<?php

/*
	This script generates a LaTeX include file that contains macros specifying
	the date ranges for every week of the three main teaching periods through
	the year (i.e., summer school, first semester, second semester). Simply set
	the configuration as outlined below and run the script, saving the output
	in a suitable location, ideally only once for all papers. A good spot would
	be somewhere in the TeX search path.
*/

// LaTeX macro names can't include numbers, so we have to convert them to words.
include( "Numbers/Words.php" );

/*
	Teaching period configuration. It's easily extensible to a new teaching
	period simply by adding a new specification for that period. The key should
	be valid as a LaTeX macro name (i.e., no spaces, no digits, no punctuation).
	The components of each period specification are:
	
	start_date:		The date of the first day of the first week of the period.
		
	num_weeks:		The total number of weeks in the period, /including/ any
					breaks (e.g., 13 teaching weeks plus 1 week mid-semester
					break = 14 weeks).
		
	break_weeks:	A list of breaks that occur during the teaching period.
					Each is specified by the start (break_start) and end
					(break_end) week. If a break is only one week long, then
					break_start and break_end should be equal. If there are no
					breaks in the teaching period, include a single break
					specification with both break_start and break_end set to zero.
					
					The list should ideally be in ascending order, but the
					script doesn't assume this and sorts the list anyway. Weeks
					are numbered by absolute calendar week number (i.e., week
					1 is the first calendar week of the year). The date of the
					first Monday of the year is stored in $first_monday below
					(everything is Monday-indexed).
*/
$first_monday = new DateTime( "2012-12-31" );

$periods = array(
	'SummerSchool' => array(
		'first_week'  => 2,
		'last_week'   => 7,
		'break_weeks' => array(
			array(
		    	'break_starts' => 0,
		        'break_ends'  => 0,
		    ),
		),
	),
	'SemesterOne' => array(
		'first_week'  => 9,
		'last_week'   => 22,
		'break_weeks' => array(
			array(
		    	'break_starts' => 14,
		        'break_ends'  => 14,
		    ),
		),
	),
	'SemesterTwo' => array(
		'first_week'  => 28,
		'last_week'   => 41,
		'break_weeks' => array(
			array(
		    	'break_starts' => 35,
		        'break_ends'  => 35,
		    ),
		),
	),
	'FullYear' => array(
		'first_week'  => 9,
		'last_week'   => 41,
		'break_weeks' => array(
			array(
		    	'break_starts' => 23,
		        'break_ends'  => 27,
		    ),
			array(
		    	'break_starts' => 15,
		        'break_ends'  => 15,
		    ),
			array(
		    	'break_starts' => 35,
		        'break_ends'  => 35,
		    ),
		),
	),
);


// A couple of handy date intervals: four days to the end of the current week,
// and seven days to the start of next week.
$plus_four_days = new DateInterval( 'P4D' );
$plus_seven_days = new DateInterval( 'P7D' );

$numwords = new Numbers_Words();

foreach ( $periods as $period_name => $period_data )
{
	$week_start = clone( $first_monday );
	// Jump forward the correct number of weeks to the start of the teaching period.
	$week_start->add( new DateInterval( sprintf( "P%dD", ( $period_data['first_week'] - 1 ) * 7 ) ) );
	
	$week_number = 0;
	$num_breaks = 0;
	
	// Grab the first break week off the front of the list.
	sort( $period_data['break_weeks'] );
	$break_week = array_shift( $period_data['break_weeks'] );
	
	for ( $week = $period_data['first_week']; $week <= $period_data['last_week']; $week++ )
	{
		$week_end = clone( $week_start );
		$week_end->add( $plus_four_days );
		
		// Handle break weeks.
		if ( ( $week >= $break_week['break_starts'] ) && ( $week <= $break_week['break_ends'] ) )
		{
			if ( $week == $break_week['break_starts'] )
			{
				$num_breaks++;
				
				// Work out the end date of the break.
				$break_end = clone( $week_start );
				// Note: +4 days to get to Friday.
				$break_end->add(
					new DateInterval(
						sprintf( "P%dD",  ( ( $break_week['break_ends'] - $break_week['break_starts'] ) * 7 ) + 4 )
					)
				);
				
				// Output macro for inclusion in paper calendar.
				printf(	"\\newcommand{\\%sBreak%s}{%s--%s}\n",
					$period_name,
					str_replace( "-", "", ucfirst( $numwords->toWords( $num_breaks ) ) ),
					// If the week start and end dates are in the same month, we only
					// need to output the month name once.
					( $week_start->format( 'n' ) == $break_end->format( 'n' ) ) ? $week_start->format( 'j' ) : $week_start->format( 'j M' ),
					$break_end->format( 'j M' )
				);
			} // if current week == first week of break
			
			if ( $week == $break_week['break_ends'] )
			{
				// Grab the next break week off the front of the list.
				$break_week = array_shift( $period_data['break_weeks'] );
			} // if current week == last week of break
		} // if current week is a break week
		else
		{
			$week_number++;
			
			// If the week start and end dates are in the same month, we only
			// need to output the month name once.
			if ( $week_start->format( 'n' ) == $week_end->format( 'n' ) )
			{
				// Output macro for inclusion in paper calendar.
				printf(	"\\newcommand{\\%sWeek%s}{%s--%s \\\\ %s}\n",
					$period_name,
					str_replace( "-", "", ucfirst( $numwords->toWords( $week_number ) ) ),
					$week_start->format( 'j' ),
					$week_end->format( 'j' ),
					$week_end->format( 'M' )
				);
			} // if same month
			else
			{
				// Output macro for inclusion in paper calendar.
				printf(	"\\newcommand{\\%sWeek%s}{%s \\\\ --%s}\n",
					$period_name,
					str_replace( "-", "", ucfirst( $numwords->toWords( $week_number ) ) ),
					$week_start->format( 'j M' ),
					$week_end->format( 'j M' )
				);
			} // else different months
		} // else normal teaching week
		
		$week_start->add( $plus_seven_days );
	} // for each week
} // foreach teaching period

?>