<?php

declare(strict_types=1);

namespace App\Services;

use App\Models\Artwork;
use App\Services\Uploads\UploadStorageService;
use Illuminate\Support\Facades\Storage;

final class ArtworkOriginalFileLocator
{
    /** @var list<string> */
    private const ALLOWED_EXTENSIONS = [
        'jpg', 'jpeg', 'png', 'gif', 'webp', 'bmp', 'tiff',
        'zip', 'rar', '7z', 'tar', 'gz',
    ];

    public function __construct(
        private readonly UploadStorageService $storage,
    ) {}

    public function resolveLocalPath(Artwork $artwork): string
    {
        $objectPath = $this->resolveObjectPath($artwork);
        $prefix = $this->originalObjectPrefix();

        if ($objectPath !== '' && str_starts_with($objectPath, $prefix)) {
            $suffix = substr($objectPath, strlen($prefix));
            $root = rtrim($this->storage->localOriginalsRoot(), DIRECTORY_SEPARATOR);

            return $root . DIRECTORY_SEPARATOR . str_replace(['/', '\\'], DIRECTORY_SEPARATOR, (string) $suffix);
        }

        $hash = strtolower((string) $artwork->hash);
        $ext = $this->safeExtension($artwork);

        if (! $this->isValidHash($hash) || $ext === '') {
            return '';
        }

        $root = rtrim($this->storage->localOriginalsRoot(), DIRECTORY_SEPARATOR);

        return $root
            . DIRECTORY_SEPARATOR . substr($hash, 0, 2)
            . DIRECTORY_SEPARATOR . substr($hash, 2, 2)
            . DIRECTORY_SEPARATOR . $hash . '.' . $ext;
    }

    /** @return array{status:string,source:?string,disk:?string,path:string,object_key:string,exists:bool,size:?int,file_name:string,file_ext:string} */
    public function resolve(Artwork $artwork): array
    {
        $fileName = trim((string) ($artwork->file_name ?? ''));
        $extension = $this->safeExtension($artwork);
        $localPath = $this->resolveLocalPath($artwork);

        if ($localPath !== '' && is_file($localPath)) {
            return $this->result('available', 'local', null, $localPath, '', true, (int) filesize($localPath), $fileName, $extension);
        }

        if ($this->isTruePending($artwork)) {
            return $this->result('pending', null, null, $localPath, '', false, null, $fileName, $extension);
        }

        $objectKey = $this->resolveObjectPath($artwork);
        if ($objectKey !== '') {
            try {
                $diskName = $this->storage->objectDiskName();
                $disk = Storage::disk($diskName);
                if ($disk->exists($objectKey)) {
                    return $this->result('available', 'object', $diskName, '', $objectKey, true, (int) $disk->size($objectKey), $fileName, $extension);
                }
            } catch (\Throwable) {
                // Treat unavailable storage as unresolved; the route logs context.
            }
        }

        $legacyPath = $this->resolveReadonlyLegacyPath($artwork);
        if ($legacyPath !== '' && is_file($legacyPath)) {
            return $this->result('available', 'legacy', null, $legacyPath, '', true, (int) filesize($legacyPath), $fileName, $extension);
        }

        if ($this->hasIncompleteLegacyMetadata($artwork)) {
            return $this->result('unknown', null, null, $localPath, $objectKey, false, null, $fileName, $extension);
        }

        return $this->result('missing', null, null, $localPath, $objectKey, false, null, $fileName, $extension);
    }

    private function isTruePending(Artwork $artwork): bool
    {
        return strtolower(trim((string) ($artwork->file_name ?? ''))) === 'pending'
            && trim((string) ($artwork->hash ?? '')) === ''
            && trim((string) ($artwork->file_ext ?? '')) === ''
            && trim((string) ($artwork->file_path ?? '')) === '';
    }

    private function hasIncompleteLegacyMetadata(Artwork $artwork): bool
    {
        return ! $this->isValidHash(strtolower((string) ($artwork->hash ?? '')))
            || $this->safeExtension($artwork) === '';
    }

    private function resolveReadonlyLegacyPath(Artwork $artwork): string
    {
        $legacyRoot = rtrim(str_replace(['/', '\\'], DIRECTORY_SEPARATOR, trim((string) config('uploads.legacy_originals_root', ''))), DIRECTORY_SEPARATOR);
        $legacyRelative = $this->legacyRelativePath($artwork);
        if ($legacyRoot !== '' && $legacyRelative !== '') {
            return $legacyRoot . DIRECTORY_SEPARATOR . str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $legacyRelative);
        }

