<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Support\Facades\DB;

/**
 * 按账户滚动计算每日资金流水，并回写账户当前余额、每日可出金额和店铺余额。
 *
 * 计算口径固定在服务端，页面只读结果：
 *   期末 = 期初 + 当日入账 - 当日出账
 *   账户当前余额 = 最新一条流水期末
 *   每日可出金额 = 当前余额 - 卡住金额
 *   店铺余额 = 店铺所属公司名下账户当前余额合计（待财务确认）
 */
class FinanceLedgerCalculator
{
    public function recalculate(): array
    {
        $connection = $this->connection();
        $openingDate = (string) config('finance_ledger.opening_date', '2026-10-17');
        $now = now();

        $opening = $connection->table('fin_account_opening')
            ->where('opening_date', '<=', $openingDate)
            ->orderBy('opening_date')
            ->get()
            ->groupBy('account_short')
            ->map(static fn ($rows) => $rows->last());

        $accountCompanies = $connection->table('fin_accounts')
            ->select(['account_short', 'company_name'])
            ->get()
            ->groupBy('account_short')
            ->map(static fn ($rows) => (string) ($rows->first()->company_name ?? ''));

        $mapping = $connection->table('fin_account_map')
            ->whereNotNull('account_short')
            ->where('account_short', '<>', '')
            ->get(['source', 'source_value', 'account_short'])
            ->keyBy(static fn ($row): string => $row->source . "\0" . $row->source_value);

        $transactions = $connection->table('fin_transactions')
            ->where('txn_date', '>=', $openingDate)
            ->orderBy('txn_date')
            ->orderBy('id')
            ->get(['txn_date', 'account_short', 'source', 'source_value', 'income', 'expense']);

        $daily = [];
        $balances = [];

        foreach ($transactions as $transaction) {
            $mapKey = $transaction->source . "\0" . $transaction->source_value;
            $account = (string) ($mapping->get($mapKey)->account_short ?? '');
            if ($account === '') {
                $account = trim((string) $transaction->account_short);
            }
            if ($account === '' || ! $opening->has($account)) {
                continue;
            }

            $date = (string) $transaction->txn_date;
            $key = $account . "\0" . $date;
            $daily[$key] ??= [
                'account_short' => $account,
                'flow_date' => $date,
                'inflow' => 0.0,
                'outflow' => 0.0,
            ];
            $daily[$key]['inflow'] += (float) $transaction->income;
            $daily[$key]['outflow'] += (float) $transaction->expense;
        }

        $flows = [];
        $latest = [];

        foreach ($opening as $account => $openingRow) {
            $account = (string) $account;
            $balance = (float) $openingRow->opening_balance;
            $company = $accountCompanies->get($account, '');
            $start = max((string) $openingRow->opening_date, $openingDate);

            $rows = array_values(array_filter(
                $daily,
                static fn (array $row): bool => $row['account_short'] === $account,
            ));
            usort($rows, static fn (array $a, array $b): int => strcmp($a['flow_date'], $b['flow_date']));

            $openingFlow = [
                'flow_date' => $start,
                'company_name' => $company,
                'account_short' => $account,
                'opening_balance' => round($balance, 2),
                'inflow' => 0.0,
                'outflow' => 0.0,
                'closing_balance' => round($balance, 2),
                'remark' => '期初',
                'created_at' => $now,
                'updated_at' => $now,
            ];
            $flows[] = $openingFlow;
            $openingIndex = array_key_last($flows);

            foreach ($rows as $row) {
                if ($row['flow_date'] < $start) {
                    continue;
                }
                $inflow = round((float) $row['inflow'], 2);
                $outflow = round((float) $row['outflow'], 2);
                if (abs($inflow) < 0.005 && abs($outflow) < 0.005) {
                    continue;
                }

                if ($row['flow_date'] === $start) {
                    // 期初日发生动账时合并到同一行，避免唯一键冲突。
                    $balance = round($balance + $inflow - $outflow, 2);
                    $flows[$openingIndex]['inflow'] = $inflow;
                    $flows[$openingIndex]['outflow'] = $outflow;
                    $flows[$openingIndex]['closing_balance'] = $balance;
                    $flows[$openingIndex]['remark'] = null;
                    continue;
                }

                $balance = round($balance + $inflow - $outflow, 2);
                $flows[] = [
                    'flow_date' => $row['flow_date'],
                    'company_name' => $company,
                    'account_short' => $account,
                    'opening_balance' => round($balance - $inflow + $outflow, 2),
                    'inflow' => $inflow,
                    'outflow' => $outflow,
                    'closing_balance' => $balance,
                    'remark' => null,
                    'created_at' => $now,
                    'updated_at' => $now,
                ];
            }

            $latest[$account] = $balance;
        }

        $connection->transaction(function () use ($connection, $flows, $latest, $now): void {
            $connection->table('fin_daily_flows')->delete();
            foreach (array_chunk($flows, 500) as $chunk) {
                $connection->table('fin_daily_flows')->insert($chunk);
            }

            foreach ($latest as $account => $balance) {
                $connection->table('fin_accounts')
                    ->where('account_short', $account)
                    ->update([
                        'current_balance' => round((float) $balance, 2),
                        'daily_available' => $connection->raw('ROUND(current_balance - blocked_amount, 2)'),
                        'updated_at' => $now,
                    ]);
            }

            $companies = $connection->table('fin_accounts')
                ->selectRaw('company_name, SUM(current_balance) AS balance')
                ->groupBy('company_name')
                ->pluck('balance', 'company_name');

            foreach ($companies as $company => $balance) {
                $connection->table('fin_shops')
                    ->where('company_name', (string) $company)
                    ->update(['shop_balance' => round((float) $balance, 2), 'updated_at' => $now]);
            }
        });

        return [
            'accounts' => count($latest),
            'flows' => count($flows),
            'opening_date' => $openingDate,
            'balance_sum' => round(array_sum($latest), 2),
        ];
    }

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