<?php

namespace App\Business\KukaPostingPerformance;

use Carbon\CarbonImmutable;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Throwable;

class KukaPostingPerformancePageData
{
    private const EXCLUDED_PLATFORMS = ['京东网银钱包'];

    private const INCOME_SQL = 'COALESCE(income_amount, 0)'
        . ' + COALESCE(discount_amount, 0)'
        . ' + COALESCE(offset_amount, 0)'
        . ' + COALESCE(refund_amount, 0)'
        . ' + COALESCE(default_compensation_amount, 0)';

    /**
     * 业绩明细的 12 家店铺月度收入汇总。
     *
     * 收入口径：账单收入 + 优惠金额 + 冲减金额 + 退款金额 + 违约赔付（冲减收入）。
     *
     * @return array<string,mixed>
     */
    public function build(Request $request): array
    {
        $stores = array_values(array_unique(array_filter(array_map(
            static fn (mixed $store): string => trim((string) $store),
            (array) config('kuka_posting.stores', []),
        ))));

        if ($stores === []) {
            return $this->emptyResult($stores, '尚未配置灵珊店铺业绩的店铺范围。');
        }

        try {
            $months = $this->availableMonths();
            $month = $this->selectedMonth((string) $request->query('month', ''), $months);
            if ($month === null) {
                return $this->emptyResult($stores, '业绩明细暂时没有可汇总的月份。');
            }

            $storeRows = cache()->remember(
                $this->cacheKey('stores', $month, $stores),
                now()->addMinutes(10),
                fn (): array => $this->storeRows($month, $stores),
            );

            $monthlyTotals = cache()->remember(
                $this->cacheKey('months', implode('|', $months), $stores),
                now()->addMinutes(10),
                fn (): array => $this->monthlyTotals($months, $stores),
            );

            $summary = $this->summary($storeRows);

            return [
                'stores' => $storeRows,
                'months' => $months,
                'month' => $month,
                'month_label' => $this->monthLabel($month),
                'summary' => $summary,
                'monthly_totals' => $monthlyTotals,
                'error' => null,
            ];
        } catch (Throwable $exception) {
            report($exception);

            return $this->emptyResult(
                $stores,
                '灵珊店铺业绩暂时无法读取，请稍后重试；这不代表该月收入为 0。',
            );
        }
    }

    /**
     * @return list<string>
     */
    private function availableMonths(): array
    {
        return cache()->remember(
            $this->cacheKey('available-months'),
            now()->addMinutes(10),
            function (): array {
                $range = $this->connection()
                    ->table('store_receipt_order_match_rows')
                    ->whereNotIn('platform', self::EXCLUDED_PLATFORMS)
                    ->whereNotNull('report_month')
                    ->selectRaw('MIN(report_month) as min_month, MAX(report_month) as max_month')
                    ->first();

                if (($range->min_month ?? null) === null || ($range->max_month ?? null) === null) {
                    return [];
                }

                $end = CarbonImmutable::parse((string) $range->max_month)->startOfMonth();
                $start = CarbonImmutable::parse((string) $range->min_month)->startOfMonth();
                $earliest = now()->startOfMonth()->subMonthsNoOverflow(11);
                if ($start->lt($earliest)) {
                    $start = $earliest;
                }

                $months = [];
                for ($cursor = $end; $cursor->gte($start); $cursor = $cursor->subMonthNoOverflow()) {
                    $months[] = $cursor->format('Y-m');
                }

                return $months;
            },
        );
    }

    /**
     * @param  list<string>  $months
     */
    private function selectedMonth(string $requested, array $months): ?string
    {
        if (preg_match('/^\d{4}-\d{2}$/', $requested) === 1 && in_array($requested, $months, true)) {
            return $requested;
        }

        $previousMonth = now()->subMonthNoOverflow()->format('Y-m');

        return in_array($previousMonth, $months, true) ? $previousMonth : ($months[0] ?? null);
    }

    /**
     * @param  list<string>  $stores
     * @return list<array<string,mixed>>
     */
    private function storeRows(string $month, array $stores): array
    {
        $aggregates = $this->connection()
            ->table('store_receipt_order_match_rows')
            ->where('report_month', $month . '-01')
            ->whereIn('store_name', $stores)
            ->whereNotIn('platform', self::EXCLUDED_PLATFORMS)
            ->selectRaw(
                'store_name,
                COUNT(*) as row_count,
                SUM(COALESCE(income_amount, 0)) as income_amount,
                SUM(COALESCE(discount_amount, 0)) as discount_amount,
                SUM(COALESCE(offset_amount, 0)) as offset_amount,
                SUM(COALESCE(refund_amount, 0)) as refund_amount,
                SUM(COALESCE(default_compensation_amount, 0)) as default_compensation_amount,
                SUM(' . self::INCOME_SQL . ') as total_income,
                MAX(imported_at) as imported_at'
            )
            ->groupBy('store_name')
            ->get()
            ->keyBy('store_name');

