From 1ac5b20e1edcaf6173f3b6ed1cef7a8e0a6beb2f Mon Sep 17 00:00:00 2001
From: Clement Desmidt <clement@desmidt.fr>
Date: Thu, 12 Dec 2019 14:09:52 +0100
Subject: [PATCH] :sparkles: Add day 12 part 1

---
 day_12/Moon.php      | 139 +++++++++++++++++++++++++++++++++++++++++++
 day_12/Velocity.php  |  75 +++++++++++++++++++++++
 day_12/functions.php |  66 ++++++++++++++++++++
 day_12/part_1.php    |  21 +++++++
 4 files changed, 301 insertions(+)
 create mode 100644 day_12/Moon.php
 create mode 100644 day_12/Velocity.php
 create mode 100644 day_12/functions.php
 create mode 100644 day_12/part_1.php

diff --git a/day_12/Moon.php b/day_12/Moon.php
new file mode 100644
index 0000000..20b35f0
--- /dev/null
+++ b/day_12/Moon.php
@@ -0,0 +1,139 @@
+<?php
+
+class Moon
+{
+    /** @var int */
+    protected $x;
+    /** @var int */
+    protected $y;
+    /** @var int */
+    protected $z;
+
+    /** @var string[] */
+    protected $history = [];
+
+    /**
+     * @var Velocity
+     */
+    protected $velocity;
+
+    /**
+     * Moon constructor.
+     * @param int $x
+     * @param int $y
+     * @param int $z
+     */
+    public function __construct(int $x, int $y, int $z)
+    {
+        $this->x = $x;
+        $this->y = $y;
+        $this->z = $z;
+        $this->addHistory(sprintf('%s,%s,%s,0,0,0', $this->getX(), $this->getY(), $this->getZ()));
+        $this->velocity = new Velocity(0,0,0);
+    }
+
+    /**
+     * @return int
+     */
+    public function getX(): int
+    {
+        return $this->x;
+    }
+
+    /**
+     * @param int $x
+     * @return Moon
+     */
+    public function setX(int $x): Moon
+    {
+        $this->x = $x;
+        return $this;
+    }
+
+    /**
+     * @return int
+     */
+    public function getY(): int
+    {
+        return $this->y;
+    }
+
+    /**
+     * @param int $y
+     * @return Moon
+     */
+    public function setY(int $y): Moon
+    {
+        $this->y = $y;
+        return $this;
+    }
+
+    /**
+     * @return int
+     */
+    public function getZ(): int
+    {
+        return $this->z;
+    }
+
+    /**
+     * @param int $z
+     * @return Moon
+     */
+    public function setZ(int $z): Moon
+    {
+        $this->z = $z;
+        return $this;
+    }
+
+    /**
+     * @return Velocity
+     */
+    public function getVelocity(): Velocity
+    {
+        return $this->velocity;
+    }
+
+    /**
+     * @param Velocity $velocity
+     * @return Moon
+     */
+    public function setVelocity(Velocity $velocity): Moon
+    {
+        $this->velocity = $velocity;
+        return $this;
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getHistory(): array
+    {
+        return $this->history;
+    }
+
+    /**
+     * @param string $history
+     * @return Moon
+     */
+    public function addHistory($history): Moon
+    {
+        $this->history[] = $history;
+        return $this;
+    }
+
+    public function saveHistory()
+    {
+        $velocity = $this->getVelocity();
+        $this->history[] = sprintf(
+            '%s,%s,%s,%s,%s,%s',
+            $this->getX(),
+            $this->getY(),
+            $this->getZ(),
+            $velocity->getX(),
+            $velocity->getY(),
+            $velocity->getZ()
+        );
+        return $this;
+    }
+}
diff --git a/day_12/Velocity.php b/day_12/Velocity.php
new file mode 100644
index 0000000..f1a0b32
--- /dev/null
+++ b/day_12/Velocity.php
@@ -0,0 +1,75 @@
+<?php
+
+class Velocity
+{
+    protected $x;
+    protected $y;
+    protected $z;
+
+    /**
+     * Velocity constructor.
