<?php
// bootstrap.php — Core helpers, DB init, session auth

define('ROOT_DIR', __DIR__);
define('CONFIG_FILE', ROOT_DIR . '/config.json');

// ─── Error handling: always return JSON, never raw PHP errors ────────────
set_error_handler(function(int $errno, string $errstr, string $errfile, int $errline): bool {
    // Only intercept fatal-ish errors during API requests
    if (defined('CYBERCHAT_API') && CYBERCHAT_API) {
        http_response_code(500);
        header('Content-Type: application/json');
        echo json_encode(['error' => 'Server error: ' . $errstr . ' in ' . basename($errfile) . ':' . $errline]);
        exit;
    }
    return false;
});

set_exception_handler(function(Throwable $e): void {
    if (defined('CYBERCHAT_API') && CYBERCHAT_API) {
        http_response_code(500);
        header('Content-Type: application/json');
        echo json_encode(['error' => 'Server exception: ' . $e->getMessage()]);
        exit;
    }
});

// ─── CORS headers (needed if embedding cross-origin) ─────────────────────
function sendCorsHeaders(): void {
    $origin = $_SERVER['HTTP_ORIGIN'] ?? '';
    // Allow same-origin and any origin configured in config
    // For strictest security, lock this to your domain
    if ($origin) {
        header('Access-Control-Allow-Origin: ' . $origin);
        header('Access-Control-Allow-Credentials: true');
        header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
        header('Access-Control-Allow-Headers: Content-Type, X-Requested-With');
    }
    // Handle preflight
    if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
        http_response_code(204);
        exit;
    }
}

// ─── Config ───────────────────────────────────────────────────────────────
function getConfig(): array {
    static $config = null;
    if ($config === null) {
        if (!file_exists(CONFIG_FILE)) {
            throw new RuntimeException('config.json not found at: ' . CONFIG_FILE);
        }
        $raw = file_get_contents(CONFIG_FILE);
        $config = json_decode($raw, true);
        if ($config === null) {
            throw new RuntimeException('config.json is not valid JSON: ' . json_last_error_msg());
        }
    }
    return $config;
}

function getConfigVal(string $path, mixed $default = null): mixed {
    $config = getConfig();
    $keys = explode('.', $path);
    $val = $config;
    foreach ($keys as $key) {
        if (!is_array($val) || !array_key_exists($key, $val)) return $default;
        $val = $val[$key];
    }
    return $val;
}

// ─── Database ─────────────────────────────────────────────────────────────
function getDB(): PDO {
    static $db = null;
    if ($db === null) {
        $dbRelPath = getConfigVal('database.main_db', 'db/chat.sqlite');
        $dbPath = ROOT_DIR . '/' . ltrim($dbRelPath, '/');
        $dir = dirname($dbPath);

        if (!is_dir($dir)) {
            if (!mkdir($dir, 0755, true)) {
                throw new RuntimeException("Cannot create db directory: $dir — check permissions");
            }
        }
        if (!is_writable($dir)) {
            throw new RuntimeException("db directory is not writable: $dir — run: chmod 755 $dir");
        }

        $db = new PDO('sqlite:' . $dbPath);
        $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        $db->exec('PRAGMA journal_mode=WAL');
        $db->exec('PRAGMA synchronous=NORMAL');
        $db->exec('PRAGMA foreign_keys=ON');
        initDB($db);
    }
    return $db;
}

function initDB(PDO $db): void {
    $db->exec("CREATE TABLE IF NOT EXISTS users (
        id            INTEGER PRIMARY KEY AUTOINCREMENT,
        username      TEXT    UNIQUE NOT NULL COLLATE NOCASE,
        password_hash TEXT    NOT NULL,
        color         TEXT    NOT NULL,
        created_at    INTEGER NOT NULL DEFAULT (strftime('%s','now')),
        last_seen     INTEGER
    )");

