<?php
namespace Relay\Files;

use Relay\Multisite\Scope;
use Relay\Multisite\SubsiteFiles;

use Relay\Jobs\Job;
use Relay\Support\Paths;

/** A migration's file parts and working files, wherever the job runs (initiator or receiver). */
final class JobFiles
{
    public static function parts(Job $job): array
    {
        return FileParts::normalize($job->settings['files'] ?? null);
    }

    public static function any(Job $job): bool
    {
        return FileParts::any(self::parts($job));
    }

    /** The site whose files these are: this one, or on a network the job's subsite. */
    public static function scope(Job $job): Scope
    {
        return Scope::for_settings($job->settings);
    }

    /** @return array<string, string> the job's file groups' folders on this site (a subsite's uploads are its own) */
    public static function roots(Job $job): array
    {
        return Groups::roots(self::scope($job));
    }

    /** The file list: built here (this site has the files) or received (this site gets them). */
    public static function list(Job $job): FileList
    {
        return new FileList(Paths::job_dir($job->id) . '/manifest.jsonl');
    }

    /** Comparison of the list with this site's files; its needed() list is also where a pushing site keeps the receiver's answer. */
    public static function diff(Job $job): FileDiff
    {
        $scope = self::scope($job);
        return new FileDiff(self::list($job), Groups::roots($scope), self::parts($job), Paths::job_dir($job->id), SubsiteFiles::policies($scope), SubsiteFiles::untouched($scope));
    }

    /**
     * The copy's progress for the screens (both directions): files and bytes copied so far, and which group — themes,
     * plugins, uploads or other — comes next; null once everything is copied.
     *
     * @param array<string, mixed> $c the files:transfer cursor
     */
    public static function report(Job $job, array $c, FileList $list, IndexList $needed): void
    {
        $job->stats['transfer']['copied'] = ['count' => (int) $c['count'], 'bytes' => (int) $c['bytes'], 'gone' => (int) $c['gone']];
        $next = empty($c['done']) ? ($needed->slice((int) $c['pos'], 1)[0] ?? null) : null;
        $job->stats['transfer']['now'] = $next !== null ? ($list->get($next)['g'] ?? null) : null;
    }

    public static function unpacker(Job $job): Unpacker
    {
        return new Unpacker(self::list($job), Paths::staging_dir($job->id), self::parts($job)['low_disk'] ? self::roots($job)['uploads'] : null);
    }

    public static function swap(Job $job): FileSwap
    {
        return new FileSwap(Paths::journal($job->id));
    }

    public static function placer(Job $job): FilePlacer
    {
        $diff = self::diff($job);
        $scope = self::scope($job);
        return new FilePlacer(self::list($job), $diff->needed(), $diff->extras_path(), Groups::roots($scope), Paths::staging_dir($job->id), self::swap($job), Paths::aside($job->id), SubsiteFiles::policies($scope));
    }

    /** The file restore point to record with the job's restore point, when any file was moved. */
    public static function point(Job $job): ?array
    {
        return is_file(Paths::journal($job->id)) ? ['journal' => Paths::journal($job->id), 'dir' => Paths::aside($job->id)] : null;
    }

    /** Undo file moves after the first $keep, and tidy the restore point folder. */
    public static function put_back(Job $job, int $keep = 0): void
    {
        if (is_file(Paths::journal($job->id))) {
            self::swap($job)->rollback($keep);
        }
        Fs::remove_empty_dirs(Paths::aside($job->id));
    }
}