<?php

namespace App\Services;

use App\Models\Setting;
use App\Models\User;
use App\Models\Video;
use Illuminate\Support\Facades\Log;

class NasSyncService
{
    // ── Enable check ──────────────────────────────────────────────────────────

    public function isEnabled(): bool
    {
        return Setting::get('nas_sync_enabled', 'false') === 'true'
            && ! empty($this->cfg()['host']);
    }

    // ── Slug helpers ──────────────────────────────────────────────────────────

    public function userSlug(User $user): string
    {
        return $user->username ?: (string) $user->id;
    }

    public function titleSlug(string $title): string
    {
        $slug = mb_strtolower($title);
        $slug = preg_replace('/[^a-z0-9]+/u', '-', $slug);
        $slug = trim($slug, '-');
        return $slug ?: 'video';
    }

    /**
     * Return the NAS directory for a video.
     *
     * On first sync  → pick a conflict-free slug and create the folder.
     * On subsequent  → find the existing folder by matching video ID in meta.json
     *                  so renames of the title never lose the folder.
     */
    public function resolveVideoDir(Video $video): string
    {
        $video->loadMissing('user');
        $userSlug  = $this->userSlug($video->user);
        $base      = "users/{$userSlug}/videos";
        $titleSlug = $this->titleSlug($video->title);

        // 1. Try the current title slug and numbered variants (-2, -3 …)
        //    If any of them already hold meta.json with our video ID → reuse it.
        for ($serial = 1; $serial <= 50; $serial++) {
            $candidate = $serial === 1 ? $titleSlug : "{$titleSlug}-{$serial}";
            $meta      = $this->readMeta("{$base}/{$candidate}");

            if ($meta === null) {
                // Folder is free — this is where we'll write
                return "{$base}/{$candidate}";
            }

            if (($meta['id'] ?? null) === $video->id) {
                // This folder already belongs to our video
                return "{$base}/{$candidate}";
            }
        }

        // 2. Fallback: scan all folders in the user's videos directory
        $found = $this->scanForVideoDir($base, $video->id);
        if ($found) return $found;

        // 3. Last resort: use title slug + video ID suffix (guaranteed unique)
        return "{$base}/{$titleSlug}-{$video->id}";
    }

    /**
     * Read meta.json from a NAS directory. Returns decoded array or null.
     */
    private function readMeta(string $dir): ?array
    {
        $content = $this->getContent("{$dir}/meta.json");
        if ($content === null) return null;
        $decoded = json_decode($content, true);
        return is_array($decoded) ? $decoded : null;
    }

    /**
     * List all subdirectories under $base and find the one whose
     * meta.json carries the given video ID.
     */
    private function scanForVideoDir(string $base, int $videoId): ?string
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));

        $smbPath = str_replace('/', '\\', $base) . '\\*';
        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg("ls \"{$smbPath}\"") . ' 2>&1', $output);

        foreach ($output as $line) {
            if (! preg_match('/^  (.+?)\s{2,}D\s/', $line, $m)) continue;
            $name = trim($m[1]);
            if ($name === '.' || $name === '..') continue;

            $meta = $this->readMeta("{$base}/{$name}");
            if (($meta['id'] ?? null) === $videoId) {
                return "{$base}/{$name}";
            }
        }

        return null;
    }

    // ── Local directory layout (mirrors NAS schema) ───────────────────────────

    /**
     * Absolute path to the local directory for a video, mirroring the NAS structure:
     *   storage/app/users/{username}/videos/{title-slug}/
     *
     * If the video is already organised (video->path starts with "users/"), the dir
     * is derived directly from the stored path so title renames never relocate files.
     * Otherwise a free slug-based slot is found (same logic as resolveVideoDir but local).
     */
    public function localVideoDir(Video $video): string
    {
        // Already organised — derive from path
        if (str_starts_with($video->path, 'users/')) {
            return dirname(storage_path('app/' . $video->path));
        }

        $video->loadMissing('user');
        $userSlug  = $this->userSlug($video->user);
        $base      = storage_path("app/users/{$userSlug}/videos");
        $titleSlug = $this->titleSlug($video->title);

        for ($i = 1; $i <= 50; $i++) {
            $candidate = $i === 1 ? $titleSlug : "{$titleSlug}-{$i}";
            $dir       = "{$base}/{$candidate}";

            if (! is_dir($dir)) {
                return $dir; // free slot
            }

            $metaFile = "{$dir}/meta.json";
            if (file_exists($metaFile)) {
                $meta = @json_decode(file_get_contents($metaFile), true);
                if (is_array($meta) && ($meta['id'] ?? null) === $video->id) {
                    return $dir; // already belongs to this video
                }
            }
        }

        return "{$base}/{$titleSlug}-{$video->id}";
    }

    /**
     * Move a freshly uploaded video's files into the NAS-mirrored local directory
     * structure and update the DB record paths.
     *
     * Call this immediately after Video::create() in the upload flow.
     * The method is idempotent: if the video is already organised it does nothing.
     */
    public function organizeLocalFiles(Video $video): void
    {
        // Already organised
        if (str_starts_with($video->path, 'users/')) return;

