h-m-m/h-m-m

#!/usr/bin/env php
<?php
// {{{ settings

$mm=[];

$mm['max_parent_width']		= 25;
$mm['max_leaf_width']		= 55;
$mm['line_spacing']			= 1;
$mm['center_lock']			= false;
$mm['focus_lock']			= false;
$mm['initial_depth']		= 1;
$mm['show_logo']			= 0;

$mm['active_node_color']	= "\033[38;5;0m\033[48;5;172m\033[1m";
$mm['message_color']		= "\033[38;5;0m\033[48;5;141m\033[1m";
$mm['question_color']		= "\033[38;5;168m";


function load_settings(&$mm)
{
	global $argv;

	$conf = $argv[0].'.conf';
	if (!file_exists($conf))  return;

	$handle = fopen($conf, "r");
	if (!$handle)  return;

	while (($line = fgets($handle)) !== false)
	{
		if (empty(trim($line))) continue;

		$elements = explode('=',trim($line));
		$setting = trim($elements[0] ?? '');
		$value = trim($elements[1] ?? '');

		switch ($setting)
		{
			case 'max_parent_width':	$mm['max_parent_width']		= max( round($value), width_min ); break;
			case 'max_leaf_width':		$mm['max_leaf_width']		= max( round($value), width_min ); break;
			case 'line_spacing':		$mm['line_spacing']			= max( round($value), 0 ); break;
			case 'initial_depth':		$mm['initial_depth']		= max( round($value), 1 ); break;

			case 'active_node_color':	$mm['active_node_color']	= $value; break;
			case 'message_color':		$mm['message_color']		= $value; break;

			case 'center_lock':			$mm['center_lock']			= (bool)($value); break;
			case 'focus_lock':			$mm['focus_lock']			= (bool)($value); break;
		}
	}

	fclose($handle);
}


// }}}
// {{{ constants and defaults

// escape codes: https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797

$mm['top_left_column']		= 0;
$mm['top_left_row']			= 0;
$mm['active_column']		= 0;
$mm['active_row']			= 0;

$mm['terminal_width']		= exec('tput cols');
$mm['terminal_height']		= exec('tput lines');

$mm['win_left']				= 0;
$mm['win_top']				= 0;

$mm['root']					= 2;

const logo_color			= "\033[38;5;222m";
const default_color			= "\033[0m";

const min_indentation		= 2;
const width_tolerance		= 1.3;
const width_min				= 15;
const width_change_factor	= 1.2;
const max_width_padding		= 30;

const default_leaf_width	= 55;
const default_parent_width	= 25;

const default_spacing		= 1;

const width_wider			= 0;
const width_narrower		= 1;
const width_default			= 2;

const spacing_wider			= 0;
const spacing_narrower		= 1;
const spacing_default		= 2;

const conn_left_len			= 6;
const conn_right_len		= 4;

$mm['conn_left']			= str_repeat('─', conn_left_len );
$mm['conn_right']			= str_repeat('─', conn_right_len - 2 );
$mm['conn_single']			= str_repeat('─', conn_left_len + conn_right_len - 1 );

const vertical_offset		= 4;

const move_up				= 0;
const move_down				= 1;
const move_left				= 2;
const move_right			= 3;

const left_padding			= 1;

const insert_sibling		= 0;
const insert_child			= 1;

const ctrl_p				= "\020";
const ctrl_c				= "\003";

const arr_down				= "\033\133\102";
const arr_right 			= "\033\133\103";
const arr_up				= "\033\133\101";
const arr_left				= "\033\133\104";

const reset_page			= "\033[2J\033[0;0f";
const reset_color			= "\033[0m";

const invert_on				= "\033[7m";
const invert_off			= "\033[27m";

const dim_on				= "\033[2m";
const dim_off				= "\033[22m";

const line_on				= "\033[0m\033[38;5;95m";
const line_off				= "\033[0m";

const collapsed_symbol_on	= "\033[38;5;215m";
const collapsed_symbol_off	= "\033[0m";



// }}}
// {{{ alternative screen


function shutdown()
{
	clear();
	system("tput rmcup && tput cnorm && stty sane");
	exit;
}

if (false === check_required_extensions()) {
    return 1;
}

register_shutdown_function("shutdown");
declare(ticks = 1);
pcntl_signal(SIGINT,"shutdown");



function set_up_screen()
{
	// https://www.computerhope.com/unix/ustty.htm
	// https://www.ibm.com/docs/en/aix/7.1?topic=s-stty-command

	// system('stty cbreak -echo ');                              // testing
	system('stty cbreak -echo -crterase intr undef && tput smcup');      // production

	// the first code disables the text cursor and the second one gets rid of the mouse!
	// https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Mouse-Tracking
	// 'l' disables and 'h' enables
	echo "\033[?25l\033[?9;1000;1001;1002;1003;1004;1007;1005;1006;1015;1016l";
}


function clear()       { echo "\033[2J"; }
function move($x,$y)   { echo "\033[{$y};{$x}f"; }
function put($x,$y,$t) { echo "\033[{$y};{$x}f{$t}"; }


function mput(&$mm,$x,$y,$s)
{
	$mm['map'][round($y)]
		= mb_substr( $mm['map'][round($y)], 0, $x)
		. $s
		. mb_substr( $mm['map'][round($y)], $x + mb_strlen($s) );
}



// }}}
// {{{ debug

function debug($nodes)
{
	echo " id   pr    x    w    y   yo    h   lh  clh     title\n";
	$i = 0;
	foreach ($nodes as $id=>$data)
		echo
			 ($i++ % 4 == 0 ? "\n" : '')
			.str_pad($id,3,' ',STR_PAD_LEFT)
			.str_pad($data['parent'],5,' ',STR_PAD_LEFT)
			.str_pad($data['x']   ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['w']   ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['y']   ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['yo']  ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['h']   ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['lh']  ?? 'x',5,' ',STR_PAD_LEFT)
			.str_pad($data['clh'] ?? 'x',5,' ',STR_PAD_LEFT)
			.'     '
			.substr($data['title'],0,70)
			."\n"
		;
	echo " id   pr    x    w    y   yo    h   lh  clh     title\n";
}


// }}}
// {{{ decode tree

function decode_tree($lines, $root_id, $start_id)
{
	// calculating the indentation shift and cleaning up the special characters
	$indentation_shift = 9999999;
	foreach ($lines as $lid=>$line)
	{
		$lines[$lid] =
			str_replace
			(
				 [ "\t", "\n", "\r"]
				,[ "  ", "  ", "  "]
				,$lines[$lid]
			)
		;

		$indentation = mb_strlen($lines[$lid]) - mb_strlen(ltrim($lines[$lid]));
		$start = mb_substr($lines[$lid], $indentation, 2);

		if ($start=='* ' || $start=='- ')
		{
			$lines[$lid][$indentation] = ' ';
			$indentation += 2;
		}

		if (trim($lines[$lid])!='')
			$indentation_shift =
				min
				(
					 $indentation_shift
					,$indentation
				)
			;
	}


	// building the tree

	$nodes = [];
	$id = $start_id;

	$previous_level = 1;
	$level = 1;
	$previous_indentation = 0;

	$level_parent[1]      = $root_id;
	$level_indentation[1] = 0;

	foreach ($lines as $line)
		if (trim($line)!='')
		{
			// warming up for this round!
			$indentation = mb_strlen($line) - mb_strlen(ltrim($line)) - $indentation_shift;

			// going one level down
			if ($indentation > $previous_indentation )
			{
				$level = $previous_level + 1;
				$level_indentation[$level] = $indentation;
			}

			// going one or more levels up
			if ($indentation < $previous_indentation )
				foreach ($level_indentation as $plevel=>$pindentation)
					if ($pindentation == $indentation)
						$level = $plevel;

			// saving the latest level_parent
			if ($level > $previous_level)
				$level_parent[$level] = $id-1;

