<?php

namespace App\Business;

use Carbon\CarbonImmutable;
use Illuminate\Support\Facades\DB;

/**
 * 汇总商品月加权平均单价结果，并将入库明细差异按原因分类。
 */
class ProductMonthlyWeightedAverageReporter
{
    // 异常阈值未由业务另行指定：取至少 100 行，且不超过总行数的 0.1%。
    private const ANOMALY_THRESHOLD_MIN_ROWS = 100;

    private const ANOMALY_THRESHOLD_RATE = 0.001;

    private const ROW_TABLE = 'product_monthly_weighted_average_rows';

    private const STATE_TABLE = 'product_monthly_weighted_average_states';

    private const INBOUND_TABLE = 'inventory_inbound_detail_rows';

    private const INVENTORY_MONTH_TABLE = 'inventory_report_authoritative_months';

    private const INVENTORY_ROW_TABLE = 'inventory_report_authoritative_rows';

    /** @return array<string,mixed> */
    public function build(string $connection, CarbonImmutable $month): array
    {
        $month = $month->startOfMonth();
        $db = DB::connection($connection);
        $baseQuery = static fn () => $db->table(self::ROW_TABLE)
            ->where('report_month', $month->toDateString());

        $totals = $baseQuery()
            ->selectRaw('count(*) as total_rows')
            ->selectRaw('coalesce(sum(opening_quantity), 0) as opening_quantity')
            ->selectRaw('coalesce(sum(opening_amount), 0) as opening_amount')
            ->selectRaw('coalesce(sum(purchase_quantity), 0) as purchase_quantity')
            ->selectRaw('coalesce(sum(purchase_amount), 0) as purchase_amount')
            ->selectRaw('sum(case when weighted_average_unit_price is not null then 1 else 0 end) as weighted_price_rows')
            ->selectRaw('sum(case when weighted_average_unit_price is null then 1 else 0 end) as missing_weighted_rows')
            ->selectRaw('sum(case when pricing_status = ? then 1 else 0 end) as manual_review_rows', ['待人工核查'])
            ->first();

        if ($totals === null || (int) $totals->total_rows === 0) {
            return [
                'status' => 'missing',
                'report_month' => $month->toDateString(),
                'message' => '该月份尚未生成商品月加权平均单价。',
                'generated_at' => now()->toDateTimeString(),
            ];
        }

        $weightedKeys = [];
        foreach ($baseQuery()->select('product_code', 'warehouse_short_name')->cursor() as $row) {
            $weightedKeys[$this->key($row->product_code, $row->warehouse_short_name)] = true;
        }

        $inbound = [
            'source_rows' => 0,
            'source_quantity' => 0.0,
            'source_amount' => 0.0,
            'matched_rows' => 0,
            'matched_quantity' => 0.0,
            'matched_amount' => 0.0,
            'unmatched_rows' => 0,
            'unmatched_quantity' => 0.0,
            'unmatched_amount' => 0.0,
            'unmatched_groups' => [],
        ];
        foreach ($db->table(self::INBOUND_TABLE)
            ->where('report_month', $month->toDateString())
            ->selectRaw('upper(barcode) as code, warehouse_short_name, count(*) as rows_count')
            ->selectRaw('coalesce(sum(quantity), 0) as quantity')
            ->selectRaw('coalesce(sum(coalesce(amount, 0) + coalesce(estimated_amount, 0)), 0) as amount')
            ->groupByRaw('upper(barcode), warehouse_short_name')
            ->cursor() as $row) {
            $rows = (int) $row->rows_count;
            $quantity = (float) $row->quantity;
            $amount = (float) $row->amount;
            $inbound['source_rows'] += $rows;
            $inbound['source_quantity'] += $quantity;
            $inbound['source_amount'] += $amount;

            if (isset($weightedKeys[$this->key($row->code, $row->warehouse_short_name)])) {
                $inbound['matched_rows'] += $rows;
                $inbound['matched_quantity'] += $quantity;
                $inbound['matched_amount'] += $amount;
                continue;
            }

            $inbound['unmatched_rows'] += $rows;
            $inbound['unmatched_quantity'] += $quantity;
            $inbound['unmatched_amount'] += $amount;
            $inbound['unmatched_groups'][] = [
                'product_code' => trim((string) $row->code),
                'warehouse_short_name' => trim((string) $row->warehouse_short_name),
                'source_rows' => $rows,
                'quantity' => $this->number($quantity),
                'amount' => $this->number($amount),
                'reason' => '入库明细未匹配到商品编码 + 仓库简称行',
            ];
        }
        usort(
            $inbound['unmatched_groups'],
            static fn (array $left, array $right): int =>
                abs((float) $right['amount']) <=> abs((float) $left['amount']),
        );
        $inbound = $this->roundNestedNumbers($inbound);

        $monthState = $db->table(self::INVENTORY_MONTH_TABLE)
            ->where('dataset_key', 'jiansun.inventory-report.authoritative-month')
            ->where('source_month', $month->toDateString())
            ->first();
        $generation = $monthState?->active_generation;
        $actualSourceRows = $generation === null
            ? 0
            : $db->table(self::INVENTORY_ROW_TABLE)
                ->where('generation', (string) $generation)
                ->count();
        $expectedSourceRows = (int) ($monthState?->source_row_count ?? 0);

