags which can be both inline or block-level. # These will be treated block-level when the start tag is alone on # its line, otherwise they're not matched here and will be taken as # inline later. # * List "b" is made of tags which are always block-level; # $block_tags_a_re = 'ins|del'; $block_tags_b_re = 'p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|'. 'script|noscript|style|form|fieldset|iframe|math|svg|'. 'article|section|nav|aside|hgroup|header|footer|'. 'figure'; # Regular expression for the content of a block tag. $nested_tags_level = 4; $attr = ' (?> # optional tag attributes \s # starts with whitespace (?> [^>"/]+ # text outside quotes | /+(?!>) # slash not followed by ">" | "[^"]*" # text inside double quotes (tolerate ">") | \'[^\']*\' # text inside single quotes (tolerate ">") )* )? '; $content = str_repeat(' (?> [^<]+ # content without tag | <\2 # nested opening tag '.$attr.' # attributes (?> /> | >', $nested_tags_level). # end of opening tag '.*?'. # last level nested tag content str_repeat(' \2\s*> # closing nested tag ) | <(?!/\2\s*> # other tags with a different name ) )*', $nested_tags_level); $content2 = str_replace('\2', '\3', $content); # First, look for nested blocks, e.g.: #
` blocks.
	#
		$text = preg_replace_callback('{
				(?:\n\n|\A\n?)
				(	            # $1 = the code block -- one or more lines, starting with a space/tab
				  (?>
					[ ]{'.$this->tab_width.'}  # Lines must start with a tab or a tab-width of spaces
					.*\n+
				  )+
				)
				((?=^[ ]{0,'.$this->tab_width.'}\S)|\Z)	# Lookahead for non-space at line-start, or end of doc
			}xm',
			array($this, '_doCodeBlocks_callback'), $text);
		return $text;
	}
	protected function _doCodeBlocks_callback($matches) {
		$codeblock = $matches[1];
		$codeblock = $this->outdent($codeblock);
		if ($this->code_block_content_func) {
			$codeblock = call_user_func($this->code_block_content_func, $codeblock, "");
		} else {
			$codeblock = htmlspecialchars($codeblock, ENT_NOQUOTES);
		}
		# trim leading newlines and trailing newlines
		$codeblock = preg_replace('/\A\n+|\n+\z/', '', $codeblock);
		$codeblock = "$codeblock\n
";
		return "\n\n".$this->hashBlock($codeblock)."\n\n";
	}
	protected function makeCodeSpan($code) {
	#
	# Create a code span markup for $code. Called from handleSpanToken.
	#
		$code = htmlspecialchars(trim($code), ENT_NOQUOTES);
		return $this->hashPart("$code");
	}
	protected $em_relist = array(
		''  => '(?:(? '(? '(? '(?:(? '(? '(? '(?:(? '(? '(?em_relist as $em => $em_re) {
			foreach ($this->strong_relist as $strong => $strong_re) {
				# Construct list of allowed token expressions.
				$token_relist = array();
				if (isset($this->em_strong_relist["$em$strong"])) {
					$token_relist[] = $this->em_strong_relist["$em$strong"];
				}
				$token_relist[] = $em_re;
				$token_relist[] = $strong_re;
				
				# Construct master expression from list.
				$token_re = '{('. implode('|', $token_relist) .')}';
				$this->em_strong_prepared_relist["$em$strong"] = $token_re;
			}
		}
	}
	
	protected function doItalicsAndBold($text) {
		$token_stack = array('');
		$text_stack = array('');
		$em = '';
		$strong = '';
		$tree_char_em = false;
		
		while (1) {
			#
			# Get prepared regular expression for seraching emphasis tokens
			# in current context.
			#
			$token_re = $this->em_strong_prepared_relist["$em$strong"];
			
