<?php

namespace App\Exports;

use App\Models\PurchaseOrderModel;
use App\Models\SupplierModel;
use App\Services\PurchaseItemService;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\FromCollection;
use Maatwebsite\Excel\Concerns\WithStrictNullComparison;
use Maatwebsite\Excel\Concerns\WithStyles;
use Maatwebsite\Excel\Concerns\WithTitle;
use PhpOffice\PhpSpreadsheet\Cell\Coordinate;
use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;

/**
 * 供应商采购明细导出 · 单供应商工作表（成本口径：金额=Σ数量×成本价）
 */
class PurchaseSupplierSheet implements FromCollection, WithStrictNullComparison, WithStyles, WithTitle
{
    private ?Collection $rows = null;

    /** @var array<int, string> 特殊行索引（1 起）=> 类型（title/header/summary） */
    private array $specialRows = [];

    /** 列头所在行索引 */
    private int $headerRow = 1;

    public function __construct(
        private readonly PurchaseOrderModel $purchase,
        private readonly SupplierModel $supplier,
        private readonly string $sheetTitle,
    ) {
    }

    /**
     * 导出行：标题/空行/列头/明细/合计
     */
    public function collection(): Collection
    {
        if ($this->rows !== null) {
            return $this->rows;
        }

        $items = app(PurchaseItemService::class)->supplierRows($this->purchase->id, $this->supplier->id);

        $rows = [];
        $rowIndex = 0;

        // 标题行
        $rows[] = [$this->supplier->name . ' · 采购单 ' . $this->purchase->purchase_no];
        $this->specialRows[++$rowIndex] = 'title';

        // 空行
        $rows[] = [''];
        $rowIndex++;

        // 列头
        $rows[] = ['序号', '品名', '包规', '单位', '成本价', '数量', '重量(斤)', '金额'];
        $this->specialRows[++$rowIndex] = 'header';
        $this->headerRow = $rowIndex;

        // 明细行
        $totalQuantity = 0;
        $totalWeight = '0';
        $totalAmount = '0';
        foreach (array_values($items) as $sort => $item) {
            $rows[] = [
                $sort + 1,
                $item['product_name'],
                $item['product_spec'],
                $item['unit'],
                (float) $item['cost_price'],
                (int) $item['quantity'],
                (float) $item['weight'],
                (float) $item['amount'],
            ];
            $rowIndex++;
            $totalQuantity += (int) $item['quantity'];
            $totalWeight = bcadd($totalWeight, (string) $item['weight'], 3);
            $totalAmount = bcadd($totalAmount, (string) $item['amount'], 2);
        }

        // 合计行
        $rows[] = ['', '合计', '', '', '', $totalQuantity, (float) $totalWeight, (float) $totalAmount];
        $this->specialRows[++$rowIndex] = 'summary';

        return $this->rows = collect($rows);
    }

    public function title(): string
    {
        return $this->sheetTitle;
    }

    /**
     * 标题/列头/合计加粗，冻结列头
     */
    public function styles(Worksheet $sheet): array
    {
        $this->collection();

        $sheet->freezePane('A' . ($this->headerRow + 1));
        $widths = [6, 24, 14, 8, 10, 10, 12, 12];
        foreach ($widths as $index => $width) {
            $sheet->getColumnDimension(Coordinate::stringFromColumnIndex($index + 1))->setWidth($width);
        }

        $styles = [];
        foreach ($this->specialRows as $row => $type) {
            $style = match ($type) {
                'title' => ['font' => ['bold' => true, 'size' => 14]],
                'header', 'summary' => ['font' => ['bold' => true]],
                default => [],
            };
            if ($style !== []) {
                $styles[$row] = $style;
            }
        }

        return $styles;
    }
}