#!/usr/bin/php
<?php

/**
 * Copyright (2017-2018) The shunt_tags author(s)
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

// TODO kioclient integration
 
error_reporting(E_ALL);
ini_set('display_errors', 'On');

function fixup($input) {
	
	$tmp = $input;
	
	$extension = substr($tmp, strlen($tmp) - 4);
	$tmp = substr($tmp, 0, strlen($tmp) - 4);
	
	// Some files using period instead of space
	if (strpos($tmp, ' ') === false) {
		// Except when the period is real:
		//  - in a number string like EP##.#
		//  - ellipsis (...)
		// Find all the \d.\d and store indexes
		$matches = [];
		preg_match_all('~\d\.\d~', $tmp, $matches, PREG_OFFSET_CAPTURE);
		$match_ellipsis = [];
		preg_match_all('~\.\.\.+~', $tmp, $match_ellipsis, PREG_OFFSET_CAPTURE);
		
		// Replace
		$tmp = str_replace('.', ' ', $tmp);
		
		// Restore indexes
		foreach($matches[0] as $match) {
			$tmp[$match[1] + 1] = '.';
		}
		
		foreach($match_ellipsis[0] as $match) {
			$tmp[$match[1] + 1] = '.';
			$tmp[$match[1] + 2] = '.';
			$tmp[$match[1] + 3] = '.'; // although we matched even longer sequences...
		}
	}
	
	$fixed_point_iterate = function($tmp, $cb) {
		$seen = [];
		do {
			$seen[$tmp] = true;
			$tmp = $cb($tmp);
			
		} while (! array_key_exists($tmp, $seen));
		return $tmp;
	};

	// Some files using underscore instead of space
	// Except - preserve "G_P", that's a known sub group
	// Iterate until fixed point
	$tmp = $fixed_point_iterate($tmp, function($tmp) {
		return preg_replace_callback('~(._.)~', function($matches) {
			if ($matches[1] == "G_P") {
				return $matches[1]; // allow this case
			} else {
				return $matches[1][0].' '.$matches[1][2];
			}
		}, $tmp);
	});
	
	// Wrap loose tags
	$tmp = preg_replace('~\b((?:gg\-|UTW\-)?THORA)\b~', ' [\1] ', $tmp);
	$tmp = preg_replace('~\bXVID\b~', ' [XVID] ', $tmp);
	$tmp = preg_replace('~\b1080p\b~', ' [1080p] ', $tmp);
	$tmp = preg_replace('~([^p])v2\b~i', '\1 [v2] ', $tmp); // They could be part of the episode number - pull them out - BUT don't pull out "PV2" 
	$tmp = preg_replace('~([^p])v3\b~i', '\1 [v3] ', $tmp);
	$tmp = preg_replace('~([^p])v4\b~i', '\1 [v4] ', $tmp);

	if (strpos($tmp, '[a-s]') !== false) {
		// This sub group puts a team member username in the filename 
		$tmp = preg_replace('~\\b(rs2|pball)\\b~', '[\1]', $tmp);
	}
	
	// Remove nesting
	$drop_nested_tags = function($tmp) {
		$depth = 0;
		$ret = '';
		for ($i = 0; $i < strlen($tmp); ++$i) {
			if ($tmp[$i] == '[') {
				$depth += 1;
				if ($depth === 1) {
					$ret .= '[';
				}
			} else if ($tmp[$i] == ']') {
				$depth -= 1;
				if ($depth === 0) {
					$ret .= ']';
				}
			} else {
				$ret .= $tmp[$i];
			}
		}
		return $ret;
	};
	$tmp = $drop_nested_tags($tmp);
	
	// Convert round brackets to square brackets only if they contain tags	
	$tmp = str_replace(' ASS(EN)', '', $tmp); // messes with the (=>[, not an important tag anyway
	$tmp = preg_replace('~\(([^\)]*(?:G_P|B-A|R2J|NakamaSub|720|1080|264|BD|DVD|AAC|AC3|Dual Audio|XVID|divx|[A-F0-9]{8})[^\)]*)\)~i', '[\1]', $tmp);
	
	// Work around nightmare sub group name
	$tmp = str_replace('[Saiyan]BrollY', 'SaiyanBrollY', $tmp);
	
