<?php
define('CYBERCHAT_API', true);
require_once __DIR__ . '/../bootstrap.php';
require_once ROOT_DIR . '/lib/voice_transcoder.php';
sendCorsHeaders();

try { archiveYesterdayIfNeeded(); } catch (Throwable $e) { error_log($e->getMessage()); }
$action = $_POST['action'] ?? $_GET['action'] ?? '';

match ($action) {
    'send' => sendTextMessage(),
    'send_voice' => sendVoiceMessage(),
    'recording' => setRecordingStatus(),
    'poll' => pollMessages(),
    'history' => archiveDays(),
    default => jsonResponse(['error' => 'Unknown action'], 400),
};

function messagePayload(array $row): array {
    return [
        'id' => (int)$row['id'],
        'user_id' => isset($row['user_id']) ? (int)$row['user_id'] : null,
        'username' => $row['username'],
        'color' => $row['color'],
        'message' => $row['message'],
        'message_type' => $row['message_type'] ?? 'text',
        'voice_url' => !empty($row['voice_file']) ? voicePublicPath($row['voice_file']) : null,
        'voice_mime' => $row['voice_mime'] ?? null,
        'voice_duration' => isset($row['voice_duration']) ? (float)$row['voice_duration'] : null,
        'voice_bitrate_kbps' => isset($row['voice_bitrate_kbps']) ? (int)$row['voice_bitrate_kbps'] : null,
        'reply_to_id' => !empty($row['reply_to_id']) ? (int)$row['reply_to_id'] : null,
        'reply_depth' => isset($row['reply_depth']) ? (int)$row['reply_depth'] : 0,
        'reply_username' => $row['reply_username'] ?? null,
        'reply_message' => $row['reply_message'] ?? null,
        'reply_message_type' => $row['reply_message_type'] ?? null,
        'created_at' => (int)$row['created_at'],
        'day_key' => $row['day_key'] ?? dayKey(),
    ];
}

function messageSelectSql(string $where): string {
    return "SELECT m.*,p.username AS reply_username,p.message AS reply_message,
        p.message_type AS reply_message_type
        FROM messages m LEFT JOIN messages p ON p.id=m.reply_to_id WHERE $where";
}

function messageById(PDO $db, int $id): array {
    $stmt = $db->prepare(messageSelectSql('m.id=?'));
    $stmt->execute([$id]);
    $row = $stmt->fetch();
    if (!$row) throw new RuntimeException('Stored message could not be loaded.');
    return $row;
}

function resolveReply(PDO $db): array {
    $replyId = max(0, (int)($_POST['reply_to_id'] ?? 0));
    if ($replyId === 0) return [null, 0];
    if (!getConfigVal('chat.replies_enabled', true)) {
        jsonResponse(['error' => 'Replies are disabled'], 403);
    }
    $maxDepth = max(1, min(20, (int)getConfigVal('chat.reply_max_depth', 4)));
    $stmt = $db->prepare("SELECT id,reply_depth FROM messages WHERE id=? AND day_key=?");
    $stmt->execute([$replyId, dayKey()]);
    $parent = $stmt->fetch();
    if (!$parent) jsonResponse(['error' => 'The message being replied to is unavailable'], 404);
    $depth = (int)$parent['reply_depth'] + 1;
    if ($depth > $maxDepth) {
        jsonResponse(['error' => "Reply depth limit reached (max $maxDepth)"], 400);
    }
    return [$replyId, $depth];
}

function sendTextMessage(): never {
    $user = authRequired();
    $message = trim((string)($_POST['message'] ?? ''));
    $max = (int)getConfigVal('chat.max_message_length', 500);
    if ($message === '') jsonResponse(['error' => 'Empty message'], 400);
    if (strlen($message) > $max) jsonResponse(['error' => "Message too long (max $max chars)"], 400);

