// 使い方
echo format_phone_number('0120828828'); // 0120-828-828

function format_phone_number($input, $strict = false) {
    $groups = array(
        5 =>
        array (
            '01564' => 1,
            '01558' => 1,
            '01586' => 1,
            '01587' => 1,
            '01634' => 1,
            '01632' => 1,
            '01547' => 1,
            '05769' => 1,
            '04992' => 1,
            '04994' => 1,
            '01456' => 1,
            '01457' => 1,
            '01466' => 1,
            '01635' => 1,
            '09496' => 1,
            '08477' => 1,
            '08512' => 1,
            '08396' => 1,
            '08388' => 1,
            '08387' => 1,
            '08514' => 1,
            '07468' => 1,
            '01655' => 1,
            '01648' => 1,
            '01656' => 1,
            '01658' => 1,
            '05979' => 1,
            '04996' => 1,
            '01654' => 1,
            '01372' => 1,
            '01374' => 1,
            '09969' => 1,
            '09802' => 1,
            '09912' => 1,
            '09913' => 1,
            '01398' => 1,
            '01377' => 1,
            '01267' => 1,
            '04998' => 1,
            '01397' => 1,
            '01392' => 1,
        ),
        4 =>
        array (
            '0768' => 2,
            '0770' => 2,
            '0772' => 2,
            '0774' => 2,
            '0773' => 2,
            '0767' => 2,
            '0771' => 2,
            '0765' => 2,
            '0748' => 2,
            '0747' => 2,
            '0746' => 2,
            '0826' => 2,
            '0749' => 2,
            '0776' => 2,
            '0763' => 2,
            '0761' => 2,
            '0766' => 2,
            '0778' => 2,
            '0824' => 2,
            '0797' => 2,
            '0796' => 2,
            '0555' => 2,
            '0823' => 2,
            '0798' => 2,
            '0554' => 2,
            '0820' => 2,
            '0795' => 2,
            '0556' => 2,
            '0791' => 2,
            '0790' => 2,
            '0779' => 2,
            '0558' => 2,
            '0745' => 2,
            '0794' => 2,
            '0557' => 2,
            '0799' => 2,
            '0738' => 2,
            '0567' => 2,
            '0568' => 2,
            '0585' => 2,
            '0586' => 2,
            '0566' => 2,
            '0564' => 2,
            '0565' => 2,
            '0587' => 2,
            '0584' => 2,
            '0581' => 2,
            '0572' => 2,
            '0574' => 2,
            '0573' => 2,
            '0575' => 2,
            '0576' => 2,
            '0578' => 2,
            '0577' => 2,
            '0569' => 2,
            '0594' => 2,
            '0827' => 2,
            '0736' => 2,
            '0735' => 2,
            '0725' => 2,
            '0737' => 2,
            '0739' => 2,
            '0743' => 2,
            '0742' => 2,
            '0740' => 2,
            '0721' => 2,
            '0599' => 2,
            '0561' => 2,
            '0562' => 2,
            '0563' => 2,
            '0595' => 2,
            '0596' => 2,
            '0598' => 2,
            '0597' => 2,
            '0744' => 2,
            '0852' => 2,
            '0956' => 2,
            '0955' => 2,
            '0954' => 2,
            '0952' => 2,
            '0957' => 2,
            '0959' => 2,
            '0966' => 2,
            '0965' => 2,
            '0964' => 2,
            '0950' => 2,
            '0949' => 2,
            '0942' => 2,
            '0940' => 2,
            '0930' => 2,
            '0943' => 2,
            '0944' => 2,
            '0948' => 2,
            '0947' => 2,
            '0946' => 2,
            '0967' => 2,
            '0968' => 2,
            '0987' => 2,
            '0986' => 2,
            '0985' => 2,
            '0984' => 2,
            '0993' => 2,
            '0994' => 2,
            '0997' => 2,
            '0996' => 2,
            '0995' => 2,
            '0983' => 2,
            '0982' => 2,
            '0973' => 2,
            '0972' => 2,
            '0969' => 2,
            '0974' => 2,
            '0977' => 2,
            '0980' => 2,
            '0979' => 2,
            '0978' => 2,
            '0920' => 2,
            '0898' => 2,
            '0855' => 2,
            '0854' => 2,
            '0853' => 2,
            '0553' => 2,
            '0856' => 2,
            '0857' => 2,
            '0863' => 2,
            '0859' => 2,
            '0858' => 2,
            '0848' => 2,
            '0847' => 2,
            '0835' => 2,
            '0834' => 2,
            '0833' => 2,
            '0836' => 2,
            '0837' => 2,
            '0846' => 2,
            '0845' => 2,
            '0838' => 2,
            '0865' => 2,
            '0866' => 2,
            '0892' => 2,
            '0889' => 2,
            '0887' => 2,
            '0893' => 2,
            '0894' => 2,
            '0897' => 2,
            '0896' => 2,
            '0895' => 2,
            '0885' => 2,
            '0884' => 2,
            '0869' => 2,
            '0868' => 2,
            '0867' => 2,
            '0875' => 2,
            '0877' => 2,
            '0883' => 2,
            '0880' => 2,
            '0879' => 2,
            '0829' => 2,
            '0550' => 2,
            '0228' => 2,
            '0226' => 2,
            '0225' => 2,
            '0224' => 2,
            '0229' => 2,
            '0233' => 2,
            '0237' => 2,
            '0235' => 2,
            '0234' => 2,
            '0223' => 2,
            '0220' => 2,