	// Move tags from front to end
	if ($tmp[0] == '[') {
		$tmp = preg_replace('~^(\[.+?\])\s?([^\[]+)(.*)$~', '\2 \1 \3', $tmp);
	}
	
	// Cleanup
	$cleanup = [
		'][' => ' ',
		'] [' => ' ',
		'] - [' => ' ',
		'  ' => ' ',
		' - [' => '[',
		'()' => '',
		'( )' => '',
		'720x480' => '480p',
		'1280x720' => '720p',
		'1920x1080' => '1080p',
		'BluRay' => 'BD',
		'Blu-Ray' => 'BD',
		'BDrip' => 'BD',
		'bd-rip' => 'BD',
		'Clean Ending' => 'NCED',
		'Clean Opening' => 'NCOP',
		'Creditless Opening' => 'NCOP',
		'Creditless Ending' => 'NCED',
		'Creditless OP' => 'NCOP',
		'Creditless ED' => 'NCED',
	];
	$tmp = $fixed_point_iterate($tmp, function($tmp) use ($cleanup) {
	
		// Clean up tags
		$tmp = str_replace(array_keys($cleanup), array_values($cleanup), $tmp);
		
		// Move tags from middle to end
		$tmp = preg_replace('~([^\[\]]+)(\[[^\]]+?\])([^\[\]]+)~', '\1\3\2', $tmp);
		
		return $tmp;
	});
	
	// Cleanup commas inside tags ( [720p,Bluray] => [720p Bluray] )
	$tmp = preg_replace_callback('~\[(.+)\]~', function($matches) { return str_replace(',', ' ', $matches[0]); }, $tmp);
	
	// Remove trailing spaces before file extension
	$tmp = trim($tmp); //$tmp = preg_replace('~\s+(\..{3})$~', '\1', $tmp);
		
	// Episode numbers
	// #xx, Exx, EPxx, Ep.XX, Ep. XX, EXXv2... but not a year like 1970 or 2013
	
	$add_episode_hyphen_if_not_year = function($matches) {
		$is_year = (intval($matches[1]) > 1000);
		if ($is_year) {
			return $matches[0]; // as-is
		} else {
			return ' - '.$matches[1];
		}
	};
	
	$tmp = preg_replace_callback('~ (?:#|E(?:P(?:\. ?)?)?)(\d[\dv]*)\b~i', $add_episode_hyphen_if_not_year, $tmp);
	
	$got_episode_number = function($tmp) {
		if (preg_match('~ \- S?[\d]+~', $tmp)) {
			return true;
		}
		
		// Allow "Lesson XX" (GTO format), "OVA XX", "ONA XX"
		if (preg_match('~ \- (?:Lesson|OVA|ONA) [\d]+~', $tmp)) {
			return true;
		}
		
		return false;
	};
	
	if (! $got_episode_number($tmp)) {
		$tmp = preg_replace_callback('~ episode (\d+)~', function($matches) { return sprintf(' - %02d', $matches[1]); }, $tmp);
	}
		
	if (! $got_episode_number($tmp)) {
		// Last ditch - replace any lone 1+ digit number (but also support v2 and 0.5 episodes)
		$tmp = preg_replace_callback('~ (\d\d*(?:[v\.]\d\d?)?)\b~', $add_episode_hyphen_if_not_year, $tmp); 
	}
	
	// Two-digit episode numbers even for 0.5 and 6.75 episodes
	$tmp = preg_replace('~ - (\d)\b~', ' - 0\1', $tmp);
	$tmp = preg_replace('~ - (\d\.\d\d?)\b~', ' - 0\1', $tmp);
	
	// Anything after the episode number but before the tag is an episode title
	// Enforce dash between them if it's not there already
	$tmp = preg_replace('~ - (\d[\dv\.]+) ([^\[\-\(])~', ' - \1 - \2', $tmp);
	
	// Fix double dashes
	//$tmp = str_replace('- -', '-', $tmp);
	
	// Remove unnecessary quotes
	$tmp = preg_replace("~ - '(.+?)' ([-\\[])~", ' - \1 \2', $tmp);
	
