<?php
// Shopping-list routes:
//   POST   /api/shopping              (client)  upsert active card {uid, title, body, updated_at}
//   GET    /api/shopping              (client + session) read current state
//   POST   /api/shopping/check        (session)  toggle one line  {line, checked}
//   GET    /shopping                  (session)  phone-friendly UI
//
// Plaintext on purpose — shopping-list content is low-stakes and
// everything here is session- or client-auth'd. No per-tenant key
// dance like chat / collab-buckets. If that needs tightening later,
// it's a one-table migration.

if (!defined('RELAY_BOOTSTRAPPED')) { http_response_code(404); exit; }

$clientTenant = $clientTenant ?? authClient($db);
$tenant = $sessionTenant ?: $clientTenant;

function shoppingLoad(PDO $db, int $tenantId): ?array {
    $stmt = $db->prepare('SELECT card_uid, title, body, updated_at_client, updated_at_server FROM shopping_state WHERE tenant_id = :t');
    $stmt->execute(['t' => $tenantId]);
    $row = $stmt->fetch();
    return $row ?: null;
}

// ── POST /api/shopping ────────────────────────────────────────
// Client pushes the currently-active card's content. `updated_at`
// is the client's timestamp — used for lose-the-race checks.

if ($route === '/api/shopping' && $method === 'POST') {
    if (!$clientTenant) jsonResponse(['error' => 'unauthorized'], 401);
    $input = json_decode(file_get_contents('php://input'), true) ?: [];
    $uid   = trim((string)($input['card_uid'] ?? ''));
    $title = (string)($input['title'] ?? '');
    $body  = (string)($input['body'] ?? '');
    $clientTs = trim((string)($input['updated_at'] ?? '')) ?: gmdate('Y-m-d H:i:s');
    if ($uid === '') jsonResponse(['error' => 'card_uid required'], 400);

    // No server-side staleness guard: the client decides whether to
    // push by diffing its last-synced body against the current card,
    // not by timestamp, so cross-timezone clock comparisons can't
    // silently block edits. Last-writer per tick wins — phone-toggle
    // races lose at most one tick of flips (rare by design).
    $now = gmdate('Y-m-d H:i:s');
    $db->prepare('
        INSERT INTO shopping_state (tenant_id, card_uid, title, body, updated_at_client, updated_at_server)
        VALUES (:t, :u, :ti, :b, :c, :s)
        ON CONFLICT(tenant_id) DO UPDATE SET
            card_uid = excluded.card_uid,
            title = excluded.title,
            body = excluded.body,
            updated_at_client = excluded.updated_at_client,
            updated_at_server = excluded.updated_at_server
    ')->execute([
        't'  => $clientTenant['id'],
        'u'  => $uid,
        'ti' => $title,
        'b'  => $body,
        'c'  => $clientTs,
        's'  => $now,
    ]);
    jsonResponse(['ok' => true, 'stored' => true, 'updated_at_server' => $now]);
}

// ── GET /api/shopping ────────────────────────────────────────
// Both the client (to pull phone-made toggles back) and the
// session-auth'd phone UI poll this.

if ($route === '/api/shopping' && $method === 'GET') {
    if (!$tenant) jsonResponse(['error' => 'unauthorized'], 401);
    $state = shoppingLoad($db, (int)$tenant['id']);
    if (!$state) jsonResponse(['ok' => true, 'state' => null]);
    jsonResponse(['ok' => true, 'state' => $state]);
}

// ── POST /api/shopping/check ─────────────────────────────────
// Phone-side toggle. Body: { line: "- [ ] milk", checked: true }.
// We match the exact line once to keep merges simple; if the line
// isn't found (hyprcrd just rewrote it), the caller reloads and
// retries. Bumps updated_at_server so the next client pull sees
// the change.

if ($route === '/api/shopping/check' && $method === 'POST') {
    if (!$sessionTenant) jsonResponse(['error' => 'unauthorized'], 401);
    $input = json_decode(file_get_contents('php://input'), true) ?: [];
    $line  = (string)($input['line'] ?? '');
    $checked = !empty($input['checked']);
    if ($line === '') jsonResponse(['error' => 'line required'], 400);

    $state = shoppingLoad($db, (int)$sessionTenant['id']);
    if (!$state) jsonResponse(['error' => 'no active list'], 404);
    $body = $state['body'];
    $lines = preg_split("/\r\n|\n|\r/", $body);
    $hit = false;
    foreach ($lines as $i => $l) {
        if ($l !== $line) continue;
        $toggled = $checked
            ? preg_replace('/^(\s*-\s*)\[\s\]/', '$1[x]', $l, 1)
            : preg_replace('/^(\s*-\s*)\[[xX]\]/', '$1[ ]', $l, 1);
        if ($toggled === $l) continue; // not a checkbox line
        $lines[$i] = $toggled;
        $hit = true;
        break;
    }
    if (!$hit) jsonResponse(['error' => 'line not found (list may have been edited — reload)'], 409);

    $newBody = implode("\n", $lines);
    $now = gmdate('Y-m-d H:i:s');
    $db->prepare('UPDATE shopping_state SET body = :b, updated_at_server = :s WHERE tenant_id = :t')
        ->execute(['b' => $newBody, 's' => $now, 't' => $sessionTenant['id']]);
    jsonResponse(['ok' => true, 'updated_at_server' => $now]);
}

// Shopping list lives inside the relay UI as a regular view (see
// relay/ui/layout.php + app.js). No separate /shopping page — login
// and navigation are the same as for every other relay feature.