			#
			# Each loop iteration search for the next emphasis token. 
			# Each token is then passed to handleSpanToken.
			#
			$parts = preg_split($token_re, $text, 2, PREG_SPLIT_DELIM_CAPTURE);
			$text_stack[0] .= $parts[0];
			$token =& $parts[1];
			$text =& $parts[2];
			
			if (empty($token)) {
				# Reached end of text span: empty stack without emitting.
				# any more emphasis.
				while ($token_stack[0]) {
					$text_stack[1] .= array_shift($token_stack);
					$text_stack[0] .= array_shift($text_stack);
				}
				break;
			}
			
			$token_len = strlen($token);
			if ($tree_char_em) {
				# Reached closing marker while inside a three-char emphasis.
				if ($token_len == 3) {
					# Three-char closing marker, close em and strong.
					array_shift($token_stack);
					$span = array_shift($text_stack);
					$span = $this->runSpanGamut($span);
					$span = "$span";
					$text_stack[0] .= $this->hashPart($span);
					$em = '';
					$strong = '';
				} else {
					# Other closing marker: close one em or strong and
					# change current token state to match the other
					$token_stack[0] = str_repeat($token{0}, 3-$token_len);
					$tag = $token_len == 2 ? "strong" : "em";
					$span = $text_stack[0];
					$span = $this->runSpanGamut($span);
					$span = "<$tag>$span$tag>";
					$text_stack[0] = $this->hashPart($span);
					$$tag = ''; # $$tag stands for $em or $strong
				}
				$tree_char_em = false;
			} else if ($token_len == 3) {
				if ($em) {
					# Reached closing marker for both em and strong.
					# Closing strong marker:
					for ($i = 0; $i < 2; ++$i) {
						$shifted_token = array_shift($token_stack);
						$tag = strlen($shifted_token) == 2 ? "strong" : "em";
						$span = array_shift($text_stack);
						$span = $this->runSpanGamut($span);
						$span = "<$tag>$span$tag>";
						$text_stack[0] .= $this->hashPart($span);
						$$tag = ''; # $$tag stands for $em or $strong
					}
				} else {
					# Reached opening three-char emphasis marker. Push on token 
					# stack; will be handled by the special condition above.
					$em = $token{0};
					$strong = "$em$em";
					array_unshift($token_stack, $token);
					array_unshift($text_stack, '');
					$tree_char_em = true;
				}
			} else if ($token_len == 2) {
				if ($strong) {
					# Unwind any dangling emphasis marker:
					if (strlen($token_stack[0]) == 1) {
						$text_stack[1] .= array_shift($token_stack);
						$text_stack[0] .= array_shift($text_stack);
					}
					# Closing strong marker:
					array_shift($token_stack);
					$span = array_shift($text_stack);
					$span = $this->runSpanGamut($span);
					$span = "$span";
					$text_stack[0] .= $this->hashPart($span);
					$strong = '';
				} else {
					array_unshift($token_stack, $token);
					array_unshift($text_stack, '');
					$strong = $token;
				}
			} else {
				# Here $token_len == 1
				if ($em) {
					if (strlen($token_stack[0]) == 1) {
						# Closing emphasis marker:
						array_shift($token_stack);
						$span = array_shift($text_stack);
						$span = $this->runSpanGamut($span);
						$span = "$span";
						$text_stack[0] .= $this->hashPart($span);
						$em = '';
					} else {
						$text_stack[0] .= $token;
					}
				} else {
					array_unshift($token_stack, $token);
					array_unshift($text_stack, '');
					$em = $token;
				}
			}
		}
		return $text_stack[0];
	}
	protected function doBlockQuotes($text) {
		$text = preg_replace_callback('/
			  (								# Wrap whole match in $1
				(?>
				  ^[ ]*>[ ]?			# ">" at the start of a line
					.+\n					# rest of the first line
				  (.+\n)*					# subsequent consecutive lines