        $video->loadMissing(['user', 'slides']);

        $dir      = $this->localVideoDir($video);
        $fileSlug = $this->titleSlug($video->title);

        @mkdir($dir, 0755, true);

        $userSlug = $this->userSlug($video->user);
        $relDir   = 'users/' . $userSlug . '/videos/' . basename($dir);
        $updates  = [];

        // ── Video file ───────────────────────────────────────────────────
        $oldVideoPath = storage_path('app/' . $video->path);
        if (file_exists($oldVideoPath)) {
            $ext         = pathinfo($video->filename, PATHINFO_EXTENSION) ?: 'mp4';
            $newFileName = "{$fileSlug}.{$ext}";
            rename($oldVideoPath, "{$dir}/{$newFileName}");
            $updates['path']     = "{$relDir}/{$newFileName}";
            $updates['filename'] = $newFileName;
        }

        // ── Slides (process first; for audio, thumbnail IS slide 0) ──────
        $firstSlideRelPath = null;
        if ($video->slides->isNotEmpty()) {
            @mkdir("{$dir}/slides", 0755, true);
            foreach ($video->slides->sortBy('position') as $slide) {
                $oldSlidePath = storage_path('app/public/thumbnails/' . $slide->filename);
                if (! file_exists($oldSlidePath)) continue;
                $ext          = pathinfo($slide->filename, PATHINFO_EXTENSION) ?: 'jpg';
                $newSlideName = "{$slide->id}.{$ext}";
                rename($oldSlidePath, "{$dir}/slides/{$newSlideName}");
                $newSlideFilename = "{$relDir}/slides/{$newSlideName}";
                $slide->update(['filename' => $newSlideFilename]);
                if ($firstSlideRelPath === null) {
                    $firstSlideRelPath = $newSlideFilename;
                }
            }
            // For audio uploads the thumbnail is the first slide
            if ($firstSlideRelPath !== null) {
                $updates['thumbnail'] = $firstSlideRelPath;
            }
        }

        // ── Standalone thumbnail (video uploads, no slides) ──────────────
        if ($video->thumbnail && ! isset($updates['thumbnail'])) {
            $oldThumbPath = storage_path('app/public/thumbnails/' . $video->thumbnail);
            if (file_exists($oldThumbPath)) {
                $ext          = pathinfo($video->thumbnail, PATHINFO_EXTENSION) ?: 'jpg';
                $newThumbName = "thumb.{$ext}";
                rename($oldThumbPath, "{$dir}/{$newThumbName}");
                $updates['thumbnail'] = "{$relDir}/{$newThumbName}";
            }
        }

        // ── meta.json (enables localVideoDir to identify this dir later) ─
        $this->writeLocalMeta($video, $dir);

        if (! empty($updates)) {
            $video->update($updates);
        }
    }

    /**
     * Write a meta.json to the local video directory so localVideoDir() can
     * resolve the folder even after a title rename.
     */
    public function writeLocalMeta(Video $video, string $dir): void
    {
        $meta = json_encode([
            'id'         => $video->id,
            'user_id'    => $video->user_id,
            'title'      => $video->title,
            'created_at' => $video->created_at?->toIso8601String(),
        ], JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);

        @file_put_contents("{$dir}/meta.json", $meta);
    }

    // ── Local-cache helpers (used when NAS is the primary storage) ───────────

    /**
     * Absolute path where a NAS video is cached locally for HTTP streaming.
     * Separate from public storage so it's never accidentally served statically.
     */
    public function localCachePath(Video $video): string
    {
        return storage_path('app/nas_cache/videos/' . $video->filename);
    }

    /**
     * Ensure the video file is available at a local path for streaming.
     *
     * Priority:
     *   1. Regular local storage  (video uploaded while NAS was off, or not yet cleaned)
     *   2. NAS stream cache       (previously downloaded copy)
     *   3. Download from NAS      (first-time stream after NAS-primary upload)
     *
     * Returns the local absolute path, or null if unavailable.
     */
    public function ensureLocalCopy(Video $video): ?string
    {
        // 1. Regular local storage
        $regularPath = storage_path('app/' . $video->path);
        if (file_exists($regularPath)) return $regularPath;

