<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;

class AccountLedgerService extends Service
{
    /**
     * 계정별원장 조회
     */
    public function index(array $params): array
    {
        $tenantId = $this->tenantId();
        $startDate = $params['start_date'];
        $endDate = $params['end_date'];
        $accountCode = $params['account_code'];

        // 계정과목 정보
        $account = DB::table('account_codes')
            ->where('tenant_id', $tenantId)
            ->where('code', $accountCode)
            ->where('is_active', true)
            ->first(['code', 'name', 'category', 'sub_category']);

        if (! $account) {
            return [
                'account' => null,
                'period' => compact('startDate', 'endDate'),
                'carry_forward' => ['debit' => 0, 'credit' => 0, 'balance' => 0],
                'monthly_data' => [],
                'grand_total' => ['debit' => 0, 'credit' => 0, 'balance' => 0],
            ];
        }

        // 일반전표 분개 라인
        $journalLines = DB::table('journal_entry_lines as jel')
            ->join('journal_entries as je', 'je.id', '=', 'jel.journal_entry_id')
            ->leftJoin('trading_partners as tp', function ($join) use ($tenantId) {
                $join->on('tp.id', '=', 'jel.trading_partner_id')
                    ->where('tp.tenant_id', '=', $tenantId);
            })
            ->where('jel.tenant_id', $tenantId)
            ->where('jel.account_code', $accountCode)
            ->whereBetween('je.entry_date', [$startDate, $endDate])
            ->whereNull('je.deleted_at')
            ->select([
                'je.entry_date as date',
                'jel.description',
                'jel.trading_partner_name',
                'tp.biz_no',
                'jel.debit_amount',
                'jel.credit_amount',
                DB::raw("'journal' as source_type"),
                'jel.journal_entry_id as source_id',
            ]);

        // 홈택스 세금계산서 분개
        $hometaxLines = DB::table('hometax_invoice_journals as hij')
            ->join('hometax_invoices as hi', 'hi.id', '=', 'hij.hometax_invoice_id')
            ->where('hij.tenant_id', $tenantId)
            ->where('hij.account_code', $accountCode)
            ->whereBetween('hij.write_date', [$startDate, $endDate])
            ->whereNull('hi.deleted_at')
            ->select([
                'hij.write_date as date',
                'hij.description',
                'hij.trading_partner_name',
                DB::raw("CASE WHEN hi.invoice_type = 'sales' THEN hi.invoicee_corp_num ELSE hi.invoicer_corp_num END as biz_no"),
                'hij.debit_amount',
                'hij.credit_amount',
                DB::raw("'hometax' as source_type"),
                'hij.hometax_invoice_id as source_id',
            ]);

        $allLines = $journalLines->unionAll($hometaxLines)
            ->orderBy('date')
            ->get();

        // 이월잔액
        $carryForward = $this->calculateCarryForward($tenantId, $accountCode, $startDate, $account->category);

        // 월별 그룹핑 + 잔액 계산
        $isDebitNormal = in_array($account->category, ['asset', 'expense']);
        $runningBalance = $carryForward['balance'];
        $monthlyData = [];
        $grandDebit = 0;
        $grandCredit = 0;

        foreach ($allLines as $line) {
            $month = substr($line->date, 0, 7);

            if (! isset($monthlyData[$month])) {
                $monthlyData[$month] = [
                    'month' => $month,
                    'items' => [],
                    'subtotal' => ['debit' => 0, 'credit' => 0],
                ];
            }

            $debit = (int) $line->debit_amount;
            $credit = (int) $line->credit_amount;

            $runningBalance += $isDebitNormal ? ($debit - $credit) : ($credit - $debit);

            $monthlyData[$month]['items'][] = [
                'date' => $line->date,
                'description' => $line->description,
                'trading_partner_name' => $line->trading_partner_name,
                'biz_no' => $line->biz_no,
                'debit_amount' => $debit,
                'credit_amount' => $credit,
                'balance' => $runningBalance,
                'source_type' => $line->source_type,
                'source_id' => (int) $line->source_id,
            ];

            $monthlyData[$month]['subtotal']['debit'] += $debit;
            $monthlyData[$month]['subtotal']['credit'] += $credit;
            $grandDebit += $debit;
            $grandCredit += $credit;
        }

        // 누계
        $cumulativeDebit = 0;
        $cumulativeCredit = 0;
        foreach ($monthlyData as &$md) {
            $cumulativeDebit += $md['subtotal']['debit'];
            $cumulativeCredit += $md['subtotal']['credit'];
            $md['cumulative'] = ['debit' => $cumulativeDebit, 'credit' => $cumulativeCredit];
        }
        unset($md);

        return [
            'account' => [
                'code' => $account->code,
                'name' => $account->name,
                'category' => $account->category,
            ],
            'period' => ['start_date' => $startDate, 'end_date' => $endDate],
            'carry_forward' => $carryForward,
            'monthly_data' => array_values($monthlyData),
            'grand_total' => ['debit' => $grandDebit, 'credit' => $grandCredit, 'balance' => $runningBalance],
        ];
    }

    private function calculateCarryForward(int $tenantId, string $accountCode, string $startDate, string $category): array
    {
        $journalSums = DB::table('journal_entry_lines as jel')
            ->join('journal_entries as je', 'je.id', '=', 'jel.journal_entry_id')
            ->where('jel.tenant_id', $tenantId)
            ->where('jel.account_code', $accountCode)
            ->where('je.entry_date', '<', $startDate)
            ->whereNull('je.deleted_at')
            ->selectRaw('COALESCE(SUM(jel.debit_amount), 0) as total_debit, COALESCE(SUM(jel.credit_amount), 0) as total_credit')
            ->first();

        $hometaxSums = DB::table('hometax_invoice_journals as hij')
            ->join('hometax_invoices as hi', 'hi.id', '=', 'hij.hometax_invoice_id')
            ->where('hij.tenant_id', $tenantId)
            ->where('hij.account_code', $accountCode)
            ->where('hij.write_date', '<', $startDate)
            ->whereNull('hi.deleted_at')
            ->selectRaw('COALESCE(SUM(hij.debit_amount), 0) as total_debit, COALESCE(SUM(hij.credit_amount), 0) as total_credit')
            ->first();

        $debit = (int) $journalSums->total_debit + (int) $hometaxSums->total_debit;
        $credit = (int) $journalSums->total_credit + (int) $hometaxSums->total_credit;
        $isDebitNormal = in_array($category, ['asset', 'expense']);
        $balance = $isDebitNormal ? ($debit - $credit) : ($credit - $debit);

        return compact('debit', 'credit', 'balance');
    }
}