<?php

namespace App\Exports;

use App\Exceptions\RepositoryException;
use App\Models\BillModel;
use App\Models\ProductCategoryModel;
use App\Models\ProductModel;
use App\Services\BillDetailService;
use App\Services\WeightEstimator;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\FromCollection;
use Maatwebsite\Excel\Concerns\WithStyles;
use Maatwebsite\Excel\Concerns\WithTitle;
use PhpOffice\PhpSpreadsheet\Style\Alignment;
use PhpOffice\PhpSpreadsheet\Style\Border;
use PhpOffice\PhpSpreadsheet\Style\Fill;
use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;

/**
 * 门店账单导出：单账单可直接下载；多账单按商品合并为一张汇总表（批量导出按门店分组），
 * 明细可按一级分类过滤，表尾汇总商品金额/配送费/附加金额/售后金额/总金额
 */
class BillExport implements FromCollection, WithStyles, WithTitle
{
    /** 数量列填充色（浅黄） */
    private const string QUANTITY_FILL = 'FFFFF2CC';

    /** 金额列填充色（浅红） */
    private const string AMOUNT_FILL = 'FFFFCCCC';

    /** 金额格式：￥ + 两位小数 */
    private const string CURRENCY_FORMAT = '"￥"#,##0.00';

    private ?Collection $rows = null;

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

    /** @var array<int, int> 标签需左合并 A:G 的合计行索引 */
    private array $mergeRows = [];

    /** @var array<int, array{row: int, column: string, value: float}> 条件填色单元格（F=数量浅黄，H=金额浅红，非 0 填色） */
    private array $fillCells = [];

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

    /** 数据末行索引 */
    private int $lastRow = 1;

    /** @var Collection<int, BillModel> */
    private Collection $bills;

    /**
     * @param BillModel|Collection<int, BillModel> $bills 导出账单（with store）；多账单须属于同一门店
     * @param int $categoryId 一级分类ID（0=全部）
     * @param string $sheetTitle 工作表名称
     */
    public function __construct(
        BillModel|Collection $bills,
        private readonly int $categoryId = 0,
        private readonly string $sheetTitle = '门店账单',
    ) {
        $this->bills = $bills instanceof BillModel ? collect([$bills]) : $bills->values();
    }

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

    /**
     * 导出行：所选门店账单合并为一张表格，同商品及账单级费用分别汇总
     */
    public function collection(): Collection
    {
        if ($this->rows !== null) {
            return $this->rows;
        }

        $rows = [];
        $rowIndex = 0;
        $this->appendBillRows($this->bills, $rows, $rowIndex);

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

    /**
     * 追加所选账单的合并表格
     *
     * @param Collection<int, BillModel> $bills
     * @param array<int, array<int, mixed>> $rows
     */
    private function appendBillRows(Collection $bills, array &$rows, int &$rowIndex): void
    {
        $items = $this->mergedItems($bills);

        // 商品 => 一级分类解析（明细行「一级分类」列与分类过滤共用同一份结果）
        [$categories, $rootIds] = $this->resolveRootCategories($items);

        $categoryName = '全部';
        if ($this->categoryId > 0) {
            [$items, $categoryName] = $this->filterByRootCategory($items, $categories, $rootIds);
        }

        $bill = $bills->first();
        $isMerged = $bills->count() > 1;

        // 标题行
        $rows[] = [$isMerged ? '门店账单 合并导出（' . $bills->count() . '张）' : '门店账单 ' . $bill->bill_no];
        $this->specialRows[++$rowIndex] = 'title';

