<?php declare(strict_types=1);
/**
 * This file is part of the SplendidBear Websites' projects.
 *
 * Copyright (c) 2019 @ www.splendidbear.org
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace App\Util;

use App\Entity\Gamer;
use App\Entity\GridRow;
use App\Entity\PlayedGame;
use App\Entity\Step;
use App\Entity\User;
use App\Interfaces\TopicManagerInterface;
use App\Repository\PlayedGameRepository;
use App\Repository\UserRepository;
use Liip\ImagineBundle\Imagine\Cache\CacheManager;
use DateTimeInterface;
use DateTime;
use Doctrine\ORM\EntityManagerInterface;
use Exception;
use JsonException;
use Psr\Log\LoggerInterface;
use RuntimeException;
use Symfony\Component\Mercure\HubInterface;
use Symfony\Component\Mercure\Update;
use Symfony\Component\Security\Core\User\UserInterface;

/**
 * Class TopicManager
 *
 * @package  App\Util
 * @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. 09.
 */
readonly class TopicManager implements TopicManagerInterface
{
    public function __construct(
        private HubInterface           $hub,
        private EntityManagerInterface $entityManager,
        private LoggerInterface        $logger,
        private PlayedGameRepository   $playedGameRepository,
        private UserRepository         $userRepository,
        private CacheManager           $cacheManager,
    ) {
    }

    public function subscribe(string $gameAssoc, string $userName, ?UserInterface $user): void
    {
        $playedGame = $this->getPlayedGame($gameAssoc);
        if (null === $playedGame) {
            return;
        }

        $users = $this->getUserCollection($playedGame);
        $count = $this->getPlayerCount($users);
        $isKnown = in_array($userName, array_filter(array_values($users)), true);

        /** Reject a third player who is not a reconnecting player */
        if ($count >= 2 && !$isKnown) {
            return;
        }

        /** Save the player to the database on a fresh join */
        if (!$isKnown && $count < 2) {
            $users = $this->saveUserToDb($gameAssoc, $userName, $user, $count + 1);
            $count = $this->getPlayerCount($users);
        }

        $topic = 'mineseeker/channel/' . $gameAssoc;

        try {
            $this->hub->publish(new Update(
                $topic,
                json_encode([
                    'userTopicId' => $userName,
                    'channel'     => $topic,
                    'user'        => $userName,
                    'userCnt'     => $count,
                    'users'       => $users,
                ], JSON_THROW_ON_ERROR)
            ));
        } catch (JsonException $e) {
            throw new RuntimeException($e->getMessage());
        }

        // ── Lobby updates ──────────────────────────────────────────────────
        if ($count === 1) {
            // One player waiting — mark as active and announce to the lobby
            $playedGame->setUpdated(new DateTime());
            $this->entityManager->persist($playedGame);
            $this->entityManager->flush();

            $displayName = $users['red'] ?: $users['redAnon'] ?: $users['blue'] ?: $users['blueAnon'] ?: 'Unknown';
            $this->publishToLobby([
                'action'    => 'join',
                'gameAssoc' => $gameAssoc,
                'name'      => $displayName,
                'since'     => $playedGame->getCreated()?->format(DateTimeInterface::ATOM) ?? '',
            ]);
        } elseif ($count === 2) {
            // Both players joined — remove from lobby
            $this->publishToLobby(['action' => 'leave', 'gameAssoc' => $gameAssoc]);
        }
    }

    public function unSubscribe(string $gameAssoc, string $userName): void
    {
        // If the game was still waiting for a second player, stamp it as abandoned
        // so it no longer appears in the waiting-games query, and remove from lobby.
        $playedGame = $this->getPlayedGame($gameAssoc);
        if (null !== $playedGame) {
            $users = $this->getUserCollection($playedGame);
            if ($this->getPlayerCount($users) === 1) {
                $playedGame->setUpdated(new DateTime('2000-01-01 00:00:00'));
                $this->entityManager->persist($playedGame);
                $this->entityManager->flush();
                $this->publishToLobby(['action' => 'leave', 'gameAssoc' => $gameAssoc]);
            }
        }

