<?php

namespace Modules\Core\Shipping\Carriers\Elta;

use Carbon\CarbonInterface;
use Illuminate\Support\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Cache;
use Lunar\Models\Order;
use Modules\Core\Shipping\Carriers\Elta\Exceptions\EltaApiException;
use Modules\Core\Shipping\Contracts\CarrierFulfillmentInterface;
use Modules\Core\Shipping\Contracts\IssuesVoucherOnPrint;
use Modules\Core\Shipping\Contracts\SupportsBatchLabels;
use Modules\Core\Shipping\Contracts\SupportsExtraServices;
use Modules\Core\Shipping\Contracts\SupportsTracking;
use Modules\Core\Shipping\Contracts\SupportsVoucherListing;
use Modules\Core\Shipping\Contracts\SupportsVoucherLookup;
use Modules\Core\Shipping\DTOs\CarrierVoucher;
use Modules\Core\Shipping\DTOs\ShipmentRequest;
use Modules\Core\Shipping\DTOs\TrackingCheckpoint;
use Modules\Core\Shipping\Enums\ExtraService;
use Modules\Core\Shipping\Enums\TrackingStatus;
use Modules\Core\Shipping\Models\Shipment;

/**
 * ELTA vouchers are created **pending** (pel_insert_flag "0", live-verified):
 * ELTA stores the voucher with an internal id but no voucher number, and it
 * can still be cancelled. Printing issues it (PELVG01NEW1 — what ELTA's own
 * client does from its group-editing screen): that assigns the voucher
 * number, OCR line, destination station and service, and from then on ELTA
 * refuses to delete it ("Δεν Επιτρέπεται! Εχει Γίνει Εκτύπωση"). So a
 * shipment has no tracking_reference until its label is printed.
 *
 * Not SupportsManifestBatching — ELTA has no manifest/pickup-list step.
 */
class EltaFulfillmentService implements CarrierFulfillmentInterface, IssuesVoucherOnPrint, SupportsBatchLabels, SupportsExtraServices, SupportsTracking, SupportsVoucherListing, SupportsVoucherLookup
{
    /** PELMANIF2 / PELPARALVGNEW1 page through 100 rows at a time. */
    private const MAX_PAGES = 50;

    public function __construct(
        private readonly EltaClient $client,
        private readonly EltaLabelRenderer $labelRenderer,
    ) {}

    /**
     * ELTA surcharge codes (pel_sur_1..3), from its own client's checkboxes.
     * Insurance isn't a surcharge — it's the amount in pel_asf_poso.
     */
    public function extraServices(): array
    {
        return [
            ExtraService::SaturdayDelivery->value => '004',
            ExtraService::TimedDelivery->value => '003',
            ExtraService::SpecialHandling->value => '002',
            ExtraService::Insurance->value => 'pel_asf_poso',
        ];
    }

    public function createShipment(Order $order, ShipmentRequest $request): Shipment
    {
        $address = $order->shippingAddress;
        $weight = $request->weight ?? 0.5;
        $surcharges = $this->surchargeCodes($request);

        $params = [
            'pel_apost_code' => config('elta.apost_code'),
            'pel_paral_name' => trim("{$address->first_name} {$address->last_name}"),
            'pel_paral_address' => $address->line_one,
            'pel_paral_area' => $address->city,
            'pel_paral_tk' => $address->postcode,
            'pel_paral_thl_1' => $address->contact_phone,
            'pel_paral_thl_2' => '',
            'pel_service' => '',
            'pel_baros' => number_format($weight, 3, '.', ''),
            'pel_baros_xyz' => '',
            'pel_x' => '',
            'pel_y' => '',
            'pel_z' => '',
            'pel_temaxia' => (string) $request->packageCount,
            'pel_paral_sxolia' => '',
            'pel_sur_1' => $surcharges[0] ?? '',
            'pel_sur_2' => $surcharges[1] ?? '',
            'pel_sur_3' => $surcharges[2] ?? '',
            // pel_ant_poso is the cash-on-delivery amount; pel_ant_poso1..4
            // are cheques (with dates) in ELTA's client — never used here.
            'pel_ant_poso' => '',
            'pel_ant_poso1' => '',
            'pel_ant_poso2' => '',
            'pel_ant_poso3' => '',
            'pel_ant_poso4' => '',
            'pel_ant_date1' => '',
            'pel_ant_date2' => '',
            'pel_ant_date3' => '',
            'pel_ant_date4' => '',
            'pel_asf_poso' => $request->has(ExtraService::Insurance) && $request->insuranceAmount
                ? number_format($request->insuranceAmount, 2, '.', '')
                : '',
            'pel_user' => config('elta.user_code'),
            // Our order reference — comes back in ELTA's lists and tracking,
            // which is how we find the pending voucher's id below and match
            // vouchers to orders on the Carrier Vouchers screen.
            'pel_ref_no' => (string) $order->reference,
            // "0" = save without issuing (see this class's docblock).
            'pel_insert_flag' => '0',
            'pel_paral_code' => '',
            'pel_retur_code' => '',
        ];