			// done! saving the data

			$nodes[$id] =
			[
				 'title'   => trim($line)
				,'parent'  => $level_parent[$level]
			];

			// getting ready for the next round!
			$previous_indentation = $indentation;
			$previous_level = $level;
			$id++;
		}


	// setting a few properties that simplify future calculations

	foreach ($nodes as $id=>$node)
	{
		$nodes[$id]['collapsed'] = false;
		$nodes[$id]['is_leaf']   = true;
		$nodes[$id]['children']  = [];
	}

	foreach ($nodes as $id=>$node)
		if (isset($nodes[ $node['parent'] ]))
		{
			$nodes[ $node['parent'] ]['is_leaf']    = false;
			$nodes[ $node['parent'] ]['children'][] = $id;
		}

	return($nodes);
}


// }}}
// {{{ load_file

function load_file(&$mm)
{
	global $argv;

	if (!isset($argv[1]))
	{
		load_empty_map($mm);
		return;
	}

	$mm['filename']=$argv[1];

	if (!file_exists($argv[1]))
	{
		load_empty_map($mm);
		return;
	}

	$lines = file($argv[1], FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);

	// starting from 2 instead of 1, in case the files doesn't have
	// a single root and we have to inject one. leaving "1" empty
	// won't cause any problems.
	$new_nodes = decode_tree($lines, 0, 2);


	// checking to see how many first-level nodes we have
	$first_level_nodes = [];
	foreach ($new_nodes as $id=>$node)
		if ($id!=0 && $node['parent']==0)
			$first_level_nodes[] = $id;

	$mm['nodes'][0]['parent']   = -1;
	$mm['nodes'][0]['title']    = 'X';
	$mm['nodes'][0]['is_leaf']  = false;

	if (count($first_level_nodes)>1)
	{
		$mm['root'] = 1;

		$mm['nodes'][1]['parent']   = 0;
		$mm['nodes'][1]['title']    = 'root';
		$mm['nodes'][1]['is_leaf']  = false;
		$mm['nodes'][1]['children'] = $first_level_nodes;
		$mm['nodes'][0]['children'] = [1];

		foreach ($new_nodes as $id=>$node)
			if ($node['parent']==0)
				$new_nodes[$id]['parent'] = 1;
	}
	else
		$mm['nodes'][0]['children'] = $first_level_nodes;

	$mm['nodes'] = $mm['nodes'] + $new_nodes;

	if (isset($mm['nodes'][1]))
		$mm['active_node']=1;
	else
		$mm['active_node']=2;
}



// }}}
// {{{ calculate w, x, lh, and clh


function calculate_x_and_lh(&$mm, $id)
{
	$node = $mm['nodes'][$id];

	$mm['nodes'][$id]['x']
		= $mm['nodes'][ $node['parent'] ]['x']
		+ $mm['nodes'][ $node['parent'] ]['w']
		+ conn_left_len
		+ conn_right_len
		+ 1
		+
		(
			$node['parent']==0
			? 1 - conn_right_len - conn_left_len
			: 0
		)
	;

	$max_width
		=  ($node['is_leaf'] || ($node['collapsed'] ?? false)) * $mm['max_leaf_width']
		+ !($node['is_leaf'] || ($node['collapsed'] ?? false)) * $mm['max_parent_width'];

	if ( mb_strlen($node['title']) > width_tolerance * $max_width )
	{
		$lines = explode("\n" ,wordwrap($node['title'] ,$max_width));

		$mm['nodes'][$id]['w'] = 0;
		foreach ($lines as $line)
			$mm['nodes'][$id]['w'] =
				max($mm['nodes'][$id]['w'], trim(mb_strlen($line)));

		$mm['nodes'][$id]['lh'] = count($lines);
	}
	else
	{
		$mm['nodes'][$id]['w']  = mb_strlen($node['title']);
		$mm['nodes'][$id]['lh'] = 1;
	}

	$mm['map_width'] =
		max
		(
			  $mm['map_width']
			, $mm['nodes'][$id]['x']
			+ $mm['nodes'][$id]['w']
		)
	;

	$mm['nodes'][$id]['clh'] = 0;
	if (($mm['nodes'][$id]['collapsed'] ?? false) || $mm['nodes'][$id]['is_leaf'])
		$mm['nodes'][$id]['clh'] = $mm['nodes'][$id]['lh'];

	foreach ($node['children'] as $cid)
	{
		calculate_x_and_lh($mm, $cid);
		$mm['nodes'][$id]['clh'] += $mm['nodes'][$cid]['clh'];
	}

}


// }}}
// {{{ calculate h

function calculate_h(&$mm)
{
	$unfinished = true;
	while ($unfinished)
	{
		$unfinished = false;

		foreach ($mm['nodes'] as $id=>$node)

			if ($node['is_leaf'] || ($node['collapsed'] ?? false))

				$mm['nodes'][$id]['h'] 
					= $mm['line_spacing']
					+ $mm['nodes'][$id]['lh']
				;

			else
			{
				$h = 0;
				$unready = false;

				foreach ($node['children'] as $cid)
					if ($mm['nodes'][$cid]['h']>=0)
						$h += $mm['nodes'][$cid]['h'];
					else
					{
						$unready = true;
						break;
					}

				if ($unready)
					$unfinished = true;
				else
					$mm['nodes'][$id]['h'] 
						= max
						( 
							  $h
							, $node['lh'] 
							+ $mm['line_spacing'] 
						)
						+ ($mm['nodes'][$id]['parent'] == $mm['root'])
						* $mm['line_spacing'];
					;
			}
	}
}




// }}}
// {{{ calculate y and yo

function calculate_y(&$mm)
{
	$mm['map_top']    = 0;
	$mm['map_bottom'] = 0;
	$mm['map_height'] = $mm['nodes'][0]['h'];

	$mm['nodes'][0]['y'] = 0;
	calculate_children_y($mm, 0);
}

function calculate_children_y(&$mm,$pid)
{
	$y = $mm['nodes'][$pid]['y'];

	$mm['nodes'][$pid]['yo'] =
		round(
			(
				+ $mm['nodes'][$pid]['h']
				- $mm['nodes'][$pid]['lh']
			)/2
		)
	;

	if (!($mm['nodes'][$pid]['collapsed'] ?? false))
		foreach ($mm['nodes'][$pid]['children'] as $cid)
		{
			$mm['nodes'][$cid]['y'] = $y;

			$mm['map_bottom'] =
				max
				(
					 $mm['map_bottom']
					,$mm['nodes'][$cid]['lh']
					+$mm['line_spacing']
					+$y
				)
			;

			$mm['map_top'] = min($mm['map_top'],$y);
			$y += $mm['nodes'][$cid]['h'];
			calculate_children_y($mm,$cid);
		}
}

// }}}
// {{{ calculate top-down height shift

function calculate_height_shift(&$mm, $id, $shift = 0)
{
	$mm['nodes'][$id]['yo'] += $shift;
	$shift += max(0, round( ($mm['nodes'][$id]['lh'] - $mm['nodes'][$id]['clh'])/2 - 0.5 ));

	foreach ($mm['nodes'][$id]['children'] as $cid)
		if (!$mm['nodes'][$id]['collapsed'])
			calculate_height_shift($mm, $cid, $shift);
}



// }}}
// {{{ draw connections on the map

function draw_connections(&$mm, $id)
{
	$node = $mm['nodes'][$id];

	// if there's no child
	if ($node['is_leaf']) return;

	// if the node is collapsed
	if ($node['collapsed'] ?? false)
	{
		mput
		(
			 $mm
			,$node['x'] + $node['w']+1
			,$node['y'] + $node['yo']
			,' [+]'
		);
		return;
	}

	// if there's only one child in the same y coordinate
	if (count($node['children'] ?? [])==1)
	{
		$child_id = $node['children'][ array_key_first( $node['children'] ) ];
		$child = $mm['nodes'][ $child_id ];