	// From the first [ to the last ], no other [] should appear within, and there should be no extraneous spaces
	$tmp = preg_replace_callback('~^([^\[]*?)\[(.+)\]~', function($matches) {
		return $matches[1].'['.trim(str_replace(['[', ']', '  ', ' - ', '- ', '.'], [' ', ' ', ' ', ' ', ' ', ' '], $matches[2])).']';
	}, $tmp);
	
	// There's always a space before the tag
	$tmp = preg_replace('~([^ ])\[~', '\1 [', $tmp);
	
	// Title-case for sections (delimited by -/~)
	$fix_title_cases = function($str) {

		// First section: all words titlecase except the/and/or unless first word
		$titlecase = function($str) {
			$words = explode(" ", $str);
			for($i = 0; $i < count($words); ++$i) {
				if (strlen($words[$i]) == 0) {
					continue;
				}

				if (
					$i == 0 ||
					!in_array($words[$i], ['and', 'or', 'of', 'on', 'the', 'in', 'no', 'a'])
				) {
					$words[$i][0] = strtoupper($words[$i][0]);
				}
			}
			return implode(" ", $words);
		};

		// Second section: enforce first character uppercase if not already
		$weaktitlecase = function($str) {
			if (!ctype_upper($str[0])) {
				$str[0] = strtoupper($str[0]);
			}
			return $str;
		};

		// Only process up to the first [ (if one exists)
		$spos = strpos($str, '[');
		$consider = substr($str, 0, $spos);

		$sections = preg_split('~( - | \~ )~', $consider, -1, PREG_SPLIT_DELIM_CAPTURE);
		#var_dump($sections);
		#die();
		for($i = 0; $i < count($sections); $i += 2) {
			if (strlen($sections[$i]) == 0) {
				continue;
			}

			if ($i == 0) {
				$sections[$i] = $titlecase($sections[$i]);
			} else {
				$sections[$i] = $weaktitlecase($sections[$i]);
			}
		}
		return implode("", $sections).substr($str, $spos);
	};
	$tmp = $fix_title_cases($tmp);

	// Special fixups:

	// Fixup [Saiyan]BrollY, that's a sub group
	$tmp = str_replace('SaiyanBrollY', '[Saiyan]BrollY', $tmp);
	
	// Fixup terrible case with [m.3.3.w] sub group being detected as an episode number
	// It would be preferable for this to not happen in the first place
	$tmp = str_replace('m 03 3 w', 'm.3.3.w', $tmp);
	
	// Fixup anime_fin, that's a sub group
	$tmp = str_replace('[anime fin', '[anime_fin', $tmp);
	
	// Fixup "No. 6", that's a show title
	$tmp = str_replace('No. - 06 - ', 'No. 6 - ', $tmp);
	
	// Fixup "Oedo 808", that's a show title
	$tmp = str_replace('Oedo - 808', 'Oedo 808', $tmp);
	
	// Fixup "h264-720p"
	$tmp = str_replace("h264-", "h264 ", $tmp);
	
	// Reinstate file extension
	$tmp = $tmp.$extension;
	
	// Done
	return $tmp;
}

function tests() {
	$tests = [
		   "[a-s]_you're_under_arrest_-_07_-_strike_man_~_defender_of_justice__rs2_[54AEE83C].mkv"
		=> "You're Under Arrest - 07 - Strike man ~ Defender of justice [a-s rs2 54AEE83C].mkv"
		,
		   "[a-s]_a_certain_scientific_railgun_-_17_-_tsuzuri's_summer_vacation__pball_[1080p_bd-rip][2C2AE93D].mkv"
		=> "A Certain Scientific Railgun - 17 - Tsuzuri's summer vacation [a-s pball 1080p BD 2C2AE93D].mkv"
		,
		   '[gg]_Valvrave_the_Liberator_-_12_[F9F3F5C5].mkv'
		=> 'Valvrave the Liberator - 12 [gg F9F3F5C5].mkv'
		,
		   'Poyopoyo Kansatsu Nikki - 16 [HorribleSubs][FShahid][46B9A7B5].mkv'
		=> 'Poyopoyo Kansatsu Nikki - 16 [HorribleSubs FShahid 46B9A7B5].mkv'
		,
		   '[AHQ] Gundam Seed - 42 - Lacus Strikes.mkv'
		=> 'Gundam Seed - 42 - Lacus Strikes [AHQ].mkv'
		,
		   '[Frenchies-Mux]_True_Mazinger_Impact!_Chapter_Z_03_(720p)[7EBA0032].mkv'
		=> 'True Mazinger Impact! Chapter Z - 03 [Frenchies-Mux 720p 7EBA0032].mkv'
		,
		   '[RUELL-Next] Natsume Yuujinchou S4 EP09 (BD 1280x720 x264 AAC ASS(EN)) [BE846FE4].mkv'
		=> 'Natsume Yuujinchou S4 - 09 [RUELL-Next BD 720p x264 AAC BE846FE4].mkv'
		,
		   '[Nubles] Space Battleship Yamato 2199 (2012) episode 21 [720p 10 bit AAC][C6884514].mkv'
		=> 'Space Battleship Yamato 2199 (2012) - 21 [Nubles 720p 10 bit AAC C6884514].mkv',
		