        // 范围行：门店 / 账单日期（合并时取起止日期）/ 分类 / 导出时间
        $billDate = $bill->bill_date?->toDateString();
        if ($isMerged) {
            $dates = $bills->map(static fn (BillModel $item): ?string => $item->bill_date?->toDateString())
                ->filter()
                ->sort()
                ->values();
            $billDate = $dates->first() === $dates->last()
                ? $dates->first()
                : $dates->first() . ' 至 ' . $dates->last();
        }
        $storeName = $bill->store->name ?? ('门店#' . $bill->store_id);
        $rows[] = [
            '门店：' . $storeName
            . '    账单日期：' . $billDate
            . ($isMerged ? '    账单数量：' . $bills->count() : '')
            . '    分类：' . $categoryName
            . '    导出时间：' . now('Asia/Shanghai')->format('Y-m-d H:i:s'),
        ];
        $this->specialRows[++$rowIndex] = 'scope';

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

        // 列头（包规=包规+单位合并；单价=每件零售价+单价单位；一级分类=商品根分类名）
        $rows[] = ['序号', '品名', '一级分类', '包规', '单价', '数量', '重量(斤)', '金额'];
        $this->specialRows[++$rowIndex] = 'header';
        $this->headerRow = $rowIndex;

        // 明细行（所选账单的同商品已合并，单价为合并后的每件价折算零售价）
        $totalQuantity = 0;
        $totalWeight = '0';
        $totalAmount = '0';
        foreach (array_values($items) as $sort => $item) {
            $rows[] = [
                $sort + 1,
                $item['product_name'],
                $categories->get($rootIds[$item['product_id']] ?? 0)?->name ?? '',
                $item['product_spec'] . $item['unit'],
                self::retailPriceLabel($item),
                (int) $item['quantity'],
                (float) $item['weight'],
                (float) $item['amount'],
            ];
            $rowIndex++;
            $this->fillCells[] = ['row' => $rowIndex, 'column' => 'F', 'value' => (float) $item['quantity']];
            $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $item['amount']];
            $totalQuantity += (int) $item['quantity'];
            $totalWeight = bcadd($totalWeight, $item['weight'], 3);
            $totalAmount = bcadd($totalAmount, $item['amount'], 2);
        }

        // 商品合计行
        $rows[] = ['', '合计', '', '', '', $totalQuantity, (float) $totalWeight, (float) $totalAmount];
        $this->specialRows[++$rowIndex] = 'summary';
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'F', 'value' => (float) $totalQuantity];
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $totalAmount];

        // 配送费/附加金额/售后金额按所选账单分别累加，不受分类过滤影响
        $deliveryTotal = '0';
        $addedTotal = '0';
        $afterSaleTotal = '0';
        $boxNum = 0;
        $trayNum = 0;
        foreach ($bills as $selectedBill) {
            $deliveryTotal = bcadd($deliveryTotal, (string) $selectedBill->delivery_fee, 2);
            $addedTotal = bcadd($addedTotal, (string) $selectedBill->added_amount, 2);
            $afterSaleTotal = bcadd($afterSaleTotal, (string) $selectedBill->after_sale, 2);
            $boxNum += (int) $selectedBill->box_num;
            $trayNum += (int) $selectedBill->tray_num;
        }
        $grandTotal = bcadd(bcadd(bcadd($totalAmount, $deliveryTotal, 2), $addedTotal, 2), $afterSaleTotal, 2);

        $rows[] = ['配送费', '', '', '', '', '', '', (float) $deliveryTotal];
        $this->specialRows[++$rowIndex] = 'summary';
        $this->mergeRows[] = $rowIndex;
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $deliveryTotal];

        $rows[] = ['附加金额（周转筐 ' . $boxNum . ' 个 / 周转托盘 ' . $trayNum . ' 个）', '', '', '', '', '', '', (float) $addedTotal];
        $this->specialRows[++$rowIndex] = 'summary';
        $this->mergeRows[] = $rowIndex;
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $addedTotal];

        $rows[] = ['售后金额（可正负）', '', '', '', '', '', '', (float) $afterSaleTotal];
        $this->specialRows[++$rowIndex] = 'summary';
        $this->mergeRows[] = $rowIndex;
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $afterSaleTotal];

