<?php
declare(strict_types=1);

header('Content-Type: application/json; charset=utf-8');
header('Cache-Control: no-store, no-cache, must-revalidate, max-age=0');
header('X-Content-Type-Options: nosniff');

const ACHIEVEMENT_IDS = [
    'first_birth',
    'natural_zunchi_slave',
    'natural_tarinai_king',
    'self_zunchi_death',
    'natural_zunchi_slave_5_generations',
    'natural_tarinai_king_3_generations',
    'death_50_in_10_seconds',
    'birth_50_in_60_seconds',
    'great_mother_1000_births',
    'lifespan_completed',
    'soccer_ball_death',
    'fight_pair_danger_kill',
    'all_non_sleep_diseased_25',
    'colony_happy',
    'direct_feed_33',
    'ignite_during_birth_ritual',
    'laxative_starvation',
    'idle_observer_5_minutes',
    'placed_objects_100',
    'mechanized_industry',
    'safe_colony_25_5_minutes',
    'ants_alive_25',
    'ants_killed_100',
    'secret_collection_9_slots',
    'pause_spam_4_in_1_second',
    'continuous_play_1_hour',
    'below_absolute_zero_item',
    'undo_mass_revival',
    'robot_cleaner_100',
    'held_30_seconds',
    'minimalist_happy',
    'overprotective',
    'self_sufficient',
    'unplanned_city_30',
    'sauna_cold_plunge',
    'rain_shelter_all',
    'medicine_ledger_all',
    'mercury_lifespan',
    'enemy_enemy_friend',
    'revolution',
    'fuel_to_fire',
    'undo_20',
    'redo_20',
    'eternal_history_generation_10',
    'king_full_satisfaction',
    'slave_zero_satisfaction',
    'town_doctor_50',
    'poke_plushie_fling',
    'chaos_seeker_666_fights',
    'clean_freak_robot_only',
    'true_tarinai_observer',
];
const DATA_DIR_NAME = '.achievement_data';
const DATA_FILE_NAME = 'state.json';

function respond(array $payload, int $status = 200): never {
    http_response_code($status);
    echo json_encode($payload, JSON_UNESCAPED_SLASHES | JSON_INVALID_UTF8_SUBSTITUTE);
    exit;
}

function valid_player_id(string $value): bool {
    return preg_match('/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i', $value) === 1;
}

function empty_state(): array {
    return ['players' => [], 'unlocks' => []];
}

function normalize_state(mixed $value): array {
    if (!is_array($value)) return empty_state();
    $players = [];
    $unlocks = [];

    if (($value['v'] ?? null) === 2 && isset($value['p'], $value['u']) && is_array($value['p']) && is_array($value['u'])) {
        $playerIds = [];
        foreach ($value['p'] as $row) {
            if (!is_array($row) || !isset($row[0]) || !is_string($row[0]) || !valid_player_id($row[0])) continue;
            $id = $row[0];
            $playerIds[] = $id;
            $players[$id] = [
                'firstSeen' => max(1, (int)($row[1] ?? 1)),
                'lastSeen' => max(1, (int)($row[2] ?? ($row[1] ?? 1))),
                'gameVersion' => substr((string)($row[3] ?? ''), 0, 32),
            ];
        }
        foreach ($value['u'] as $achievementId => $flat) {
            if (!is_string($achievementId) || !is_array($flat)) continue;
            $records = [];
            $count = count($flat);
            for ($i = 0; $i + 1 < $count; $i += 2) {
                $playerIndex = (int)$flat[$i];
                if (!isset($playerIds[$playerIndex])) continue;
                $records[$playerIds[$playerIndex]] = max(1, (int)$flat[$i + 1]);
            }
            if ($records) $unlocks[$achievementId] = $records;
        }
    } else {
        $players = isset($value['players']) && is_array($value['players']) ? $value['players'] : [];
        $unlocks = isset($value['unlocks']) && is_array($value['unlocks']) ? $value['unlocks'] : [];
    }