		$y1  = round( $node['y']  + $node['yo']  ) + round( ($node['lh'] ) / 2 - 0.6 );
		$y2  = round( $child['y'] + $child['yo'] ) + round( ($child['lh']) / 2 - 0.6 );

		mput
		(
			 $mm
			,$child['x'] - conn_left_len - conn_right_len
			,min($y1,$y2)
			,$mm['conn_single']
		);

		if (abs(min($y1,$y2)-$y2)>0)
		{
			for ($yy=min($y1,$y2); $yy<max($y1,$y2); $yy++)
				mput
				(
					 $mm
					,$child['x'] - 2
					,$yy
					,'│'
				);

			mput
			(
				$mm
				,$child['x'] - 2
				,$y2
				,( $y2 > $y1 ? '╰' : '╭' )
			);

			mput
			(
				 $mm
				,$child['x'] - 2
				,min($y1,$y2)
				,( $y2 > $y1 ? '╮' : '╯' )
			);
		}

		draw_connections($mm, $child_id );
		return;
	}

	// if there's more than one child
	$bottom = 0;
	$bottom_child = 0;
	$top = $mm['map_height'];
	$top_child = 0;

	foreach ($node['children'] as $cid)
	{
		if ($mm['nodes'][$cid]['y'] + $mm['nodes'][$cid]['yo'] > $bottom)
		{
			$bottom = $mm['nodes'][$cid]['y'] + $mm['nodes'][$cid]['yo'];
			$bottom_child = $cid;
		}

		if ($mm['nodes'][$cid]['y'] + $mm['nodes'][$cid]['yo'] < $top)
		{
			$top = $mm['nodes'][$cid]['y'] + $mm['nodes'][$cid]['yo'];
			$top_child = $cid;
		}
	}

	$middle  = round($node['y']+$node['yo']) + round($node['lh']/2-0.6);

	mput
	(
		 $mm
		,$mm['nodes'][$top_child]['x'] - conn_left_len - conn_right_len
		,$middle
		,$mm['conn_left']
	);

	for ( $i = $top ; $i < $bottom ; $i++ )
		mput
		(
			 $mm
			,$mm['nodes'][$top_child]['x'] - conn_right_len
			,$i
			,'│'
		);

	mput
	(
		 $mm
		,$mm['nodes'][$top_child]['x'] - conn_right_len
		,$top
		,'╭'
		.$mm['conn_right']
	);

	mput
	(
		 $mm
		,$mm['nodes'][$top_child]['x']-conn_right_len
		,$bottom
		,'╰'
		.$mm['conn_right']
	);

	if (count($node['children'])>2)
		foreach ($node['children'] as $cid)
			if ($cid!=$top_child && $cid!=$bottom_child)
				mput
				(
					 $mm
					,$mm['nodes'][$cid]['x']-conn_right_len
					,$mm['nodes'][$cid]['y']
					+$mm['nodes'][$cid]['lh']/2-0.2
					+$mm['nodes'][$cid]['yo']
					,'├'
					.$mm['conn_right']
				);


	$existing_char =
		mb_substr
		(
			 $mm['map'][$middle]
			,$mm['nodes'][$top_child]['x'] - conn_right_len
			,1
		);

	if ($existing_char=='│')
		mput
		(
			 $mm
			,$mm['nodes'][$top_child]['x'] - conn_right_len
			,$middle
			,'┤'
		);

	if ($existing_char=='╭')
		mput
		(
			 $mm
			,$mm['nodes'][$top_child]['x'] - conn_right_len
			,$middle
			,'┬'
		);

	if ($existing_char=='├')
		mput
		(
			 $mm
			,$mm['nodes'][$top_child]['x'] - conn_right_len
			,$middle
			,'┼'
		);

	foreach ($node['children'] as $cid)
		draw_connections($mm, $cid);
}


// }}}
// {{{ add content to the map

function add_content_to_the_map(&$mm, $id)
{
	$node = $mm['nodes'][$id];

	$max_width
		=  ($node['is_leaf'] || ($node['collapsed'] ?? false)) * $mm['max_leaf_width']
		+ !($node['is_leaf'] || ($node['collapsed'] ?? false)) * $mm['max_parent_width']
	;

	if ( mb_strlen($node['title']) > width_tolerance * $max_width)
		$lines =
			explode
			(
				"\n",
				wordwrap
				(
					$node['title'],
					$max_width
				)
			)
		;
	else
		$lines = [$node['title']];

	$num_lines = count($lines);
	for ( $i=0 ; $i<$num_lines ; $i++ )
		mput
		(
			$mm,
			$node['x'],
			round($node['y']+$node['yo'])+$i,
			$lines[$i].' '
		);

	if (!($node['collapsed'] ?? false))
		foreach ($node['children'] as $cid)
			add_content_to_the_map($mm,$cid);
}



// }}}
// {{{ build map

function build_map(&$mm)
{
	// resetting the global values
	$mm['map_width']  = 0;
	$mm['map_height'] = 0;
	$mm['map_top']    = 0;
	$mm['map_bottom'] = 0;

	// resetting the coordinates
	foreach ($mm['nodes'] as $id=>$node)
	{
		$mm['nodes'][$id]['x']  = -1;
		$mm['nodes'][$id]['y']  = -1;
		$mm['nodes'][$id]['h']  = -1;
		$mm['nodes'][$id]['lh'] = -1;
	}

	$mm['nodes'][0]['x']  = 0;
	$mm['nodes'][0]['w']  = left_padding;
	$mm['nodes'][0]['lh'] = 1;

	// resetting the map, 1/2
	$mm['map']=[];
	$mm['map_width']=0;
	$mm['map_height']=0;
	$mm['map_top']=0;
	$mm['map_bottom']=0;

	// calculating the new coordinates
	calculate_x_and_lh($mm,$mm['root']);
	calculate_h($mm);
	calculate_y($mm);
	calculate_height_shift($mm, $mm['root']);

	// resetting the map, 2/2
	$height = max($mm['map_bottom'],$mm['terminal_height']);
	$blank = str_repeat(' ', $mm['map_width']+$mm['terminal_width']);

	for ($i=$mm['map_top'] ; $i<=$height ; $i++)
		$mm['map'][$i] = $blank;

	// building the new map
	draw_connections($mm, $mm['root']);
	add_content_to_the_map($mm, $mm['root']);

}




// }}}
// {{{ toggle

function toggle(&$mm)
{
	if ($mm['nodes'][ $mm['active_node'] ]['is_leaf'])
		$mm['active_node'] = $mm['nodes'][ $mm['active_node'] ]['parent'];

	$mm['nodes'][ $mm['active_node'] ]['collapsed'] =
		!($mm['nodes'][ $mm['active_node'] ]['collapsed'] ?? false);

	build_map($mm);
	display($mm);
}



// }}}
// {{{ spacing adjuster

function adjust_spacing(&$mm, $task)
{
	if ($task==spacing_wider)     $mm['line_spacing']++;
	if ($task==spacing_narrower)  $mm['line_spacing'] = max(0, $mm['line_spacing']-1);
	if ($task==spacing_default)   $mm['line_spacing'] = default_spacing;

	build_map($mm);
	center_active_node($mm);
	display($mm);
	message($mm,'Spacing: '.$mm['line_spacing']);
}