        $weightedAnomalyRows = $baseQuery()
            ->where(function ($query): void {
                $query->whereNull('weighted_average_unit_price')
                    ->orWhere('pricing_status', '待人工核查');
            })
            ->count();
        $reasons = [];
        if ((int) $totals->missing_weighted_rows > 0) {
            $reasons[] = [
                'code' => 'missing_weighted_price',
                'label' => '加权平均单价为空',
                'rows' => (int) $totals->missing_weighted_rows,
            ];
        }
        if ((int) $totals->manual_review_rows > 0) {
            $reasons[] = [
                'code' => 'manual_review',
                'label' => '待人工核查',
                'rows' => (int) $totals->manual_review_rows,
            ];
        }
        if ((int) $inbound['unmatched_rows'] > 0) {
            $reasons[] = [
                'code' => 'inbound_without_inventory_dimension',
                'label' => '入库明细未匹配到商品编码 + 仓库简称行',
                'rows' => (int) $inbound['unmatched_rows'],
                'groups' => count($inbound['unmatched_groups']),
            ];
        }
        if ($actualSourceRows !== $expectedSourceRows) {
            $reasons[] = [
                'code' => 'upstream_source_row_mismatch',
                'label' => '上游进销存源表行数与已激活明细不一致',
                'rows' => abs($actualSourceRows - $expectedSourceRows),
            ];
        }

        $anomalyRows = $weightedAnomalyRows + (int) $inbound['unmatched_rows'];
        $threshold = max(
            self::ANOMALY_THRESHOLD_MIN_ROWS,
            (int) ceil((int) $totals->total_rows * self::ANOMALY_THRESHOLD_RATE),
        );

        return [
            'status' => $reasons === [] ? 'computed' : 'review_required',
            'report_month' => $month->toDateString(),
            'totals' => [
                'rows' => (int) $totals->total_rows,
                'opening_quantity' => $this->number((float) $totals->opening_quantity),
                'opening_amount' => $this->number((float) $totals->opening_amount),
                'purchase_quantity' => $this->number((float) $totals->purchase_quantity),
                'purchase_amount' => $this->number((float) $totals->purchase_amount),
                'weighted_price_rows' => (int) $totals->weighted_price_rows,
                'missing_weighted_rows' => (int) $totals->missing_weighted_rows,
                'manual_review_rows' => (int) $totals->manual_review_rows,
            ],
            'inbound' => $inbound,
            'source' => [
                'expected_rows' => $expectedSourceRows,
                'active_rows' => $actualSourceRows,
                'row_difference' => $actualSourceRows - $expectedSourceRows,
                'status' => (string) ($monthState?->status ?? 'missing'),
                'active_generation' => $generation,
                'source_filename' => $monthState?->source_filename,
            ],
            'anomalies' => [
                'affected_rows' => $anomalyRows,
                'threshold_rows' => $threshold,
                'threshold_exceeded' => $anomalyRows > $threshold,
                'reasons' => $reasons,
            ],
            'state' => $db->table(self::STATE_TABLE)
                ->where('report_month', $month->toDateString())
                ->first(),
            'generated_at' => now()->toDateTimeString(),
        ];
    }

    /** @param array<string,mixed> $report */
    public function brief(array $report): string
    {
        if (($report['status'] ?? null) === 'missing') {
            return (string) ($report['message'] ?? '商品月加权平均单价尚未生成');
        }

        $totals = $report['totals'] ?? [];
        $inbound = $report['inbound'] ?? [];
        $anomalies = $report['anomalies'] ?? [];
        $reasonLabels = array_map(
            static fn (array $reason): string =>
                (string) ($reason['label'] ?? $reason['code'] ?? '未知异常'),
            $anomalies['reasons'] ?? [],
        );

        return sprintf(
            '%s：总行数 %s；期初 %s 件 / %s；入库 %s 件 / %s；加权单价 %s 行；异常 %s 行%s',
            substr((string) ($report['report_month'] ?? ''), 0, 7),
            number_format((int) ($totals['rows'] ?? 0)),
            number_format((float) ($totals['opening_quantity'] ?? 0), 2),
            number_format((float) ($totals['opening_amount'] ?? 0), 2),
            number_format((float) ($inbound['matched_quantity'] ?? 0), 2),
            number_format((float) ($inbound['matched_amount'] ?? 0), 2),
            number_format((int) ($totals['weighted_price_rows'] ?? 0)),
            number_format((int) ($anomalies['affected_rows'] ?? 0)),
            $reasonLabels === [] ? '' : '（' . implode('、', $reasonLabels) . '）',
        );
    }

    private function key(mixed $productCode, mixed $warehouseShortName): string
    {
        return mb_strtoupper(trim((string) $productCode))
            . "\0"
            . trim((string) $warehouseShortName);
    }

    private function number(float $value): float
    {
        return round($value, 6);
    }

    /**
     * @param array<string,mixed> $value
     * @return array<string,mixed>
     */
    private function roundNestedNumbers(array $value): array
    {
        foreach ($value as $key => $item) {
            if (is_array($item)) {
                $value[$key] = $this->roundNestedNumbers($item);
            } elseif (is_float($item)) {
                $value[$key] = round($item, 6);
            }
        }

        return $value;
    }
}