    $legacySignal = isset($unlocks['signal_automation_first']) && is_array($unlocks['signal_automation_first'])
        ? $unlocks['signal_automation_first'] : [];
    $legacyLinks = isset($unlocks['link_craftsman']) && is_array($unlocks['link_craftsman'])
        ? $unlocks['link_craftsman'] : [];
    if ($legacySignal && $legacyLinks) {
        if (!isset($unlocks['mechanized_industry']) || !is_array($unlocks['mechanized_industry'])) {
            $unlocks['mechanized_industry'] = [];
        }
        foreach ($legacySignal as $playerId => $signalTime) {
            if (!isset($legacyLinks[$playerId])) continue;
            $unlocks['mechanized_industry'][$playerId] = max((int)$signalTime, (int)$legacyLinks[$playerId]);
        }
    }
    unset($unlocks['signal_automation_first'], $unlocks['link_craftsman']);

    return ['players' => $players, 'unlocks' => $unlocks];
}

function compact_state(array $state): array {
    $playerIds = array_keys($state['players']);
    sort($playerIds, SORT_STRING);
    $playerIndex = [];
    $players = [];
    foreach ($playerIds as $index => $id) {
        $playerIndex[$id] = $index;
        $player = is_array($state['players'][$id] ?? null) ? $state['players'][$id] : [];
        $players[] = [
            $id,
            max(1, (int)($player['firstSeen'] ?? 1)),
            max(1, (int)($player['lastSeen'] ?? ($player['firstSeen'] ?? 1))),
            substr((string)($player['gameVersion'] ?? ''), 0, 32),
        ];
    }
    $unlocks = [];
    foreach ($state['unlocks'] as $achievementId => $records) {
        if (!is_string($achievementId) || !is_array($records) || !$records) continue;
        $flat = [];
        foreach ($records as $id => $timestamp) {
            if (!isset($playerIndex[$id])) continue;
            $flat[] = $playerIndex[$id];
            $flat[] = max(1, (int)$timestamp);
        }
        if ($flat) $unlocks[$achievementId] = $flat;
    }
    ksort($unlocks, SORT_STRING);
    return ['v' => 2, 'p' => $players, 'u' => $unlocks];
}

function build_summary(array $state): array {
    $total = count($state['players']);
    $achievements = [];
    foreach (ACHIEVEMENT_IDS as $id) {
        $unlocked = isset($state['unlocks'][$id]) && is_array($state['unlocks'][$id])
            ? count($state['unlocks'][$id])
            : 0;
        $percentage = $total > 0 ? round(($unlocked / $total) * 100, 1) : 0.0;
        $achievements[$id] = [
            'unlockedPlayers' => $unlocked,
            'percentage' => $percentage,
        ];
    }
    return [
        'ok' => true,
        'totalPlayers' => $total,
        'achievements' => $achievements,
    ];
}

$method = strtoupper($_SERVER['REQUEST_METHOD'] ?? 'GET');
$payload = [];
if ($method === 'POST') {
    $raw = file_get_contents('php://input');
    $decoded = json_decode(is_string($raw) ? $raw : '', true);
    if (!is_array($decoded)) respond(['ok' => false, 'error' => 'invalid_json'], 400);
    $payload = $decoded;
}

$action = $method === 'POST'
    ? (string)($payload['action'] ?? '')
    : (string)($_GET['action'] ?? 'summary');
$playerId = $method === 'POST'
    ? (string)($payload['playerId'] ?? '')
    : (string)($_GET['playerId'] ?? '');

