<?php

namespace App\Filament\Resources\Products\Schemas;

use Filament\Forms\Components\Select;
use Filament\Forms\Components\TextInput;
use Filament\Forms\Components\Textarea;
use Filament\Forms\Components\Toggle;
use Filament\Forms\Components\DatePicker;
use Filament\Forms\Components\Checkbox;
use Filament\Forms\Components\RichEditor;
use Filament\Forms\Components\Repeater;
use Filament\Forms\Components\KeyValue;
use Filament\Forms\Components\SpatieMediaLibraryFileUpload;
use Filament\Schemas\Components\Grid;
use Filament\Schemas\Components\Section;
use Filament\Schemas\Components\Utilities\Set;
use Filament\Schemas\Schema;
use Illuminate\Support\Str;

class ProductForm
{
    public static function configure(Schema $schema): Schema
    {
        return $schema
            ->components([
                Grid::make(3)
                    ->schema([
                        // ─── Left / Main Column (span 2) ──────────────────────
                        Grid::make(1)
                            ->schema([
                                // Details Section (Name, Slug, Description)
                                Section::make()
                                    ->schema([
                                        Grid::make(2)
                                            ->schema([
                                                TextInput::make('name')
                                                    ->required()
                                                    ->live(onBlur: true)
                                                    ->afterStateUpdated(function (Set $set, ?string $state, callable $get) {
                                                        if (!empty($state)) {
                                                            $cleanName = preg_replace('/[^\p{L}\p{N}\s-]/u', '', strtolower($state));
                                                            $stopWords = [
                                                                'a', 'an', 'the', 'and', 'or', 'of', 'with', 'for', 'in', 'on', 'at', 'to', 'by', 'from', 'is', 'are', 'was', 'were', 'amp',
                                                                'এবং', 'ও', 'আর', 'জন্য', 'থেকে', 'পর', 'প্রতি', 'দিয়ে', 'দ্বারা'
                                                            ];
                                                            $words = preg_split('/\s+/', $cleanName);
                                                            $filteredWords = array_filter($words, function ($word) use ($stopWords) {
                                                                return !empty($word) && !in_array($word, $stopWords);
                                                            });
                                                            $slug = Str::slug(implode(' ', $filteredWords));
                                                            $set('slug', empty($slug) ? Str::slug($state) : $slug);
                                                            
                                                            if (empty($get('sku'))) {
                                                                $set('sku', \App\Models\Product::generateUniqueSku($state));
                                                            }
                                                        }
                                                    }),
                                                TextInput::make('slug')
                                                    ->required()
                                                    ->unique(ignoreRecord: true),
                                            ]),
                                        RichEditor::make('description')
                                            ->columnSpanFull(),
                                    ]),

                                // Images Section
                                Section::make('Images')
                                    ->schema([
                                        SpatieMediaLibraryFileUpload::make('images')
                                            ->collection('images')
                                            ->disk(config('media-library.disk_name', 'public'))
                                            ->multiple()
                                            ->reorderable()
                                            ->panelLayout('grid')
                                            ->helperText('The first image (top-left) will be used as the product thumbnail. Drag and drop to reorder images.')
                                            ->maxFiles(10)
                                            ->hiddenLabel(),
                                    ])
                                    ->collapsible(),

                                // Pricing Section
                                Section::make('Pricing')
                                    ->schema([
                                        Grid::make(2)
                                            ->schema([
                                                TextInput::make('price')
                                                    ->label('Price')
                                                    ->required()
                                                    ->numeric()
                                                    ->prefix('৳'),
                                                TextInput::make('compare_at_price')
                                                    ->label('Compare at price')
                                                    ->numeric()
                                                    ->prefix('৳'),
                                                TextInput::make('cost_price')
                                                    ->label('Cost per item')
                                                    ->required()
                                                    ->numeric()
                                                    ->prefix('৳')
                                                    ->helperText("Customers won't see this price.")
                                                    ->columnSpan(1),
                                            ]),
                                    ]),