// }}}
// {{{ width adjuster

function adjust_width(&$mm, $task)
{
	if ($task==width_wider)
	{
		$mx = $mm['terminal_width'] - max_width_padding;
		$mm['max_parent_width'] = round(min($mx, max( width_min, $mm['max_parent_width'] * width_change_factor )));
		$mm['max_leaf_width']   = round(min($mx, max( width_min, $mm['max_leaf_width']   * width_change_factor )));
	}

	if ($task==width_narrower)
	{
		$mm['max_parent_width'] = round(max( width_min, $mm['max_parent_width'] / width_change_factor ));
		$mm['max_leaf_width']   = round(max( width_min, $mm['max_leaf_width']   / width_change_factor ));
	}

	if ($task==width_default)
	{
		$mm['max_parent_width'] = default_parent_width;
		$mm['max_leaf_width']   = default_leaf_width;
	}

	build_map($mm);
	center_active_node($mm);
	display($mm);

	message($mm,'Width: '.$mm['max_parent_width'].' / '.$mm['max_leaf_width']);
}



// }}}
// {{{ move nodes

function push_node_down(&$mm, $id)
{
	if ($id==0)  return;

	$mm['modified'] = true;

	if (isset($mm['nodes'][$id+1]))
		push_node_down($mm,$id+1);

	$mm['nodes'][$id+1] = $mm['nodes'][$id];
	unset($mm['nodes'][$id]);

	$mm['nodes'][ $mm['nodes'][$id+1]['parent'] ]['children'] =
		array_diff
		(
			$mm['nodes'][ $mm['nodes'][$id+1]['parent'] ]['children'],
			[$id]
		);

	$mm['nodes'][ $mm['nodes'][$id+1]['parent'] ]['children'] =
		array_push
		(
			$mm['nodes'][ $mm['nodes'][$id+1]['parent'] ]['children'],
			[$id+1]
		);

	foreach($mm['nodes'][$id+1]['children'] as $cid=>$cdata)
		$mm['nodes'][$cid]['parent'] = $id+1;
}



// }}}
// {{{ insert node

function insert_node(&$mm, $type)
{

	if ($mm['active_node']==$mm['root'])
		$type=insert_child;

	$mm['modified'] = true;

	if ($type==insert_sibling)
		$parent_id  = $mm['nodes'][ $mm['active_node'] ]['parent'];
	else
		$parent_id  = $mm['active_node'];

	$mm['nodes'][$parent_id]['is_leaf']   = false;
	$mm['nodes'][$parent_id]['collapsed'] = false;

	$new_id = max(array_keys($mm['nodes'])) + 1;

	$mm['nodes'][$new_id] =
	[
		'title'     => 'NEW',
		'is_leaf'   => true,
		'collapsed' => false,
		'children'  => [],
		'parent'    => $parent_id
	];

	if ($type==insert_sibling)
	{
		$children = [];
		foreach ($mm['nodes'][$parent_id]['children'] as $child)
		{
			$children[] = $child;
			if ($child==$mm['active_node'])
				$children[] = $new_id;
		}
		$mm['nodes'][$parent_id]['children'] = $children;
	}
	else
		$mm['nodes'][$parent_id]['children'][] = $new_id;

	$mm['active_node'] = $new_id;

	build_map($mm);
	display($mm);

	$mm['nodes'][ $mm['active_node'] ]['title']='';
	edit_node($mm);
}



// }}}
// {{{ edit node

function show_line(&$mm, $title, $cursor, $shift)
{
	$output =
		str_pad
		(
			substr($title,$shift,$mm['terminal_width']-1),
			$mm['terminal_width']
		)
	;

	$output = substr_replace( $output, invert_off, $cursor-$shift  , 0);
	$output = substr_replace( $output, invert_on,  $cursor-$shift-1, 0);

	put(0,$mm['terminal_height'],$mm['active_node_color'].$output);
}


function edit_node(&$mm, $rewrite = false)
{
	$title = $rewrite ? '' : $mm['nodes'][ $mm['active_node'] ]['title'];
	if ($mm['active_node']==0 && $title=='root') $title='';

	$in = '';
	$cursor = strlen($title)+1;
	$shift = max( 0, $cursor - $mm['terminal_width'] );

	show_line($mm, $title, $cursor, $shift);

	while(true)
	{
		usleep(10000);
		$in = fread(STDIN, 9);

		if ($in != '')
		{
			// Esc.
			if ($in=="\033")
			{
				display($mm);
				message($mm, 'Editing cancelled');
				return;
			}

			// up arrow and home
			elseif ($in=="\033\133\101" || $in=="\033\133\110")  $cursor = 1;

			// right arrow
			elseif ($in=="\033\133\103")  $cursor = min( strlen($title)+1, $cursor+1);

			// down arrow and end
			elseif ($in=="\033\133\102" || $in=="\033\133\106")  $cursor = strlen($title)+1;

			// left arrow
			elseif ($in=="\033\133\104")  $cursor = max(1, $cursor-1);

			// ctrl+left and shift+left
			elseif ($in=="\033\133\061\073\065\104" || $in=="\033\133\061\073\062\104")
				$cursor =
					$cursor < 3
					? 1
					: max
						(
							1,
							(
								strrpos($title,' ',$cursor-strlen($title)-3) !== false
								? strrpos($title,' ',$cursor-strlen($title)-3) + 2
								: 1
							)
						);

			// ctrl+right and shift+right
			elseif ($in=="\033\133\061\073\065\103" || $in=="\033\133\061\073\062\103")
				$cursor =
					$cursor > strlen($title) -2
					? strlen($title) + 1
					: min
						(
							strlen($title)+1,
							(
								strpos($title,' ',$cursor+1) !== false
								? strpos($title,' ',$cursor+1) + 2
								: strlen($title) + 1
							)
						);

			// ctrl+backspace
			elseif ($in=="\010")
			{
				$from = mb_strrpos($title, ' ', min(1,$cursor-mb_strlen($title)-3));
				if ($from === false) $from=1;
				$title = mb_substr($title, 0, $from) . mb_substr($title,$cursor-1);
				$cursor = $from+1;
			}

			// backspace
			elseif ($in=="\177")
			{
				if ($cursor>1)
				{
					$title = substr_replace($title, '',  $cursor-2, 1);
					$cursor--;
				}
			}

			// ctrl+delete
			elseif ($in=="\033\133\63\073\065\176")
			{
				$title  = '';
				$cursor = 1;
			}

			// delete
			elseif ($in=="\033\133\63\176")
			{
				$title = substr_replace($title, '',  $cursor-1, 1);
			}

			// enter
			elseif ($in=="\012")
			{
				$title = trim($title);
				$mm['nodes'][ $mm['active_node'] ]['title'] = $title;
				$original['nodes'][ $mm['active_node'] ]['title'] = $title;
				$mm['modified'] = true;
				build_map($mm);
				display($mm);
				return;
			}

			// normal characters
			elseif (strlen($in)==1)
			{
				if ($in=="\011") $in='  ';
				$title = substr_replace($title, $in, $cursor-1, 0);
				$cursor++;
			}

			// adjusting the position and shift

			$shift = max( 0, $shift, $cursor - $mm['terminal_width'] );
			$shift = min( $shift, $cursor-1 );

			show_line($mm, $title, $cursor, $shift);
		}
	}
}



// }}}
// {{{ center active node

function center_active_node(&$mm, $only_vertically = false)
{
	$node = $mm['nodes'][ $mm['active_node'] ];

	$midx = $node['w']/2 + $node['x'];
	$midy = $node['lh']/2 + $node['y'] + $node['yo'];

	if (!$only_vertically)
		$mm['win_left'] = max(0, round( $midx - $mm['terminal_width']/2 ) );

	$mm['win_top'] = round( $midy - $mm['terminal_height']/2 );
}


// }}}
// {{{ goto's

function go_to_root(&$mm)
{
	$mm['active_node']=$mm['root'];
	display($mm, true);
}


function go_to_top(&$mm)
{
	$yid = 0;
	$y = $mm['map_height'];

	foreach ($mm['nodes'] as $id=>$node)
		if ($node['y']>=0 && $node['y']+$node['yo'] < $y)
		{
			$y = $node['y']+$node['yo'];
			$yid = $id;
		}

