<?php

namespace App\Services;

use App\Models\Log;
use App\Models\PargarSyncLog;
use App\Models\PriceSyncLog;
use App\Models\PriceSyncLogItem;
use App\Models\Tahesab;
use App\Models\Zarin;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;

/**
 * پاک‌سازی شبانهٔ لاگ‌های حجیم — همان سقف نگه‌داری جدول prices (۳۱ روز).
 */
class DatabaseLogPruneService
{
    /** هم‌راستا با حذف قطعی در PriceSnapshotService::pruneHistory */
    public const RETENTION_DAYS = 31;

    /** سقف ردیف موفق مانده/سند ورودی پرگار — بقیه (سفارش/کیف) را نمی‌بُرد */
    public const PARAGAR_INBOUND_KEEP = 2000;

    private const CHUNK = 500;

    public function pruneHistory(?Carbon $now = null): array
    {
        $cutoff = ($now ?? now())->copy()->subDays(self::RETENTION_DAYS);

        return [
            'retention_days' => self::RETENTION_DAYS,
            'cutoff' => $cutoff->toDateTimeString(),
            'pargar_inbound' => $this->prunePargarInboundOverflow(),
            'price_sync_logs' => $this->prunePriceSyncLogs($cutoff),
            'logs' => $this->pruneGenericLogs($cutoff),
            'pargar_sync_logs' => $this->pruneSuccessfulRows(
                PargarSyncLog::query(),
                'pargar_sync_logs',
                PargarSyncService::STATUS_SUCCESS,
                $cutoff
            ),
            'zarin' => $this->pruneSuccessfulRows(
                Zarin::query(),
                'zarin',
                ZarinSyncService::STATUS_SUCCESS,
                $cutoff
            ),
            'tahesab' => $this->pruneSuccessfulRows(
                Tahesab::query(),
                'tahesab',
                TahesabSyncService::STATUS_SUCCESS,
                $cutoff
            ),
        ];
    }

    /** @return array{deleted: int, items_deleted: int} */
    private function prunePriceSyncLogs(Carbon $cutoff): array
    {
        if (! Schema::hasTable('price_sync_logs')) {
            return ['deleted' => 0, 'items_deleted' => 0];
        }

        $deleted = 0;
        $itemsDeleted = 0;
        $hasItems = Schema::hasTable('price_sync_log_items');

        PriceSyncLog::query()
            ->where('created_at', '<', $cutoff)
            ->orderBy('id')
            ->select(['id'])
            ->chunkById(self::CHUNK, function ($rows) use (&$deleted, &$itemsDeleted, $hasItems) {
                $ids = $rows->pluck('id')->all();
                if ($ids === []) {
                    return;
                }
                if ($hasItems) {
                    $itemsDeleted += (int) PriceSyncLogItem::query()->whereIn('log_id', $ids)->delete();
                }
                $deleted += (int) PriceSyncLog::query()->whereIn('id', $ids)->delete();
            });

        return ['deleted' => $deleted, 'items_deleted' => $itemsDeleted];
    }

    /** @return array{deleted: int} */
    private function pruneGenericLogs(Carbon $cutoff): array
    {
        if (! Schema::hasTable('logs')) {
            return ['deleted' => 0];
        }

        $deleted = 0;

        Log::query()
            ->where('created_at', '<', $cutoff)
            ->orderBy('id')
            ->select(['id'])
            ->chunkById(self::CHUNK, function ($rows) use (&$deleted) {
                $ids = $rows->pluck('id')->all();
                if ($ids === []) {
                    return;
                }
                $deleted += (int) Log::query()->whereIn('id', $ids)->delete();
            });

        return ['deleted' => $deleted];
    }

    /**
     * فقط ردیف‌های موفق حسابداری — pending/failed برای retry می‌مانند.
     *
     * @return array{deleted: int, skipped: bool}
     */
    private function pruneSuccessfulRows(Builder $query, string $table, string $successStatus, Carbon $cutoff): array
    {
        if (! Schema::hasTable($table) || ! Schema::hasColumn($table, 'sync_status')) {
            return ['deleted' => 0, 'skipped' => true];
        }

        if (! Schema::hasColumn($table, 'created_at')) {
            return ['deleted' => 0, 'skipped' => true];
        }

