<?php
/**
 * ajax/disks.php
 *
 * Backs the Settings panel's "Format a Disk for Podman Storage" flow — for
 * a single-disk system with no cache pool set up yet, where podman's own
 * storage path (see include/Config.php's $storagePath default,
 * /mnt/cache/system/podman) has nowhere real to live, and podman never
 * fully starts as a result (found live: a fresh install on a system with
 * no cache pool failed with "cannot reach the Podman API socket" because
 * podman-storage.sh's `create` step refuses to run against a path that
 * isn't an actual mounted filesystem — see that script's header comment
 * for why /mnt/user/... FUSE paths don't work either).
 *
 * This is the one place in the plugin that formats a physical disk —
 * deliberately narrow and defensive: every candidate the "format" action
 * is asked to touch is re-derived server-side from the same safe-listing
 * logic "list_candidates" uses, never trusted from the request alone, and
 * only ever a whole, currently-unmounted, non-array disk with no existing
 * partitions is eligible in the first place.
 *
 * Actions (?action=...):
 *   list_candidates  GET  -> [{device, sizeBytes, sizeFormatted, model, hasData}, ...]
 *   format           POST {"device": "/dev/sdc"} -> {"mountPath": "/mnt/disks/podman-storage"}
 */

declare(strict_types=1);

require __DIR__ . '/../include/bootstrap.php';

const MOUNT_PATH = '/mnt/disks/podman-storage';
const MANAGED_DISK_CFG = '/boot/config/plugins/podman/managed-disk.cfg';

$action = $_GET['action'] ?? '';

switch ($action) {
    case 'list_candidates':
        podman_json_response(list_candidate_disks());
        break;

    case 'format':
        $body = podman_read_json_body();
        $device = (string) ($body['device'] ?? '');
        podman_json_response(format_disk($device));
        break;

    default:
        podman_json_error("Unknown action '{$action}'", 400);
}

/**
 * Runs a command and returns [exitCode, stdout+stderr combined]. Every
 * caller here passes a fixed argv array (never a shell string built from
 * request input), so there is no injection surface even before the
 * device-path validation in format_disk() below.
 *
 * @param array<int,string> $argv
 * @return array{0:int,1:string}
 */
function run(array $argv, int $timeoutSeconds = 30): array
{
    $descriptors = [1 => ['pipe', 'w'], 2 => ['pipe', 'w']];
    $process = proc_open($argv, $descriptors, $pipes);
    if (!is_resource($process)) {
        return [127, "could not start {$argv[0]}"];
    }
    stream_set_timeout($pipes[1], $timeoutSeconds);
    $out = (stream_get_contents($pipes[1]) ?: '') . (stream_get_contents($pipes[2]) ?: '');
    fclose($pipes[1]);
    fclose($pipes[2]);
    $code = proc_close($process);
    return [$code, trim($out)];
}

/**
 * Every whole disk (not partition) libpod's host isn't already using —
 * mounted anywhere (itself or any partition), part of Unraid's own
 * array/cache pool (cross-checked against /var/local/emhttp/disks.ini,
 * the same state file Unraid's own array management writes — the boot
 * flash device is covered by this same check, since Unraid lists it there
 * too), or the disk backing the currently-booted root/flash filesystem.
 *
 * @return array<int,array<string,mixed>>
 */
function list_candidate_disks(): array
{
    // Nested partitions come back automatically as a "children" array in
    // -J's JSON tree — CHILDREN is not a real -o column (lsblk itself
    // rejects it: "unknown column: CHILDREN"; verified live against a
    // real host's lsblk). LABEL is included specifically to catch the
    // Unraid boot flash drive, which FAT-labels itself "UNRAID" — see the
    // safety note below for why that check exists at all.
    [$code, $out] = run(['lsblk', '-J', '-b', '-p', '-o', 'NAME,SIZE,TYPE,FSTYPE,MOUNTPOINT,MODEL,LABEL'], 10);
    if ($code !== 0) {
        podman_json_error('Could not list block devices: ' . $out, 500);
    }
    $tree = json_decode($out, true);
    if (!is_array($tree) || !isset($tree['blockdevices'])) {
        podman_json_error('Unexpected lsblk output', 500);
    }