	$mm['active_node'] = $yid;
	display($mm, true);
}


function go_to_bottom(&$mm)
{
	$yid = 0;
	$y = 0;

	foreach ($mm['nodes'] as $id=>$node)
		if ($node['y']>=0 && $node['y']+$node['yo'] > $y)
		{
			$y = $node['y']+$node['yo']+$node['lh'];
			$yid = $id;
		}

	$mm['active_node'] = $yid;
	display($mm, true);
}



// }}}
// {{{ search

function search(&$mm)
{
	put(0,$mm['terminal_height'],$mm['active_node_color'].str_repeat(' ',$mm['terminal_width']));
	move(0,$mm['terminal_height']);

	system("stty sane");
	$mm['query'] = readline('Search for: ');
	system('stty cbreak -echo');

	if (empty($mm['query']))
	{
		display($mm);
		return;
	}

	if (!next_search_result($mm))
		previous_search_result($mm);
}

function previous_search_result(&$mm)
{
	$cy
		= $mm['nodes'][ $mm['active_node'] ]['y']
		+ $mm['nodes'][ $mm['active_node'] ]['yo']
	;

	$ny = -1;
	$nid = -1;

	foreach ($mm['nodes'] as $id=>$node)
		if
		(
			$id != 0 &&
			$node['y'] > -1 &&
			$node['y']+$node['yo'] < $cy &&
			$node['y']+$node['yo'] > $ny &&
			mb_stripos($node['title'],$mm['query'])!==false
		)
		{
			 $ny = $node['y'] + $node['yo'];
			 $nid = $id;
		}

	if ($nid<0)
		return false;

	$mm['active_node'] = $nid;
	display($mm);
}

function next_search_result(&$mm)
{
	$cy
		= $mm['nodes'][ $mm['active_node'] ]['y']
		+ $mm['nodes'][ $mm['active_node'] ]['yo']
	;

	$ny = $mm['map_height']+1;
	$nid = -1;

	foreach ($mm['nodes'] as $id=>$node)
		if
		(
			$id != 0 &&
			$node['y'] > -1 &&
			$node['y']+$node['yo'] > $cy &&
			$node['y']+$node['yo'] < $ny &&
			mb_stripos($node['title'],$mm['query'])!==false
		)
		{
			$ny = $node['y'] + $node['yo'];
			$nid = $id;
		}

	if ($nid<0)
		return false;

	$mm['active_node'] = $nid;
	display($mm);
}


// }}}
// {{{ move active node

function move_active_node_down(&$mm)
{
	if ($mm['active_node']==0) return;

	$mm['modified'] = true;

	$parent_id = $mm['nodes'][ $mm['active_node'] ]['parent'];
	$children = [];
	$now = false;

	foreach ($mm['nodes'][ $parent_id ]['children'] as $child)
	{
		if ($child!=$mm['active_node'])
			$children[] = $child;

		if ($now)
		{
			$children[] = $mm['active_node'];
			$now = false;
		}

		if ($child==$mm['active_node'])
			$now = true;
	}

	if ($now)
		$children[] = $mm['active_node'];

	$mm['nodes'][ $parent_id ]['children'] = $children;

	build_map($mm);
	display($mm);
}


function move_active_node_up(&$mm)
{
	if ($mm['active_node']==0) return;

	$mm['modified'] = true;

	$parent_id = $mm['nodes'][ $mm['active_node'] ]['parent'];
	$children = [];
	$now = false;
	$rev_children = array_reverse($mm['nodes'][$parent_id]['children']);

	foreach ($rev_children as $child)
	{
		if ($child!=$mm['active_node'])
			$children[] = $child;

		if ($now)
		{
			$children[] = $mm['active_node'];
			$now = false;
		}

		if ($child==$mm['active_node'])
			$now = true;
	}

	if ($now)
		$children[] = $mm['active_node'];

	$mm['nodes'][ $parent_id ]['children'] = array_reverse($children);

	build_map($mm);
	display($mm);
}



// }}}
// {{{ export html

function export_html(&$mm)
{

	if (empty($mm['filename']))
	{
		message($mm, "Can't export the map when it doesn't have a file name yet. Save it first.");
		return;
	}

	$file = fopen($mm['filename'].'.html', "w");

	if ($file===false)
	{
		message($mm, 'ERROR! Could not save the file');
		return;
	}


	fwrite
	(
		$file
		,'<!DOCTYPE html>'
		.'<html lang=en>'
		.'<head>'
		.'<title>'
		.$mm['nodes'][ $mm['root'] ]['title']
		.'</title>'
		.'<meta charset="UTF-8">'
    	.'<meta name=viewport content="width=device-width,initial-scale=1,user-scalable=yes">'
		.'<style>'
		.'body { background-color: #222; color: #ddd; font-family: monospace; padding: 0; font-size: 16px; }'
		.'#root {margin:10px 0}'
		.'p:before { content: "━ "; }'
		.'p, summary { padding: 8px; margin: 0; font-size: 16px; }'
		.'details, p { padding-left: 29px; border-left: 3px solid #444; font-size:16px; }'
		.'summary { margin-left: -10px; cursor: pointer; }'
		.'summary:hover, p:hover { color: #fbc531; }'
		.'details:hover, p:hover { border-color: #e1b12c; }'
		.'#source { position: absolute; bottom: 0; left: 0; padding: 5px 15px 8px 15px; margin: 100px 0 0 0; }'
		.'#source { background-color: #333; border: none; box-sizing: border-box;}'
		.'#source > summary { list-style: none; }'
		.'#source[open] { position: static; margin: 100px 0 0 0; font-size: 16px; }'
		.'#map { margin: 40px 30px; }'
		.'</style>'
		.'</head>'
		.'<body>'
		.'<div id=map>'
		.export_html_node($mm, $mm['root'])
		.'</div>'
		.'<details id=source>'
		.'<summary>This is a limited, read-only version of a mind-map created in h-m-m | view source!</summary>'
		.'<pre>'
		.encode_tree($mm,$mm['root'])
		.'</pre>'
		.'</details>'
		.'</body>'
		.'</html>'
	);

	fclose($file);

	message($mm, 'Exported as '.$mm['filename'].'.html');
	copy_to_clipboard($mm['filename'].'.html');

}


function export_html_node(&$mm, $parent_id)
{
	if ($mm['nodes'][$parent_id]['children']==[])
	{
		$output =
			"<p>"
			.$mm['nodes'][$parent_id]['title']
			."</p>";
	}
	elseif ($parent_id==$mm['root'])
	{
		$output = 
			"<div id=root>"
			.$mm['nodes'][$parent_id]['title']
			."</div>";

		foreach ($mm['nodes'][$parent_id]['children'] as $cid)
			$output .= export_html_node($mm, $cid);
	}
	else
	{
		$output =
			"<details>"
			."<summary>"
			.$mm['nodes'][$parent_id]['title']
			."</summary>";

		foreach ($mm['nodes'][$parent_id]['children'] as $cid)
			$output .= export_html_node($mm, $cid);

		$output .=
			"</details>";
	}

	return $output;
}



// }}}
// {{{ save

function save(&$mm, $new_name = false)
{
	if (empty($mm['filename']))
		$new_name = true;

	if ($new_name)
	{
		$path = exec('pwd');
		put(0,$mm['terminal_height'],$mm['active_node_color'].str_repeat(' ',$mm['terminal_width']));
		put(0,$mm['terminal_height']," $path -- new path and file name: ");

		system("stty sane");
		$mm['filename'] = trim(readline());
		system('stty cbreak -echo');

		if ($mm['filename']=='')
		{
			display($mm);
			message($mm, 'Saving cancelled');
			return;
		}

		$ext = mb_substr( $mm['filename'], mb_strrpos($mm['filename'],'.') + 1);

		if ($ext!='hmm')
			$mm['filename'] .= '.hmm';

		display($mm);
	}

	if (file_exists($mm['filename']) && !is_writable($mm['filename']))
	{
		message($mm, "ERROR! I don't have access to write into \"$mm[filename]\". Use shift+s and set another path and filename.");
		sleep(1);
		return;
	}