        $deleted = 0;

        (clone $query)
            ->where('sync_status', $successStatus)
            ->where('created_at', '<', $cutoff)
            ->orderBy('id')
            ->select(['id'])
            ->chunkById(self::CHUNK, function ($rows) use (&$deleted, $query) {
                $ids = $rows->pluck('id')->all();
                if ($ids === []) {
                    return;
                }
                $deleted += (int) (clone $query)->whereIn('id', $ids)->delete();
            });

        return ['deleted' => $deleted, 'skipped' => false];
    }

    /**
     * فقط لاگ ورودی پرگار (mande/document). سفارش و سند کیف دست نخورده می‌ماند.
     *
     * @return array{mande: int, document: int}
     */
    /** هر بار حداکثر — برای afterResponse؛ تریگر MySQL هم LIMIT 4000 دارد */
    private const PARAGAR_PRUNE_BATCH = 4000;

    public function prunePargarInboundOverflow(?int $maxDeletePerType = null): array
    {
        if (! Schema::hasTable('pargar_sync_logs')) {
            return ['mande' => 0, 'document' => 0];
        }

        $batch = $maxDeletePerType ?? self::PARAGAR_PRUNE_BATCH;

        ignore_user_abort(true);
        if (function_exists('set_time_limit')) {
            @set_time_limit(180);
        }

        $this->ensureTypeStatusIndex();

        $locked = $this->acquirePruneLock();
        if ($locked === false) {
            return ['mande' => 0, 'document' => 0];
        }

        try {
            return [
                'mande' => $this->pruneOldestSuccessBeyond(PargarSyncService::TYPE_MANDE, $batch),
                'document' => $this->pruneOldestSuccessBeyond(PargarSyncService::TYPE_DOCUMENT, $batch),
            ];
        } finally {
            if ($locked === true) {
                $this->releasePruneLock();
            }
        }
    }

    private function pruneOldestSuccessBeyond(string $type, int $maxDelete): int
    {
        $cutoffId = PargarSyncLog::query()
            ->where('type', $type)
            ->where('sync_status', PargarSyncService::STATUS_SUCCESS)
            ->orderByDesc('id')
            ->skip(self::PARAGAR_INBOUND_KEEP)
            ->value('id');

        if (! $cutoffId) {
            return 0;
        }

        $query = PargarSyncLog::query()
            ->where('type', $type)
            ->where('sync_status', PargarSyncService::STATUS_SUCCESS)
            ->where('id', '<=', $cutoffId)
            ->orderBy('id');

        if ($maxDelete <= 0) {
            $maxDelete = self::PARAGAR_PRUNE_BATCH;
        }

        return (int) $query->limit($maxDelete)->delete();
    }

    private function ensureTypeStatusIndex(): void
    {
        try {
            $names = collect(DB::select('SHOW INDEX FROM `pargar_sync_logs`'))
                ->pluck('Key_name')
                ->all();
            if (in_array('pargar_sync_logs_type_status_index', $names, true)) {
                return;
            }
            DB::statement(
                'ALTER TABLE `pargar_sync_logs` ADD INDEX `pargar_sync_logs_type_status_index` (`type`, `sync_status`)'
            );
        } catch (\Throwable) {
        }
    }

    /** @return bool|null true=locked, false=busy, null=no lock support */
    private function acquirePruneLock(): ?bool
    {
        try {
            $row = DB::selectOne('SELECT GET_LOCK(?, 3) AS l', ['khanegi_pargar_inbound_prune']);

            return (int) ($row->l ?? 0) === 1;
        } catch (\Throwable) {
            return null;
        }
    }

    private function releasePruneLock(): void
    {
        try {
            DB::selectOne('SELECT RELEASE_LOCK(?) AS l', ['khanegi_pargar_inbound_prune']);
        } catch (\Throwable) {
        }
    }
}