+     * @param $x
+     * @param $y
+     * @param $z
+     */
+    public function __construct($x, $y, $z)
+    {
+        $this->x = $x;
+        $this->y = $y;
+        $this->z = $z;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getX()
+    {
+        return $this->x;
+    }
+
+    /**
+     * @param mixed $x
+     * @return Velocity
+     */
+    public function setX($x)
+    {
+        $this->x = $x;
+        return $this;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getY()
+    {
+        return $this->y;
+    }
+
+    /**
+     * @param mixed $y
+     * @return Velocity
+     */
+    public function setY($y)
+    {
+        $this->y = $y;
+        return $this;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getZ()
+    {
+        return $this->z;
+    }
+
+    /**
+     * @param mixed $z
+     * @return Velocity
+     */
+    public function setZ($z)
+    {
+        $this->z = $z;
+        return $this;
+    }
+}
diff --git a/day_12/functions.php b/day_12/functions.php
new file mode 100644
index 0000000..82346a5
--- /dev/null
+++ b/day_12/functions.php
@@ -0,0 +1,66 @@
+<?php
+
+
+/**
+ * @param Moon[] $moons
+ */
+function calculateVelocity(array $moons)
+{
+    foreach ($moons as $i => $base_moon) {
+        foreach ($moons as $j => $target_moon) {
+            if ($i === $j) {
+                // same planet
+                continue;
+            }
+
+            $velocity_x = $base_moon->getVelocity()->getX();
+            $velocity_y = $base_moon->getVelocity()->getY();
+            $velocity_z = $base_moon->getVelocity()->getZ();
+            if ($base_moon->getX() > $target_moon->getX()) {
+                --$velocity_x;
+            } elseif ($base_moon->getX() < $target_moon->getX()) {
+                ++$velocity_x;
+            }
+            if ($base_moon->getY() > $target_moon->getY()) {
+                --$velocity_y;
+            } elseif ($base_moon->getY() < $target_moon->getY()) {
+                ++$velocity_y;
+            }
+            if ($base_moon->getZ() > $target_moon->getZ()) {
+                --$velocity_z;
+            } elseif ($base_moon->getZ() < $target_moon->getZ()) {
+                ++$velocity_z;
+            }
+            $base_moon->getVelocity()->setX($velocity_x)->setY($velocity_y)->setZ($velocity_z);
+        }
+    }
+}
+
+/**
+ * @param Moon[] $moons
+ */
+function updateCoordinates(array $moons)
+{
+    foreach ($moons as $moon) {
+        $moon->setX($moon->getX() + $moon->getVelocity()->getX());
+        $moon->setY($moon->getY() + $moon->getVelocity()->getY());
+        $moon->setZ($moon->getZ() + $moon->getVelocity()->getZ());
+    }
+}
+
+/**
+ * @param Moon[] $moons
+ * @return float|int
+ */
+function calculateEnergy(array $moons)
+{
+    $energy = 0;
+    foreach ($moons as $moon) {
+        $pot = abs($moon->getX()) + abs($moon->getY()) + abs($moon->getZ());
+        $velocity = $moon->getVelocity();
+        $kin = abs($velocity->getX()) + abs($velocity->getY()) + abs($velocity->getZ());
+        $energy += $pot * $kin;
+    }
+
+    return $energy;
+}
\ No newline at end of file
diff --git a/day_12/part_1.php b/day_12/part_1.php
new file mode 100644
index 0000000..8f87093
--- /dev/null
+++ b/day_12/part_1.php
@@ -0,0 +1,21 @@
+<?php
+
+include 'Moon.php';
+include 'Velocity.php';
+include 'functions.php';
+
+$moons = array_map(function ($moon) {
+        $moon_coordinates = explode(', ', substr($moon, 1, -1));
+        $x = (int) substr($moon_coordinates[0], 2);
+        $y = (int) substr($moon_coordinates[1], 2);
+        $z = (int) substr($moon_coordinates[2], 2);
+        return new Moon($x, $y, $z);
+    }, explode("\n", file_get_contents('input.txt'))
+);
+
+for ($i = 0; $i < 1000; $i++) {
+    calculateVelocity($moons);
+    updateCoordinates($moons);
+}
+
+var_dump(calculateEnergy($moons));