        $topic = 'mineseeker/channel/' . $gameAssoc;

        $this->hub->publish(new Update(
            $topic,
            json_encode(['msg' => $userName . ' has left ' . $topic])
        ));
    }

    /**
     * Resolve the revealed cells for a step, persist it, and broadcast via Mercure.
     * Returns the step result data (same shape as what is broadcast in `data`).
     */
    public function publish(string $gameAssoc, string $userName, array $event): array
    {
        if (null !== $event['resign']) {
            $this->saveResignToDb($gameAssoc, $event['resign']);

            $playedGame = $this->getPlayedGame($gameAssoc);
            $users = $this->getUserCollection($playedGame);
            $count = $this->getPlayerCount($users);
            $topic = 'mineseeker/channel/' . $gameAssoc;

            $data = ['resign' => $event['resign'], 'coords' => null];

            try {
                $this->hub->publish(new Update(
                    $topic,
                    json_encode([
                        'userTopicId' => $userName,
                        'channel'     => $topic,
                        'user'        => $userName,
                        'userCnt'     => $count,
                        'data'        => $data,
                    ], JSON_THROW_ON_ERROR)
                ));
            } catch (JsonException $e) {
                throw new RuntimeException($e->getMessage());
            }

            return $data;
        }

        // ------------------------------------------------------------------ //
        //  Normal move
        // ------------------------------------------------------------------ //
        $coords = $event['coords'];
        $player = $event['player'];          // 'red' | 'blue'
        $isBomb = (bool)$event['bomb'];

        $playedGame = $this->getPlayedGame($gameAssoc);
        $grid = $this->loadGrid($gameAssoc);

        // Cells already revealed by previous steps (as "row,col" => true map)
        $alreadyRevealed = $this->buildRevealedMap($playedGame);

        // Determine which cells to reveal for this step
        if ($isBomb) {
            $revealedCells = $this->getBombRevealedCells($grid, $coords[0], $coords[1], $alreadyRevealed);
        } elseif ('m' === ($grid[$coords[0]][$coords[1]] ?? null)) {
            // Direct click on a mine — reveal it immediately (flood-fill skips mines)
            $revealedCells = [['row' => $coords[0], 'col' => $coords[1], 'value' => 'm']];
        } else {
            $revealedCells = $this->floodFill($grid, $coords[0], $coords[1], $alreadyRevealed);
        }

        $minesFound = count(array_filter($revealedCells, static fn($c) => 'm' === $c['value']));
        $redPoints = ($playedGame->getRedPoints() ?? 0) + ('red' === $player ? $minesFound : 0);
        $bluePoints = ($playedGame->getBluePoints() ?? 0) + ('blue' === $player ? $minesFound : 0);
        $gameOver = $redPoints > 25 || $bluePoints > 25;

        // Reveal remaining mines when the game ends
        $leftMines = [];
        if ($gameOver) {
            $finalRevealed = $alreadyRevealed;
            foreach ($revealedCells as $c) {
                $finalRevealed[$c['row'] . ',' . $c['col']] = true;
            }
            $leftMines = $this->getLeftMines($grid, $finalRevealed);
        }

        $this->saveStepToDb($gameAssoc, $event, $player, $revealedCells, $redPoints, $bluePoints);

        $users = $this->getUserCollection($playedGame);
        $count = $this->getPlayerCount($users);
        $topic = 'mineseeker/channel/' . $gameAssoc;

        $data = [
            'coords'        => $coords,
            'player'        => $player,
            'bomb'          => $isBomb,
            'revealedCells' => $revealedCells,
            'minesFound'    => $minesFound,
            'redPoints'     => $redPoints,
            'bluePoints'    => $bluePoints,
            'resign'        => null,
            'gameOver'      => $gameOver,
            'leftMines'     => $leftMines,
        ];

        try {
            $this->hub->publish(new Update(
                $topic,
                json_encode([
                    'userTopicId' => $userName,
                    'channel'     => $topic,
                    'user'        => $userName,
                    'userCnt'     => $count,
                    'data'        => $data,
                ], JSON_THROW_ON_ERROR)
            ));
        } catch (JsonException $e) {
            throw new RuntimeException($e->getMessage());
        }

        return $data;
    }

    // ------------------------------------------------------------------ //
    //  Grid helpers
    // ------------------------------------------------------------------ //

