spacemines.php

<?php

/*
 * PHP Space Mines Simulation
 * Based upon Space Mines from Usborne Computer Space Games
 * @see https://photogabble.co.uk/noteworthy/php-space-mines-introduction/
 */

function lerp($a, $b, $t): float
{
    return $a + ($b - $a) * $t;
}

function minMax($value, $min = 0, $max = 1)
{
    if ($value < $min) return $min;
    if ($value > $max) return $max;
    return $value;
}

enum BuildingKind: string
{
    case Mine = 'Mine';
}

enum ResourceKind: string
{
    case Ore = 'Ore';
    case Food = 'Food';
}

interface ColonyModifier
{
    public function modify(Colony $colony);
}

interface HasBuildings
{
    public function buildings(): array;

    public function buildingsOfKind(BuildingKind $kind): array;
}

abstract class Building implements ColonyModifier
{
    public BuildingKind $kind;

    public function __construct(BuildingKind $kind)
    {
        $this->kind = $kind;
    }
}

class Mine extends Building
{

    public function __construct()
    {
        parent::__construct(BuildingKind::Mine);
    }

    public function modify(Colony $colony)
    {
        $oreProduction = 60 + (60 * $this->productionPopulationModifier(count($colony->buildingsOfKind($this->kind)), $colony->population));
        $oreProduction += ($oreProduction * $this->productionSatisfactionModifier($colony->happiness));

        $colony->ore += ceil($oreProduction);
    }

    private function productionPopulationModifier(int $mines, int $population): float
    {
        $skeletonCrew = 20 * $mines;

        $workLoadPercentage = $population > 0
            ? minMax($population / $skeletonCrew)
            : 0;
        return round(lerp(-1, 1, $workLoadPercentage), 2);
    }

    private function productionSatisfactionModifier(float $satisfaction): float
    {
        if ($satisfaction < 0) return -0.5;
        if ($satisfaction > 0 && $satisfaction < 10) return 0.15;
        return 0.25;
    }
}

class Colony implements HasBuildings
{
    public int $ore;
    public int $oreSold;
    public int $meals;
    public int $population;
    public float $happiness;
    public int $money;
    public int $turn;
    private array $buildings;

    public function __construct(int $ore = 0, int $meals = 1500, int $population = 35, float $happiness = 0.0, int $money = 0, int $turn = 1, array $buildings = null)
    {
        $this->ore = $ore;
        $this->meals = $meals;
        $this->population = $population;
        $this->happiness = $happiness;
        $this->money = $money;
        $this->turn = $turn;

        $this->oreSold = 0;

        if (is_null($buildings)) {
            $this->buildings = [
                new Mine(),
                new Mine(),
                new Mine(),
            ];
        } else {
            $this->buildings = $buildings;
        }
    }

    public function buildings(): array
    {
        return $this->buildings;
    }

    public function buildingsOfKind(BuildingKind $kind): array
    {
        return array_filter($this->buildings, function (Building $item) use ($kind) {
            return $item->kind === $kind;
        });
    }

    public function score(): int
    {
        $mod = $this->happiness < 0
            ? -0.2
            : 0.2;
        $score = (($this->population * 1000) + ($this->oreSold / 2) + ($this->money * 2));
        return floor($score + ($score - ($score * $mod)));
    }

    public function status(): void
    {
        echo "TURN $this->turn" . PHP_EOL;
        echo "There are $this->population people in the colony" . PHP_EOL;
        echo "You have " . count($this->buildingsOfKind(BuildingKind::Mine)) . " mines and $this->money money" . PHP_EOL;
        echo "Ore in store: $this->ore, total ore sold $this->oreSold" . PHP_EOL;
        echo "Meals in store: $this->meals" . PHP_EOL;
        echo "Satisfaction: $this->happiness" . PHP_EOL;
    }
}

class SatisfactionModifier implements ColonyModifier
{
    public function modify(Colony $colony)
    {
        $colony->happiness += (
            $this->foodModifier($colony->meals, $colony->population) +
            $this->mineModifier(count($colony->buildingsOfKind(BuildingKind::Mine)), $colony->population)
        );

        $colony->happiness = minMax($colony->happiness, -20, 20);
    }

    private function foodModifier(int $foodReserve, int $population): float
    {
        $days = 28; // 4 weeks
        $mealsPerDay = 3;
        $mealsRequired = $population * $days * $mealsPerDay;
        $foodReservePercentage = $foodReserve > 0
            ? minMax($foodReserve / $mealsRequired)
            : 0;
        return round(lerp(-1.5, 1.5, $foodReservePercentage), 2);
    }

    private function mineModifier(int $mines, int $population): float
    {
        // min of 10 people per mine until they get over-worked, 20 is the optimal
        $skeletonCrew = 20 * $mines;

        $workLoadPercentage = $population > 0
            ? minMax($population / $skeletonCrew)
            : 0;
        return round(lerp(-1.5, 1.5, $workLoadPercentage), 2);
    }
}

class PopulationModifier implements ColonyModifier
{

    public function modify(Colony $colony)
    {
        // Migration
        // TODO this should be between 1 and the value found based upon happiness
        $colony->population += (int)($colony->happiness / 2);
        if ($colony->population < 0) $colony->population = 0;

