<?php declare(strict_types=1);
/*
 * This file is part of the SplendidBear Websites' projects.
 *
 * Copyright (c) 2026 @ www.splendidbear.org
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace App\Service;

use App\Entity\PlayedGame;
use Symfony\Component\Uid\Uuid;

/**
 * Class BattleCardGenerator
 *
 * Generates a 1200x630 PNG battle card for Open Graph sharing.
 *
 * @package  App\Service
 * @author   Lang <https://www.splendidbear.org>
 * @category Class
 * @license  https://www.gnu.org/licenses/lgpl-3.0.en.html GNU Lesser General Public License
 * @link     www.splendidbear.org
 * @since    2026. 04. 14.
 */
class BattleCardGenerator
{
    private const W    = 1200;
    private const H    = 630;
    private const FONT = '/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf';

    public function __construct(private readonly string $cacheDir) { }

    /** Returns a deterministic UUID v5 for the given battle ID — same battle always maps to the same filename. */
    public function cachePath(int $battleId): string
    {
        $uuid = Uuid::v5(Uuid::fromString(Uuid::NAMESPACE_URL), 'mineseeker-battle-' . $battleId);

        return $this->cacheDir . '/' . $uuid->toRfc4122() . '.png';
    }

    public function generate(PlayedGame $game): string
    {
        $path = $this->cachePath((int)$game->getId());

        if (is_file($path)) {
            return $path;
        }

        if (!is_dir($this->cacheDir)) {
            mkdir($this->cacheDir, 0755, true);
        }

        $this->render($game, $path);

        return $path;
    }

    private function render(PlayedGame $game, string $dest): void
    {
        $im = imagecreatetruecolor(self::W, self::H);

        // Palette
        $bg = imagecolorallocate($im, 13, 13, 28);
        $dot = imagecolorallocate($im, 30, 30, 55);
        $divider = imagecolorallocate($im, 40, 40, 70);
        $white = imagecolorallocate($im, 230, 230, 240);
        $muted = imagecolorallocate($im, 90, 90, 115);
        $red = imagecolorallocate($im, 246, 125, 82);
        $blue = imagecolorallocate($im, 149, 207, 245);
        $gold = imagecolorallocate($im, 255, 200, 50);

        // Background
        imagefill($im, 0, 0, $bg);

        // Dot-grid texture
        for ($x = 40; $x < self::W; $x += 40) {
            for ($y = 40; $y < self::H; $y += 40) {
                imagesetpixel($im, $x, $y, $dot);
            }
        }

        // Horizontal accent lines
        imageline($im, 0, 90, self::W, 90, $divider);
        imageline($im, 0, self::H - 60, self::W, self::H - 60, $divider);

        // Vertical centre divider
        imageline($im, self::W / 2, 110, self::W / 2, self::H - 80, $divider);

        // Resolve names
        $redName = $game->getRed()?->getUsername()
            ?? ($game->getRedAnon() !== null ? 'Anonymous' : 'Guest');
        $blueName = $game->getBlue()?->getUsername()
            ?? ($game->getBlueAnon() !== null ? 'Anonymous' : 'Guest');
        $redPts = $game->getRedPoints();
        $bluePts = $game->getBluePoints();
        $resign = $game->getResign();

        // Winner
        $winner = null;
        if ($resign === 'red') {
            $winner = 'blue';
        } elseif ($resign === 'blue') {
            $winner = 'red';
        } elseif ($redPts !== null && $bluePts !== null) {
            if ($redPts > $bluePts) $winner = 'red';
            elseif ($bluePts > $redPts) $winner = 'blue';
            else $winner = 'draw';
        }

        $this->centeredText($im, 'MineSeeker', 20, self::W / 2, 58, $muted);

        $this->centeredText($im, 'RED', 16, self::W / 4, 130, $red);
        $this->centeredText($im, 'BLUE', 16, self::W * 3 / 4, 130, $blue);

        $redColor = $winner === 'red' ? $gold : ($winner === 'draw' ? $white : $red);
        $blueColor = $winner === 'blue' ? $gold : ($winner === 'draw' ? $white : $blue);

        $this->centeredTextFit($im, $redName, 48, self::W / 4, 265, $redColor, self::W / 2 - 80);
        $this->centeredTextFit($im, $blueName, 48, self::W * 3 / 4, 265, $blueColor, self::W / 2 - 80);

        $scoreText = $redPts !== null && $bluePts !== null ? $redPts . '  :  ' . $bluePts : 'VS';
        $this->centeredText($im, $scoreText, 72, self::W / 2, 390, $white);

        if ($winner === 'red') {
            $resultText = $redName . ' wins';
            $resultColor = $gold;
        } elseif ($winner === 'blue') {
            $resultText = $blueName . ' wins';
            $resultColor = $gold;
        } elseif ($winner === 'draw') {
            $resultText = 'Draw';
            $resultColor = $muted;
        } else {
            $resultText = '';
            $resultColor = $muted;
        }

        if ($resultText !== '') {
            $this->centeredText($im, $resultText, 30, self::W / 2, 460, $resultColor);
        }

        if ($resign) {
            $this->centeredText($im, ucfirst($resign) . ' resigned', 18, self::W / 2, 498, $muted);
        }

        $this->centeredText($im, 'mineseeker.hu', 16, self::W / 2, self::H - 20, $muted);

        imagepng($im, $dest);
        imagedestroy($im);
    }

    /** Render text centered on $cx. */
    private function centeredText(\GdImage $im, string $text, int $size, int $cx, int $y, int $color): void
    {
        $bbox = imagettfbbox($size, 0, self::FONT, $text);
        $w = $bbox[2] - $bbox[0];
        imagettftext($im, $size, 0, (int)($cx - $w / 2), $y, $color, self::FONT, $text);
    }

    /** Render text centered on $cx, shrinking font size to fit $maxWidth. */
    private function centeredTextFit(
        \GdImage $im,
        string   $text,
        int      $size,
        int      $cx,
        int      $y,
        int      $color,
        int      $maxWidth
    ): void {
        $bbox = imagettfbbox($size, 0, self::FONT, $text);
        $w = $bbox[2] - $bbox[0];
        if ($w > $maxWidth) {
            $size = (int)($size * $maxWidth / $w);
        }
        $this->centeredText($im, $text, $size, $cx, $y, $color);
    }
}