	$file = fopen($mm['filename'], "w");

	$mm['modified'] = false;

	if ($file===false)
	{
		message($mm, 'ERROR! Could not save the file');
		$mm['modified'] = true;
		return;
	}

	fwrite($file, encode_tree($mm, $mm['root']));
	fclose($file);

	display($mm);
	message($mm, 'Saved '.$mm['filename']);
}



// }}}
// {{{ message

function message(&$mm, $text)
{
	put
	(
		$mm['terminal_width'] - strlen($text) - 1,
		$mm['terminal_height'],
		$mm['message_color'].' '.$text.' '.reset_color
	);

	usleep(200000);
}


// }}}
// {{{ quit

function quit(&$mm)
{
	if (($mm['modified'] ?? false) === false) exit;
	message($mm, "You have unsaved changes. Save them, or use shift+Q to quit without saving.");
}


// }}}
// {{{ move_window

function move_window(&$mm)
{
	$node = $mm['nodes'][ $mm['active_node'] ];

	$x1 = max(0, $node['x'] - conn_right_len - 2);
	$x2 = $node['x'] + $node['w'] + 2;
	$y1 = max(0, $node['y'] + $node['yo'] - vertical_offset);
	$y2 = $y1 + $node['lh'] + vertical_offset*2;

	$mm['win_left'] = min( $mm['win_left'], $x1);
	$mm['win_left'] = max( $mm['win_left'], $x2 - $mm['terminal_width']);

	$mm['win_top']  = min( $mm['win_top'],  $y1);
	$mm['win_top']  = max( $mm['win_top'],  $y2 - $mm['terminal_height']);
}


// }}}
// {{{ change active node

function change_active_node(&$mm, $direction)
{
	$node = $mm['nodes'][ $mm['active_node'] ];

	// we go to the child that is closest to the parent node;
	// i.e., closest to the middle.

	if ($direction==move_right)
	{
		if ($node['is_leaf'] || ($node['collapsed'] ?? false) ) return;

		$distance = [];
		foreach ($node['children'] as $cid)
			$distance[$cid] =
				abs
				(
					+ $node['y']
					+ $node['yo']
					+ $node['lh']/2
					- $mm['nodes'][$cid]['y']
					- $mm['nodes'][$cid]['yo']
					- $mm['nodes'][$cid]['lh']/2
				)
			;

		asort($distance);

		$mm['active_node'] = array_keys($distance)[0];

		display($mm);
		return;
	}


	// no other movement applies to the root element
	if ( $mm['active_node']==0 ) return;


	// it can't be easier than moving to the left!
	if ($direction==move_left)
	{
		if ($mm['active_node']==$mm['root']) return;
		$mm['active_node'] = $node['parent'];
		display($mm);
		return;
	}


	// for up and down, we'll try to move between siblings first,
	// considering that their order is set based on their list
	// in the parent item.

	if ($direction==move_up)
	{
		$rchildren = array_reverse($mm['nodes'][ $node['parent'] ]['children']);
		foreach ($rchildren as $cid)
			if ($mm['nodes'][$cid]['y']+$mm['nodes'][$cid]['yo'] < $node['y']+$node['yo'])
			{
				$mm['active_node'] = $cid;
				display($mm);
				return;
			}
	}

	if ($direction==move_down)
		foreach ($mm['nodes'][ $node['parent'] ]['children'] as $cid)
			if ($mm['nodes'][$cid]['y']+$mm['nodes'][$cid]['yo'] > $node['y']+$node['yo'])
			{
				$mm['active_node'] = $cid;
				display($mm);
				return;
			}


	// if it's not possible to move up or down between siblings,
	// we'll measure distance and move to the nearest node.
	// because the goal is to move vertically, and also because
	// the aspect ratio of characters is not 1, there's a factor
	// for y to give it more importance. I've set the amount by
	// trial and erros and doesn't follow an exact logic. It may
	// need refinements in the future.

	$distance = [];

	foreach ($mm['nodes'] as $id=>$nd)
		if ($id != $mm['active_node'] && $nd['y']!=-1)
		{
			$dy = $nd['y'] + $nd['yo'] + $nd['lh']/2 - $node['y'] - $node['yo'] - $node['lh']/2;
			if ( ($direction==move_down && $dy>0) || ($direction==move_up && $dy<0) )
			{
				$dx = $nd['x'] + $nd['w']/2 - $node['x'] - $node['w']/2;
				$distance[$id] = pow($dy*15,2) + pow($dx,2);
			}
		}

	if ($distance==[]) return;
	asort($distance);

	$mm['active_node'] = array_keys($distance)[0];

	display($mm);
	return;
}



// }}}
// {{{ expand

function expand(&$mm, $id)
{
	$mm['nodes'][$id]['collapsed'] = false;

	foreach ($mm['nodes'][$id]['children'] as $cid)
		expand($mm, $cid);
}


function expand_all(&$mm)
{
	foreach ($mm['nodes'] as $id=>$node)
		$mm['nodes'][$id]['collapsed'] = false;

	$mm['show_logo'] = 0;
	build_map($mm);
	center_active_node($mm);
	display($mm);
}


// }}}
// {{{ encode tree

function encode_tree(&$mm, $id, $exclude_parent = false, $base = 0)
{
	if (!$exclude_parent)
		$output = str_repeat("\t",$base).$mm['nodes'][$id]['title']."\n";
	else
		$output = '';

	foreach ($mm['nodes'][$id]['children'] as $cid)
		$output .= encode_tree($mm, $cid, false, $base+1-$exclude_parent);

	return $output;
}


// }}}
// {{{ append

function append(&$mm)
{
	$mm['nodes'][ $mm['active_node'] ]['title'] .= 
		' '. str_replace("\n",' ',str_replace("\t",' ',trim(get_from_clipboard())));
	build_map($mm);
	display($mm);
}



// }}}
// {{{ paste sub-tree

function paste_sub_tree(&$mm, $as_sibling )
{

	if ($as_sibling && $mm['active_node']==$mm['root']) return;

	$mm['modified'] = true;

	if ($as_sibling)
		$parent_id = $mm['nodes'][ $mm['active_node'] ]['parent'];
	else
		$parent_id = $mm['active_node'];

	$mm['nodes'][$parent_id]['collapsed'] = false;
	$mm['nodes'][ $parent_id ]['is_leaf'] = false;

	$new_id = 1 + max(array_keys($mm['nodes']));

	$st =
		decode_tree
		(
			explode("\n",get_from_clipboard()),
			$parent_id,
			$new_id
		)
	;

	$mm['nodes'] += $st;


	// doing it like this, in case the sub-tree has more than
	// one top-level element.

	foreach ($st as $cid=>$cdata)
		if ($cdata['parent'] == $parent_id)
			$mm['nodes'][ $parent_id ]['children'][] = $cid;


	// rearranging the items only if they are pasted as siblings
	// (for pasting as children, it makes sense to have them
	// at the end)

	if ($as_sibling)
	{
		$sub_roots = [];
		foreach ($st as $cid=>$cdata)
			if ($cdata['parent']==$parent_id)
				$sub_roots[] = $cid;

		$children = [];

		foreach ($mm['nodes'][ $parent_id ]['children'] as $child_id)
		{
			if (!in_array($child_id, $sub_roots))
				$children[] = $child_id;

			if ($child_id == $mm['active_node'])
				$children = array_merge($children, $sub_roots);
		}