				  \n*						# blanks
				)+
			  )
			/xm',
			array($this, '_doBlockQuotes_callback'), $text);
		return $text;
	}
	protected function _doBlockQuotes_callback($matches) {
		$bq = $matches[1];
		# trim one level of quoting - trim whitespace-only lines
		$bq = preg_replace('/^[ ]*>[ ]?|^[ ]+$/m', '', $bq);
		$bq = $this->runBlockGamut($bq);		# recurse
		$bq = preg_replace('/^/m', "  ", $bq);
		# These leading spaces cause problem with  content, 
		# so we need to fix that:
		$bq = preg_replace_callback('{(\s*.+?
)}sx', 
			array($this, '_doBlockQuotes_callback2'), $bq);
		return "\n". $this->hashBlock("\n$bq\n
")."\n\n";
	}
	protected function _doBlockQuotes_callback2($matches) {
		$pre = $matches[1];
		$pre = preg_replace('/^  /m', '', $pre);
		return $pre;
	}
	protected function formParagraphs($text) {
	#
	#	Params:
	#		$text - string to process with html  tags
	#
		# Strip leading and trailing lines:
		$text = preg_replace('/\A\n+|\n+\z/', '', $text);
		$grafs = preg_split('/\n{2,}/', $text, -1, PREG_SPLIT_NO_EMPTY);
		#
		# Wrap 
 tags and unhashify HTML blocks
		#
		foreach ($grafs as $key => $value) {
			if (!preg_match('/^B\x1A[0-9]+B$/', $value)) {
				# Is a paragraph.
				$value = $this->runSpanGamut($value);
				$value = preg_replace('/^([ ]*)/', "
", $value);
				$value .= "
";
				$grafs[$key] = $this->unhash($value);
			}
			else {
				# Is a block.
				# Modify elements of @grafs in-place...
				$graf = $value;
				$block = $this->html_hashes[$graf];
				$graf = $block;
//				if (preg_match('{
//					\A
//					(							# $1 =  tag
//					  ]*
//					  \b
//					  markdown\s*=\s*  ([\'"])	#	$2 = attr quote char
//					  1
//					  \2
//					  [^>]*
//					  >
//					)
//					(							# $3 = contents
//					.*
//					)
//					()					# $4 = closing tag
//					\z
//					}xs', $block, $matches))
//				{
//					list(, $div_open, , $div_content, $div_close) = $matches;
//
//					# We can't call Markdown(), because that resets the hash;
//					# that initialization code should be pulled into its own sub, though.
//					$div_content = $this->hashHTMLBlocks($div_content);
//					
//					# Run document gamut methods on the content.
//					foreach ($this->document_gamut as $method => $priority) {
//						$div_content = $this->$method($div_content);
//					}
//
//					$div_open = preg_replace(
//						'{\smarkdown\s*=\s*([\'"]).+?\1}', '', $div_open);
//
//					$graf = $div_open . "\n" . $div_content . "\n" . $div_close;
//				}
				$grafs[$key] = $graf;
			}
		}
		return implode("\n\n", $grafs);
	}
	protected function encodeAttribute($text) {
	#
	# Encode text for a double-quoted HTML attribute. This function
	# is *not* suitable for attributes enclosed in single quotes.
	#
		$text = $this->encodeAmpsAndAngles($text);
		$text = str_replace('"', '"', $text);
		return $text;
	}
	protected function encodeURLAttribute($url, &$text = null) {
	#
	# Encode text for a double-quoted HTML attribute containing a URL,
	# applying the URL filter if set. Also generates the textual
	# representation for the URL (removing mailto: or tel:) storing it in $text.
	# This function is *not* suitable for attributes enclosed in single quotes.
	#
		if ($this->url_filter_func)
			$url = call_user_func($this->url_filter_func, $url);
		if (preg_match('{^mailto:}i', $url))
			$url = $this->encodeEntityObfuscatedAttribute($url, $text, 7);
		else if (preg_match('{^tel:}i', $url))
		{
			$url = $this->encodeAttribute($url);
			$text = substr($url, 4);
		}
		else
		{
			$url = $this->encodeAttribute($url);
			$text = $url;
		}
		return $url;
	}
	