    $arrayDevices = unraid_array_device_names();

    $candidates = [];
    foreach ($tree['blockdevices'] as $dev) {
        if (($dev['type'] ?? '') !== 'disk') {
            continue;
        }
        $name = (string) ($dev['name'] ?? '');
        $baseName = basename($name);
        if (in_array($baseName, $arrayDevices, true)) {
            continue;
        }
        // zram devices report TYPE "disk" too (RAM-backed, not persistent
        // storage — pointless and misleading to offer for this) and an
        // empty card-reader slot with no card inserted reports as a real
        // "disk" at 0 bytes; both are excluded outright rather than left
        // for the size-based hasData check below.
        if (str_starts_with($baseName, 'zram') || (int) ($dev['size'] ?? 0) <= 0) {
            continue;
        }
        if (device_or_children_mounted($dev)) {
            continue;
        }
        if (device_or_children_labeled_unraid($dev)) {
            continue;
        }
        // Deliberately excludes (not just warns about) ANY disk that
        // already has a filesystem, partition, or other signature on it
        // or any of its partitions — not just ones lsblk reports as
        // currently mounted. Found live: a real host's cache pool disks
        // showed up here as "safe" with only a soft warning, because
        // they're ZFS pool members (fstype "zfs_member"/partition
        // present) rather than plain mounts, so the earlier
        // mounted-only check missed them entirely — the same blind spot
        // that also let the Unraid boot USB stick's own partition
        // through (FAT, not reported as "mounted" by lsblk either). A
        // disk being reused for podman storage must be genuinely blank;
        // asking a user to wipe it themselves first is a small price for
        // this being impossible to get wrong.
        if (!empty($dev['fstype']) || !empty($dev['children'])) {
            continue;
        }

        $candidates[] = [
            'device' => $name,
            'sizeBytes' => (int) ($dev['size'] ?? 0),
            'sizeFormatted' => podman_format_bytes((int) ($dev['size'] ?? 0)),
            'model' => trim((string) ($dev['model'] ?? '')) ?: null,
        ];
    }

    return $candidates;
}

function device_or_children_mounted(array $dev): bool
{
    if (!empty($dev['mountpoint'])) {
        return true;
    }
    foreach ($dev['children'] ?? [] as $child) {
        if (device_or_children_mounted($child)) {
            return true;
        }
    }
    return false;
}

/**
 * Catches the Unraid boot flash drive specifically: it FAT-labels itself
 * "UNRAID" (verified live: `blkid` on a real host's boot partition shows
 * LABEL_FATBOOT="UNRAID" LABEL="UNRAID") and — on at least one real,
 * modern Unraid setup — /boot is actually backed by a ZFS dataset
 * ("flash/boot"), not a direct mount of that partition, so it does NOT
 * show up as "mounted" via lsblk's own MOUNTPOINT column at all. This
 * label check is a second, independent layer specifically because that
 * gap meant the boot drive briefly passed every other check here during
 * development — never rely on a single signal for something this
 * destructive.
 */
function device_or_children_labeled_unraid(array $dev): bool
{
    if (strtoupper(trim((string) ($dev['label'] ?? ''))) === 'UNRAID') {
        return true;
    }
    foreach ($dev['children'] ?? [] as $child) {
        if (device_or_children_labeled_unraid($child)) {
            return true;
        }
    }
    return false;
}

