<?php

namespace App\Filament\Resources\TextbookResource\Schemas;

use App\Filament\Resources\TextbookResource;
use App\Services\TextbookApiService;
use App\Services\TextbookCoverStorageService;
use Closure;
use Filament\Forms\Components\BaseFileUpload;
use Filament\Forms\Components\FileUpload;
use Filament\Forms\Components\Select;
use Filament\Schemas\Components\Section;
use Filament\Forms\Components\TextInput;
use Filament\Forms\Components\Textarea;
use Filament\Schemas\Schema;
use Illuminate\Filesystem\FilesystemAdapter;
use League\Flysystem\UnableToCheckFileExistence;
use Throwable;

class TextbookFormSchema
{
    /**
     * 封面多图上传。库存为春笋云等返回的绝对 URL 时，Filament 默认会对 disk 做 exists()，
     * 非磁盘路径会被过滤掉，编辑页无法预览；需关闭远程信息拉取并为绝对 URL 直接提供预览地址。
     */
    public static function coverPathFileUpload(Closure $saveUploadedFileUsing): FileUpload
    {
        return FileUpload::make('cover_path')
            ->label('教材配图')
            ->image()
            ->multiple()
            ->reorderable()
            ->directory('textbook-covers')
            ->fetchFileInformation(false)
            ->formatStateUsing(function ($state) {
                // FileUploadStateCast::get() 会把 DB 里「逗号拼接的一整串」变成单元素数组
                // ['https://a.jpg,https://b.jpg']，必须逐项再按逗号拆开，否则会当成一个路径无法预览。
                if (is_string($state)) {
                    return array_values(array_filter(array_map('trim', explode(',', $state))));
                }

                if (! is_array($state)) {
                    return [];
                }

                $urls = [];
                foreach ($state as $part) {
                    if (! is_string($part) || $part === '') {
                        continue;
                    }
                    foreach (array_map('trim', explode(',', $part)) as $piece) {
                        if ($piece !== '') {
                            $urls[] = $piece;
                        }
                    }
                }

                return array_values(array_unique($urls));
            })
            ->dehydrateStateUsing(function ($state) {
                if (is_string($state)) {
                    return trim($state);
                }
                if (! is_array($state)) {
                    return null;
                }

                $urls = array_values(array_filter(array_map(static fn ($item) => trim((string) $item), $state)));

                return empty($urls) ? null : implode(',', $urls);
            })
            ->getUploadedFileUsing(static function (BaseFileUpload $component, string $file, string|array|null $storedFileNames): ?array {
                $trimmed = trim($file);
                if (str_starts_with($trimmed, 'http://') || str_starts_with($trimmed, 'https://')) {
                    $path = parse_url($trimmed, PHP_URL_PATH) ?: '';
                    $name = basename((string) $path) ?: 'image';

                    return [
                        'name' => $name,
                        'size' => 0,
                        'type' => null,
                        'url' => $trimmed,
                    ];
                }

                /** @var FilesystemAdapter $storage */
                $storage = $component->getDisk();
                $shouldFetchFileInformation = $component->shouldFetchFileInformation();

                if ($shouldFetchFileInformation) {
                    try {
                        if (! $storage->exists($file)) {
                            return null;
                        }
                    } catch (UnableToCheckFileExistence $exception) {
                        return null;
                    }
                }

                $url = null;

                if ($component->getVisibility() === 'private') {
                    try {
                        $url = $storage->temporaryUrl(
                            $file,
                            now()->addMinutes(30)->endOfHour(),
                        );
                    } catch (Throwable $exception) {
                        // Driver may not support temporary URLs.
                    }
                }

