<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
*/

declare(strict_types=1);

namespace pocketmine\level;

use pocketmine\block\Block;
use pocketmine\block\BlockFactory;
use pocketmine\block\TNT;
use pocketmine\entity\Entity;
use pocketmine\event\block\BlockUpdateEvent;
use pocketmine\event\entity\EntityDamageByBlockEvent;
use pocketmine\event\entity\EntityDamageByEntityEvent;
use pocketmine\event\entity\EntityDamageEvent;
use pocketmine\event\entity\EntityExplodeEvent;
use pocketmine\item\Item;
use pocketmine\item\ItemFactory;
use pocketmine\level\particle\HugeExplodeSeedParticle;
use pocketmine\math\AxisAlignedBB;
use pocketmine\math\Math;
use pocketmine\math\Vector3;
use pocketmine\network\mcpe\protocol\ExplodePacket;
use pocketmine\network\mcpe\protocol\LevelSoundEventPacket;

class Explosion{

	private $rays = 16; //Rays
	public $level;
	public $source;
	public $size;
	/**
	 * @var Block[]
	 */
	public $affectedBlocks = [];
	public $stepLen = 0.3;
	/** @var Entity|Block */
	private $what;

	public function __construct(Position $center, $size, $what = null){
		$this->level = $center->getLevel();
		$this->source = $center;
		$this->size = max($size, 0);
		$this->what = $what;
	}

	/**
	 * @return bool
	 */
	public function explodeA() : bool{
		if($this->size < 0.1){
			return false;
		}

		$vector = new Vector3(0, 0, 0);
		$vBlock = new Position(0, 0, 0, $this->level);

		$currentX = ((int) $this->source->x) >> 4;
		$currentZ = ((int) $this->source->z) >> 4;
		$currentChunk = $this->level->getChunk($currentX, $currentZ, true);

		$currentSubY = ((int) $this->source->y) >> 4;
		$currentSubChunk = $currentChunk->getSubChunk($currentSubY);

		$mRays = (int) ($this->rays - 1);
		for($i = 0; $i < $this->rays; ++$i){
			for($j = 0; $j < $this->rays; ++$j){
				for($k = 0; $k < $this->rays; ++$k){
					if($i === 0 or $i === $mRays or $j === 0 or $j === $mRays or $k === 0 or $k === $mRays){
						$vector->setComponents($i / $mRays * 2 - 1, $j / $mRays * 2 - 1, $k / $mRays * 2 - 1);
						$vector->setComponents(($vector->x / ($len = $vector->length())) * $this->stepLen, ($vector->y / $len) * $this->stepLen, ($vector->z / $len) * $this->stepLen);
						$pointerX = $this->source->x;
						$pointerY = $this->source->y;
						$pointerZ = $this->source->z;

						for($blastForce = $this->size * (mt_rand(700, 1300) / 1000); $blastForce > 0; $blastForce -= $this->stepLen * 0.75){
							$x = (int) $pointerX;
							$y = (int) $pointerY;
							$z = (int) $pointerZ;
							$vBlock->x = $pointerX >= $x ? $x : $x - 1;
							$vBlock->y = $pointerY >= $y ? $y : $y - 1;
							$vBlock->z = $pointerZ >= $z ? $z : $z - 1;


							if(($vBlock->x >> 4) !== $currentX or ($vBlock->z >> 4) !== $currentZ){
								$currentX = $vBlock->x >> 4;
								$currentZ = $vBlock->z >> 4;

								$currentChunk = $this->level->getChunk($currentX, $currentZ);
								if($currentChunk === null){
									continue;
								}
							}

							if(($vBlock->y >> 4) !== $currentSubY){
								$currentSubY = $vBlock->y >> 4;
								$currentSubChunk = $currentChunk->getSubChunk($currentSubY);
								if($currentSubChunk === null){
									continue;
								}
							}

							$blockId = $currentSubChunk->getBlockId($vBlock->x & 0x0f, $vBlock->y & 0x0f, $vBlock->z & 0x0f);

							if($blockId !== 0){
								$blastForce -= (BlockFactory::$blastResistance[$blockId] / 5 + 0.3) * $this->stepLen;
								if($blastForce > 0){
									if(!isset($this->affectedBlocks[$index = Level::blockHash($vBlock->x, $vBlock->y, $vBlock->z)])){
										$this->affectedBlocks[$index] = BlockFactory::get($blockId, $currentSubChunk->getBlockData($vBlock->x & 0x0f, $vBlock->y & 0x0f, $vBlock->z & 0x0f), $vBlock);
									}
								}
							}