    $db->exec("CREATE TABLE IF NOT EXISTS sessions (
        id          TEXT    PRIMARY KEY,
        user_id     INTEGER NOT NULL,
        ip          TEXT    NOT NULL,
        created_at  INTEGER NOT NULL DEFAULT (strftime('%s','now')),
        last_active INTEGER NOT NULL DEFAULT (strftime('%s','now')),
        FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE CASCADE
    )");

    $db->exec("CREATE TABLE IF NOT EXISTS messages (
        id         INTEGER PRIMARY KEY AUTOINCREMENT,
        user_id    INTEGER NOT NULL,
        username   TEXT    NOT NULL,
        color      TEXT    NOT NULL,
        message    TEXT    NOT NULL,
        message_type TEXT  NOT NULL DEFAULT 'text',
        voice_file   TEXT,
        voice_mime   TEXT,
        voice_duration REAL,
        created_at INTEGER NOT NULL DEFAULT (strftime('%s','now')),
        day_key    TEXT    NOT NULL,
        FOREIGN KEY(user_id) REFERENCES users(id)
    )");

    ensureMessageColumns($db);
    $db->exec("CREATE INDEX IF NOT EXISTS idx_msg_day     ON messages(day_key)");
    $db->exec("CREATE INDEX IF NOT EXISTS idx_msg_created ON messages(created_at)");
    $db->exec("CREATE INDEX IF NOT EXISTS idx_sess_user   ON sessions(user_id)");
    $db->exec("CREATE INDEX IF NOT EXISTS idx_sess_active ON sessions(last_active)");
}

function ensureMessageColumns(PDO $db): void {
    $columns = [];
    foreach ($db->query("PRAGMA table_info(messages)") as $column) {
        $columns[$column['name']] = true;
    }
    $additions = [
        'message_type' => "TEXT NOT NULL DEFAULT 'text'",
        'voice_file' => 'TEXT',
        'voice_mime' => 'TEXT',
        'voice_duration' => 'REAL',
    ];
    foreach ($additions as $name => $definition) {
        if (!isset($columns[$name])) {
            $db->exec("ALTER TABLE messages ADD COLUMN $name $definition");
        }
    }
}

function voiceUploadDir(): string {
    $relative = getConfigVal('voice.upload_dir', 'uploads/voice');
    return ROOT_DIR . '/' . trim((string)$relative, '/');
}

function voicePublicPath(string $filename): string {
    $relative = trim((string)getConfigVal('voice.upload_dir', 'uploads/voice'), '/');
    return $relative . '/' . rawurlencode($filename);
}

function deleteVoiceFile(?string $filename): void {
    if (!$filename || basename($filename) !== $filename) return;
    $path = voiceUploadDir() . '/' . $filename;
    if (is_file($path)) unlink($path);
}

// ─── Archive DB ───────────────────────────────────────────────────────────
function getArchiveDB(string $year, string $month, string $day): PDO {
    $tpl     = getConfigVal('database.archive_path', 'archive/{year}/{month}/{day}.sqlite');
    $relPath = str_replace(['{year}','{month}','{day}'], [$year,$month,$day], $tpl);
    $fullPath = ROOT_DIR . '/' . ltrim($relPath, '/');
    $dir = dirname($fullPath);
    if (!is_dir($dir)) mkdir($dir, 0755, true);

    $adb = new PDO('sqlite:' . $fullPath);
    $adb->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $adb->exec('PRAGMA journal_mode=WAL');

    $adb->exec("CREATE TABLE IF NOT EXISTS messages (
        id         INTEGER PRIMARY KEY AUTOINCREMENT,
        user_id    INTEGER NOT NULL,
        username   TEXT    NOT NULL,
        color      TEXT    NOT NULL,
        message    TEXT    NOT NULL,
        message_type TEXT  NOT NULL DEFAULT 'text',
        voice_file   TEXT,
        voice_mime   TEXT,
        voice_duration REAL,
        created_at INTEGER NOT NULL,
        day_key    TEXT    NOT NULL
    )");
    ensureMessageColumns($adb);
    $adb->exec("CREATE TABLE IF NOT EXISTS archive_meta (
        key   TEXT PRIMARY KEY,
        value TEXT
    )");