        // 2. Existing stream cache
        $cachePath = $this->localCachePath($video);
        if (file_exists($cachePath)) return $cachePath;

        // 3. Download from NAS
        if (! $this->isEnabled()) return null;

        $cacheDir = dirname($cachePath);
        if (! is_dir($cacheDir)) mkdir($cacheDir, 0755, true);

        $nasDir   = $this->resolveVideoDir($video);
        $ext      = pathinfo($video->filename, PATHINFO_EXTENSION) ?: 'mp4';
        $fileSlug = $this->titleSlug($video->title);
        $nasFile  = "{$nasDir}/{$fileSlug}.{$ext}";

        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));

        exec('smbclient ' . $target . ' -U ' . $cred
            . ' -c ' . escapeshellarg('get "' . $nasFile . '" "' . $cachePath . '"')
            . ' 2>&1', $out, $code);

        if ($code !== 0 || ! file_exists($cachePath)) {
            @unlink($cachePath);
            Log::warning('NAS: failed to cache video for streaming', [
                'video_id' => $video->id,
                'nas_path' => $nasFile,
                'output'   => implode(' ', $out),
            ]);
            return null;
        }

        Log::info('NAS: video cached locally for streaming', ['video_id' => $video->id]);
        return $cachePath;
    }

    /**
     * Ensure a local asset file exists, downloading it from the NAS if missing.
     * Used by MediaController to serve thumbnails, avatars, and banners with a NAS fallback.
     *
     * Returns true if the file is available locally after the call.
     */
    public function ensureLocalAsset(string $localPath, string $nasPath): bool
    {
        if (file_exists($localPath)) return true;

        $dir = dirname($localPath);
        if (! is_dir($dir)) @mkdir($dir, 0755, true);

        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));

        exec('smbclient ' . $target . ' -U ' . $cred
            . ' -c ' . escapeshellarg('get "' . $nasPath . '" "' . $localPath . '"')
            . ' 2>&1', $out, $code);

        if ($code !== 0 || ! file_exists($localPath)) {
            @unlink($localPath);
            Log::warning('NAS: failed to fetch asset', [
                'nas_path' => $nasPath,
                'output'   => implode(' ', $out),
            ]);
            return false;
        }

        return true;
    }

    /**
     * Delete the local video file after it has been successfully pushed to NAS.
     */
    public function deleteLocalVideo(Video $video): void
    {
        $path = storage_path('app/' . $video->path);
        if (file_exists($path)) {
            @unlink($path);
            Log::info('NAS: local video removed after NAS push', ['video_id' => $video->id]);
        }
    }

    /**
     * Delete local thumbnail and slide images after they have been pushed to NAS.
     * MediaController will re-fetch them from NAS on demand via ensureLocalAsset().
     */
    public function deleteLocalAssets(Video $video): void
    {
        $thumb = $video->localThumbnailPath();
        if ($thumb && file_exists($thumb)) {
            @unlink($thumb);
        }

        $video->loadMissing('slides');
        foreach ($video->slides as $slide) {
            $path = $slide->localPath();
            if (file_exists($path)) {
                @unlink($path);
            }
        }

        Log::info('NAS: local assets removed after NAS push', ['video_id' => $video->id]);
    }

    // ── Direct NAS upload (NAS-primary mode) ──────────────────────────────────

    /**
     * Push a freshly uploaded video directly to the NAS without keeping a local copy.
     *
     * Called from VideoController::store() when NAS is enabled.
     * Updates video->path, video->filename, video->thumbnail, and status in the DB.
     *
     * @param Video       $video
     * @param string      $tempVideoPath   Absolute path to the temporary local video file
     * @param string|null $tempThumbPath   Absolute path to the temporary thumbnail (may be null)
     * @param array       $slideAbsPaths   [ position => absPath ] for audio slides
     */
    public function uploadDirectToNas(
        Video $video,
        string $tempVideoPath,
        ?string $tempThumbPath,
        array $slideAbsPaths = []
    ): void {
        $video->loadMissing(['user', 'slides']);

        $dir      = $this->resolveVideoDir($video);   // NAS-relative, e.g. users/john/videos/my-video
        $fileSlug = $this->titleSlug($video->title);

        $this->mkdirp($dir);

        $updates = [];