                                // Inventory Section
                                Section::make('Inventory')
                                    ->schema([
                                        Grid::make(2)
                                            ->schema([
                                                TextInput::make('sku')
                                                    ->label('SKU (Stock Keeping Unit)')
                                                    ->required()
                                                    ->unique(ignoreRecord: true)
                                                    ->suffixAction(
                                                        \Filament\Actions\Action::make('generateSku')
                                                            ->icon('heroicon-m-arrow-path')
                                                            ->tooltip('Generate SKU from Name')
                                                            ->action(function (Set $set, callable $get) {
                                                                $name = $get('name');
                                                                if (!empty($name)) {
                                                                    $set('sku', \App\Models\Product::generateUniqueSku($name));
                                                                } else {
                                                                    \Filament\Notifications\Notification::make()
                                                                        ->warning()
                                                                        ->title('Please enter a product name first.')
                                                                        ->send();
                                                                }
                                                            })
                                                    ),
                                                TextInput::make('quantity')
                                                    ->label('Stock Quantity')
                                                    ->required()
                                                    ->numeric()
                                                    ->default(0),
                                                TextInput::make('security_stock')
                                                    ->label('Safety Stock')
                                                    ->required()
                                                    ->numeric()
                                                    ->default(0)
                                                    ->hintIcon('heroicon-m-question-mark-circle')
                                                    ->hintIconTooltip('Low stock alert fires at or below this level.')
                                                    ->columnSpanFull(),
                                            ]),
                                    ]),

                                // Shipping Section
                                Section::make('Shipping')
                                    ->schema([
                                        Grid::make(2)
                                            ->schema([
                                                Checkbox::make('can_be_returned')
                                                    ->label('This product can be returned')
                                                    ->default(true),
                                                Checkbox::make('will_be_shipped')
                                                    ->label('This product will be shipped')
                                                    ->default(true),
                                            ]),

                                        Toggle::make('is_weight_based')
                                            ->label('Enable Weight-Based Shipping')
                                            ->default(false)
                                            ->live()
                                            ->columnSpanFull(),

                                        // Weight input + unit selector
                                        Grid::make(3)
                                            ->schema([
                                                TextInput::make('weight_grams')
                                                    ->label('Product Weight')
                                                    ->numeric()
                                                    ->minValue(0)
                                                    ->placeholder(fn (callable $get): string =>
                                                        $get('weight_unit') === 'kg' ? 'e.g. 0.5' : 'e.g. 500'
                                                    )
                                                    ->helperText('Used to calculate shipping cost for weight-based methods.')
                                                    ->afterStateHydrated(function (TextInput $component, $state, callable $set) {
                                                        if (blank($state)) {
                                                            $set('weight_unit', 'g');
                                                            return;
                                                        }

                                                        $grams = (int) $state;
                                                        if ($grams >= 1000) {
                                                            $component->state(round($grams / 1000, 3));
                                                            $set('weight_unit', 'kg');
                                                        } else {
                                                            $component->state($grams);
                                                            $set('weight_unit', 'g');
                                                        }
                                                    })
                                                    ->dehydrateStateUsing(function ($state, callable $get): ?int {
                                                        if (blank($state)) return null;
                                                        // If user typed in kg, convert back to grams for storage
                                                        if (($get('weight_unit') ?? 'g') === 'kg') {
                                                            return (int) round((float) $state * 1000);
                                                        }
                                                        return (int) $state;
                                                    })
                                                    ->columnSpan(2),

                                                Select::make('weight_unit')
                                                    ->label('Unit')
                                                    ->options([
                                                        'g'  => 'Grams (g)',
                                                        'kg' => 'Kilograms (kg)',
                                                    ])
                                                    ->default('g')
                                                    ->native(false)
                                                    ->dehydrated(false) // virtual — not saved to DB
                                                    ->live()
                                                    ->afterStateUpdated(function (
                                                        ?string $state,
                                                        ?string $old,
                                                        callable $get,
                                                        callable $set
                                                    ): void {
                                                        $current = (float) ($get('weight_grams') ?? 0);
                                                        if ($current <= 0) return;