        $rows[] = ['总金额（商品金额+配送费+附加金额+售后金额）', '', '', '', '', '', '', (float) $grandTotal];
        $this->specialRows[++$rowIndex] = 'grand';
        $this->mergeRows[] = $rowIndex;
        $this->fillCells[] = ['row' => $rowIndex, 'column' => 'H', 'value' => (float) $grandTotal];
        $this->lastRow = $rowIndex;
    }

    /**
     * 合并所选账单商品：数量、重量、金额累加，单价按总金额 ÷ 总数量重新加权
     *
     * @param Collection<int, BillModel> $bills
     * @return array<int, array{product_id: int, product_name: string, product_spec: string, unit: string, price: string, quantity: int, weight: string, amount: string, spec: string, price_unit: string, image: string}>
     */
    private function mergedItems(Collection $bills): array
    {
        $merged = [];
        $service = app(BillDetailService::class);
        foreach ($bills as $bill) {
            foreach ($service->mergedItems($bill) as $item) {
                $productId = (int) $item['product_id'];
                if (! isset($merged[$productId])) {
                    $merged[$productId] = $item;
                    continue;
                }

                $merged[$productId]['quantity'] += (int) $item['quantity'];
                $merged[$productId]['weight'] = bcadd($merged[$productId]['weight'], $item['weight'], 3);
                $merged[$productId]['amount'] = bcadd($merged[$productId]['amount'], $item['amount'], 2);
                $merged[$productId]['price'] = bcdiv(
                    $merged[$productId]['amount'],
                    (string) $merged[$productId]['quantity'],
                    2
                );
            }
        }

        return array_values($merged);
    }

    /**
     * 标题/列头/合计行加粗，合计行标签左合并 A:G；全表居中 + 全边框；金额列货币格式；
     * 数量（浅黄）/金额（浅红）非 0 条件填色（0 不填、列头固定填色），冻结列头
     */
    public function styles(Worksheet $sheet): array
    {
        $this->collection();

        $sheet->freezePane('A' . ($this->headerRow + 1));
        $sheet->getColumnDimension('A')->setWidth(6);
        $sheet->getColumnDimension('B')->setWidth(24);
        $sheet->getColumnDimension('C')->setWidth(12);
        $sheet->getColumnDimension('D')->setWidth(14);
        $sheet->getColumnDimension('E')->setWidth(12);
        $sheet->getColumnDimension('F')->setWidth(10);
        $sheet->getColumnDimension('G')->setWidth(12);
        $sheet->getColumnDimension('H')->setWidth(12);

        foreach ($this->mergeRows as $row) {
            $sheet->mergeCells('A' . $row . ':G' . $row);
        }

        // 全部单元格水平/垂直居中（合计行标签保持左对齐）
        $sheet->getStyle('A1:H' . $this->lastRow)
            ->getAlignment()
            ->setHorizontal(Alignment::HORIZONTAL_CENTER)
            ->setVertical(Alignment::VERTICAL_CENTER);
        foreach ($this->mergeRows as $row) {
            $sheet->getStyle('A' . $row)->getAlignment()->setHorizontal(Alignment::HORIZONTAL_LEFT);
        }

        // 表格区域（列头 → 末行）添加所有边框
        $sheet->getStyle('A' . $this->headerRow . ':H' . $this->lastRow)
            ->getBorders()
            ->getAllBorders()
            ->setBorderStyle(Border::BORDER_THIN);

        // 金额列货币格式：￥ + 两位小数（单价列为文本，不设格式）
        $sheet->getStyle('H' . ($this->headerRow + 1) . ':H' . $this->lastRow)
            ->getNumberFormat()
            ->setFormatCode(self::CURRENCY_FORMAT);

        // 列头固定填色：数量列（F）浅黄、金额列（H）浅红
        $this->fillCell($sheet, 'F' . $this->headerRow, self::QUANTITY_FILL);
        $this->fillCell($sheet, 'H' . $this->headerRow, self::AMOUNT_FILL);