    $db = getDB();
    [$replyId, $replyDepth] = resolveReply($db);
    $db->prepare("INSERT INTO messages
        (user_id,username,color,message,reply_to_id,reply_depth,created_at,day_key)
        VALUES (?,?,?,?,?,?,CAST(strftime('%s','now') AS INTEGER),?)")->execute([
            $user['id'], $user['username'], $user['color'], $message,
            $replyId, $replyDepth, dayKey(),
        ]);
    $messageId = (int)$db->lastInsertId();
    trackEvent('message_text', '/api/messages.php', (int)$user['id']);
    jsonResponse(['success' => true, 'message' => messagePayload(messageById($db, $messageId))]);
}

function sendVoiceMessage(): never {
    $user = authRequired();
    if (!getConfigVal('voice.enabled', true) || !featureValue($user, 'voice_messages', true)) {
        jsonResponse(['error' => 'Your plan does not include voice messages'], 403);
    }
    if (empty($_FILES['voice']) || !is_array($_FILES['voice'])) {
        jsonResponse(['error' => 'No voice clip uploaded'], 400);
    }
    $file = $_FILES['voice'];
    if (($file['error'] ?? UPLOAD_ERR_NO_FILE) !== UPLOAD_ERR_OK) {
        jsonResponse(['error' => 'Voice upload failed'], 400);
    }
    $maxBytes = (int)getConfigVal('voice.max_upload_bytes', 12582912);
    if (($file['size'] ?? 0) < 1 || $file['size'] > $maxBytes) {
        jsonResponse(['error' => 'Voice clip exceeds the upload limit'], 400);
    }
    $duration = (float)($_POST['duration'] ?? 0);
    $maxSeconds = max(1, (int)getConfigVal('voice.max_duration_seconds', 60));
    if ($duration <= 0 || $duration > $maxSeconds + 1) {
        jsonResponse(['error' => "Voice clip must be $maxSeconds seconds or less"], 400);
    }

    $mime = class_exists('finfo') ? (string)(new finfo(FILEINFO_MIME_TYPE))->file($file['tmp_name']) : '';
    $header = (string)file_get_contents($file['tmp_name'], false, null, 0, 16);
    if (str_starts_with($header, "\x1A\x45\xDF\xA3")) $mime = 'audio/webm';
    elseif (str_starts_with($header, 'RIFF') && substr($header, 8, 4) === 'WAVE') $mime = 'audio/wav';
    elseif (strlen($header) >= 8 && substr($header, 4, 4) === 'ftyp') $mime = 'audio/mp4';
    elseif (strlen($header) >= 2 && ord($header[0]) === 0xFF && (ord($header[1]) & 0xF0) === 0xF0) $mime = 'audio/aac';
    $allowed = [
        'audio/webm' => 'webm',
        'video/webm' => 'webm',
        'audio/wav' => 'wav',
        'audio/x-wav' => 'wav',
        'audio/wave' => 'wav',
        'audio/mp4' => 'm4a',
        'video/mp4' => 'm4a',
        'audio/aac' => 'aac',
        'audio/x-aac' => 'aac',
    ];
    if (!isset($allowed[$mime])) jsonResponse(['error' => 'Voice clips must be WebM, MP4/M4A, AAC, or WAV'], 400);

    $db = getDB();
    [$replyId, $replyDepth] = resolveReply($db);
    $dir = voiceUploadDir();
    ensureWritableDirectory($dir, 'Voice storage');
    $token = bin2hex(random_bytes(20));
    $sourceFilename = $token . '.' . $allowed[$mime];
    $sourcePath = $dir . '/' . $sourceFilename;
    if (!move_uploaded_file($file['tmp_name'], $sourcePath)) {
        jsonResponse(['error' => 'Could not store voice clip'], 500);
    }