                                                        if ($state === 'kg' && $old === 'g') {
                                                            // grams → kg: divide by 1000
                                                            $set('weight_grams', round($current / 1000, 3));
                                                        } elseif ($state === 'g' && $old === 'kg') {
                                                            // kg → grams: multiply by 1000
                                                            $set('weight_grams', (int) round($current * 1000));
                                                        }
                                                    })
                                                    ->columnSpan(1),
                                            ])
                                            ->visible(fn (callable $get) => (bool) $get('is_weight_based')),
                                    ]),

                                // Product Variants Section
                                Section::make('Product Variants')
                                    ->icon('heroicon-m-squares-plus')
                                    ->description('Each variant must have a unique option combination.')
                                    ->schema([
                                        Repeater::make('variants')
                                            ->relationship('variants')
                                            ->hiddenLabel()
                                            ->collapseAllAction(fn (\Filament\Actions\Action $action) => $action->hidden())
                                            ->expandAllAction(fn (\Filament\Actions\Action $action) => $action->hidden())
                                            ->addActionLabel('+ Add Variant')
                                            ->schema([
                                                // ── Row 1: Attributes (full width, most important) ──
                                                Repeater::make('options')
                                                    ->label('Variant Options')
                                                    ->hintIcon('heroicon-m-question-mark-circle')
                                                    ->hintIconTooltip('Select unique attributes (e.g. Size, Color) for this variant.')
                                                    ->addActionLabel('+ Add Attribute (e.g. Size, Color, Weight)')
                                                    ->schema([
                                                        Select::make('attribute_name')
                                                            ->label('Attribute')
                                                            ->placeholder('e.g. Size, Color, Weight')
                                                            ->options(\App\Models\ProductAttribute::pluck('name', 'name'))
                                                            ->required()
                                                            ->live()
                                                            ->disableOptionsWhenSelectedInSiblingRepeaterItems(),
                                                        Select::make('attribute_value')
                                                            ->label('Value')
                                                            ->placeholder('← Select an attribute first')
                                                            ->options(fn (callable $get) =>
                                                                \App\Models\ProductAttributeValue::whereHas('attribute', fn ($q) => $q->where('name', $get('attribute_name')))
                                                                    ->pluck('value', 'value')
                                                            )
                                                            ->required()
                                                            ->live(),
                                                    ])
                                                    ->columns(2)
                                                    ->columnSpanFull()
                                                    ->maxItems(5)
                                                    ->defaultItems(1)
                                                    ->reorderable(false)
                                                    ->live()
                                                    ->afterStateUpdated(function (Set $set, callable $get) {
                                                        $currentSku = $get('sku');
                                                        if (empty($currentSku)) {
                                                            $mainSku = $get('../../sku') ?? 'PROD';
                                                            $options = $get('options') ?? [];
                                                            $parts = [];
                                                            foreach ($options as $opt) {
                                                                if (!empty($opt['attribute_value'])) {
                                                                    $parts[] = strtoupper(str_replace(' ', '', $opt['attribute_value']));
                                                                }
                                                            }
                                                            if (!empty($parts)) {
                                                                $set('sku', "{$mainSku}-" . implode('-', $parts));
                                                            }
                                                        }
                                                    })
                                                    ->afterStateHydrated(function (Repeater $component, $state) {
                                                        // Convert {"Size": "L", "Color": "Blue"} → [{attribute_name, attribute_value}]
                                                        if (is_array($state) && !empty($state)) {
                                                            $firstItem = reset($state);
                                                            if (!is_array($firstItem)) {
                                                                $formatted = [];
                                                                foreach ($state as $key => $val) {
                                                                    $formatted[] = [
                                                                        'attribute_name' => $key,
                                                                        'attribute_value' => $val,
                                                                    ];
                                                                }
                                                                $component->state($formatted);
                                                            }
                                                        }
                                                        $component->hydrateItems();
                                                    }),