/**
 * @return array<int,string> bare device names ("sda", "nvme0n1", ...) Unraid
 *   itself has assigned to the array or a cache pool, read from the same
 *   /var/local/emhttp/disks.ini Unraid's own array management writes —
 *   NOT parsed/guessed, so this stays correct across whatever array
 *   layout a given host actually has.
 */
function unraid_array_device_names(): array
{
    $path = '/var/local/emhttp/disks.ini';
    if (!is_readable($path)) {
        return [];
    }
    $ini = @parse_ini_file($path, true);
    if (!is_array($ini)) {
        return [];
    }
    $names = [];
    foreach ($ini as $section) {
        if (is_array($section) && !empty($section['device'])) {
            $names[] = basename((string) $section['device']);
        }
    }
    return $names;
}

/** @return array<string,mixed> */
function format_disk(string $device): array
{
    if (!preg_match('#^/dev/(sd[a-z]+|nvme\d+n\d+|vd[a-z]+)$#', $device)) {
        podman_json_error('Invalid or unsupported device path', 400);
    }

    $allowed = array_column(list_candidate_disks(), 'device');
    if (!in_array($device, $allowed, true)) {
        podman_json_error("{$device} is not a currently-eligible disk (already in use, part of the array, or not found) — refusing to format it.", 400);
    }

    $partDevice = preg_match('#nvme\d+n\d+$#', $device) ? "{$device}p1" : "{$device}1";

    [$code, $out] = run(['wipefs', '-a', $device], 30);
    if ($code !== 0) {
        podman_json_error("wipefs failed: {$out}", 500);
    }

    [$code, $out] = run(['parted', '-s', $device, 'mklabel', 'gpt', 'mkpart', 'primary', '1MiB', '100%'], 30);
    if ($code !== 0) {
        podman_json_error("parted failed: {$out}", 500);
    }

    run(['partprobe', $device], 10);
    // Partition device nodes can take a moment to appear after partprobe.
    for ($i = 0; $i < 20 && !file_exists($partDevice); $i++) {
        usleep(250000);
    }
    if (!file_exists($partDevice)) {
        podman_json_error("Partition {$partDevice} did not appear after partitioning {$device}", 500);
    }

    [$code, $out] = run(['mkfs.xfs', '-f', '-n', 'ftype=1', '-L', 'podmanstorage', $partDevice], 60);
    if ($code !== 0) {
        podman_json_error("mkfs.xfs failed: {$out}", 500);
    }

    [$code, $uuid] = run(['blkid', '-s', 'UUID', '-o', 'value', $partDevice], 10);
    $uuid = trim($uuid);
    if ($code !== 0 || $uuid === '') {
        podman_json_error('Could not determine filesystem UUID after formatting', 500);
    }

    if (!is_dir(MOUNT_PATH) && !mkdir(MOUNT_PATH, 0755, true) && !is_dir(MOUNT_PATH)) {
        podman_json_error('Could not create ' . MOUNT_PATH, 500);
    }
    [$code, $out] = run(['mount', 'UUID=' . $uuid, MOUNT_PATH], 15);
    if ($code !== 0) {
        podman_json_error("mount failed: {$out}", 500);
    }

    // Persisted so plugin/sbin/podman-mount-managed-disk.sh (called from
    // the disks_mounted event hook, before rc.podman start) can remount
    // this same disk by UUID on every future boot — nothing else on the
    // system knows about this disk, since it's deliberately outside
    // Unraid's own array/cache pool management.
    $cfgDir = dirname(MANAGED_DISK_CFG);
    if (!is_dir($cfgDir) && !mkdir($cfgDir, 0755, true) && !is_dir($cfgDir)) {
        podman_json_error('Could not create ' . $cfgDir, 500);
    }
    $cfgContent = "# Written by the unraid-podman WebUI (ajax/disks.php) — do not edit by hand.\n"
        . 'UUID="' . $uuid . "\"\n"
        . 'MOUNTPOINT="' . MOUNT_PATH . "\"\n";
    if (file_put_contents(MANAGED_DISK_CFG, $cfgContent, LOCK_EX) === false) {
        podman_json_error('Formatted and mounted, but could not persist ' . MANAGED_DISK_CFG . ' for future boots', 500);
    }

    return ['mountPath' => MOUNT_PATH];
}