		   '[Nubles] Space Battleship Yamato 2199 (2012) episode 8 (720p 10 bit AAC).mkv'
		=> 'Space Battleship Yamato 2199 (2012) - 08 [Nubles 720p 10 bit AAC].mkv'
		,
		   "Salaryman_Kintaro_-_15_[A-Et]_(0F83C5FF).mkv"
		=> "Salaryman Kintaro - 15 [A-Et 0F83C5FF].mkv"
		,
		   '[Elysium]Shiki.EP15(BD.720p.Hi10P.AAC)[0437F1F6].mkv'
		=> 'Shiki - 15 [Elysium BD 720p Hi10P AAC 0437F1F6].mkv'
		,
		   '[Elysium]Shiki.EP20.5(BD.720p.Hi10P.AAC)[BFE4B6BF].mkv'
		=> 'Shiki - 20.5 [Elysium BD 720p Hi10P AAC BFE4B6BF].mkv'
		,
		   '(G_P) Phoenix 03(x264)(17A173E7).mkv'
		=> 'Phoenix - 03 [G_P x264 17A173E7].mkv'
		,
		   '[Commie] Teekyuu - OVA 1 [BD 720p AAC] [58F19BF2].mkv'
		=> 'Teekyuu - OVA 1 [Commie BD 720p AAC 58F19BF2].mkv'
		,
		   '[Kametsu]_Your_Lie_in_April_11v2_[Blu-Ray][720p][Hi10][588D1B1F].mkv'
		=> 'Your Lie in April - 11 [Kametsu v2 BD 720p Hi10 588D1B1F].mkv'
		,
		   'Patlabor.TV.38v2.(Dual.Audio).XVID.[AM].ogm'
		=> 'Patlabor TV - 38 [v2 Dual Audio XVID AM].ogm'
		,
		   'Laputa_Castle_in_the_Sky_(1986)_[720p,BluRay,x264]_-_THORA.mkv'
		=> 'Laputa Castle in the Sky (1986) [720p BD x264 THORA].mkv'
		,
		   '[HorribleSubs] 91 Days - 7.5 [720p].mkv'
		=> '91 Days - 07.5 [HorribleSubs 720p].mkv'
		,
		   'Code_Geass_Ep01_The_Day_the_Demon_was_Born_[720p,BluRay,x264]_-_gg-THORA.mkv'
		=> 'Code Geass - 01 - The Day the Demon was Born [720p BD x264 gg-THORA].mkv'
		,
		   '[Z-Z] Blood + Ep. 01 - First Kiss.mkv'
		=> 'Blood + - 01 - First Kiss [Z-Z].mkv'
		,
		   'Code_Geass_Picture_Drama_6.75_[720p,BluRay,x264]_-_gg-THORA v2.mkv'
		=> 'Code Geass Picture Drama - 06.75 [720p BD x264 gg-THORA v2].mkv'
		,
		   'Baccano - 14 (OVA).mkv'
		=> 'Baccano - 14 (OVA).mkv' // no change expected
		,
		   '[Jarzka] Cromartie High School 05 - Sentimental Bus [480p 10bit X264 DVD Dual-Audio] [A63E3F52].mkv'
		=> 'Cromartie High School - 05 - Sentimental Bus [Jarzka 480p 10bit X264 DVD Dual-Audio A63E3F52].mkv'
		,
		   'Area 88 OVA - 01 [Blitz flawed 5EF8A0E2].mkv'
		=> 'Area 88 OVA - 01 [Blitz flawed 5EF8A0E2].mkv' // no change expected
		,
		   '[m.3.3.w]_Genshiken_Nidaime_no_Roku_-_OAD_[v0][A6EF7886].mkv'
		=> 'Genshiken Nidaime no Roku - OAD [m.3.3.w v0 A6EF7886].mkv'
		,
		   'Gintama - 21 [Rumbel XviD 3E184082 v2].avi'
		=> 'Gintama - 21 [Rumbel XviD 3E184082 v2].avi' // no change expected
		,
		   'Patlabor 1 (1989) [THORA].mkv'
		=> 'Patlabor - 01 (1989) [THORA].mkv'
		,
		   '[ACX]Immortal_Grand_Prix_-_01_-_Time_to_Shine_[[Saiyan]BrollY]_[7A73D794].mkv'
		=> 'Immortal Grand Prix - 01 - Time to Shine [ACX [Saiyan]BrollY 7A73D794].mkv'
		,
		   '[AnimeNOW] Danshi Koukousei no Nichijou - OP (BD 1280x720 10-bit x264 AAC) [429C5783].mkv'
		=> 'Danshi Koukousei no Nichijou - OP [AnimeNOW BD 720p 10-bit x264 AAC 429C5783].mkv'
		,
		   '(B-A)Great_Teacher_Onizuka_-_Lesson_01_(6F68CC7E).mkv'
