<?php

$start = date("Y-m-d", strtotime("now"));
$end = date("Y-m-d", strtotime("+3 hours"));
$form = new stdObject;
$form->st = $start;
$form->et = $end;

$processor = new EPGProcessor($form);
$packages = $processor->process();


class EPGProcessor
{

    private $form;
    private $st;
    private $et;
    private $ipp;
    private $pg;

    public function __construct($form)
    {

        $this->form = $this->setupForm($form);
        $this->factory = new EpgFactory();

    }

    private function setupForm($form)
    {
      foreach (['st', 'et', 'pg', 'ipp'] as $key) {
        $this->$key = (int)$form->$key;
        $form->$key = false;
      }
      return $form;
    }

    public function process()
    {
        $queue = $this->buildQueue();
        $collection = $this->processQueue();
        $provider = $this->getDataProvider($collection);
        return $provider;
    }

    private function getDataProvider(array $collection) {

        $dataProvider=new CArrayDataProvider($collection, array(
            'id'=>'epg',
            'sort'=>array(
              'attributes'=>array(
                'title','startTime'
              ),
            ),
            'pagination'=>array(
              'pageSize'=>$this->ipp,
              'currentPage'=>$this->pg
            ),
          )
        );

        return $dataProvider;
    }

    private function getMidnightDate($timestamp)
    {
        $day = date("Y-m-d", $timestamp);
        $date = new DateTime($day . ' 00:00:00');
        return $date;
    }

    private function getDateRange(DateTime $day)
    {

        $start = $this->getMidnightDate($day->getTimestamp());
        $end = clone $start;
        $end->modify("+1 day");

        return [$start->getTimestamp(), $end->getTimestamp()];
    }

    private function dateDiff(DateTime $dayStart, DateTime $dayEnd)
    {
        $diff = $dayEnd->diff($dayStart)->format("%a");
        return $diff;
    }

    private function processQueue($queue)
    {
        $collection = [];

        foreach ($queue as $day => $timestamps) {
            $form = $this->form;
            $form->st = $timestamps[0];
            $form->et = $timestamps[1];

            if ($package = $this->factory->getPackage($form) === true) {
                $this->processPackage($package, $collection);
            } else {
                $package = $this->factory->buildPackage($form);
                $this->factory->storePackage($package, $form);
                $this->processPackage($package, $collection);
            }
        }
        return $collection;
    }

    private function processPackage(EpgPackage $package, &$collection) {
        $form = $this->form;
        $form->st = $this->st;
        $form->et = $this->et;
        $collection = $collection + $package->getData($form);
    }

    private function buildQueue()
    {
        $st = $this->getMidnightDate($this->st);
        $et = $this->getMidnightDate($this->et);

        $days = 1;
        $diff = $this->dateDiff($st, $et);
        $days += $diff;

        $queue = [];

        for ($i = 0; $i < $days; $i++) {
            $day = $st->format("Y-m-d");
            $queue[$day] = $this->getDateRange($st);
            $st->modify("+1 day");
            $i++;
        }

        return $queue;
    }
}

class EPGPackage {

  private $start;
  private $end;
  private $data;

  public function getAll() {
      return $this->data;
  }

  public function getRange($start, $end) {

  }

  public function normalize() {

  }

  public function setPagination($pagination) {

        $this->pagination = $data['pagination'];
  }

  public function setForm($form) {
      $this->start = $form->st;
      $this->end = $form->end;
  }

  public function getData($form) {
    if ($this->start < $form->st && $this->end > $form->et) {
      return $this->getAll();
    } else {
      return $this->getRange($form->st, $form->et);
    }
  }

  public function setData(array $data) {

      $this->data = $this->normalize($data['res']);

  }

}

class EPGPackageFactory {

    private function buildPackage($form)
    {
        $data = EPGFactory::getEpgData($form);
        $package = new EPGPackage();
        $package->setData($data);
        $package->setForm($form);

        return $package;
    }

    private function storePackage(EPGPackage $data, $form)
    {
        $expiration = $form->et;
        $cacheKey = $this->buildCacheKey($form);

        return Yii::app()->cacheManager->set($cacheKey, $data, $expiration, false, ['gzip' => true]);
    }

    private function getPackage($form)
    {
        $key = $this->buildCacheKey($form);
        if ($package = Yii::app()->cacheManager->get($key, ['gzip' => true])) {
            return $package;
        }

        return false;
    }

    private function buildCacheKey($form)
    {
        $day = date("Y-m-d", $form->st);
        $key = md5(json_encode([$form->attributes, $day]));

        return $key;
    }

}