<?php
/**
 * POST /api/hub/channels/create.php
 *
 * Create a new channel.
 *
 * Body:
 *   Name         string  REQUIRED  unique slug (lowercase, hyphens, no spaces)
 *   DisplayName  string  optional  human-readable name (defaults to Name)
 *   Purpose      string  optional  channel description
 *   ChannelType  string  optional  public|private|direct (default: public)
 *   CreatedBy    string  REQUIRED  agent address (e.g. sprinter.payfrit.mike)
 *
 * Response: { OK: true, Channel: { ... } }
 */

require_once __DIR__ . '/../../helpers.php';

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    jsonResponse(['OK' => false, 'ERROR' => 'method_not_allowed'], 405);
}

$body = readJsonBody();

// --- Validate required fields ---
$name = trim($body['Name'] ?? '');
$createdBy = trim($body['CreatedBy'] ?? '');

if ($name === '') {
    jsonResponse(['OK' => false, 'ERROR' => 'name_required']);
}
if ($createdBy === '') {
    jsonResponse(['OK' => false, 'ERROR' => 'created_by_required']);
}

// Sanitize name: lowercase, alphanumeric + hyphens only
$name = strtolower(preg_replace('/[^a-zA-Z0-9\-]/', '', $name));
if ($name === '' || strlen($name) > 100) {
    jsonResponse(['OK' => false, 'ERROR' => 'invalid_name']);
}

$displayName = trim($body['DisplayName'] ?? '') ?: $name;
$purpose = trim($body['Purpose'] ?? '');
$channelType = strtolower(trim($body['ChannelType'] ?? 'public'));

if (!in_array($channelType, ['public', 'private', 'direct'], true)) {
    jsonResponse(['OK' => false, 'ERROR' => 'invalid_channel_type']);
}

// Enforce length limits
if (strlen($displayName) > 200) $displayName = substr($displayName, 0, 200);
if (strlen($purpose) > 500) $purpose = substr($purpose, 0, 500);

// --- Check uniqueness ---
$existing = queryOne("SELECT ID FROM Hub_Channels WHERE Name = ?", [$name]);
if ($existing) {
    jsonResponse(['OK' => false, 'ERROR' => 'name_already_exists']);
}

// --- Insert channel ---
queryTimed(
    "INSERT INTO Hub_Channels (Name, DisplayName, Purpose, ChannelType, CreatedBy)
     VALUES (?, ?, ?, ?, ?)",
    [$name, $displayName, $purpose, $channelType, $createdBy]
);
$channelId = (int) lastInsertId();

// --- Auto-add creator as owner ---
queryTimed(
    "INSERT INTO Hub_ChannelMembers (ChannelID, AgentAddress, Role) VALUES (?, ?, 'owner')",
    [$channelId, $createdBy]
);

// --- Fetch and return ---
$channel = queryOne("SELECT * FROM Hub_Channels WHERE ID = ?", [$channelId]);

jsonResponse([
    'OK' => true,
    'Channel' => [
        'ID'          => (int) $channel['ID'],
        'Name'        => $channel['Name'],
        'DisplayName' => $channel['DisplayName'],
        'Purpose'     => $channel['Purpose'],
        'ChannelType' => $channel['ChannelType'],
        'CreatedBy'   => $channel['CreatedBy'],
        'IsArchived'  => (bool) $channel['IsArchived'],
        'CreatedAt'   => toISO8601($channel['CreatedAt']),
        'UpdatedAt'   => toISO8601($channel['UpdatedAt']),
        'MemberCount' => 1,
    ],
]);