        $codAmount = null;

        if ($request->paymentMode === 'cod') {
            $codAmount = $request->amountToCollect ?? $order->total->decimal;
            $params['pel_ant_poso'] = number_format($codAmount, 2, '.', '');
        }

        $this->client->createVoucher($params)->throwIfError();

        $pieces = max(1, $request->packageCount);

        // PELVGNEW doesn't return the new voucher's id, so find it in the
        // pending list by our reference. Saved even if that lookup fails —
        // the voucher exists at ELTA either way, and printing retries it.
        $master = Shipment::create([
            'order_id' => $order->id,
            'carrier' => 'elta',
            'source' => Shipment::SOURCE_CREATED,
            'tracking_reference' => null,
            'meta' => [
                'carrier_id' => $this->findPendingVoucherId((string) $order->reference),
                'reference' => (string) $order->reference,
                'weight' => $weight,
                'package_count' => $pieces,
                'cod_amount' => $codAmount,
                'services' => $request->serviceValues(),
                'insurance_amount' => $request->has(ExtraService::Insurance) ? $request->insuranceAmount : null,
                ...($pieces > 1 ? ['piece' => 1, 'pieces' => $pieces] : []),
            ],
        ]);

        // One row per extra parcel straight away, so the order shows every
        // parcel; ELTA gives them their own voucher numbers only when the
        // main voucher is issued (issue()). They belong to the main voucher:
        // no COD or services of their own.
        for ($piece = 2; $piece <= $pieces; $piece++) {
            Shipment::create([
                'order_id' => $order->id,
                'carrier' => 'elta',
                'source' => Shipment::SOURCE_CREATED,
                'tracking_reference' => null,
                'meta' => [
                    'master_shipment_id' => $master->id,
                    'reference' => (string) $order->reference,
                    'piece' => $piece,
                    'pieces' => $pieces,
                    'weight' => $weight,
                    'package_count' => $pieces,
                ],
            ]);
        }

        return $master;
    }

    /**
     * Like ELTA's own client: printing the main voucher of a multi-parcel
     * send prints every parcel (main first, then each child); printing a
     * child prints just that parcel. Either way the main voucher is issued
     * first — that's what gives the children their numbers.
     */
    public function printLabel(Shipment $shipment): string
    {
        $master = $this->masterOf($shipment);

        $this->issue($master);

        $labels = $shipment->is($master)
            ? collect([$master->refresh(), ...$this->childrenOf($master)])
            : collect([$shipment->refresh()]);

        $pdf = $this->labelRenderer->renderMany($labels);

        Shipment::whereIn('id', $labels->pluck('id'))->update(['label_printed_at' => now()]);

        return $pdf;
    }

    /**
     * Several labels in one PDF. A selected main voucher brings its
     * children along (as printLabel() does); each parcel is printed once,
     * main voucher before its children.
     */
    public function printLabels(Collection $shipments): string
    {
        $labels = collect();

        foreach ($shipments as $shipment) {
            $master = $this->masterOf($shipment);
            $this->issue($master);

            $group = $shipment->is($master)
                ? [$master->refresh(), ...$this->childrenOf($master)]
                : [$shipment->refresh()];

            foreach ($group as $label) {
                $labels->put($label->id, $label);
            }
        }

        $pdf = $this->labelRenderer->renderMany($labels->values());