        // ── Video file ───────────────────────────────────────────────────
        $ext = pathinfo($video->filename, PATHINFO_EXTENSION) ?: 'mp4';
        if (file_exists($tempVideoPath)) {
            $this->putFile($tempVideoPath, "{$dir}/{$fileSlug}.{$ext}");
            @unlink($tempVideoPath);
            $updates['path']     = "{$dir}/{$fileSlug}.{$ext}";
            $updates['filename'] = "{$fileSlug}.{$ext}";
        }

        // ── Slides (audio uploads — thumbnail IS the first slide) ────────
        $firstSlideNasPath = null;
        if (! empty($slideAbsPaths)) {
            $this->mkdirp("{$dir}/slides");
            foreach ($video->slides->sortBy('position') as $slide) {
                $absPath = $slideAbsPaths[$slide->position] ?? null;
                if (! $absPath || ! file_exists($absPath)) continue;
                $slideExt     = pathinfo($absPath, PATHINFO_EXTENSION) ?: 'jpg';
                $nasSlideFile = "{$dir}/slides/{$slide->position}.{$slideExt}";
                $this->putFile($absPath, $nasSlideFile);
                @unlink($absPath);
                $slideRelPath = "{$dir}/slides/{$slide->position}.{$slideExt}";
                $slide->update(['filename' => $slideRelPath]);
                if ($firstSlideNasPath === null) {
                    $firstSlideNasPath = $slideRelPath;
                }
            }
            if ($firstSlideNasPath !== null) {
                $updates['thumbnail'] = $firstSlideNasPath;
            }
        }

        // ── Standalone thumbnail (video uploads without slides) ──────────
        if ($tempThumbPath && file_exists($tempThumbPath) && $firstSlideNasPath === null) {
            $this->putFile($tempThumbPath, "{$dir}/thumb.webp");
            @unlink($tempThumbPath);
            $updates['thumbnail'] = "{$dir}/thumb.webp";
        }

        // ── meta.json ────────────────────────────────────────────────────
        $this->putContent(json_encode([
            'id'         => $video->id,
            'user_id'    => $video->user_id,
            'title'      => $video->title,
            'created_at' => $video->created_at?->toIso8601String(),
        ], JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE), "{$dir}/meta.json");

        // File is now on NAS and accessible — mark as ready
        $updates['status'] = 'ready';

        Log::info('NAS: direct upload complete', ['video_id' => $video->id, 'dir' => $dir]);

        $video->update($updates);
    }

    // ── High-level sync methods ───────────────────────────────────────────────

    public function syncVideo(Video $video): void
    {
        $video->loadMissing('user');
        $dir       = $this->resolveVideoDir($video);
        $fileSlug  = $this->titleSlug($video->title);
        $this->mkdirp($dir);

        // {title-slug}.{ext}
        $localVideo = storage_path('app/' . $video->path);
        if (file_exists($localVideo)) {
            $ext = pathinfo($video->filename, PATHINFO_EXTENSION) ?: 'mp4';
            $this->putFile($localVideo, "{$dir}/{$fileSlug}.{$ext}");
        }

        // thumb.webp
        $localThumb = $video->localThumbnailPath();
        if ($localThumb && file_exists($localThumb)) {
            $this->putFile($localThumb, "{$dir}/thumb.webp");
        }

        // slides/{position}.{ext}
        $video->loadMissing('slides');
        if ($video->slides->isNotEmpty()) {
            $this->mkdirp("{$dir}/slides");
            foreach ($video->slides as $slide) {
                $localSlide = $slide->localPath();
                if (file_exists($localSlide)) {
                    $ext = pathinfo($slide->filename, PATHINFO_EXTENSION) ?: 'jpg';
                    $this->putFile($localSlide, "{$dir}/slides/{$slide->position}.{$ext}");
                }
            }
        }

        // meta.json  (always written last so readMeta can find the folder)
        $this->putContent(json_encode([
            'id'          => $video->id,
            'user_id'     => $video->user_id,
            'title'       => $video->title,
            'description' => $video->description,
            'type'        => $video->type,
            'visibility'  => $video->visibility,
            'status'      => $video->status,
            'duration'    => $video->duration,
            'width'       => $video->width,
            'height'      => $video->height,
            'orientation' => $video->orientation,
            'mime_type'   => $video->mime_type,
            'size'        => $video->size,
            'created_at'  => $video->created_at?->toIso8601String(),
        ], JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE), "{$dir}/meta.json");
    }

    public function syncVideoMeta(Video $video): void
    {
        $video->loadMissing('user');
        $dir = $this->resolveVideoDir($video);
        $this->mkdirp($dir);