        // 数据区条件填色：非 0 填色，0 无背景（金额含负值）
        foreach ($this->fillCells as $cell) {
            if ((float) $cell['value'] !== 0.0) {
                $this->fillCell(
                    $sheet,
                    $cell['column'] . $cell['row'],
                    $cell['column'] === 'F' ? self::QUANTITY_FILL : self::AMOUNT_FILL
                );
            }
        }

        $styles = [];
        foreach ($this->specialRows as $row => $type) {
            $style = match ($type) {
                'title' => ['font' => ['bold' => true, 'size' => 14]],
                'header', 'summary' => ['font' => ['bold' => true]],
                'grand' => ['font' => ['bold' => true, 'size' => 12]],
                default => [],
            };
            if ($style !== []) {
                $styles[$row] = $style;
            }
        }

        return $styles;
    }

    /**
     * 单元格纯色填充
     */
    private function fillCell(Worksheet $sheet, string $coordinate, string $argb): void
    {
        $sheet->getStyle($coordinate)
            ->getFill()
            ->setFillType(Fill::FILL_SOLID)
            ->getStartColor()
            ->setARGB($argb);
    }

    /**
     * 单价列文本：每件零售价（明细每件价 ÷ 包规折算每件斤数）+ 单价单位（如「1.74元/斤」）；
     * 包规无法折算（散装/无数字）时按每件原价显示
     *
     * @param array{price: string, product_spec: string, unit: string, price_unit?: string} $item
     */
    private static function retailPriceLabel(array $item): string
    {
        $jinPerPiece = WeightEstimator::perUnitJin($item['product_spec'], $item['unit']);
        $retail = (float) $jinPerPiece > 0
            ? bcdiv($item['price'], $jinPerPiece, 2)
            : $item['price'];

        return $retail . ($item['price_unit'] ?? '');
    }

    /**
     * 按一级分类过滤明细：仅保留根分类为所选分类的行
     *
     * @param array<int, array> $items 合并后的商品明细
     * @param Collection<int, ProductCategoryModel> $categories 全部分类（id => 分类）
     * @param array<int, int> $rootIds 商品ID => 一级分类ID
     * @return array{0: array<int, array>, 1: string} [过滤后明细, 一级分类名]
     */
    private function filterByRootCategory(array $items, Collection $categories, array $rootIds): array
    {
        $categoryName = $categories->get($this->categoryId)?->name ?? ('分类#' . $this->categoryId);

        $categoryId = $this->categoryId;
        $filtered = array_values(array_filter(
            $items,
            static fn (array $row): bool => ($rootIds[$row['product_id']] ?? 0) === $categoryId
        ));

        if ($filtered === []) {
            throw new RepositoryException('所选账单在「' . $categoryName . '」分类下无商品明细');
        }

        return [$filtered, $categoryName];
    }

    /**
     * 解析明细商品的一级分类：沿 parent_id 上溯取根分类（商品含软删除，保证历史账单可导出）
     *
     * @param array<int, array> $items 合并后的商品明细
     * @return array{0: Collection<int, ProductCategoryModel>, 1: array<int, int>} [全部分类(id=>分类), 商品ID=>一级分类ID]
     */
    private function resolveRootCategories(array $items): array
    {
        $categories = ProductCategoryModel::all()->keyBy('id');

        $productCategoryIds = ProductModel::withTrashed()
            ->whereIn('id', array_column($items, 'product_id'))
            ->pluck('category_id', 'id');

        // 商品ID => 根分类ID（与采购单导出同口径的上溯解析）
        $rootIds = [];
        foreach ($productCategoryIds as $productId => $categoryId) {
            $rootId = 0;
            $cursor = (int) $categoryId;
            $guard = 0;
            while ($cursor > 0 && $guard++ < 20) {
                $category = $categories->get($cursor);
                if ($category === null) {
                    break;
                }
                $rootId = (int) $category->id;
                $cursor = (int) $category->parent_id;
            }
            $rootIds[(int) $productId] = $rootId;
        }

        return [$categories, $rootIds];
    }
}