<?php
/*****************************************************************************
 * PhotoMosaic.php
 * Contains the photo mosaic model, an iterator to create tiled photo galleries.
 *
 * Kabuki CMS (C) 2013-2015, Aaron van Geffen
 *****************************************************************************/

class PhotoMosaic
{
	private $queue = [];

	const NUM_DAYS_CUTOFF = 7;
	private AssetIterator $iterator;

	public function __construct(AssetIterator $iterator)
	{
		$this->iterator = $iterator;
	}

	public function __destruct()
	{
		$this->iterator->clean();
	}

	public static function getRecentPhotos()
	{
		return new self(AssetIterator::getByOptions([
			'tag' => 'photo',
			'order' => 'date_captured',
			'direction' => 'desc',
			'limit' => 15, // worst case: 3 rows * (portrait + 4 thumbs)
		]));
	}

	private static function matchTypeMask(Image $image, $type_mask)
	{
		return ($type_mask & Image::TYPE_PANORAMA)  && $image->isPanorama()  ||
			   ($type_mask & Image::TYPE_LANDSCAPE) && $image->isLandscape() ||
			   ($type_mask & Image::TYPE_PORTRAIT)  && $image->isPortrait();
	}

	private function fetchImage($desired_type = Image::TYPE_PORTRAIT | Image::TYPE_LANDSCAPE | Image::TYPE_PANORAMA, Image $refDateImage = null)
	{
		// First, check if we have what we're looking for in the queue.
		foreach ($this->queue as $i => $image)
		{
			// Image has to match the desired type and be taken within a week of the reference image.
			if (self::matchTypeMask($image, $desired_type) && !(isset($refDateImage) && abs(self::daysApart($image, $refDateImage)) > self::NUM_DAYS_CUTOFF))
			{
				unset($this->queue[$i]);
				return $image;
			}
		}

		// Check whatever's next up!
		while (($asset = $this->iterator->next()) && ($image = $asset->getImage()))
		{
			// Image has to match the desired type and be taken within a week of the reference image.
			if (self::matchTypeMask($image, $desired_type) && !(isset($refDateImage) && abs(self::daysApart($image, $refDateImage)) > self::NUM_DAYS_CUTOFF))
				return $image;
			else
				$this->pushToQueue($image);
		}

		return false;
	}

	private function pushToQueue(Image $image)
	{
		$this->queue[] = $image;
	}

	private static function orderPhotos(Image $a, Image $b)
	{
		// Show images of highest priority first.
		$priority_diff = $a->getPriority() - $b->getPriority();
		if ($priority_diff !== 0)
			return -$priority_diff;

		// In other cases, we'll just show the newest first.
		return $a->getDateCaptured() <=> $b->getDateCaptured();
	}

	private static function daysApart(Image $a, Image $b)
	{
		return $a->getDateCaptured()->diff($b->getDateCaptured())->days;
	}

	public function getRow()
	{
		// Fetch the first image...
		$image = $this->fetchImage();

		// No image at all?
		if (!$image)
			return false;

		// Is it a panorama? Then we've got our row!
		elseif ($image->isPanorama())
			return [[$image], 'panorama'];

		// Alright, let's initalise a proper row, then.
		$photos = [$image];
		$num_portrait  = $image->isPortrait()  ? 1 : 0;
		$num_landscape = $image->isLandscape() ? 1 : 0;

		// Get an initial batch of non-panorama images to work with.
		for ($i = 1; $i < 3 && ($image = $this->fetchImage(Image::TYPE_LANDSCAPE | Image::TYPE_PORTRAIT, $image)); $i++)
		{
			$num_portrait  += $image->isPortrait()  ? 1 : 0;
			$num_landscape += $image->isLandscape() ? 1 : 0;
			$photos[] = $image;
		}

		// Sort photos by priority and date captured.
		usort($photos, self::orderPhotos(...));

		// Three portraits?
		if ($num_portrait === 3)
			return [$photos, 'portraits'];

		// At least one portrait?
		if ($num_portrait >= 1)
		{
			// Grab two more landscapes, so we can put a total of four tiles on the side.
			for ($i = 0; $image && $i < 2 && ($image = $this->fetchImage(Image::TYPE_LANDSCAPE, $image)); $i++)
				$photos[] = $image;

			// We prefer to have the portrait on the side, so prepare to process that first.
			usort($photos, function($a, $b) {
				if ($a->isPortrait() && !$b->isPortrait())
					return -1;
				elseif ($b->isPortrait() && !$a->isPortrait())
					return 1;
				else
					return self::orderPhotos($a, $b);
			});

			// We might not have a full set of photos, but only bother if we have at least three.
			if (count($photos) > 3)
				return [$photos, 'portrait'];
		}

		// One landscape at least, hopefully?
		if ($num_landscape >= 1)
		{
			if (count($photos) === 3)
			{
				// We prefer to have the landscape on the side, so prepare to process that first.
				usort($photos, function($a, $b) {
					if ($a->isLandscape() && !$b->isLandscape())
						return -1;
					elseif ($b->isLandscape() && !$a->isLandscape())
						return 1;
					else
						return self::orderPhotos($a, $b);
				});

				return [$photos, 'landscape'];
			}
			elseif (count($photos) === 2)
				return [$photos, 'duo'];
			else
				return [$photos, 'single'];
		}

		// Last resort: majority vote
		if ($num_portrait > $num_landscape)
			return [$photos, 'portraits'];
		else
			return [$photos, 'landscapes'];
	}
}