if (!in_array($action, ['session', 'unlock', 'sync', 'reset', 'summary'], true)) {
    respond(['ok' => false, 'error' => 'invalid_action'], 400);
}
if (!valid_player_id($playerId)) {
    respond(['ok' => false, 'error' => 'invalid_player'], 400);
}
$syncUnlocks = [];
if ($action === 'unlock') {
    $achievementId = (string)($payload['achievementId'] ?? '');
    if (!in_array($achievementId, ACHIEVEMENT_IDS, true)) {
        respond(['ok' => false, 'error' => 'invalid_achievement'], 400);
    }
} elseif ($action === 'sync') {
    $submittedUnlocks = $payload['unlocked'] ?? null;
    if (!is_array($submittedUnlocks) || count($submittedUnlocks) > count(ACHIEVEMENT_IDS)) {
        respond(['ok' => false, 'error' => 'invalid_unlocks'], 400);
    }
    foreach ($submittedUnlocks as $achievementId => $timestamp) {
        if (!is_string($achievementId) || !in_array($achievementId, ACHIEVEMENT_IDS, true)) {
            respond(['ok' => false, 'error' => 'invalid_achievement'], 400);
        }
        if (!is_int($timestamp) && !is_float($timestamp) && !is_string($timestamp)) {
            respond(['ok' => false, 'error' => 'invalid_timestamp'], 400);
        }
        $numericTimestamp = filter_var($timestamp, FILTER_VALIDATE_FLOAT);
        if ($numericTimestamp === false || $numericTimestamp <= 0) {
            respond(['ok' => false, 'error' => 'invalid_timestamp'], 400);
        }
        $syncUnlocks[$achievementId] = (float)$numericTimestamp;
    }
}

$dataDir = __DIR__ . DIRECTORY_SEPARATOR . DATA_DIR_NAME;
if (!is_dir($dataDir) && !mkdir($dataDir, 0775, true) && !is_dir($dataDir)) {
    respond(['ok' => false, 'error' => 'storage_unavailable'], 503);
}
$dataPath = $dataDir . DIRECTORY_SEPARATOR . DATA_FILE_NAME;
$handle = fopen($dataPath, 'c+');
if ($handle === false || !flock($handle, LOCK_EX)) {
    if (is_resource($handle)) fclose($handle);
    respond(['ok' => false, 'error' => 'storage_locked'], 503);
}

try {
    rewind($handle);
    $contents = stream_get_contents($handle);
    $state = normalize_state(json_decode(is_string($contents) ? $contents : '', true));
    $now = time();
    $player = isset($state['players'][$playerId]) && is_array($state['players'][$playerId])
        ? $state['players'][$playerId]
        : ['firstSeen' => $now];
    $player['lastSeen'] = $now;
    $player['gameVersion'] = substr((string)($payload['gameVersion'] ?? ''), 0, 32);
    $state['players'][$playerId] = $player;

    if ($action === 'unlock') {
        $achievementId = (string)$payload['achievementId'];
        if (!isset($state['unlocks'][$achievementId]) || !is_array($state['unlocks'][$achievementId])) {
            $state['unlocks'][$achievementId] = [];
        }
        if (!isset($state['unlocks'][$achievementId][$playerId])) {
            $state['unlocks'][$achievementId][$playerId] = $now;
        }
    } elseif ($action === 'sync') {
        foreach ($syncUnlocks as $achievementId => $submittedTimestamp) {
            if (!isset($state['unlocks'][$achievementId]) || !is_array($state['unlocks'][$achievementId])) {
                $state['unlocks'][$achievementId] = [];
            }
            if (isset($state['unlocks'][$achievementId][$playerId])) continue;
            $timestampSeconds = $submittedTimestamp >= 100000000000
                ? (int)floor($submittedTimestamp / 1000)
                : (int)floor($submittedTimestamp);
            $state['unlocks'][$achievementId][$playerId] = max(1, min($now, $timestampSeconds));
        }
    } elseif ($action === 'reset') {
        foreach ($state['unlocks'] as $achievementId => $records) {
            if (is_array($records)) unset($state['unlocks'][$achievementId][$playerId]);
        }
    }

    rewind($handle);
    ftruncate($handle, 0);
    fwrite($handle, json_encode(compact_state($state), JSON_UNESCAPED_SLASHES | JSON_INVALID_UTF8_SUBSTITUTE));
    fflush($handle);
    $summary = build_summary($state);
} finally {
    flock($handle, LOCK_UN);
    fclose($handle);
}

respond($summary);