    $sourceMime = match ($mime) {
        'video/webm' => 'audio/webm',
        'video/mp4' => 'audio/mp4',
        'audio/x-wav', 'audio/wave' => 'audio/wav',
        'audio/x-aac' => 'audio/aac',
        default => $mime,
    };
    $bitrate = max(48, min(320, (int)featureValue($user, 'voice_bitrate_kbps', 64)));
    try {
        $stored = transcodeVoiceRecording($sourcePath, $sourceFilename, $sourceMime, $bitrate);
    } catch (Throwable $e) {
        if (is_file($sourcePath)) @unlink($sourcePath);
        throw $e;
    }
    $filename = $stored['filename'];
    $storedMime = $stored['mime'];
    try {
        $db->prepare("INSERT INTO messages
            (user_id,username,color,message,message_type,voice_file,voice_mime,voice_duration,
             voice_bitrate_kbps,reply_to_id,reply_depth,created_at,day_key)
            VALUES (?,?,?,?,'voice',?,?,?,?,?,?,CAST(strftime('%s','now') AS INTEGER),?)")->execute([
                $user['id'], $user['username'], $user['color'], '[Voice clip]',
                $filename, $storedMime, $duration, $bitrate, $replyId, $replyDepth, dayKey(),
            ]);
    } catch (Throwable $e) {
        deleteVoiceFile($filename);
        throw $e;
    }
    $messageId = (int)$db->lastInsertId();
    $db->prepare("DELETE FROM recording_status WHERE channel_key='public' AND user_id=?")
        ->execute([$user['id']]);
    trackEvent('message_voice', '/api/messages.php', (int)$user['id']);
    jsonResponse(['success' => true, 'message' => messagePayload(messageById($db, $messageId))]);
}

function setRecordingStatus(): never {
    $user = authRequired();
    if (!featureValue($user, 'recording_status', false)) {
        jsonResponse(['error' => 'Your plan does not include recording indicators'], 403);
    }
    $active = filter_var($_POST['active'] ?? false, FILTER_VALIDATE_BOOLEAN);
    $db = getDB();
    if ($active) {
        $db->prepare("INSERT INTO recording_status (channel_key,user_id,expires_at) VALUES ('public',?,?)
            ON CONFLICT(channel_key,user_id) DO UPDATE SET expires_at=excluded.expires_at")
            ->execute([$user['id'], time() + 10]);
    } else {
        $db->prepare("DELETE FROM recording_status WHERE channel_key='public' AND user_id=?")
            ->execute([$user['id']]);
    }
    jsonResponse(['success' => true]);
}

function pollMessages(): never {
    $user = authRequired();
    $since = max(0, (int)($_GET['since'] ?? 0));
    $limit = max(1, min(250, (int)getConfigVal('chat.messages_per_page', 100)));
    $db = getDB();

    if ($since === 0) {
        $stmt = $db->prepare(messageSelectSql('m.day_key=?') . " ORDER BY m.id DESC LIMIT ?");
        $stmt->execute([dayKey(), $limit]);
        $rows = $stmt->fetchAll();
        usort($rows, 'compareMessagesChronologically');
        $hasMore = false;
    } else {
        $stmt = $db->prepare(messageSelectSql('m.day_key=? AND m.id>?') . " ORDER BY m.id LIMIT ?");
        $stmt->execute([dayKey(), $since, $limit + 1]);
        $rows = $stmt->fetchAll();
        $hasMore = count($rows) > $limit;
        if ($hasMore) $rows = array_slice($rows, 0, $limit);
    }

    $cursor = $since;
    foreach ($rows as $row) $cursor = max($cursor, (int)$row['id']);

    $cutoff = time() - 300;
    $onlineStmt = $db->prepare("SELECT COUNT(*) FROM sessions WHERE last_active>?");
    $onlineStmt->execute([$cutoff]);

    $recording = [];
    $db->prepare("DELETE FROM recording_status WHERE expires_at<=?")->execute([time()]);
    if (featureValue($user, 'recording_status', false)) {
        $recordStmt = $db->prepare("SELECT u.id,u.username,u.color FROM recording_status r
            JOIN users u ON u.id=r.user_id
            WHERE r.channel_key='public' AND r.expires_at>? AND r.user_id!=?");
        $recordStmt->execute([time(), $user['id']]);
        $recording = $recordStmt->fetchAll();
    }

    jsonResponse([
        'messages' => array_map('messagePayload', $rows),
        'cursor' => $cursor,
        'has_more' => $hasMore,
        'online' => (int)$onlineStmt->fetchColumn(),
        'recording' => $recording,
        'server_time' => time(),
    ]);
}

function compareMessagesChronologically(array $a, array $b): int {
    return ((int)$a['created_at'] <=> (int)$b['created_at'])
        ?: ((int)$a['id'] <=> (int)$b['id']);
}

function archiveDays(): never {
    $user = authRequired();
    $rows = personalArchiveRows($user, '', 1000);
    $days = array_values(array_unique(array_column($rows, 'day_key')));
    rsort($days);
    jsonResponse(['days' => $days]);
}