    return $adb;
}

// ─── Helpers ──────────────────────────────────────────────────────────────
function dayKey(): string {
    return date('Y-m-d');
}

function clientIP(): string {
    foreach (['HTTP_CF_CONNECTING_IP','HTTP_X_FORWARDED_FOR','HTTP_X_REAL_IP','REMOTE_ADDR'] as $key) {
        if (!empty($_SERVER[$key])) {
            $ip = trim(explode(',', $_SERVER[$key])[0]);
            if (filter_var($ip, FILTER_VALIDATE_IP)) return $ip;
        }
    }
    return '0.0.0.0';
}

function jsonResponse(array $data, int $code = 200): never {
    http_response_code($code);
    header('Content-Type: application/json');
    header('Cache-Control: no-store');
    echo json_encode($data);
    exit;
}

// ─── Auth guard ───────────────────────────────────────────────────────────
function authRequired(): array {
    $db  = getDB();
    $sid = $_COOKIE['cyberchat_sid'] ?? '';

    if (!$sid) {
        jsonResponse(['error' => 'Not authenticated'], 401);
    }

    $timeout = (int)getConfigVal('security.session_timeout_hours', 24) * 3600;
    $cutoff  = time() - $timeout;

    $stmt = $db->prepare("
        SELECT s.id, s.ip, s.last_active,
               u.id AS uid, u.username, u.color
        FROM sessions s
        JOIN users u ON u.id = s.user_id
        WHERE s.id = ? AND s.last_active > ?
    ");
    $stmt->execute([$sid, $cutoff]);
    $session = $stmt->fetch();

    if (!$session) {
        jsonResponse(['error' => 'Session expired'], 401);
    }

    if (getConfigVal('chat.session_lock_ip', true) && $session['ip'] !== clientIP()) {
        jsonResponse(['error' => 'Session IP mismatch — logged in elsewhere'], 401);
    }

    $db->prepare("UPDATE sessions SET last_active = ? WHERE id = ?")->execute([time(), $sid]);

    return $session;
}

// ─── Daily archive ────────────────────────────────────────────────────────
function archiveYesterdayIfNeeded(): void {
    $yesterday = date('Y-m-d', strtotime('-1 day'));
    $flagFile  = ROOT_DIR . '/db/.archived_' . $yesterday;
    if (file_exists($flagFile)) return;

    $db   = getDB();
    $stmt = $db->prepare("SELECT * FROM messages WHERE day_key = ? ORDER BY created_at ASC");
    $stmt->execute([$yesterday]);
    $rows = $stmt->fetchAll();

    if (!empty($rows)) {
        [$y, $m, $d] = explode('-', $yesterday);
        $adb = getArchiveDB($y, $m, $d);
        $adb->beginTransaction();
        $ins = $adb->prepare("INSERT OR IGNORE INTO messages
            (id,user_id,username,color,message,message_type,voice_file,voice_mime,voice_duration,created_at,day_key)
            VALUES (?,?,?,?,?,?,?,?,?,?,?)");
        foreach ($rows as $r) {
            $ins->execute([
                $r['id'],$r['user_id'],$r['username'],$r['color'],$r['message'],
                $r['message_type'] ?? 'text',$r['voice_file'] ?? null,$r['voice_mime'] ?? null,
                $r['voice_duration'] ?? null,$r['created_at'],$r['day_key']
            ]);
        }
        $adb->exec("INSERT OR REPLACE INTO archive_meta(key,value) VALUES('archived_at','" . time() . "')");
        $adb->exec("INSERT OR REPLACE INTO archive_meta(key,value) VALUES('message_count','" . count($rows) . "')");
        $adb->commit();
    }

    $db->prepare("DELETE FROM messages WHERE day_key = ?")->execute([$yesterday]);
    file_put_contents($flagFile, date('c'));
}