        // Food consumption
        $colony->meals -= $colony->population * 3;
        if ($colony->meals < 0) $colony->meals = 0;
    }
}

class GatherResources implements ColonyModifier
{
    public function modify(Colony $colony)
    {
        /** @var Mine $mine */
        foreach ($colony->buildingsOfKind(BuildingKind::Mine) as $mine) {
            $mine->modify($colony);
        }
    }
}

class SellOre implements ColonyModifier {

    private int $amount;
    private int $value;

    public function __construct(int $amount, int $value) {
        $this->amount = $amount;
        $this->value = $value;
    }

    public function modify(Colony $colony)
    {
        $colony->oreSold += $this->amount;
        $colony->ore -= $this->amount;
        $colony->money += $this->amount * $this->value;
    }
}

$player = new Colony();

for ($i = 0; $i < 30; $i++) {
    $player->status();

    (new SatisfactionModifier)->modify($player);
    (new PopulationModifier())->modify($player);
    (new GatherResources())->modify($player);
    (new SellOre($player->ore, rand(7,12)))->modify($player);

    if ($player->happiness == -20) break;
    $player->turn++;
}

echo "Player Score: " . $player->score() . PHP_EOL;

Default output is:

TURN 1
There are 35 people in the colony
You have 3 mines and 0 money
Ore in store: 0, total ore sold 0
Meals in store: 1500
Satisfaction: 0
TURN 2
There are 35 people in the colony
You have 3 mines and 2187 money
Ore in store: 0, total ore sold 243
Meals in store: 1395
Satisfaction: 0.28
TURN 3
There are 35 people in the colony
You have 3 mines and 3888 money
Ore in store: 0, total ore sold 486
Meals in store: 1290
Satisfaction: 0.45
TURN 4
There are 35 people in the colony
You have 3 mines and 6318 money
Ore in store: 0, total ore sold 729
Meals in store: 1185
Satisfaction: 0.52
TURN 5
There are 35 people in the colony
You have 3 mines and 8262 money
Ore in store: 0, total ore sold 972
Meals in store: 1080
Satisfaction: 0.48
TURN 6
There are 35 people in the colony
You have 3 mines and 10449 money
Ore in store: 0, total ore sold 1215
Meals in store: 975
Satisfaction: 0.33
TURN 7
There are 35 people in the colony
You have 3 mines and 12636 money
Ore in store: 0, total ore sold 1458
Meals in store: 870
Satisfaction: 0.07
TURN 8
There are 35 people in the colony
You have 3 mines and 13932 money
Ore in store: 0, total ore sold 1566
Meals in store: 765
Satisfaction: -0.29
TURN 9
There are 35 people in the colony
You have 3 mines and 15228 money
Ore in store: 0, total ore sold 1674
Meals in store: 660
Satisfaction: -0.76
TURN 10
There are 35 people in the colony
You have 3 mines and 16308 money
Ore in store: 0, total ore sold 1782
Meals in store: 555
Satisfaction: -1.34
TURN 11
There are 34 people in the colony
You have 3 mines and 17430 money
Ore in store: 0, total ore sold 1884
Meals in store: 453
Satisfaction: -2.02
TURN 12
There are 33 people in the colony
You have 3 mines and 18420 money
Ore in store: 0, total ore sold 1983
Meals in store: 354
Satisfaction: -2.84
TURN 13
There are 32 people in the colony
You have 3 mines and 19113 money
Ore in store: 0, total ore sold 2082
Meals in store: 258
Satisfaction: -3.81
TURN 14
There are 30 people in the colony
You have 3 mines and 20013 money
Ore in store: 0, total ore sold 2172
Meals in store: 168
Satisfaction: -4.92
TURN 15
There are 27 people in the colony
You have 3 mines and 20661 money
Ore in store: 0, total ore sold 2253
Meals in store: 87
Satisfaction: -6.22
TURN 16
There are 24 people in the colony
You have 3 mines and 21165 money
Ore in store: 0, total ore sold 2325
Meals in store: 15
Satisfaction: -7.75
TURN 17
There are 20 people in the colony
You have 3 mines and 21732 money
Ore in store: 0, total ore sold 2388
Meals in store: 0
Satisfaction: -9.53
TURN 18
There are 15 people in the colony
You have 3 mines and 22137 money
Ore in store: 0, total ore sold 2433
Meals in store: 0
Satisfaction: -11.53
TURN 19
There are 9 people in the colony
You have 3 mines and 22434 money
Ore in store: 0, total ore sold 2460
Meals in store: 0
Satisfaction: -13.78
TURN 20
There are 1 people in the colony
You have 3 mines and 22458 money
Ore in store: 0, total ore sold 2463
Meals in store: 0
Satisfaction: -16.33
TURN 21
There are 0 people in the colony
You have 3 mines and 22458 money
Ore in store: 0, total ore sold 2463
Meals in store: 0
Satisfaction: -19.28
Player Score: 101524