#!/usr/bin/php -q
<?php
// ═══════════════════════════════════════════════════════════════════════════════════════════════
// PURPOSE
//   Creates or updates the per-partner folder in folder.view3 — "<PartnerShort>-Fallback" — that
//   holds the containers this host runs on the partner's behalf. Named from master.conf, so the
//   folder name follows the hostnames rather than a value someone has to keep in step by hand.
//
//   Onboard calls this on the mirror after deploying the owner's stack, so those containers land
//   somewhere that says whose they are instead of scattering into the mirror's own groups.
//
// OPERATIONAL MODEL
//   Create-or-update, never replace. The named folder is found in folder.view3 if it exists and
//   is amended in place; only its absence causes one to be created. Every other folder in the
//   file, and every container already filed elsewhere, is left exactly as it was — this is one
//   shelf in someone else's cupboard.
//
//   Called during onboard on the mirror, after the owner's stack has been deployed there, so the
//   containers exist by the time anything tries to file them.
//
//   The icon is resolved separately from the folder and never gates it. --icon-only performs
//   just that lookup and prints the URL, which is how onboard asks for it without writing
//   anything.
//
// DESIGN PRINCIPLES
//   The name comes from master.conf, never from a second source.
//       HOST2="unRAID-Jayred36" → "Jayred36-Fallback". The convention already existed by hand as
//       "Jayred365-Fallback", which did not match any derivable value — so the folder is renamed
//       to follow the conf rather than a conf field being invented to follow the folder.
//
//   Upsert by name, never append.
//       folder.view3 keys folders by a random id, so writing without looking produces a second
//       folder with the same name and half the contents. That is exactly what happened here: a
//       "Jayred365-Fallback" with the icon and no containers, beside one with the containers and
//       no icon. Match on name, keep the existing id.
//
//   This writes one folder, it does not replace the file.
//       include/docker.php used to mirror Varaverk's whole folder store over the top of
//       folder.view3's, destroying anything created in that plugin's UI. That write is gone. A
//       co-writer that edits a single key it owns is a different thing from one that overwrites
//       everything, and only the second kind loses data.
//
//   Closest Emby user wins the icon, and a wrong guess costs nothing.
//       The folder image is decoration. Exact match first, then lowest Levenshtein distance
//       within a bound. "Jayred36" resolves to "Jayred365" (distance 1) over "Jayred" (2).
//       This is deliberately unlike resolve_tailscale_ip's exact-prefix-plus-ambiguity-guard —
//       there, a wrong match sends data to the wrong machine; here it picks the wrong avatar.
//
// OPERATIONAL SAFEGUARDS
//   Atomic write — .vv.tmp then rename(), so folder.view3 never reads a truncated file.
//   Absent plugin is a clean skip, not an error — nothing to do if folder.view3 is not installed.
//   --dry-run prints the resulting folder and writes nothing.
//   Icon resolution failing never blocks the folder: no image is a cosmetic loss, no folder is not.
//
// RUNTIME MODES
//   fallback_folder.php --host=HOST2 [--containers=A,B,C] [--icon=URL] [--dry-run]
//   fallback_folder.php --host=HOST2 --icon-only        resolve and print the icon URL, write nothing
//
// CONFIGURATION
//   HOST1/HOST2…             master.conf — the hostname the folder is named after
//   HOST*_EMBY_URL           where to look users up (local is fine, it is a server-side call)
//   HOST*_EMBY_API_KEY       "
//   HOST*_EMBY_PUBLIC_URL    base the ICON is built from. Must be reachable from a browser on
//                            either host, so localhost:8096 is not it — the icon renders in the
//                            WebGUI of whichever machine is looking. Empty means no icon.
// ═══════════════════════════════════════════════════════════════════════════════════════════════

$pluginDir = dirname(__DIR__);
require_once $pluginDir . '/include/config.php';

define('FV3_JSON', '/boot/config/plugins/folder.view3/docker.json');