		=> 'Great Teacher Onizuka - Lesson 01 [B-A 6F68CC7E].mkv'
		,
		   "[OZC]Mobile Suit Gundam - The 08th MS Team Blu-ray Box E01 'War for Two' [720p].mkv"
		=> "Mobile Suit Gundam - The 08th MS Team Blu-ray Box - 01 - War for Two [OZC 720p].mkv"
		,
		   'Gundam SEED Destiny 14[AEF97E04].avi'
		=> 'Gundam SEED Destiny - 14 [AEF97E04].avi'
		,
		   'Gundam SEED Destiny 1.avi'
		=> 'Gundam SEED Destiny - 01.avi'
		,
		   '[Exiled-Destiny]_Girls_Bravo_Ep01v3_[R2_Video]_(94D81F22).mkv'
		=> 'Girls Bravo - 01 [Exiled-Destiny v3 R2 Video 94D81F22].mkv'
		,
		   '[ACX]Immortal_Grand_Prix_-_11_-_And_Then_..._[[Saiyan]BrollY]_[50EC0CBC].mkv'
		=> 'Immortal Grand Prix - 11 - And Then ... [ACX [Saiyan]BrollY 50EC0CBC].mkv'
		,
		   '[DmonHiro] Kyousougiga #00v2 - Recap (BD, 720p) [47986C5A].mkv'
		=> 'Kyousougiga - 00 - Recap [DmonHiro v2 BD 720p 47986C5A].mkv'
		,
		   'Legend.of.the.Galactic.Heroes.110.[x264.720p.10bit.AAC].mkv'
		=> 'Legend of the Galactic Heroes - 110 [x264 720p 10bit AAC].mkv'
		,
		   'Minipato OVA [anime_fin 2906CE7D].avi'
		=> 'Minipato OVA [anime_fin 2906CE7D].avi' // no change expected
		,
		   '[Doki] No. 6 - NCOP (1280x720 h264 BD AAC) [0A4A8A9B].mkv'
		=> 'No. 6 - NCOP [Doki 720p h264 BD AAC 0A4A8A9B].mkv'
		,
		   '[RG Genshiken] Gintama - Creditless Ending ep.088-095, 097-099 [DVDRip 704x528 x264 PCM].mkv'
		=> 'Gintama - NCED - 088-095, 097-099 [RG Genshiken DVDRip 704x528 x264 PCM].mkv'
		,
		   'Cyber City Oedo 808 - Art Gallery (XviD)[anibalance][4C7F6645].mkv'
		=> 'Cyber City Oedo 808 - Art Gallery [XviD anibalance 4C7F6645].mkv'
		,
		   'Death Billiards (Anime Mirai 2013) [gg 29BE9711].mkv'
		=> 'Death Billiards (Anime Mirai 2013) [gg 29BE9711].mkv' // no change expected
		,
		   'King of Thorn (Ibara no Ou) [Harth-QTS-v2].mkv'
		=> 'King of Thorn (Ibara no Ou) [Harth-QTS v2].mkv'
		,
		   'Lupin III - [fong] Lupin III - Kutabare! Nostradamus [BDrip.720p.10bit.DualAudio].mkv'
		=> 'Lupin III Lupin III - Kutabare! Nostradamus [fong BD 720p 10bit DualAudio].mkv'
		,
		   "[JoJo]_Jojo's_Bizarre_Adventure_-_20_[BD][h264-720p_AAC][054C181A].mkv"
		=> "Jojo's Bizarre Adventure - 20 [JoJo BD h264 720p AAC 054C181A].mkv"
		,
		   "Ghost in the Shell Arise - 04 [THORA 1080p].mkv"
		=> "Ghost in the Shell Arise - 04 [THORA 1080p].mkv" // no change expected
		,
		   "Cowboy_Bebop_Knockin'_on_Heaven's_Door_(2001)_[1080p,BluRay,x264,flac]_-_THORA.mkv"
		=> "Cowboy Bebop Knockin' on Heaven's Door (2001) [1080p BD x264 flac THORA].mkv"
		,
		   '[EG]Turn-A_Gundam_01_V2[E8F575A6].mkv'
		=> 'Turn-A Gundam - 01 [EG v2 E8F575A6].mkv'
		,
		   'PV2.mp4'
		=> 'PV2.mp4' // no change expected
		,
		   '[DmonHiro] Kyousougiga - Clean Ending (v2) (BD, 720p) [F1849601].mkv'
		=> 'Kyousougiga - NCED [DmonHiro v2 BD 720p F1849601].mkv'
		,
	];
	
