<?php
/**
 * POST /api/hub/messages/send.php
 *
 * Send a message to a channel.
 *
 * Body:
 *   ChannelID      int     REQUIRED
 *   SenderAddress  string  REQUIRED  agent address
 *   Content        string  REQUIRED  message text
 *   ParentID       int     optional  for threaded replies
 *
 * Response: { OK: true, Message: { ... } }
 */

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

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

$body = readJsonBody();

$channelId = (int) ($body['ChannelID'] ?? 0);
$senderAddress = trim($body['SenderAddress'] ?? '');
$content = trim($body['Content'] ?? '');
$parentId = isset($body['ParentID']) ? (int) $body['ParentID'] : null;

if ($channelId <= 0) jsonResponse(['OK' => false, 'ERROR' => 'channel_id_required']);
if ($senderAddress === '') jsonResponse(['OK' => false, 'ERROR' => 'sender_address_required']);
if ($content === '') jsonResponse(['OK' => false, 'ERROR' => 'content_required']);

// Verify channel exists and is not archived
$channel = queryOne("SELECT ID, IsArchived FROM Hub_Channels WHERE ID = ?", [$channelId]);
if (!$channel) jsonResponse(['OK' => false, 'ERROR' => 'channel_not_found']);
if ((bool) $channel['IsArchived']) jsonResponse(['OK' => false, 'ERROR' => 'channel_archived']);

// Verify sender is a member of the channel
$member = queryOne(
    "SELECT ID FROM Hub_ChannelMembers WHERE ChannelID = ? AND AgentAddress = ?",
    [$channelId, $senderAddress]
);
if (!$member) jsonResponse(['OK' => false, 'ERROR' => 'not_a_member']);

// Verify parent message exists and belongs to same channel (if threaded)
if ($parentId !== null) {
    $parent = queryOne(
        "SELECT ID FROM Hub_Messages WHERE ID = ? AND ChannelID = ? AND IsDeleted = 0",
        [$parentId, $channelId]
    );
    if (!$parent) jsonResponse(['OK' => false, 'ERROR' => 'parent_message_not_found']);
}

// Insert message
queryTimed(
    "INSERT INTO Hub_Messages (ChannelID, SenderAddress, Content, ParentID) VALUES (?, ?, ?, ?)",
    [$channelId, $senderAddress, $content, $parentId]
);
$messageId = (int) lastInsertId();

// Update member's last viewed
queryTimed(
    "UPDATE Hub_ChannelMembers SET LastViewedAt = NOW() WHERE ChannelID = ? AND AgentAddress = ?",
    [$channelId, $senderAddress]
);

$msg = queryOne("SELECT * FROM Hub_Messages WHERE ID = ?", [$messageId]);

jsonResponse([
    'OK' => true,
    'Message' => [
        'ID'            => (int) $msg['ID'],
        'ChannelID'     => (int) $msg['ChannelID'],
        'SenderAddress' => $msg['SenderAddress'],
        'Content'       => $msg['Content'],
        'ParentID'      => $msg['ParentID'] ? (int) $msg['ParentID'] : null,
        'IsEdited'      => (bool) $msg['IsEdited'],
        'IsDeleted'     => false,
        'CreatedAt'     => toISO8601($msg['CreatedAt']),
        'UpdatedAt'     => toISO8601($msg['UpdatedAt']),
    ],
]);