<?php

namespace App\Engine\Map;

/** A wall line between two vertices: front side on its right (line_t). */
final class Line
{
    public const BLOCKING = 1;        // players and monsters
    public const BLOCK_MONSTERS = 2;
    public const TWO_SIDED = 4;
    public const UNPEG_TOP = 8;
    public const UNPEG_BOTTOM = 16;
    public const SECRET = 32;         // drawn as a wall on the map
    public const SOUND_BLOCK = 64;
    public const MAPPED = 256;

    public float $dx;
    public float $dy;
    public float $length;
    /** bounding box: top, bottom, left, right */
    public array $bbox;
    public int $flags = 0;
    /** use / walk action: '', 'door', 'exit', 'switch', 'lift'... */
    public string $special = '';
    /** extra data of the action: key, target sector char... */
    public array $args = [];
    public ?Side $back = null;
    public ?Sector $backSector = null;
    public Sector $frontSector;
    public int $validCount = 0;
    public bool $mapped = false;

    public function __construct(public int $id, public float $x1, public float $y1, public float $x2, public float $y2, public Side $front)
    {
        $this->dx = $x2 - $x1;
        $this->dy = $y2 - $y1;
        $this->length = sqrt($this->dx ** 2 + $this->dy ** 2);
        $this->bbox = [max($y1, $y2), min($y1, $y2), min($x1, $x2), max($x1, $x2)];
        $this->frontSector = $front->sector;
    }

    public function setBack(Side $back): void
    {
        $this->back = $back;
        $this->backSector = $back->sector;
        $this->flags |= self::TWO_SIDED;
    }

    /** 0 = front (right) side, 1 = back (P_PointOnLineSide). */
    public function side(float $x, float $y): int
    {
        return (($x - $this->x1) * $this->dy - ($y - $this->y1) * $this->dx) >= 0 ? 0 : 1;
    }
}