    /** Load the grid rows from the database as a 2-D array. */
    private function loadGrid(string $gameAssoc): array
    {
        $playedGame = $this->getPlayedGame($gameAssoc);
        $gridEntity = $playedGame?->getGrid();

        if (null === $gridEntity) {
            return [];
        }

        $grid = [];
        /** @var GridRow $row */
        foreach ($gridEntity->getGridRow() as $row) {
            $grid[] = $row->getGridCol();
        }

        return $grid;
    }

    /**
     * BFS flood-fill starting at (row, col).
     * Reveals the clicked cell plus all connected zero-value cells and their non-mine borders.
     * Mines are never added to the result.
     *
     * @param array<string, true> $visited Map of "row,col" already revealed; updated in-place.
     */
    private function floodFill(array $grid, int $row, int $col, array &$visited): array
    {
        $cells = [];
        $queue = [[$row, $col]];
        $dirs = [[-1, -1], [-1, 0], [-1, 1], [0, -1], [0, 1], [1, -1], [1, 0], [1, 1]];

        while (!empty($queue)) {
            [$r, $c] = array_shift($queue);
            $key = $r . ',' . $c;

            if (isset($visited[$key])) {
                continue;
            }
            $visited[$key] = true;

            if (!isset($grid[$r][$c])) {
                continue;
            }

            $value = $grid[$r][$c];

            // Mines are never cascade-revealed
            if ('m' === $value) {
                continue;
            }

            $cells[] = ['row' => $r, 'col' => $c, 'value' => $value];

            // Only expand neighbours for zero-cells
            if (0 === $value) {
                foreach ($dirs as [$dr, $dc]) {
                    $nr = $r + $dr;
                    $nc = $c + $dc;
                    $nKey = $nr . ',' . $nc;
                    if (!isset($visited[$nKey]) && isset($grid[$nr][$nc])) {
                        $queue[] = [$nr, $nc];
                    }
                }
            }
        }

        return $cells;
    }

    /**
     * Compute the 25-cell bomb radius (mirrors the JS getBombRadius logic).
     */
    private function getBombRadius(int $row, int $col): array
    {
        $max = 13; // grid is 16×16 (0–15); clamped centre must be in 2–13
        if (!($row > 1 && $row < 14 && $col > 1 && $col < 14)) {
            $row = max(2, min($row, $max));
            $col = max(2, min($col, $max));
        }

        return [
            [$row, $col], [$row - 2, $col - 2], [$row - 2, $col], [$row - 2, $col + 2],
            [$row, $col - 2], [$row, $col + 2], [$row + 2, $col - 2], [$row + 2, $col],
            [$row + 2, $col + 2], [$row - 2, $col + 1], [$row - 2, $col - 1],
            [$row - 1, $col - 2], [$row - 1, $col - 1], [$row - 1, $col], [$row - 1, $col + 1], [$row - 1, $col + 2],
            [$row, $col - 1], [$row, $col + 1],
            [$row + 1, $col - 2], [$row + 1, $col - 1], [$row + 1, $col], [$row + 1, $col + 1], [$row + 1, $col + 2],
            [$row + 2, $col - 1], [$row + 2, $col + 1],
        ];
    }

