<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Database\ConnectionInterface;
use Illuminate\Database\DatabaseManager;

/** A small index into the existing raw mirror; the original JSON stays authoritative. */
class WorkOrderWaybillLookup
{
    public const SOURCE = 'js_jst_work_order_info';
    public const TABLE = 'work_order_waybill_lookup';
    public const STATE = 'work_order_waybill_lookup_states';

    private readonly ConnectionInterface $connection;
    private ?bool $available = null;

    public function __construct(DatabaseManager $database)
    {
        $this->connection = $database->connection((string) config('upstream_mirrors.connection', 'business_mirror'));
    }

    public function available(): bool
    {
        return $this->available ??= $this->connection->getSchemaBuilder()->hasTable(self::TABLE)
            && $this->connection->getSchemaBuilder()->hasTable(self::STATE);
    }

    public function ready(): bool
    {
        return $this->available() && $this->connection->table(self::STATE)->where('id', 1)->whereNotNull('completed_at')->exists();
    }

    /** Called inside the raw mirror's transaction, including changes to title/waybill. */
    public function storeBatch(array $rows): void
    {
        if ($rows === [] || ! $this->available()) return;
        $keys = [];
        $values = [];
        foreach ($rows as $row) {
            $row = (array) $row;
            $key = (string) $row['_mirror_key'];
            $keys[] = $key;
            if (($row['title'] ?? '') !== '查件') continue;
            $fields = json_decode((string) ($row['businessFieldList'] ?? ''), true);
            if (! is_array($fields)) continue;
            $waybill = '';
            // Same last-field-wins semantics as the existing settlement parser.
            foreach ($fields as $field) {
                if (is_array($field) && ($field['fieldId'] ?? null) === 'lIdField') {
                    $waybill = trim((string) ($field['value'] ?? ''));
                }
            }
            if ($waybill !== '' && mb_strlen($waybill) <= 191) {
                $values[] = ['mirror_key' => $key, 'waybill' => $waybill, 'source_id' => (int) ($row['Id'] ?? 0)];
            }
        }
        // Remove renamed/invalid records too, so an old waybill never survives an update.
        $this->connection->table(self::TABLE)->whereIn('mirror_key', $keys)->delete();
        foreach (array_chunk($values, 500) as $chunk) {
            $this->connection->table(self::TABLE)->insert($chunk);
        }
    }

    public function prune(): void
    {
        if (! $this->available()) return;
        $this->connection->table(self::TABLE)->whereNotExists(function ($query): void {
            $query->selectRaw('1')->from(self::SOURCE)
                ->whereColumn(self::SOURCE . '._mirror_key', self::TABLE . '.mirror_key');
        })->delete();
    }

    /** Resume a bounded keyset pass; production invokes this through the global sync lock. */
    public function backfill(int $batchSize = 500, int $maxBatches = 2, int $pauseMs = 50): array
    {
        if (! $this->available()) throw new \RuntimeException('work_order_waybill_lookup_not_migrated');
        $state = $this->connection->table(self::STATE)->where('id', 1)->first();
        if ($state?->completed_at) return ['complete' => true, 'rows' => 0, 'batches' => 0];
        $cursor = $state?->cursor;
        $rows = $batches = 0;
        $batchSize = min(max(1, $batchSize), 1000);
        do {
            $batch = $this->connection->table(self::SOURCE)->when($cursor, fn ($query) => $query->where('_mirror_key', '>', $cursor))
                ->orderBy('_mirror_key')->limit($batchSize)->get(['_mirror_key', 'Id', 'title', 'businessFieldList']);
            $complete = $batch->count() < $batchSize;
            $this->connection->transaction(function () use ($batch, $complete, &$cursor): void {
                $this->storeBatch($batch->all());
                $cursor = $batch->last()?->_mirror_key ?? $cursor;
                if ($complete) $this->prune();
                $this->connection->table(self::STATE)->updateOrInsert(['id' => 1], [
                    'cursor' => $cursor, 'completed_at' => $complete ? now() : null, 'updated_at' => now(),
                ]);
            });
            $rows += $batch->count();
            $batches++;
            if (! $complete && $pauseMs > 0) usleep(min($pauseMs, 1000) * 1000);
        } while (! $complete && ($maxBatches === 0 || $batches < $maxBatches));

        return compact('complete', 'rows', 'batches');
    }
}