<?php

namespace App\Sim;

/** Plays a level's 'solution' on its World: the title demo, the smoke test, the proof that a level can be won. */
final class Autoplay
{
    private int $next = 0;

    public function __construct(private World $world, private array $steps)
    {
    }

    public function done(): bool
    {
        return $this->next >= count($this->steps);
    }

    /** Call once per tick, after World::step(). */
    public function step(): void
    {
        if ($this->done()) {
            return;
        }
        $s = $this->steps[$this->next];
        [$skill, $who, $x, $dir] = $s;
        $leader = null;
        foreach ($this->world->lumis as $l) {
            if ($l->alive && !$l->is(Lumi::STOP) && ($leader === null || $l->x > $leader->x)) {
                $leader = $l;
            }
        }
        if (isset($s[5])) {
            $ref = $s[4] === -5 ? $leader : ($this->world->lumis[$s[4]] ?? null);
            if ($this->world->saved === 0 && ($ref === null || ($ref->alive && $ref->x < $s[5]))) {
                return;
            }
        }
        foreach ($this->world->lumis as $l) {
            if (!$l->alive) {
                continue;
            }
            $match = match (true) {
                $who >= 0 => $l->id === $who,
                $who === -1 => $l !== $leader && $l->state === Lumi::WALK,
                $who === -5 => $l === $leader,
                $who === -2 => $l->state === Lumi::STOP,
                default => $l->state === Lumi::WALK,
            };
            if (!$match || ($dir !== 0 && $l->dir !== $dir)) {
                continue;
            }
            if ($x > 0 && ($l->dir > 0 ? $l->x < $x : $l->x > $x)) {
                continue;
            }
            if ($x > 0 && $who < 0 && $who !== -5 && abs($l->x - $x) > 3) {
                continue;
            }
            if ($this->world->assign($l, $skill)) {
                $this->next++;
                return;
            }
        }
    }
}