<?php

namespace App\Game;

/**
 * Plays by itself (the title screen's demo, the smoke test): walks the level, opens doors, turns at walls,
 * shoots the monsters it sees.
 */
final class Bot
{
    private float $lastX = 0.0;
    private float $lastY = 0.0;
    private int $stuck = 0;
    private float $turnLeft = 0.0;
    private int $tics = 0;

    public function cmd(World $w): array
    {
        $this->tics++;
        $mo = $w->player->mo;
        $cmd = ['forward' => 1.0, 'side' => 0.0, 'turn' => 0.0, 'fire' => false, 'use' => $this->tics % 24 < 2, 'weapon' => null];
        // the nearest monster in sight
        $best = null;
        $bestD = 1400.0;
        foreach ($w->mobjs as $th) {
            if (!$th->is(Info::COUNTKILL) || $th->health <= 0) {
                continue;
            }
            $d = hypot($th->x - $mo->x, $th->y - $mo->y);
            if ($d < $bestD && $w->checkSight($mo, $th)) {
                $best = $th;
                $bestD = $d;
            }
        }
        if ($best !== null) {
            $want = atan2($best->y - $mo->y, $best->x - $mo->x);
            $delta = fmod($want - $mo->angle + 5 * M_PI, 2 * M_PI) - M_PI;
            $cmd['turn'] = max(-0.12, min(0.12, $delta));
            $cmd['fire'] = abs($delta) < 0.12;
            $cmd['forward'] = $bestD > 200 ? 0.5 : -0.3;
            $cmd['side'] = sin($this->tics / 20) * 0.6;
            // the best weapon it has
            foreach ([4, 3, 2] as $n) {
                $def = Weapons::LIST[$n];
                if (!empty($w->player->weapons[$n]) && $w->player->ammo[$def['ammo']] > 0) {
                    $cmd['weapon'] = $n;
                    break;
                }
            }
            return $cmd;
        }
        // wander: turn when stuck
        $moved = hypot($mo->x - $this->lastX, $mo->y - $this->lastY);
        $this->lastX = $mo->x;
        $this->lastY = $mo->y;
        $this->stuck = $moved < 0.6 ? $this->stuck + 1 : 0;
        if ($this->stuck > 6 && $this->turnLeft == 0.0) {
            $this->turnLeft = (M_PI / 2 + ($w->random() / 255) * M_PI) * (($w->random() & 1) ? 1 : -1);
            $this->stuck = 0;
        }
        if ($this->turnLeft != 0.0) {
            $step = max(-0.12, min(0.12, $this->turnLeft));
            $cmd['turn'] = $step;
            $this->turnLeft -= $step;
            if (abs($this->turnLeft) < 0.01) {
                $this->turnLeft = 0.0;
            }
            $cmd['forward'] = 0.2;
        }
        return $cmd;
    }
}