		$mm['nodes'][ $parent_id ]['children'] = $children;
	}


	$mm['active_node'] = $new_id;

	build_map($mm);
	display($mm);
}



// }}}
// {{{ clipboard

function copy_to_clipboard($text)
{
	if     (PHP_OS_FAMILY === "Linux")    $clip = popen('xclip -selection clipboard','wb');
	elseif (PHP_OS_FAMILY === "Windows")  $clip = popen("clip","wb");
	elseif (PHP_OS_FAMILY === "Darwin")   $clip = popen('pbcopy','wb');

	if (!isset($clip)) return;

	fwrite($clip,$text);
	pclose($clip);
}

function get_from_clipboard()
{
	if     (PHP_OS_FAMILY === "Linux")
		return shell_exec('xclip -out -selection clipboard');

	elseif (PHP_OS_FAMILY === "Windows")
		return shell_exec('powershell -sta "add-type -as System.Windows.Forms; [windows.forms.clipboard]::GetText()"');

	elseif (PHP_OS_FAMILY === "Darwin")
		return shell_exec('pbpaste');
}


// }}}
// {{{ load empty map

function load_empty_map(&$mm)
{
	if (isset($mm['nodes']))  unset($mm['nodes']);

	$mm['nodes'][0] = [ 'title'=>'X',    'is_leaf'=>false, 'children'=>[1], 'collapsed'=>false, 'parent'=>-1 ];
	$mm['nodes'][1] = [ 'title'=>'root', 'is_leaf'=>true,  'children'=>[],  'collapsed'=>false, 'parent'=>0 ];

	$mm['active_node']=1;
	$mm['root']=1;
}


// }}}
// {{{ yank

function yank_node(&$mm, $exclude_parent = false )
{
	copy_to_clipboard(encode_tree($mm, $mm['active_node'], $exclude_parent));
	message($mm, 'Item(s) are copied to the clipboard.');
}

// }}}
// {{{ delete

function delete_node(&$mm, $exclude_parent = false )
{
	if ($mm['active_node']==$mm['root']) $exclude_parent = true;

	copy_to_clipboard( encode_tree($mm, $mm['active_node'], $exclude_parent) );

	$mm['modified'] = true;

	delete_node_internal($mm, $mm['active_node'], $exclude_parent);

	build_map($mm);
	display($mm);

	message($mm, 'Item(s) are cut and placed into the clipboard.');
}


function delete_node_internal(&$mm, $active_node, $exclude_parent = false )
{

	// taking a shorter approach if it's for the whole tree

	if ($active_node==$mm['root'] && !$exclude_parent)
	{
		load_empty_map($mm);
		display($mm, true);
		return;
	}


	// if it's for a sub-tree, then...

	delete_children($mm, $active_node);

	if ($exclude_parent)
	{
		$mm['nodes'][ $active_node ]['is_leaf'] = true;
		$mm['nodes'][ $active_node ]['children'] = [];

	}
	else
	{

		$parent_id = $mm['nodes'][ $active_node ]['parent'];

		$previous_sibling = 0;
		$passed = false;
		foreach ($mm['nodes'][$parent_id]['children'] as $cid)
			if ($cid==$active_node)
			{
				if ($previous_sibling!=0) break;
				$passed = true;
			}
			else
			{
				$previous_sibling = $cid;
				if ($passed) break;
			}

		$mm['nodes'][$parent_id]['children'] =
			array_diff
			(
				$mm['nodes'][$parent_id]['children'],
				[$active_node]
			)
		;

		if (count($mm['nodes'][$parent_id]['children'])==0)
			$mm['nodes'][$parent_id]['is_leaf'] = true;

		unset($mm['nodes'][ $active_node ]);

		if ($mm['nodes'][$parent_id]['is_leaf'])
			$mm['active_node'] = $parent_id;
		else
			$mm['active_node'] = $previous_sibling;
	}
}


function delete_children(&$mm,$id)
{
	foreach (($mm['nodes'][$id]['children'] ?? []) as $cid)
	{
		delete_children($mm, $cid);
		unset($mm['nodes'][$cid]);
	}
}


// }}}
// {{{ focus

function toggle_focus(&$mm)
{
	$mm['focus_lock'] = !$mm['focus_lock'];
	
	message($mm, $mm['focus_lock'] ? 'Focus locked' : 'Focus unlocked');

	build_map($mm);
	display($mm);
}

function focus(&$mm)
{
	collapse_siblings($mm, $mm['active_node']);
	expand_siblings($mm, $mm['active_node']);
}

function collapse_siblings(&$mm, $id)
{
	if ($id <= $mm['root']) return;

	$parent_id = $mm['nodes'][$id]['parent'];

	foreach ($mm['nodes'][$parent_id]['children'] as $cid)
		if ($cid!=$id)
			$mm['nodes'][$cid]['collapsed'] = true;

	collapse_siblings($mm, $parent_id);
}


function expand_siblings(&$mm, $id)
{
	if ($mm['nodes'][$id]['is_leaf']) return;

	$mm['nodes'][$id]['collapsed'] = false;
	foreach ($mm['nodes'][$id]['children'] as $cid)
		expand_siblings($mm, $cid);
}



// }}}
// {{{ collapse

function collapse_other_branches(&$mm)
{
	if ($mm['active_node'] == $mm['root'])
		return;

	$branch = find_branch($mm, $mm['active_node']);

	foreach ($mm['nodes'][ $mm['root'] ]['children'] as $bid)
		if ($bid != $branch)
			$mm['nodes'][$bid]['collapsed'] = true;

	build_map($mm);
	center_active_node($mm);
	display($mm);
}


function collapse_inner(&$mm)
{
	foreach ($mm['nodes'][ $mm['active_node'] ]['children'] as $cid)
		$mm['nodes'][$cid]['collapsed'] = true;

	$mm['nodes'][ $mm['active_node'] ]['collapsed'] = false;

	build_map($mm);
	center_active_node($mm);
	display($mm);
}


function find_branch(&$mm, $cid)
{
	if ($mm['nodes'][$cid]['parent'] == $mm['root'])
		return $cid;
	else
		return find_branch($mm, $mm['nodes'][$cid]['parent']);
}


function collapse_all(&$mm)
{
	foreach ($mm['nodes'] as $id=>$node)
		if (!$node['is_leaf'] && $id!=0 && $id!=$mm['root'])
			$mm['nodes'][$id]['collapsed'] = true;

	$mm['active_node'] = $mm['root'];

	build_map($mm);
	center_active_node($mm);
	display($mm);
}


function collapse(&$mm, $id, $keep)
{
	if ($mm['nodes'][$id]['is_leaf']) return;

	if ($keep<=0)
		$mm['nodes'][$id]['collapsed'] = true;
	else
	{
		$mm['nodes'][$id]['collapsed'] = false;
		foreach ($mm['nodes'][$id]['children'] as $cid)
			collapse($mm, $cid, $keep-1);
	}

}



function collapse_level(&$mm, $level, $no_display = false)
{
	collapse($mm, $mm['root'], $level);

	$id_collapsed = [];
	$current = $mm['active_node'];
	while ($current != $mm['root'])
	{
		$id_collapsed[$current] = $mm['nodes'][$current]['collapsed'];
		$current = $mm['nodes'][$current]['parent'];
	}

	$id_collapsed = array_reverse( $id_collapsed, true);
	foreach ($id_collapsed as $id=>$collapsed)
		if ($collapsed)
		{
			$mm['active_node'] = $id;
			break;
		}

	if ($no_display) return;

	build_map($mm);
	center_active_node($mm);
	display($mm);
}



// }}}
// {{{ display

function display(&$mm, $force_center = false)
{
	if ($mm['focus_lock'])
	{
		focus($mm);
		build_map($mm);
	}

	if ($mm['center_lock'] || $force_center)
		center_active_node($mm);
	else
		move_window($mm);

	$mm['terminal_width']  = exec('tput cols');
	$mm['terminal_height'] = exec('tput lines');

	$blank = str_repeat(' ', $mm['terminal_width']);


