<?php
    
    //domingo 0
    //segunda 1
    //terça   2
    //quarta  3
	//quinta  4
	//sexta   5
	//sabado  6	
	//0 (para domingo) até 6 (para sábado)
	
	
	function render($date = null)
	{
		$current = is_null($date)
			? date('w')		
			: date('w', strtotime($date));

		$now = is_null($date)
			? strtotime('now')
			: strtotime($date);

		$week = ['dom' => '',
			'seg' => '',
			'ter' => '',
			'qua' => '',
			'qui' => '',
			'sex' => '',
			'sab' => ''];		
		$keys = array_keys($week);
		if ($current > 0)
		{ 
			$now = strtotime('-'.($current).' day', $now);		
		}
		for($i = 0; $i < 7; $i++)
		{
			$week[$keys[$i]] = date('d/m/Y', 
				strtotime("+$i day", $now));			
		}
		return $week;
	}


	var_dump(render());
	var_dump(render('2017-08-06'));