        Shipment::whereIn('id', $labels->keys())->update(['label_printed_at' => now()]);

        return $pdf;
    }

    /**
     * Pending (not yet printed) vouchers are deleted at ELTA. Issued ones
     * can't be — ELTA only allows that before printing.
     */
    public function cancelShipment(Shipment $shipment): void
    {
        $master = $this->masterOf($shipment);

        if (! $shipment->is($master)) {
            $piece = $shipment->meta['piece'] ?? null;

            throw new EltaApiException(
                'This is '.($piece ? "parcel {$piece}" : 'an extra parcel').' of a multi-parcel ELTA voucher — ELTA cancels the whole voucher, so cancel the main parcel instead.',
            );
        }

        if (filled($shipment->tracking_reference)) {
            throw new EltaApiException(
                "ELTA voucher {$shipment->tracking_reference} is already printed, and ELTA only allows cancelling vouchers that haven't been printed yet. Contact ELTA to cancel it.",
            );
        }

        $this->client->deleteVoucher(['pel_vg_id' => $this->pendingVoucherId($shipment)])->throwIfError();

        $shipment->update(['cancelled_at' => now()]);
        $this->childrenOf($shipment)->each->update(['cancelled_at' => now()]);
    }

    /**
     * The main voucher's shipment for a child parcel, or the shipment
     * itself. Children created by createShipment() point at it via
     * meta.master_shipment_id; older ones only via parent_reference.
     */
    private function masterOf(Shipment $shipment): Shipment
    {
        if ($id = $shipment->meta['master_shipment_id'] ?? null) {
            return Shipment::find($id) ?? $shipment;
        }

        if (filled($shipment->parent_reference)) {
            return Shipment::where('tracking_reference', $shipment->parent_reference)->first() ?? $shipment;
        }

        return $shipment;
    }

    /**
     * @return Collection<int, Shipment>  the main voucher's child parcels, in piece order
     */
    private function childrenOf(Shipment $master): Collection
    {
        return Shipment::query()
            ->where('carrier', 'elta')
            ->where(fn ($query) => $query
                ->where('meta->master_shipment_id', $master->id)
                ->when($master->tracking_reference, fn ($q) => $q->orWhere('parent_reference', $master->tracking_reference)))
            ->orderBy('id')
            ->get()
            ->sortBy(fn (Shipment $child) => $child->meta['piece'] ?? PHP_INT_MAX)
            ->values();
    }

    public function trackShipment(Shipment $shipment): Collection
    {
        // ELTA tracks a multi-parcel send by its main voucher only — an
        // extra parcel's own number is rejected ("Λάθος ΣΥΔΕΤΑ"). Its
        // history is the main voucher's, which is tracked on its own row.
        if (! $shipment->is($this->masterOf($shipment))) {
            return collect();
        }

        $response = $this->client->getTracking([
            'web_vg' => $shipment->tracking_reference,
            'pel_code' => config('elta.apost_code'),
        ])->throwIfError();

        $rows = array_filter(
            (array) ($response->data['web_status'] ?? []),
            fn (array $row) => filled($row['web_date_time'] ?? null),
        );

        // No explicit delivered-confirmation field like the old
        // PELTT01's pod_name — pel_rec.a_rec_date_time is blank until
        // delivery per the real client's own rendering, used as the
        // delivered signal here; unconfirmed against a genuinely
        // delivered parcel yet.
        $isDelivered = filled(trim($response->data['pel_rec']['a_rec_date_time'] ?? '', ' /:'));

        return collect(array_values($rows))->map(function (array $row, int $index) use ($rows, $isDelivered) {
            $isLast = $index === count($rows) - 1;
            $dateTime = $row['web_date_time'] ?? '';

            return new TrackingCheckpoint(
                status: $isLast && $isDelivered
                    ? TrackingStatus::Delivered
                    : $this->guessStatusFromTitle($row['web_status_name'] ?? ''),
                carrierStatus: $row['web_status_name'] ?? null,
                message: $row['web_sxolia'] ?: ($row['web_status_name'] ?? null),
                location: $row['web_station'] ?? null,
                // ELTA reports Greek local time.
                occurredAt: Carbon::createFromFormat('YmdHi', substr($dateTime, 0, 12), 'Europe/Athens')->setTimezone(config('app.timezone')),
                meta: $row,
            );
        });
    }