	
	protected function encodeAmpsAndAngles($text) {
	#
	# Smart processing for ampersands and angle brackets that need to 
	# be encoded. Valid character entities are left alone unless the
	# no-entities mode is set.
	#
		if ($this->no_entities) {
			$text = str_replace('&', '&', $text);
		} else {
			# Ampersand-encoding based entirely on Nat Irons's Amputator
			# MT plugin:  
			$text = preg_replace('/&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)/', 
								'&', $text);
		}
		# Encode remaining <'s
		$text = str_replace('<', '<', $text);
		return $text;
	}
	protected function doAutoLinks($text) {
		$text = preg_replace_callback('{<((https?|ftp|dict|tel):[^\'">\s]+)>}i',
			array($this, '_doAutoLinks_url_callback'), $text);
		# Email addresses: 
		$text = preg_replace_callback('{
			<
			(?:mailto:)?
			(
				(?:
					[-!#$%&\'*+/=?^_`.{|}~\w\x80-\xFF]+
				|
					".*?"
				)
				\@
				(?:
					[-a-z0-9\x80-\xFF]+(\.[-a-z0-9\x80-\xFF]+)*\.[a-z]+
				|
					\[[\d.a-fA-F:]+\]	# IPv4 & IPv6
				)
			)
			>
			}xi',
			array($this, '_doAutoLinks_email_callback'), $text);
		return $text;
	}
	protected function _doAutoLinks_url_callback($matches) {
		$url = $this->encodeURLAttribute($matches[1], $text);
		$link = "$text";
		return $this->hashPart($link);
	}
	protected function _doAutoLinks_email_callback($matches) {
		$addr = $matches[1];
		$url = $this->encodeURLAttribute("mailto:$addr", $text);
		$link = "$text";
		return $this->hashPart($link);
	}
	protected function encodeEntityObfuscatedAttribute($text, &$tail = null, $head_length = 0) {
	#
	#	Input: some text to obfuscate, e.g. "mailto:foo@example.com"
	#
	#	Output: the same text but with most characters encoded as either a
	#		decimal or hex entity, in the hopes of foiling most address
	#		harvesting spam bots. E.g.:
	#
	#        mailto:foo
	#        @example.co
	#        m
	#
	#	Note: the additional output $tail is assigned the same value as the
	#	ouput, minus the number of characters specified by $head_length.
	#
	#	Based by a filter by Matthew Wickline, posted to BBEdit-Talk.
	#   With some optimizations by Milian Wolff. Forced encoding of HTML
	#	attribute special characters by Allan Odgaard.
	#
		if ($text == "") return $tail = "";
		$chars = preg_split('/(? $char) {
			$ord = ord($char);
			# Ignore non-ascii chars.
			if ($ord < 128) {
				$r = ($seed * (1 + $key)) % 100; # Pseudo-random function.
				# roughly 10% raw, 45% hex, 45% dec
				# '@' *must* be encoded. I insist.
				# '"' and '>' have to be encoded inside the attribute
				if ($r > 90 && strpos('@"&>', $char) === false) /* do nothing */;
				else if ($r < 45) $chars[$key] = ''.dechex($ord).';';
				else              $chars[$key] = ''.$ord.';';
			}
		}
		$text = implode('', $chars);
		$tail = $head_length ? implode('', array_slice($chars, $head_length)) : $text;
		return $text;
	}
	protected function parseSpan($str) {
	#
	# Take the string $str and parse it into tokens, hashing embeded HTML,
	# escaped characters and handling code spans.
	#
		$output = '';
		