	$any_failures = false;
	
	foreach($tests as $input => $expected) {
		$result = fixup($input);
		if ($result !== $expected) {
			echo "Test failed\n";
			echo "  Input    : $input \n";
			echo "  Got      : $result \n";
			echo "  Expected : $expected \n";
			$any_failures = true;
		}
	}
	
	if (! $any_failures) {
		echo "All tests passed.\n";
	}
	
	return !$any_failures;
}

function findFilesNeedingReplacement($basedir, $recursive, $quiet) {
	
	$iterator = $recursive
		? new RecursiveIteratorIterator(new RecursiveDirectoryIterator($basedir), RecursiveIteratorIterator::SELF_FIRST)
		: new DirectoryIterator($basedir)
	;
	
	if (! $quiet) {
		echo "Scanning...";
	}
	$ct = 0;

	$replacements = [];

	foreach ($iterator as $file) {
		if (! $quiet) {
			if (++$ct % 100 == 0) {
				echo ".";
			}
		}
		
		if ($file->isDir()) {
			continue;
		}
		
		$fname = $file->getFilename();
		
		if (! preg_match("~\\.(?:mkv|mp4|avi|ogm|ogv)$~", $fname)) {
			continue;
		}
		
		$new = fixup($fname);
		if ($new !== $fname) {
			$replacements[] = [
				$file->getPath(),
				$fname,
				$new
			];
		}
		
	}

	if (! $quiet) {
		echo "\n";
	}
	
	// Alphabetic sort
	usort($replacements, function($a, $b) {
		$pc = strcasecmp($a[0], $b[0]);
		if ($pc !== 0) {
			return $pc;
		}
		
		return strcasecmp($a[1], $b[1]);
	});
	
	return $replacements;
}

function displayReplacementsTable(array $replacements) {
	$max_length = 10;
	foreach($replacements as $r) {
		$display_width = mb_strwidth($r[1], 'UTF-8'); // strlen($r[1])
		$max_length = max($max_length, $display_width);
	}
	
