<?php
namespace pocketmine\level\generator\populator;

use pocketmine\block\Block;
use pocketmine\level\ChunkManager;
use pocketmine\level\generator\biome\Biome;
use pocketmine\utils\Random;

class GroundCover extends Populator{

	public function populate(ChunkManager $level, $chunkX, $chunkZ, Random $random){
		$chunk = $level->getChunk($chunkX, $chunkZ);
		for($x = 0; $x < 16; ++$x){
			for($z = 0; $z < 16; ++$z){
				$biome = Biome::getBiome($chunk->getBiomeId($x, $z));
				$cover = $biome->getGroundCover();
				if(count($cover) > 0){
					$diffY = 0;
					if(!$cover[0]->isSolid()){
						$diffY = 1;
					}

					$column = $chunk->getBlockIdColumn($x, $z);
					for($y = 127; $y > 0; --$y){
						if($column{$y} !== "\x00" and !Block::get(ord($column{$y}))->isTransparent()){
							break;
						}
					}
					$startY = min(127, $y + $diffY);
					$endY = $startY - count($cover);
					for($y = $startY; $y > $endY and $y >= 0; --$y){
						$b = $cover[$startY - $y];
						if($column{$y} === "\x00" and $b->isSolid()){
							break;
						}
						if($b->getDamage() === 0){
							$chunk->setBlockId($x, $y, $z, $b->getId());
						}else{
							$chunk->setBlock($x, $y, $z, $b->getId(), $b->getDamage());
						}
					}
				}
			}
		}
	}
}