		$span_re = '{
				(
					\\\\'.$this->escape_chars_re.'
				|
					(?no_markup ? '' : '
				|
							# comment
				|
					<\?.*?\?> | <%.*?%>		# processing instruction
				|
					<[!$]?[-a-zA-Z0-9:_]+	# regular tags
					(?>
						\s
						(?>[^"\'>]+|"[^"]*"|\'[^\']*\')*
					)?
					>
				|
					<[-a-zA-Z0-9:_]+\s*/> # xml-style empty tag
				|
					[-a-zA-Z0-9:_]+\s*> # closing tag
			').'
				)
				}xs';
		while (1) {
			#
			# Each loop iteration seach for either the next tag, the next 
			# openning code span marker, or the next escaped character. 
			# Each token is then passed to handleSpanToken.
			#
			$parts = preg_split($span_re, $str, 2, PREG_SPLIT_DELIM_CAPTURE);
			
			# Create token from text preceding tag.
			if ($parts[0] != "") {
				$output .= $parts[0];
			}
			
			# Check if we reach the end.
			if (isset($parts[1])) {
				$output .= $this->handleSpanToken($parts[1], $parts[2]);
				$str = $parts[2];
			}
			else {
				break;
			}
		}
		
		return $output;
	}
	
	
	protected function handleSpanToken($token, &$str) {
	#
	# Handle $token provided by parseSpan by determining its nature and 
	# returning the corresponding value that should replace it.
	#
		switch ($token{0}) {
			case "\\":
				return $this->hashPart("". ord($token{1}). ";");
			case "`":
				# Search for end marker in remaining text.
				if (preg_match('/^(.*?[^`])'.preg_quote($token).'(?!`)(.*)$/sm', 
					$str, $matches))
				{
					$str = $matches[2];
					$codespan = $this->makeCodeSpan($matches[1]);
					return $this->hashPart($codespan);
				}
				return $token; // return as text since no ending marker found.
			default:
				return $this->hashPart($token);
		}
	}
	protected function outdent($text) {
	#
	# Remove one level of line-leading tabs or spaces
	#
		return preg_replace('/^(\t|[ ]{1,'.$this->tab_width.'})/m', '', $text);
	}
	# String length function for detab. `_initDetab` will create a function to 
	# hanlde UTF-8 if the default function does not exist.
	protected $utf8_strlen = 'mb_strlen';
	
	protected function detab($text) {
	#
	# Replace tabs with the appropriate amount of space.
	#
		# For each line we separate the line in blocks delemited by
		# tab characters. Then we reconstruct every line by adding the 
		# appropriate number of space between each blocks.
		
		$text = preg_replace_callback('/^.*\t.*$/m',
			array($this, '_detab_callback'), $text);
		return $text;
	}
	protected function _detab_callback($matches) {
		$line = $matches[0];
		$strlen = $this->utf8_strlen; # strlen function for UTF-8.
		
		# Split in blocks.
		$blocks = explode("\t", $line);
		# Add each blocks to the line.
		$line = $blocks[0];
		unset($blocks[0]); # Do not add first block twice.
		foreach ($blocks as $block) {
			# Calculate amount of space, insert spaces, insert block.
			$amount = $this->tab_width - 
				$strlen($line, 'UTF-8') % $this->tab_width;
			$line .= str_repeat(" ", $amount) . $block;
		}
		return $line;
	}
	protected function _initDetab() {
	#
	# Check for the availability of the function in the `utf8_strlen` property
	# (initially `mb_strlen`). If the function is not available, create a 
	# function that will loosely count the number of UTF-8 characters with a
	# regular expression.
	#
		if (function_exists($this->utf8_strlen)) return;
		$this->utf8_strlen = create_function('$text', 'return preg_match_all(
			"/[\\\\x00-\\\\xBF]|[\\\\xC0-\\\\xFF][\\\\x80-\\\\xBF]*/", 
			$text, $m);');
	}
	protected function unhash($text) {
	#
	# Swap back in all the tags hashed by _HashHTMLBlocks.
	#
		return preg_replace_callback('/(.)\x1A[0-9]+\1/', 
			array($this, '_unhash_callback'), $text);
	}
	protected function _unhash_callback($matches) {
		return $this->html_hashes[$matches[0]];
	}
}