        $this->putContent(json_encode([
            'id'          => $video->id,
            'user_id'     => $video->user_id,
            'title'       => $video->title,
            'description' => $video->description,
            'type'        => $video->type,
            'visibility'  => $video->visibility,
            'status'      => $video->status,
            'duration'    => $video->duration,
            'width'       => $video->width,
            'height'      => $video->height,
            'orientation' => $video->orientation,
            'mime_type'   => $video->mime_type,
            'size'        => $video->size,
            'updated_at'  => $video->updated_at?->toIso8601String(),
        ], JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE), "{$dir}/meta.json");
    }

    public function deleteVideo(Video $video): void
    {
        $video->loadMissing('user');
        $dir = $this->resolveVideoDir($video);
        $ext = pathinfo($video->filename, PATHINFO_EXTENSION) ?: 'mp4';

        $this->deleteFile("{$dir}/" . $this->titleSlug($video->title) . ".{$ext}");
        $this->deleteFile("{$dir}/thumb.webp");
        $this->deleteFile("{$dir}/meta.json");
        $this->deleteFile("{$dir}/view-log.json");
        $this->deleteFile("{$dir}/edit-log.json");
        $this->deleteFolder($dir);
    }

    public function syncAvatar(User $user, string $localAbsPath): void
    {
        $dir = "users/{$this->userSlug($user)}/profile";
        $this->mkdirp($dir);
        $this->putFile($localAbsPath, "{$dir}/avatar.webp");
    }

    public function syncCover(User $user, string $localAbsPath): void
    {
        $dir = "users/{$this->userSlug($user)}/profile";
        $this->mkdirp($dir);
        $this->putFile($localAbsPath, "{$dir}/cover.webp");
    }

    // ── SMB primitives ────────────────────────────────────────────────────────

    public function mkdirp(string $path): void
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));

        $parts = array_values(array_filter(explode('/', str_replace('\\', '/', $path))));
        $cmds  = [];
        $built = '';
        foreach ($parts as $part) {
            $built  = $built ? "{$built}/{$part}" : $part;
            $cmds[] = 'mkdir "' . $built . '"';
        }

        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg(implode('; ', $cmds)) . ' 2>&1');
        // Intentionally ignore exit code — NT_STATUS_OBJECT_NAME_COLLISION means dir exists
    }

    public function putFile(string $localAbsPath, string $nasRelPath): bool
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));
        $cmd    = 'put "' . $localAbsPath . '" "' . $nasRelPath . '"';

        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg($cmd) . ' 2>&1', $output, $code);

        if ($code !== 0) {
            Log::warning('NAS putFile failed [' . $nasRelPath . ']: ' . implode(' ', $output));
        }

        return $code === 0;
    }

    public function putContent(string $content, string $nasRelPath): bool
    {
        $tmp = tempnam(sys_get_temp_dir(), 'nassync_');
        file_put_contents($tmp, $content);
        $ok = $this->putFile($tmp, $nasRelPath);
        @unlink($tmp);
        return $ok;
    }

    public function getContent(string $nasRelPath): ?string
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));
        $tmp    = tempnam(sys_get_temp_dir(), 'nasget_');
        $cmd    = 'get "' . $nasRelPath . '" "' . $tmp . '"';

        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg($cmd) . ' 2>&1', $output, $code);

        if ($code !== 0 || ! file_exists($tmp)) {
            @unlink($tmp);
            return null;
        }

        $content = file_get_contents($tmp);
        @unlink($tmp);
        return $content !== false ? $content : null;
    }

    public function deleteFile(string $nasRelPath): void
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));
        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg('rm "' . $nasRelPath . '"') . ' 2>&1');
    }

    public function deleteFolder(string $nasRelPath): void
    {
        $cfg    = $this->cfg();
        $target = escapeshellarg($this->smbTarget($cfg));
        $cred   = escapeshellarg($this->smbCredential($cfg));
        exec('smbclient ' . $target . ' -U ' . $cred . ' -c ' . escapeshellarg('rmdir "' . $nasRelPath . '"') . ' 2>&1');
    }

    // ── Helpers ───────────────────────────────────────────────────────────────

    private function cfg(): array
    {
        return app(\P7H\NasFileManager\NasStorageService::class)->cfg();
    }

    private function smbTarget(array $cfg): string
    {
        return '//' . $cfg['host'] . '/' . trim($cfg['smb_share'] ?? '', '/');
    }

    private function smbCredential(array $cfg): string
    {
        $domain = ! empty($cfg['smb_domain']) ? $cfg['smb_domain'] . '/' : '';
        return $domain . ($cfg['username'] ?? '') . '%' . ($cfg['password'] ?? '');
    }
}