    /**
     * Reveal cells hit by a bomb.  Direct mine hits are revealed (flagged);
     * non-mine cells trigger a normal flood-fill (so zero-cells still cascade).
     */
    private function getBombRevealedCells(array $grid, int $row, int $col, array $alreadyRevealed): array
    {
        $bombCells = $this->getBombRadius($row, $col);
        $visited = $alreadyRevealed;
        $cells = [];

        foreach ($bombCells as [$r, $c]) {
            $key = $r . ',' . $c;
            if (isset($visited[$key]) || !isset($grid[$r][$c])) {
                continue;
            }

            if ('m' === $grid[$r][$c]) {
                $visited[$key] = true;
                $cells[] = ['row' => $r, 'col' => $c, 'value' => 'm'];
            } else {
                // flood-fill handles the zero-cascade and deduplication via $visited
                $newCells = $this->floodFill($grid, $r, $c, $visited);
                $cells = array_merge($cells, $newCells);
            }
        }

        return $cells;
    }

    /**
     * Build a "row,col" => true map from every previously saved step.
     */
    private function buildRevealedMap(PlayedGame $playedGame): array
    {
        $map = [];
        foreach ($playedGame->getSteps() as $step) {
            foreach ($step->getRevealedCells() ?? [] as $cell) {
                $map[$cell['row'] . ',' . $cell['col']] = true;
            }
        }

        return $map;
    }

    /**
     * Return coordinates of mines that have NOT yet been revealed.
     *
     * @param array<string, true> $alreadyRevealed
     */
    private function getLeftMines(array $grid, array $alreadyRevealed): array
    {
        $mines = [];

        foreach ($grid as $r => $row) {
            foreach ($row as $c => $value) {
                if ('m' === $value && !isset($alreadyRevealed["$r,$c"])) {
                    $mines[] = ['row' => $r, 'col' => $c];
                }
            }
        }

        return $mines;
    }

    // ------------------------------------------------------------------ //
    //  Database helpers
    // ------------------------------------------------------------------ //

    private function getPlayedGame(string $gameAssoc): ?PlayedGame
    {
        return $this->playedGameRepository->findOneByGameAssoc($gameAssoc);
    }

    private function getPlayerCount(array $users): int
    {
        $red = '' !== $users['red'] || '' !== $users['redAnon'] ? 1 : 0;
        $blue = '' !== $users['blue'] || '' !== $users['blueAnon'] ? 1 : 0;

        return $red + $blue;
    }

    private function saveResignToDb(string $gameAssoc, string $color): void
    {
        $playedGame = $this->getPlayedGame($gameAssoc);
        $playedGame->setResign($color);
        $this->entityManager->persist($playedGame);
        $this->entityManager->flush();
    }

    private function saveStepToDb(
        string $gameAssoc,
        array  $event,
        string $player,
        array  $revealedCells,
        int    $redPoints,
        int    $bluePoints,
    ): void {
        try {
            $playedGame = $this->getPlayedGame($gameAssoc);

            $step = new Step();
            $step->setRow($event['coords'][0]);
            $step->setCol($event['coords'][1]);
            $step->setWBomb((bool)$event['bomb']);
            $step->setPlayer($player);
            $step->setRevealedCells($revealedCells);
            $step->setPlayedGame($playedGame);
            $step->setCreated(new DateTime());
            $this->entityManager->persist($step);

            $playedGame->setRedPoints($redPoints);
            $playedGame->setBluePoints($bluePoints);
            $playedGame->setRedExplodedBomb((bool)$event['bomb'] && 'red' === $player ? true : null);
            $playedGame->setBlueExplodedBomb((bool)$event['bomb'] && 'blue' === $player ? true : null);
            $playedGame->setUpdated(new DateTime());
            $this->entityManager->persist($playedGame);

            $this->entityManager->flush();
        } catch (Exception $e) {
            $this->logger->error($e->getMessage());
        }
    }

    private function saveUserToDb(string $gameAssoc, string $userName, ?UserInterface $user, int $count): array
    {
        $playedGame = $this->getPlayedGame($gameAssoc);

        null !== $user
            ? $this->saveRegisteredUser($userName, $count, $playedGame)
            : $this->saveAnonUser($userName, $count, $playedGame);