    /**
     * PELMANIF2 (the client's "Πολλαπλή Αναζήτηση"): every issued voucher
     * in the date range with its latest status. A second pass with
     * status_flag 3 ("Προς Επιστροφή") marks the ones heading back to us.
     */
    public function listVouchers(CarbonInterface $from, CarbonInterface $to): iterable
    {
        $returning = collect($this->searchVouchers($from, $to, '3'))->pluck('pel_col_1')->flip();

        foreach ($this->searchVouchers($from, $to, '0') as $row) {
            $number = trim($row['pel_col_1']);

            yield new CarrierVoucher(
                carrier: 'elta',
                voucherNumber: $number,
                reference: filled($row['pel_col_2'] ?? null) ? trim($row['pel_col_2']) : null,
                recipientName: trim($row['pel_col_3'] ?? '') ?: null,
                postcode: trim($row['pel_col_4'] ?? '') ?: null,
                statusText: trim($row['pel_col_6'] ?? '') ?: null,
                status: filled(trim($row['pel_col_6'] ?? '')) ? $this->guessStatusFromTitle(trim($row['pel_col_6'])) : null,
                codAmount: (float) ($row['pel_col_8'] ?? 0) ?: null,
                isReturn: $returning->has($row['pel_col_1']),
                date: $this->dateFromListRow($row['pel_col_7'] ?? ''),
                raw: $row,
            );
        }
    }

    /**
     * PELTTNEW01 (tracking) also returns the voucher's details (pel_rec):
     * recipient, postcode, our reference, cash on delivery.
     */
    public function lookupVoucher(string $voucherNumber): ?CarrierVoucher
    {
        $response = $this->client->getTracking([
            'web_vg' => trim($voucherNumber),
            'pel_code' => config('elta.apost_code'),
        ]);

        $record = $response->data['pel_rec'] ?? [];

        if ($response->hasError || blank($record['a_vg_3'] ?? null)) {
            return null;
        }

        $statuses = array_values(array_filter(
            (array) ($response->data['web_status'] ?? []),
            fn (array $row) => filled($row['web_date_time'] ?? null),
        ));

        return new CarrierVoucher(
            carrier: 'elta',
            voucherNumber: trim($record['a_vg_3']),
            reference: trim($record['a_ref'] ?? '') ?: null,
            recipientName: trim($record['a_rec_title'] ?? '') ?: null,
            postcode: trim($record['a_rec_postal'] ?? '') ?: null,
            phone: trim($record['a_rec_tel_1'] ?? '') ?: null,
            statusText: filled($statuses) ? trim(end($statuses)['web_status_name'] ?? '') : null,
            status: filled($statuses) ? $this->guessStatusFromTitle(trim(end($statuses)['web_status_name'] ?? '')) : null,
            codAmount: (float) ($record['a_antik'] ?? 0) ?: null,
            date: $this->dateFromListRow($record['a_sender_date'] ?? ''),
            raw: $record,
        );
    }

    /**
     * Issues a pending voucher (no-op once it has a number): stores the
     * voucher number and what ELTA returns for the label, plus one shipment
     * per child voucher of a multi-piece send.
     */
    private function issue(Shipment $shipment): void
    {
        if (filled($shipment->tracking_reference)) {
            return;
        }

        $response = $this->client->issueVoucher([
            'pel_id' => $this->pendingVoucherId($shipment),
            'sender_station' => $this->senderStation(),
        ])->throwIfError();

        $data = $response->data;
        $voucherNo = trim((string) ($data['vg_code'] ?? ''));

        if ($voucherNo === '') {
            throw new EltaApiException('ELTA issued the voucher but returned no voucher number.', $data);
        }

        $shipment->tracking_reference = $voucherNo;
        $shipment->meta = array_merge($shipment->meta?->toArray() ?? [], [
            'ocr_line' => $data['ocr_line'] ?? null,
            'date_time' => $data['date_time'] ?? null,
            'rec_station' => $data['rec_station'] ?? null,
            'rec_station_t' => $data['rec_station_t'] ?? null,
            'rec_srv' => $data['rec_srv'] ?? null,
            'rec_srv_t' => $data['rec_srv_t'] ?? null,
            'return_vg' => trim((string) ($data['return_vg'] ?? '')) ?: null,
            'epitagh_vg' => trim((string) ($data['epitagh_vg'] ?? '')) ?: null,
        ]);
        $shipment->save();