	// calculating the coordinates of the active node

	$x1 =
		max
		(
			 0
			,$mm['nodes'][ $mm['active_node'] ]['x']
			-1
			-$mm['win_left']
		)
	;

	$x2 
		= $mm['nodes'][ $mm['active_node'] ]['w']
		+ $x1
		+ 2
		- ($mm['active_node']==0 && left_padding==0)
	;

	$y1 =
		max
		(
			  0
			, $mm['nodes'][ $mm['active_node'] ]['y']
			+ $mm['nodes'][ $mm['active_node'] ]['yo']
			- $mm['win_top']
		)
	;

	$y2 
		= $mm['nodes'][ $mm['active_node'] ]['lh']
		+ $y1
	;


	// building the output

	$output = '';

	for ( $y = 0 ; $y < $mm['terminal_height'] ; $y++ )
	{
		if (isset($mm['map'][$y+$mm['win_top']]))
			$line =
				mb_substr(
					$mm['map'][$y+$mm['win_top']],
					$mm['win_left'],
					$mm['terminal_width']
				)
			;
		else
			$line = $blank;

		// this one really depends on (x,y), but after this, the
		// coordinates are not reliable anymore because of the
		// added escape codes.

		if ( $y >= $y1 && $y < $y2 )
			$line =
				 mb_substr($line, 0, $x1)
				.$mm['active_node_color']
				.mb_substr($line, $x1, $x2-$x1)
				.reset_color
				.mb_substr($line, $x2)
			;
		else // styling the codes when the node is not active
			$line =
				mb_ereg_replace
				(
					'\b(.\d)\. '
					,dim_on.'\\1. '.dim_off
					,$line
				)
			;

		// styling the search results

		if ($mm['query'] ?? '' != '')
			$line =
				str_ireplace
				(
					$mm['query']
					,invert_on.$mm['query'].invert_off
					,$line
				)
			;

		// styling the collapsed symbol

		$line =
			str_replace
			(
				 ' [+]'
				,' '
				.collapsed_symbol_on
				.'[+]'
				.collapsed_symbol_off
				,$line
			)
		;

		// styling the lines

		mb_regex_encoding("UTF-8");
		mb_internal_encoding("UTF-8");
		$line =
			mb_ereg_replace
			(
				'([─-╱]+)'
				,line_on.'\\1'.line_off
				,$line
			)
		;

		// styling "???"

		$line = 
			str_replace
			(
				 '???'
				,$mm['question_color'].'???'.default_color
				,$line
			);

		// dimming {meta}s

		$line = 
			str_replace
			(
				'{'
				,dim_on.'{'
				,$line
			);

		$line = 
			str_replace
			(
				 '}'
				,'}'.dim_off
				,$line
			);

		// adding the logo

		if ($mm['show_logo']>0)
		{
			if     ($y==2)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. ' ╭────────────╮    '.default_color;
			elseif ($y==3)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. ' │     ┏━ m   │    '.default_color;
			elseif ($y==4)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. ' │ h ━━┫      │    '.default_color;
			elseif ($y==5)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. ' │     ┗━━━ m │    '.default_color;
			elseif ($y==6)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. ' ╰────────────╯    '.default_color;
			elseif ($y==7)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. '                   '.default_color;
			elseif ($y==8)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. '       hackers     '.default_color;
			elseif ($y==9)  $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. '          mind     '.default_color;
			elseif ($y==10) $line = mb_substr($line, 0, $mm['terminal_width']-19).logo_color. '           map     '.default_color;
		}

		// done!
		$output .= $line;
	}

	echo reset_page.reset_color.$output;
	$mm['show_logo']--;
}



// }}}
// {{{ monitor key presses

function monitor_key_presses(&$mm)
{
	stream_set_blocking(STDIN,false);

	while(true)
	{
		usleep(20000);
		$in = fread(STDIN, 16);
		if (empty($in)) continue;

		switch ($in)
		{

			case 'b':			expand_all($mm); break;

			case 'c':			{ center_active_node($mm); display($mm); } break;
			case 'C':			{ $mm['center_lock'] = !$mm['center_lock']; display($mm); } break;
			case ctrl_c:		quit($mm); break;

			case 'd':			delete_node($mm); break;
			case 'D':			delete_node($mm, true); break;

			case 'e':			edit_node($mm); break;
			case 'E':			edit_node($mm, true); break;

			case 'f':			{ focus($mm); build_map($mm); display($mm,true); } break;
			case 'F':			toggle_focus($mm); break;

			case 'g':			go_to_top($mm); break;
			case 'G':			go_to_bottom($mm); break;

			case 'h':			change_active_node($mm, move_left); break;

			case 'i':			collapse_other_branches($mm); break;
			case 'I':			collapse_inner($mm); break;

			case 'j':			change_active_node($mm, move_down); break;
			case 'J':			move_active_node_down($mm); break;

			case 'k':			change_active_node($mm, move_up); break;
			case 'K':			move_active_node_up($mm); break;

			case 'l':			change_active_node($mm, move_right); break;

			case 'm':			go_to_root($mm); break;

			case 'n':			next_search_result($mm); break;
			case 'N':			previous_search_result($mm); break;

			case 'o':			insert_node($mm, insert_sibling); break;
			case 'O':			insert_node($mm, insert_child); break;

			case 'p':			paste_sub_tree($mm, false); break;
			case 'P':			paste_sub_tree($mm, true); break;
			case ctrl_p:		append($mm); break;

			case 'q':			quit($mm); break;
			case 'Q':			exit; break;

			case 's':			save($mm); break;
			case 'S':			save($mm, true); break;

			case 'U':			debug($mm['nodes']); break;

			case 'v':			collapse_all($mm); break;

			case 'w':			adjust_width($mm, width_wider); break;
			case 'W':			adjust_width($mm, width_narrower); break;

			case 'x':			export_html($mm); break;

			case 'y':			yank_node($mm); break;
			case 'Y':			yank_node($mm, true); break;

			case 'Z':			adjust_spacing($mm, spacing_wider); break;
			case 'z':			adjust_spacing($mm, spacing_narrower); break;

			case arr_down:		change_active_node($mm, move_down); break;
			case arr_right:		change_active_node($mm, move_right); break;
			case arr_up:		change_active_node($mm, move_up); break;
			case arr_left:		change_active_node($mm, move_left); break;

			case '1':			collapse_level($mm, 1); break;
			case '2':			collapse_level($mm, 2); break;
			case '3':			collapse_level($mm, 3); break;
			case '4':			collapse_level($mm, 4); break;
			case '5':			collapse_level($mm, 5); break;
			case '6':			collapse_level($mm, 6); break;
			case '7':			collapse_level($mm, 7); break;
			case '8':			collapse_level($mm, 8); break;
			case '9':			collapse_level($mm, 9); break;

			case '~':			go_to_root($mm); break;
			case ' ':			toggle($mm); break;
			case '/':			search($mm); break;

			case "\n":			insert_node($mm, insert_sibling); break;
			case "\t":			insert_node($mm, insert_child); break;

		}

		// move(1,1);
		// for ($i=0; $i<strlen($in); $i++)
		//   echo base_convert(ord($in[$i]),10,8).' ';
		// echo '                    ';
	}
}

function check_required_extensions(): bool
{
    if (!function_exists('pcntl_signal')) {
        echo 'Required extension pcntl is not enabled; please check your php installation!';
        echo PHP_EOL;
        return false;
    }

    if (!function_exists('mb_strlen')) {
        echo 'Required extension mbstring is not enabled; please check your php installation!';
        echo PHP_EOL;
        return false;
    }

    return true;
}

// }}}
// {{{ main

set_up_screen();
load_settings($mm);
clear();
load_file($mm);

collapse_all($mm);
collapse_level($mm, $mm['initial_depth'], true);

build_map($mm);
center_active_node($mm);
display($mm);
monitor_key_presses($mm);


// }}}