        $this->entityManager->persist($playedGame);
        $this->entityManager->flush();

        return $this->getUserCollection($playedGame);
    }

    private function saveRegisteredUser(string $userName, int $count, PlayedGame $playedGame): void
    {
        /** @var User $user */
        $user = $this->userRepository->findOneByUsername($userName);

        try {
            if ($count === 1) {
                $random = random_int(0, 1);
                !$random ? $playedGame->setRed($user) : $playedGame->setBlue($user);
            } else {
                null === $playedGame->getRed() && null === $playedGame->getRedAnon()
                    ? $playedGame->setRed($user)
                    : $playedGame->setBlue($user);
            }
        } catch (Exception $e) {
            $this->logger->error($e->getMessage());
        }
    }

    private function saveAnonUser(string $userName, int $count, PlayedGame $playedGame): void
    {
        try {
            $anon = new Gamer();
            $anon->setUsername($userName);
            $anon->setConnTimestamp(new DateTime());
            $this->entityManager->persist($anon);

            if ($count === 1) {
                $random = random_int(0, 1);
                !$random ? $playedGame->setRedAnon($anon) : $playedGame->setBlueAnon($anon);
            } else {
                null === $playedGame->getRed() && null === $playedGame->getRedAnon()
                    ? $playedGame->setRedAnon($anon)
                    : $playedGame->setBlueAnon($anon);
            }
        } catch (Exception $e) {
            $this->logger->error($e->getMessage());
        }
    }

    private function getUserCollection(PlayedGame $playedGame): array
    {
        $redUser   = $playedGame->getRed();
        $blueUser  = $playedGame->getBlue();

        return [
            'red'        => null !== $redUser ? $redUser->getUsername() : '',
            'blue'       => null !== $blueUser ? $blueUser->getUsername() : '',
            'redAnon'    => null !== $playedGame->getRedAnon() ? $playedGame->getRedAnon()->getUserName() : '',
            'blueAnon'   => null !== $playedGame->getBlueAnon() ? $playedGame->getBlueAnon()->getUserName() : '',
            'redAvatar'  => null !== $redUser && null !== $redUser->getAvatarPath()
                            ? $this->cacheManager->generateUrl($redUser->getAvatarPath(), 'avatar_thumb')
                            : null,
            'blueAvatar' => null !== $blueUser && null !== $blueUser->getAvatarPath()
                            ? $this->cacheManager->generateUrl($blueUser->getAvatarPath(), 'avatar_thumb')
                            : null,
        ];
    }

    public function publishChallenge(string $targetGameAssoc, string $challengerGameAssoc): void
    {
        $challengerGame = $this->getPlayedGame($challengerGameAssoc);
        $challengerName = 'Unknown';
        if (null !== $challengerGame) {
            $users = $this->getUserCollection($challengerGame);
            $challengerName = $users['red'] ?: $users['redAnon'] ?: $users['blue'] ?: $users['blueAnon'] ?: 'Unknown';
        }

        try {
            $this->hub->publish(new Update(
                'mineseeker/channel/' . $targetGameAssoc,
                json_encode([
                    'type'                => 'challenge',
                    'challengerName'      => $challengerName,
                    'challengerGameAssoc' => $challengerGameAssoc,
                ], JSON_THROW_ON_ERROR)
            ));
        } catch (JsonException $e) {
            $this->logger->error('Challenge publish error: ' . $e->getMessage());
        }
    }

    public function publishChallengeResponse(string $challengerGameAssoc, bool $accepted, string $targetGameAssoc): void
    {
        try {
            $this->hub->publish(new Update(
                'mineseeker/channel/' . $challengerGameAssoc,
                json_encode([
                    'type'            => 'challenge-response',
                    'accepted'        => $accepted,
                    'targetGameAssoc' => $targetGameAssoc,
                ], JSON_THROW_ON_ERROR)
            ));
        } catch (JsonException $e) {
            $this->logger->error('Challenge response publish error: ' . $e->getMessage());
        }
    }

    private function publishToLobby(array $data): void
    {
        try {
            $this->hub->publish(new Update(
                'mineseeker/lobby',
                json_encode($data, JSON_THROW_ON_ERROR)
            ));
        } catch (JsonException $e) {
            $this->logger->error('Lobby publish error: ' . $e->getMessage());
        }
    }
}