							$pointerX += $vector->x;
							$pointerY += $vector->y;
							$pointerZ += $vector->z;
						}
					}
				}
			}
		}

		return true;
	}

	public function explodeB() : bool{
		$send = [];
		$updateBlocks = [];

		$source = (new Vector3($this->source->x, $this->source->y, $this->source->z))->floor();
		$yield = (1 / $this->size) * 100;

		if($this->what instanceof Entity){
			$this->level->getServer()->getPluginManager()->callEvent($ev = new EntityExplodeEvent($this->what, $this->source, $this->affectedBlocks, $yield));
			if($ev->isCancelled()){
				return false;
			}else{
				$yield = $ev->getYield();
				$this->affectedBlocks = $ev->getBlockList();
			}
		}

		$explosionSize = $this->size * 2;
		$minX = Math::floorFloat($this->source->x - $explosionSize - 1);
		$maxX = Math::ceilFloat($this->source->x + $explosionSize + 1);
		$minY = Math::floorFloat($this->source->y - $explosionSize - 1);
		$maxY = Math::ceilFloat($this->source->y + $explosionSize + 1);
		$minZ = Math::floorFloat($this->source->z - $explosionSize - 1);
		$maxZ = Math::ceilFloat($this->source->z + $explosionSize + 1);

		$explosionBB = new AxisAlignedBB($minX, $minY, $minZ, $maxX, $maxY, $maxZ);

		$list = $this->level->getNearbyEntities($explosionBB, $this->what instanceof Entity ? $this->what : null);
		foreach($list as $entity){
			$distance = $entity->distance($this->source) / $explosionSize;

			if($distance <= 1){
				$motion = $entity->subtract($this->source)->normalize();

				$impact = (1 - $distance) * ($exposure = 1);

				$damage = (int) ((($impact * $impact + $impact) / 2) * 8 * $explosionSize + 1);

				if($this->what instanceof Entity){
					$ev = new EntityDamageByEntityEvent($this->what, $entity, EntityDamageEvent::CAUSE_ENTITY_EXPLOSION, $damage);
				}elseif($this->what instanceof Block){
					$ev = new EntityDamageByBlockEvent($this->what, $entity, EntityDamageEvent::CAUSE_BLOCK_EXPLOSION, $damage);
				}else{
					$ev = new EntityDamageEvent($entity, EntityDamageEvent::CAUSE_BLOCK_EXPLOSION, $damage);
				}

				$entity->attack($ev);
				$entity->setMotion($motion->multiply($impact));
			}
		}


		$air = ItemFactory::get(Item::AIR);

		foreach($this->affectedBlocks as $block){
			if($block instanceof TNT){
				$block->ignite(mt_rand(10, 30));
			}elseif(mt_rand(0, 100) < $yield){
				foreach($block->getDrops($air) as $drop){
					$this->level->dropItem($block->add(0.5, 0.5, 0.5), $drop);
				}
			}

			$this->level->setBlockIdAt($block->x, $block->y, $block->z, 0);

			$pos = new Vector3($block->x, $block->y, $block->z);

			for($side = 0; $side <= 5; $side++){
				$sideBlock = $pos->getSide($side);
				if(!$this->level->isInWorld($sideBlock->x, $sideBlock->y, $sideBlock->z)){
					continue;
				}
				if(!isset($this->affectedBlocks[$index = Level::blockHash($sideBlock->x, $sideBlock->y, $sideBlock->z)]) and !isset($updateBlocks[$index])){
					$this->level->getServer()->getPluginManager()->callEvent($ev = new BlockUpdateEvent($this->level->getBlock($sideBlock)));
					if(!$ev->isCancelled()){
						$ev->getBlock()->onUpdate(Level::BLOCK_UPDATE_NORMAL);
					}
					$updateBlocks[$index] = true;
				}
			}
			$send[] = new Vector3($block->x - $source->x, $block->y - $source->y, $block->z - $source->z);
		}

		$pk = new ExplodePacket();
		$pk->position = $this->source->asVector3();
		$pk->radius = $this->size;
		$pk->records = $send;
		$this->level->addChunkPacket($source->x >> 4, $source->z >> 4, $pk);

		$this->level->addParticle(new HugeExplodeSeedParticle($source));
		$this->level->broadcastLevelSoundEvent($source, LevelSoundEventPacket::SOUND_EXPLODE);

		return true;
	}
}