<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Support\Facades\DB;
use RuntimeException;

/**
 * 动账明细写入器：全量替换 fin_transactions，刷新映射统计并重算流水。
 *
 * 同一笔业务在相同输入下生成稳定的 row_key；完全重复的行保留出现序号，
 * 以保持规格书 12,037 笔的口径。
 */
class FinanceLedgerTransactionWriter
{
    public const MANUAL_SOURCE = 'manual';

    public const SHOP_WITHDRAWAL_SOURCE = 'shop_bill';

    public function replace(array $transactions, bool $recalculate = true): array
    {
        return $this->persist($transactions, $recalculate, true);
    }

    /** 只更新/插入本次快照，不删除历史明细；用于每日增量。 */
    public function merge(array $transactions, bool $recalculate = true): array
    {
        return $this->persist($transactions, $recalculate, false);
    }

    private function persist(array $transactions, bool $recalculate, bool $replaceExisting): array
    {
        if ($transactions === []) {
            throw new RuntimeException('没有可写入的动账明细。');
        }

        $connection = $this->connection();
        $now = now();
        $rows = [];
        $occurrences = [];

        foreach ($transactions as $item) {
            $date = $this->date($item['txn_date'] ?? null);
            if ($date === null) {
                continue;
            }

            $source = (string) ($item['source'] ?? '');
            if ($source === '') {
                throw new RuntimeException('动账明细缺少 source。');
            }

            $income = round((float) ($item['income'] ?? 0), 2);
            $expense = round((float) ($item['expense'] ?? 0), 2);
            $detail = mb_substr($this->normalizeText($item['detail'] ?? ''), 0, 4000);
            $approvalNo = mb_substr(trim((string) ($item['approval_no'] ?? '')), 0, 100);
            $sourceValue = mb_substr($this->normalizeText($item['source_value'] ?? ''), 0, 200);
            $rawAccount = mb_substr($this->normalizeText($item['account_short'] ?? ''), 0, 100);
            $processType = mb_substr(trim((string) ($item['process_type'] ?? '')), 0, 50);
            $pid = trim((string) ($item['pid'] ?? ''));
            $seq = trim((string) ($item['seq'] ?? ''));
            $acctCode = trim((string) ($item['acct_code'] ?? ''));
            $acctName = trim((string) ($item['acct_name'] ?? ''));

            $canonical = implode("\0", [
                $source, $processType, $pid, $seq, $approvalNo, $acctCode, $acctName,
                number_format($income, 2, '.', ''), number_format($expense, 2, '.', ''), $detail,
            ]);
            $occurrences[$canonical] = ($occurrences[$canonical] ?? 0) + 1;

            $rows[] = [
                'txn_date' => $date,
                'account_short' => $rawAccount,
                'detail' => $detail,
                'income' => $income,
                'expense' => $expense,
                'approval_no' => $approvalNo,
                'source' => $source,
                'source_value' => $sourceValue,
                'process_type' => $processType,
                'row_key' => substr(hash('sha256', $canonical), 0, 56) . ':' . $occurrences[$canonical],
                'synced_at' => $now,
                'created_at' => $now,
                'updated_at' => $now,
            ];
        }

        if ($rows === []) {
            throw new RuntimeException('动账明细没有有效日期。');
        }

        $connection->transaction(function () use ($connection, $rows, $now, $replaceExisting): void {
            if ($replaceExisting) {
                $connection->table('fin_transactions')
                    ->whereNotIn('source', [self::MANUAL_SOURCE, self::SHOP_WITHDRAWAL_SOURCE])
                    ->delete();
            }
            foreach (array_chunk($rows, 500) as $chunk) {
                if ($replaceExisting) {
                    $connection->table('fin_transactions')->insert($chunk);
                } else {
                    $connection->table('fin_transactions')->upsert(
                        $chunk,
                        ['row_key'],
                        ['txn_date', 'account_short', 'detail', 'income', 'expense', 'approval_no',
                            'source', 'source_value', 'process_type', 'synced_at', 'updated_at'],
                    );
                }
            }
            $this->refreshMappingStats($connection, $now, $replaceExisting);
        });

        $result = [
            'rows' => count($rows),
            'income' => round(array_sum(array_column($rows, 'income')), 2),
            'expense' => round(array_sum(array_column($rows, 'expense')), 2),
            'from' => min(array_column($rows, 'txn_date')),
            'to' => max(array_column($rows, 'txn_date')),
        ];

        if ($recalculate) {
            $result['recalculated'] = app(FinanceLedgerCalculator::class)->recalculate();
        }

        return $result;
    }

    private function refreshMappingStats($connection, $now, bool $pruneStale = true): void
    {
        $stats = $connection->table('fin_transactions')
            ->selectRaw('source, source_value, COUNT(*) AS txn_count, SUM(income) AS income_sum, SUM(expense) AS expense_sum')
            ->whereNotIn('source', [self::MANUAL_SOURCE, self::SHOP_WITHDRAWAL_SOURCE])
            ->whereNotNull('source_value')
            ->where('source_value', '<>', '')
            ->groupBy('source', 'source_value')
            ->get();

        $rows = [];
        $keys = [];
        foreach ($stats as $stat) {
            $source = (string) $stat->source;
            $value = mb_substr((string) $stat->source_value, 0, 200);
            $keys[$source . "\0" . $value] = true;
            $rows[] = [
                'source' => $source,
                'source_value' => $value,
                'txn_count' => (int) $stat->txn_count,
                'income_sum' => round((float) $stat->income_sum, 2),
                'expense_sum' => round((float) $stat->expense_sum, 2),
                'created_at' => $now,
                'updated_at' => $now,
            ];
        }

        // 上游删除或改写的来源值不能继续留在映射表里；只清理本次未出现的行，
        // 保留已有 account_short，避免重同步覆盖人工映射。
        if ($pruneStale) {
            $stale = [];
            foreach ($connection->table('fin_account_map')->get(['id', 'source', 'source_value']) as $existing) {
                if (! isset($keys[(string) $existing->source . "\0" . (string) $existing->source_value])) {
                    $stale[] = (int) $existing->id;
                }
            }
            foreach (array_chunk($stale, 500) as $ids) {
                $connection->table('fin_account_map')->whereIn('id', $ids)->delete();
            }
        }

        foreach (array_chunk($rows, 500) as $chunk) {
            $connection->table('fin_account_map')->upsert(
                $chunk,
                ['source', 'source_value'],
                ['txn_count', 'income_sum', 'expense_sum', 'updated_at'],
            );
        }
    }

    private function normalizeText(mixed $value): string
    {
        $text = trim((string) ($value ?? ''));

        return preg_replace('/\s+/u', ' ', $text) ?? $text;
    }

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

    private function date(mixed $value): ?string
    {
        $text = trim((string) ($value ?? ''));
        if (preg_match('/^(\d{4})[-\/](\d{1,2})[-\/](\d{1,2})/', $text, $matches) !== 1) {
            return null;
        }

        return sprintf('%04d-%02d-%02d', $matches[1], $matches[2], $matches[3]);
    }
}