        return array_map(static function (string $store) use ($aggregates): array {
            $row = $aggregates->get($store);

            return [
                'store_name' => $store,
                'row_count' => (int) ($row->row_count ?? 0),
                'income_amount' => round((float) ($row->income_amount ?? 0), 2),
                'discount_amount' => round((float) ($row->discount_amount ?? 0), 2),
                'offset_amount' => round((float) ($row->offset_amount ?? 0), 2),
                'refund_amount' => round((float) ($row->refund_amount ?? 0), 2),
                'default_compensation_amount' => round((float) ($row->default_compensation_amount ?? 0), 2),
                'total_income' => round((float) ($row->total_income ?? 0), 2),
                'imported_at' => $row->imported_at ?? null,
                'has_data' => $row !== null,
            ];
        }, $stores);
    }

    /**
     * @param  list<string>  $months
     * @param  list<string>  $stores
     * @return list<array{month:string,label:string,total_income:float,row_count:int}>
     */
    private function monthlyTotals(array $months, array $stores): array
    {
        $totals = [];
        foreach ($months as $month) {
            $row = $this->connection()
                ->table('store_receipt_order_match_rows')
                ->where('report_month', $month . '-01')
                ->whereIn('store_name', $stores)
                ->whereNotIn('platform', self::EXCLUDED_PLATFORMS)
                ->selectRaw(
                    'COUNT(*) as row_count,
                    SUM(' . self::INCOME_SQL . ') as total_income'
                )
                ->first();

            $totals[] = [
                'month' => $month,
                'label' => $this->monthLabel($month),
                'total_income' => round((float) ($row->total_income ?? 0), 2),
                'row_count' => (int) ($row->row_count ?? 0),
            ];
        }

        return $totals;
    }

    /**
     * @param  list<array<string,mixed>>  $rows
     * @return array<string,mixed>
     */
    private function summary(array $rows): array
    {
        $summary = [
            'row_count' => 0,
            'stores_with_data' => 0,
            'income_amount' => 0.0,
            'discount_amount' => 0.0,
            'offset_amount' => 0.0,
            'refund_amount' => 0.0,
            'default_compensation_amount' => 0.0,
            'total_income' => 0.0,
            'imported_at' => null,
        ];

        foreach ($rows as $row) {
            $summary['row_count'] += (int) $row['row_count'];
            $summary['stores_with_data'] += $row['has_data'] ? 1 : 0;
            foreach ([
                'income_amount',
                'discount_amount',
                'offset_amount',
                'refund_amount',
                'default_compensation_amount',
                'total_income',
            ] as $field) {
                $summary[$field] += (float) $row[$field];
            }

            if ($row['imported_at'] !== null
                && ($summary['imported_at'] === null || $row['imported_at'] > $summary['imported_at'])) {
                $summary['imported_at'] = $row['imported_at'];
            }
        }

        foreach ([
            'income_amount',
            'discount_amount',
            'offset_amount',
            'refund_amount',
            'default_compensation_amount',
            'total_income',
        ] as $field) {
            $summary[$field] = round((float) $summary[$field], 2);
        }

        return $summary;
    }

    /**
     * @param  list<string>  $stores
     * @return array<string,mixed>
     */
    private function emptyResult(array $stores, string $error): array
    {
        return [
            'stores' => array_map(static fn (string $store): array => [
                'store_name' => $store,
                'row_count' => 0,
                'income_amount' => 0.0,
                'discount_amount' => 0.0,
                'offset_amount' => 0.0,
                'refund_amount' => 0.0,
                'default_compensation_amount' => 0.0,
                'total_income' => 0.0,
                'imported_at' => null,
                'has_data' => false,
            ], $stores),
            'months' => [],
            'month' => null,
            'month_label' => '—',
            'summary' => [
                'row_count' => 0,
                'stores_with_data' => 0,
                'income_amount' => 0.0,
                'discount_amount' => 0.0,
                'offset_amount' => 0.0,
                'refund_amount' => 0.0,
                'default_compensation_amount' => 0.0,
                'total_income' => 0.0,
                'imported_at' => null,
            ],
            'monthly_totals' => [],
            'error' => $error,
        ];
    }

    private function connection()
    {
        return DB::connection((string) config('upstream_mirrors.connection', 'business_mirror'));
    }

    private function monthLabel(string $month): string
    {
        return substr($month, 0, 4) . '年' . (int) substr($month, 5, 2) . '月';
    }

    /**
     * @param  list<string>  $stores
     */
    private function cacheKey(string $scope, string $period = '', array $stores = []): string
    {
        return 'kuka-posting-performance-v1:' . $scope . ':' . md5(json_encode([
            $period,
            $stores,
        ], JSON_UNESCAPED_UNICODE | JSON_THROW_ON_ERROR));
    }
}