                $url ??= $storage->url($file);

                return [
                    'name' => ($component->isMultiple() ? ($storedFileNames[$file] ?? null) : $storedFileNames) ?? basename($file),
                    'size' => $shouldFetchFileInformation ? $storage->size($file) : 0,
                    'type' => $shouldFetchFileInformation ? $storage->mimeType($file) : null,
                    'url' => $url,
                ];
            })
            ->saveUploadedFileUsing($saveUploadedFileUsing)
            ->helperText('支持多张图片上传（如封面、目录页），保存时按上传/排序顺序以英文逗号拼接。');
    }

    public static function make(Schema $schema): Schema
    {
        return $schema
            ->schema([
                Section::make('基本信息')
                    ->schema([
                        Select::make('series_id')
                            ->label('教材系列')
                            ->options(function () {
                                $series = app(TextbookApiService::class)->getTextbookSeries();
                                $options = [];
                                foreach ($series['data'] as $s) {
                                    $displayName = $s['name'] ?? '未命名系列';
                                    if (!empty($s['publisher'])) {
                                        $displayName .= ' (' . $s['publisher'] . ')';
                                    }
                                    $options[$s['id']] = $displayName;
                                }
                                return $options;
                            })
                            ->required()
                            ->searchable()
                            ->preload(),
                        TextInput::make('official_title')
                            ->label('教材名称')
                            ->maxLength(512)
                            ->helperText('教材名称（用户输入）'),
                        TextInput::make('isbn')
                            ->label('ISBN')
                            ->maxLength(20),
                        Textarea::make('aliases')
                            ->label('别名')
                            ->helperText('JSON 格式，如：["别名1", "别名2"]')
                            ->formatStateUsing(fn ($state) => is_array($state) ? json_encode($state, JSON_UNESCAPED_UNICODE) : $state)
                            ->dehydrateStateUsing(fn ($state) => is_string($state) ? json_decode($state, true) : $state)
                            ->columnSpanFull(),
                    ])
                    ->columns(2),

                Section::make('学段/年级/学期')
                    ->schema([
                        Select::make('stage')
                            ->label('学段')
                            ->options([
                                'primary' => '小学',
                                'junior' => '初中',
                                'senior' => '高中',
                            ])
                            ->default('junior')
                            ->required()
                            ->reactive(),
                        Select::make('schooling_system')
                            ->label('学制')
                            ->options([
                                '63' => '六三学制',
                                '54' => '五四学制',
                            ])
                            ->default('63')
                            ->visible(fn ($get): bool => in_array($get('stage'), ['primary', 'junior'])),
                        TextInput::make('grade')
                            ->label('年级')
                            ->numeric()
                            ->minValue(1)
                            ->maxValue(12)
                            ->helperText('数字1-12，例：1年级填1'),
                        Select::make('semester')
                            ->label('学期')
                            ->options([
                                1 => '上学期',
                                2 => '下学期',
                            ])
                            ->required(),
                    ])
                    ->columns(2),


                Section::make('封面上传')
                    ->schema([
                        static::coverPathFileUpload(function ($component, $file) {
                            $uploader = app(TextbookCoverStorageService::class);
                            $url = $uploader->uploadCover($file, null);
                            if ($url) {
                                return $url;
                            }

                            return $file->storePubliclyAs(
                                $component->getDirectory(),
                                $component->getUploadedFileNameForStorage($file),
                                $component->getDiskName(),
                            );
                        }),
                    ]),

                Section::make('发布与排序')
                    ->schema([
                        Select::make('status')
                            ->label('状态')
                            ->options([
                                'draft' => '草稿',
                                'published' => '已发布',
                                'archived' => '已归档',
                            ])
                            ->default('draft')
                            ->required(),
                        TextInput::make('sort_order')
                            ->label('排序')
                            ->numeric()
                            ->default(0)
                            ->helperText('数字越小排序越靠前'),
                        Textarea::make('meta')
                            ->label('扩展信息')
                            ->helperText('JSON 格式')
                            ->formatStateUsing(fn ($state) => is_array($state) ? json_encode($state, JSON_UNESCAPED_UNICODE) : $state)
                            ->dehydrateStateUsing(fn ($state) => is_string($state) ? json_decode($state, true) : $state)
                            ->columnSpanFull(),
                    ])
                    ->columns(2),
            ])
            ->columns(2);
    }
}