// ── Args ──────────────────────────────────────────────────────────────────────
$opts = ['host' => '', 'containers' => '', 'icon' => '', 'dry-run' => false, 'icon-only' => false];
foreach (array_slice($argv, 1) as $a) {
    if ($a === '--dry-run')  { $opts['dry-run']   = true; continue; }
    if ($a === '--icon-only'){ $opts['icon-only'] = true; continue; }
    if (preg_match('/^--([a-z-]+)=(.*)$/', $a, $m)) $opts[$m[1]] = $m[2];
}
$hostId = strtoupper(trim($opts['host']));
if (!preg_match('/^HOST\d+$/', $hostId)) {
    fwrite(STDERR, "usage: fallback_folder.php --host=HOST2 [--containers=A,B] [--dry-run]\n");
    exit(2);
}

$vars     = vv_conf_vars();
$hostname = trim($vars[$hostId] ?? '');
if ($hostname === '') { fwrite(STDERR, "$hostId is not set in master.conf\n"); exit(1); }


// derive_short_name() in common.sh: lowercase, strip a leading "unraid-", capitalise.
$short = preg_replace('/^unraid-/i', '', $hostname);
$short = ucfirst($short);
$folderName = $short . '-Fallback';

// ── Icon: closest Emby user ───────────────────────────────────────────────────
function vv_closest_emby_icon(string $short, array $vars, string $meId): array {
    $url = rtrim(trim($vars[$meId . '_EMBY_URL'] ?? ''), '/');
    $key = trim($vars[$meId . '_EMBY_API_KEY'] ?? '');
    $pub = rtrim(trim($vars[$meId . '_EMBY_PUBLIC_URL'] ?? ''), '/');
    if ($url === '' || $key === '') return ['', 'no Emby url/key configured'];

    $raw = @file_get_contents("$url/Users?api_key=" . urlencode($key), false,
        stream_context_create(['http' => ['timeout' => 10]]));
    $users = json_decode((string)$raw, true);
    if (!is_array($users) || !$users) return ['', 'Emby returned no users'];

    $needle = strtolower($short);
    $best = null; $bestD = PHP_INT_MAX; $runnerUp = null;
    foreach ($users as $u) {
        $name = (string)($u['Name'] ?? '');
        if ($name === '' || empty($u['Id'])) continue;
        $d = levenshtein($needle, strtolower($name));
        if ($d < $bestD) { $runnerUp = $best; $bestD = $d; $best = $u; }
        elseif ($runnerUp === null || $d < levenshtein($needle, strtolower((string)$runnerUp['Name']))) {
            $runnerUp = $u;
        }
    }
    if (!$best) return ['', 'no candidate users'];

    // Bound it so an unrelated name never wins by being the least-bad of a bad field.
    $limit = max(2, (int)floor(strlen($needle) * 0.5));
    if ($bestD > $limit) {
        return ['', sprintf('closest was "%s" (distance %d > limit %d) — too far, no icon',
                            $best['Name'], $bestD, $limit)];
    }
    if ($pub === '') {
        return ['', sprintf('matched Emby user "%s" (distance %d) but %s_EMBY_PUBLIC_URL is unset — '
                          . 'a localhost icon would not render in a browser', $best['Name'], $bestD, $meId)];
    }
    $tag  = (string)($best['PrimaryImageTag'] ?? '');
    if ($tag === '') return ['', sprintf('Emby user "%s" has no primary image', $best['Name'])];

    $icon = sprintf('%s/Users/%s/Images/Primary?maxWidth=200&tag=%s&quality=90',
                    $pub, $best['Id'], $tag);
    $note = sprintf('matched Emby user "%s" (distance %d%s)', $best['Name'], $bestD,
                    $runnerUp ? sprintf(', next "%s" at %d', $runnerUp['Name'],
                                        levenshtein($needle, strtolower((string)$runnerUp['Name']))) : '');
    return [$icon, $note];
}

$meId = strtoupper(vv_detect_host());