            '0192' => 2,
            '0191' => 2,
            '0187' => 2,
            '0193' => 2,
            '0194' => 2,
            '0198' => 2,
            '0197' => 2,
            '0195' => 2,
            '0238' => 2,
            '0240' => 2,
            '0260' => 2,
            '0259' => 2,
            '0258' => 2,
            '0257' => 2,
            '0261' => 2,
            '0263' => 2,
            '0266' => 2,
            '0265' => 2,
            '0264' => 2,
            '0256' => 2,
            '0255' => 2,
            '0243' => 2,
            '0242' => 2,
            '0241' => 2,
            '0244' => 2,
            '0246' => 2,
            '0254' => 2,
            '0248' => 2,
            '0247' => 2,
            '0186' => 2,
            '0185' => 2,
            '0144' => 2,
            '0143' => 2,
            '0142' => 2,
            '0139' => 2,
            '0145' => 2,
            '0146' => 2,
            '0154' => 2,
            '0153' => 2,
            '0152' => 2,
            '0138' => 2,
            '0137' => 2,
            '0125' => 2,
            '0124' => 2,
            '0123' => 2,
            '0126' => 2,
            '0133' => 2,
            '0136' => 2,
            '0135' => 2,
            '0134' => 2,
            '0155' => 2,
            '0156' => 2,
            '0176' => 2,
            '0175' => 2,
            '0174' => 2,
            '0178' => 2,
            '0179' => 2,
            '0184' => 2,
            '0183' => 2,
            '0182' => 2,
            '0173' => 2,
            '0172' => 2,
            '0162' => 2,
            '0158' => 2,
            '0157' => 2,
            '0163' => 2,
            '0164' => 2,
            '0167' => 2,
            '0166' => 2,
            '0165' => 2,
            '0267' => 2,
            '0250' => 2,
            '0533' => 2,
            '0422' => 2,
            '0532' => 2,
            '0531' => 2,
            '0436' => 2,
            '0428' => 2,
            '0536' => 2,
            '0299' => 2,
            '0294' => 2,
            '0293' => 2,
            '0475' => 2,
            '0295' => 2,
            '0297' => 2,
            '0296' => 2,
            '0495' => 2,
            '0438' => 2,
            '0466' => 2,
            '0465' => 2,
            '0467' => 2,
            '0478' => 2,
            '0476' => 2,
            '0470' => 2,
            '0463' => 2,
            '0479' => 2,
            '0493' => 2,
            '0494' => 2,
            '0439' => 2,
            '0268' => 2,
            '0480' => 2,
            '0460' => 2,
            '0538' => 2,
            '0537' => 2,
            '0539' => 2,
            '0279' => 2,
            '0548' => 2,
            '0280' => 2,
            '0282' => 2,
            '0278' => 2,
            '0277' => 2,
            '0269' => 2,
            '0270' => 2,
            '0274' => 2,
            '0276' => 2,
            '0283' => 2,
            '0551' => 2,
            '0289' => 2,
            '0287' => 2,
            '0547' => 2,
            '0288' => 2,
            '0544' => 2,
            '0545' => 2,
            '0284' => 2,
            '0291' => 2,
            '0285' => 2,
            '0120' => 3,
            '0570' => 3,
            '0800' => 3,
            '0990' => 3,
        ),
        3 =>
        array (
            '099' => 3,
            '054' => 3,
            '058' => 3,
            '098' => 3,
            '095' => 3,
            '097' => 3,
            '052' => 3,
            '053' => 3,
            '011' => 3,
            '096' => 3,
            '049' => 3,
            '015' => 3,
            '048' => 3,
            '072' => 3,
            '084' => 3,
            '028' => 3,
            '024' => 3,
            '076' => 3,
            '023' => 3,
            '047' => 3,
            '029' => 3,
            '075' => 3,
            '025' => 3,
            '055' => 3,
            '026' => 3,
            '079' => 3,
            '082' => 3,
            '027' => 3,
            '078' => 3,
            '077' => 3,
            '083' => 3,
            '022' => 3,
            '086' => 3,
            '089' => 3,
            '045' => 3,
            '044' => 3,
            '092' => 3,
            '046' => 3,
            '017' => 3,
            '093' => 3,
            '059' => 3,
            '073' => 3,
            '019' => 3,
            '087' => 3,
            '042' => 3,
            '018' => 3,
            '043' => 3,
            '088' => 3,
            '050' => 4,
        ),
        2 =>
        array (
            '04' => 4,
            '03' => 4,
            '06' => 4,
        ),
    );
    $groups[3] +=
        $strict ?
        array(
            '020' => 3,
            '070' => 3,
            '080' => 3,
            '090' => 3,
        ) :
        array(
            '020' => 4,
            '070' => 4,
            '080' => 4,
            '090' => 4,
        )
    ;
    $number = preg_replace('/[^\d]++/', '', $input);
    foreach ($groups as $len => $group) {
        $area = substr($number, 0, $len);
        if (isset($group[$area])) {
            $formatted = implode('-', array(
                $area,
                substr($number, $len, $group[$area]),
                substr($number, $len + $group[$area])
            ));
            return strrchr($formatted, '-') !== '-' ? $formatted : $input;
        }
    }
    $pattern = '/\A(00(?:[013-8]|2\d|91[02-9])\d)(\d++)\z/';
    if (preg_match($pattern, $number, $matches)) {
        return $matches[1] . '-' . $matches[2];
    }
    return $input;
}