                                                // ── Row 2: SKU ──
                                                TextInput::make('sku')
                                                    ->label('Variant SKU')
                                                    ->hintIcon('heroicon-m-question-mark-circle')
                                                    ->hintIconTooltip('Auto-generated variant code. Editable.')
                                                    ->required()
                                                    ->unique(ignoreRecord: true)
                                                    ->columnSpan(1)
                                                    ->suffixAction(
                                                        \Filament\Actions\Action::make('generateVariantSku')
                                                            ->icon('heroicon-m-arrow-path')
                                                            ->tooltip('Re-generate SKU from options')
                                                            ->action(function (Set $set, callable $get) {
                                                                $mainSku = $get('../../sku') ?? 'PROD';
                                                                $options = $get('options') ?? [];
                                                                $parts = [];
                                                                foreach ($options as $opt) {
                                                                    if (!empty($opt['attribute_value'])) {
                                                                        $parts[] = strtoupper(str_replace(' ', '', $opt['attribute_value']));
                                                                    }
                                                                }
                                                                $suffix = !empty($parts) ? implode('-', $parts) : random_int(100, 999);
                                                                $set('sku', "{$mainSku}-{$suffix}");
                                                             })
                                                    ),

                                                // ── Row 3: Stock & Price ──
                                                TextInput::make('quantity')
                                                    ->label('Stock Qty')
                                                    ->numeric()
                                                    ->required()
                                                    ->default(0)
                                                    ->minValue(0)
                                                    ->suffix('pcs'),

                                                TextInput::make('price')
                                                    ->label('Price Override (optional)')
                                                    ->numeric()
                                                    ->prefix('৳')
                                                    ->hintIcon('heroicon-m-question-mark-circle')
                                                    ->hintIconTooltip('Leave empty to use the base product price.'),

                                                TextInput::make('security_stock')
                                                    ->label('Safety Stock')
                                                    ->numeric()
                                                    ->nullable()
                                                    ->default(0)
                                                    ->hintIcon('heroicon-m-question-mark-circle')
                                                    ->hintIconTooltip('Low stock alert fires at or below this level.'),
                                            ])
                                            ->columns(2)
                                            ->itemLabel(fn (array $state): ?string =>
                                                ($state['sku'] ?? 'New Variant') .
                                                (isset($state['options']) && is_array($state['options'])
                                                    ? ' (' . implode(', ', array_map(function ($k, $v) {
                                                        if (is_array($v)) {
                                                            return ($v['attribute_name'] ?? '') . ': ' . ($v['attribute_value'] ?? '');
                                                        }
                                                        return "$k: $v";
                                                    }, array_keys($state['options']), $state['options'])) . ')'
                                                    : '')
                                            )
                                            ->defaultItems(0)
                                            ->columnSpanFull()
                                            ->collapsed()
                                            ->cloneable(),
                                    ])
                                    ->collapsible(),


                                // SEO Settings Section
                                Section::make('SEO Settings')
                                    ->schema([
                                        TextInput::make('seo_title')
                                            ->label('Meta Title')
                                            ->placeholder('Defaults to product name'),
                                        Textarea::make('seo_description')
                                            ->label('Meta Description')
                                            ->rows(3)
                                            ->columnSpanFull(),
                                    ])
                                    ->collapsible()
                                    ->collapsed(),
                            ])
                            ->columnSpan(2),

                        // ─── Right Sidebar Column (span 1) ───────────────────
                        Grid::make(1)
                            ->schema([
                                // Status Section
                                Section::make('Status')
                                    ->schema([
                                        Toggle::make('is_visible')
                                            ->label('Visibility')
                                            ->helperText('This product will be hidden from all sales channels.')
                                            ->default(true),
                                        DatePicker::make('published_at')
                                            ->label('Publishing date')
                                            ->required()
                                            ->default(now()),
                                    ]),

                                // Associations Section
                                Section::make('Associations')
                                    ->schema([
                                        Select::make('brand_id')
                                            ->relationship('brand', 'name')
                                            ->label('Brand')
                                            ->searchable(),
                                        Select::make('category_id')
                                            ->relationship('category', 'name')
                                            ->label('Product categories')
                                            ->required()
                                            ->searchable(),
                                    ]),
                            ])
                            ->columnSpan(1),
                    ])
                    ->columnSpanFull(),
            ]);
    }
}