        $root = rtrim(str_replace(['/', '\\'], DIRECTORY_SEPARATOR, trim((string) config('uploads.readonly_backup_originals_root', ''))), DIRECTORY_SEPARATOR);
        $hash = strtolower((string) $artwork->hash);
        $extension = $this->safeExtension($artwork);
        if ($root === '' || ! $this->isValidHash($hash) || $extension === '') {
            return '';
        }

        return $root . DIRECTORY_SEPARATOR . substr($hash, 0, 2) . DIRECTORY_SEPARATOR . substr($hash, 2, 2) . DIRECTORY_SEPARATOR . $hash . '.' . $extension;
    }

    private function legacyRelativePath(Artwork $artwork): string
    {
        $path = trim((string) ($artwork->file_path ?? ''), '/\\');
        if ($path === '' || ! str_starts_with(strtolower($path), 'legacy/uploads/')) {
            return '';
        }

        $relative = substr($path, strlen('legacy/uploads/'));
        if ($relative === false || $relative === '' || str_contains($relative, '..')) {
            return '';
        }

        return 'legacy/uploads/' . ltrim($relative, '/\\');
    }

    private function safeExtension(Artwork $artwork): string
    {
        $stored = strtolower(ltrim(trim((string) ($artwork->file_ext ?? '')), '.'));
        if (in_array($stored, self::ALLOWED_EXTENSIONS, true)) {
            return $stored;
        }

        foreach ([(string) ($artwork->file_name ?? ''), (string) ($artwork->file_path ?? '')] as $candidate) {
            $inferred = strtolower(ltrim((string) pathinfo($candidate, PATHINFO_EXTENSION), '.'));
            if (in_array($inferred, self::ALLOWED_EXTENSIONS, true)) {
                return $inferred;
            }
        }

        return '';
    }

    private function result(string $status, ?string $source, ?string $disk, string $path, string $objectKey, bool $exists, ?int $size, string $fileName, string $extension): array
    {
        return [
            'status' => $status,
            'source' => $source,
            'disk' => $disk,
            'path' => $path,
            'object_key' => $objectKey,
            'exists' => $exists,
            'size' => $size,
            'file_name' => $fileName,
            'file_ext' => $extension,
        ];
    }

    public function resolveObjectPath(Artwork $artwork): string
    {
        $relative = trim((string) $artwork->file_path, '/');
        $prefix = $this->originalObjectPrefix();

        if ($relative !== '' && (str_starts_with($relative, $prefix) || str_starts_with(strtolower($relative), 'legacy/uploads/'))) {
            return $relative;
        }

        $hash = strtolower((string) $artwork->hash);
        $ext = $this->safeExtension($artwork);

        if (! $this->isValidHash($hash) || $ext === '') {
            return '';
        }

        return $this->storage->objectPathForVariant('original', $hash, $hash . '.' . $ext);
    }

    public function resolveObjectUrl(Artwork $artwork): ?string
    {
        $objectPath = $this->resolveObjectPath($artwork);
        if ($objectPath === '') {
            return null;
        }

        return Storage::disk($this->storage->objectDiskName())->url($objectPath);
    }

    private function originalObjectPrefix(): string
    {
        return trim($this->storage->objectBasePrefix(), '/') . '/original/';
    }

    private function isValidHash(string $hash): bool
    {
        return preg_match('/^[a-f0-9]{40}$/', $hash) === 1;
    }
}