// --icon= skips the lookup entirely. The mirror needs this: it is being given a folder named
// after the OWNER, and the avatar lives in the owner's Emby — which the mirror has no key for and
// may not run at all. So the owner resolves the URL with --icon-only and hands it over, rather
// than the mirror guessing from a userbase it cannot see.
if (trim($opts['icon']) !== '') {
    $icon     = trim($opts['icon']);
    $iconNote = 'supplied by caller';
} else {
    [$icon, $iconNote] = vv_closest_emby_icon($short, $vars, $meId);
}

// --icon-only: resolve and print, touch nothing. Exits non-zero when there is no icon, so a
// caller can tell "no image" from "empty string because something broke".
if ($opts['icon-only']) {
    if ($icon === '') { fwrite(STDERR, "no icon: $iconNote\n"); exit(1); }
    echo $icon . "\n";
    exit(0);
}

// ── Upsert the folder ─────────────────────────────────────────────────────────
// A host does not keep a fallback folder for itself — the folder means "containers I run on
// SOMEONE ELSE's behalf", so naming it after this machine is always wrong. Checked here rather
// than at argument parsing, because --icon-only legitimately asks for THIS host's own avatar:
// the owner resolves its own picture to hand to the mirror, which is the whole point of that mode.
//
// Refused rather than created, because the failure is otherwise silent — an empty folder named
// after yourself looks plausible enough to survive a glance. One appeared on HOST1 exactly this
// way, when an older copy of this script ignored an unrecognised flag and ran the upsert anyway.
if (strcasecmp($hostId, strtoupper(vv_detect_host())) === 0) {
    fwrite(STDERR, "$hostId is this host — a fallback folder is named after the PARTNER, not self\n");
    exit(2);
}

if (!file_exists(FV3_JSON)) {
    echo "folder.view3 is not installed — nothing to do\n";
    exit(0);
}
$j = json_decode((string)@file_get_contents(FV3_JSON), true);
if (!is_array($j)) { fwrite(STDERR, "folder.view3 docker.json is unreadable\n"); exit(1); }

$containers = array_values(array_filter(array_map('trim', explode(',', (string)$opts['containers']))));

// Match on name, case-insensitively, so a hand-made folder is adopted rather than duplicated.
$targetId = null;
foreach ($j as $id => $f) {
    if (is_array($f) && strcasecmp((string)($f['name'] ?? ''), $folderName) === 0) { $targetId = $id; break; }
}
$created = false;
if ($targetId === null) {
    // folder.view3's own id shape: 20 chars of url-safe base64.
    $targetId = substr(str_replace(['+', '/', '='], '', base64_encode(random_bytes(15))), 0, 20);
    $j[$targetId] = ['name' => $folderName, 'icon' => '', 'settings' => ['', '', '1', '', '1', ''],
                     'regex' => '', 'containers' => [], 'containerImages' => []];
    $created = true;
}
$j[$targetId]['name'] = $folderName;
if ($icon !== '') $j[$targetId]['icon'] = $icon;
foreach ($containers as $c) {
    if (!in_array($c, (array)$j[$targetId]['containers'], true)) $j[$targetId]['containers'][] = $c;
}
$j[$targetId]['containers'] = array_values((array)$j[$targetId]['containers']);

printf("%s %s (id %s)\n", $created ? 'create' : 'update', $folderName, $targetId);
printf("  icon      : %s\n", $icon !== '' ? $icon : '(none) — ' . $iconNote);
if ($icon !== '') printf("  via       : %s\n", $iconNote);
printf("  containers: %s\n", implode(', ', (array)$j[$targetId]['containers']) ?: '(none)');

if ($opts['dry-run']) { echo "  DRY RUN — nothing written\n"; exit(0); }

$tmp = FV3_JSON . '.vv.tmp';
if (file_put_contents($tmp, json_encode($j, JSON_UNESCAPED_SLASHES)) === false || !rename($tmp, FV3_JSON)) {
    fwrite(STDERR, "failed to write " . FV3_JSON . "\n"); exit(1);
}
echo "  written ✅\n";