	foreach($replacements as $r) {
		echo sprintf("%-{$max_length}s   %s\n", $r[1], $r[2]);
	}
}

function applyReplacements(array $replacements, $echo_undo_script) {
	$any_errors = false;
	
	if ($echo_undo_script) {
		echo "#!/bin/bash\nset -eu\n\n";
	}
	
	foreach($replacements as $r) {
		$src_path = $r[0].'/'.$r[1];
		$dest_path = $r[0].'/'.$r[2];
		
		if (file_exists($dest_path)) {
			if ($echo_undo_script) {
				echo "# ";
			}
			echo "Skipping {$r[1]} (destination path already exists)\n";
			$any_errors = true;
			continue;
		}
		
		rename($src_path, $dest_path);
		if ($echo_undo_script) {
			echo "mv ".escapeshellarg($dest_path)." ".escapeshellarg($src_path)."\n";
		}
	}
	
	return $any_errors;
}

function usage() {
	echo <<<EOD
Usage:
  shunt_tags [OPTIONS]
  
Options:
  -y  --accept                  Apply updates without prompting. (false)
  -d  --directory DIR           Set directory. (pwd)
      --display table|dump|none Choose display mode. ('table')
  -n  --dry-run                 Display proposed updates and exit. (false)
      --help, --usage           Display this message
      --interactive             Prompt whether to apply updates. (true)
  -q  --quiet                   Quiet mode hides scanning progress. (false)
  -qq --quiet2                  Equivalent to "-q --display none"
  -r  --recursive               Apply to subdirectories. (false)
      --test-suite              Run test suite and exit  
      --undo                    Display an undo script

EOD;
	die(0);
}

function main($argv) {
	
	$recursive = false;
	$directory = getcwd(); // __DIR__;
	$dryrun = false;
	$shouldprompt = true;
	$displaymode = "table";
	$quiet = false;
	$echo_undo_script = false;
	
	for($i = 0; $i < count($argv); ++$i) {
		if ($argv[$i] == "-r" || $argv[$i] == "--recursive") {
			$recursive = true;
			
		} else if ($argv[$i] == "-d" || $argv[$i] == "-directory") {
			$directory = $argv[++$i];
			
		} else if ($argv[$i] == "--test-suite") {
			die(tests() ? 0 : 1);
			
		} else if ($argv[$i] == "--interactive") {
			$shouldprompt = true;
			
		} else if ($argv[$i] == "-y" || $argv[$i] == "--accept") {
			$shouldprompt = false;
			
		} else if ($argv[$i] == "-n" || $argv[$i] == "--dry-run") {
			$dryrun = true;
			
		} else if ($argv[$i] == "--display") {
			$displaymode = $argv[++$i];
			
		} else if ($argv[$i] == "-q" || $argv[$i] == "--quiet") {
			$quiet = true;
			
		} else if ($argv[$i] == "-qq" || $argv[$i] == "--quiet2") {
			$quiet = true;
			$displaymode = "none";
			
		} else if ($argv[$i] == "--undo") {
			$echo_undo_script = true;
			
		} else if ($argv[$i] == "--help" || $argv[$i] == "--usage") {
			usage();
			
		} else {
			echo "Unknown argument {$argv[$i]} (try --help)\n";
			die(1);
		
		}
	}
	
	$replacements = findFilesNeedingReplacement($directory, $recursive, $quiet);
	
	if (count($replacements) === 0) {
		echo "No candidates for renaming.\n";
		die(0);
	}
		
	switch($displaymode) {
		case "table": {
			displayReplacementsTable($replacements);
		} break;
		
		case "dump": {
			var_dump($replacements);
		} break;
		
		case "none": break;
		
		default: {
			echo "Unknown display mode {$displaymode}\n";
			die(1);
		}
	}
	
	if ($dryrun) {
		die(0);
	}
	
	if ($shouldprompt) {
		echo "Apply changes? [y/N] > ";
		$line = trim(fgets(STDIN));
		if ($line !== "y") {
			echo "Not applying changes.\n";
			die(0);
		}
	}
	
	$any_errors = applyReplacements($replacements, $echo_undo_script);
	
	die($any_errors ? 1 : 0);
}

main(array_slice($_SERVER['argv'], 1));