        // The children's numbers, in ELTA's order (vg_child_no), go to the
        // pending child rows in piece order; any parcel without a row (older
        // shipments) gets one.
        $pending = $this->childrenOf($shipment)->filter(fn (Shipment $child) => blank($child->tracking_reference))->values();
        $pieces = (int) ($shipment->meta['package_count'] ?? 1);
        $childNumbers = array_values(array_filter(array_map('trim', (array) ($data['vg_child_no'] ?? []))));

        foreach ($childNumbers as $i => $childVoucherNo) {
            $child = $pending->get($i) ?? new Shipment([
                'order_id' => $shipment->order_id,
                'carrier' => 'elta',
                'source' => Shipment::SOURCE_CREATED,
                'meta' => [
                    'master_shipment_id' => $shipment->id,
                    'reference' => $shipment->meta['reference'] ?? null,
                    'piece' => $i + 2,
                    'pieces' => max($pieces, count($childNumbers) + 1),
                    'weight' => $shipment->meta['weight'] ?? null,
                    'package_count' => max($pieces, count($childNumbers) + 1),
                ],
            ]);

            $child->tracking_reference = $childVoucherNo;
            $child->parent_reference = $voucherNo;
            $child->save();
        }
    }

    /**
     * @return array<int, string>
     */
    private function surchargeCodes(ShipmentRequest $request): array
    {
        $codes = $this->extraServices();

        return collect($request->services)
            ->reject(fn (ExtraService $service) => $service === ExtraService::Insurance)
            ->map(fn (ExtraService $service) => $codes[$service->value] ?? null)
            ->filter()
            ->values()
            ->take(3)
            ->all();
    }

    private function pendingVoucherId(Shipment $shipment): string
    {
        $id = $shipment->meta['carrier_id'] ?? null;

        if (blank($id) && $shipment->order) {
            $id = $this->findPendingVoucherId((string) $shipment->order->reference);

            if ($id) {
                $shipment->meta = array_merge($shipment->meta?->toArray() ?? [], ['carrier_id' => $id]);
                $shipment->save();
            }
        }

        if (blank($id)) {
            throw new EltaApiException("Couldn't find this shipment's pending voucher at ELTA.");
        }

        return $id;
    }

    /**
     * The newest not-yet-issued voucher in ELTA's list carrying our
     * reference. flag_1/flag_2 are the client's "Show all" / "All users"
     * checkboxes — both "1", or even a just-created voucher is filtered out.
     */
    private function findPendingVoucherId(string $reference): ?string
    {
        $inId = '0';
        $match = null;

        for ($page = 0; $page < self::MAX_PAGES; $page++) {
            $rows = array_values(array_filter(
                (array) ($this->client->listVouchers([
                    'pel_code' => config('elta.apost_code'),
                    'pel_user_code' => config('elta.user_code'),
                    'flag_1' => '1',
                    'flag_2' => '1',
                    'in_id' => $inId,
                ])->throwIfError()->data['vg_rec'] ?? []),
                fn (array $row) => filled($row['pel_vg_id'] ?? null),
            ));

            foreach ($rows as $row) {
                if (trim($row['pel_ref_no'] ?? '') === $reference && blank(trim($row['pel_paral_vg'] ?? ''))
                    && ($match === null || $row['pel_vg_id'] > $match)) {
                    $match = $row['pel_vg_id'];
                }
            }

            if (count($rows) < 100) {
                break;
            }

            $inId = (string) end($rows)['pel_vg_id'];
        }

        return $match;
    }

    /**
     * @return array<int, array<string, string>>
     */
    private function searchVouchers(CarbonInterface $from, CarbonInterface $to, string $statusFlag): array
    {
        $inId = '0';
        $all = [];

        for ($page = 0; $page < self::MAX_PAGES; $page++) {
            $rows = array_values(array_filter(
                (array) ($this->client->searchVouchers([
                    'pel_code' => config('elta.apost_code'),
                    'date_1' => $from->format('d/m/Y'),
                    'date_2' => $to->format('d/m/Y'),
                    'paral_code' => '',
                    'status_flag' => $statusFlag,
                    'in_id' => $inId,
                ])->throwIfError()->data['ag_pel_rec'] ?? []),
                fn (array $row) => filled(trim($row['pel_col_1'] ?? '')),
            ));

            array_push($all, ...$rows);

            if (count($rows) < 100) {
                break;
            }

            $inId = (string) end($rows)['pel_col_id'];
        }

        return $all;
    }

    /**
     * ELTA dates in its lists look like "29/09/26   09:41 PEL CLIENT" or
     * "29/09/2026 09:51".
     */
    private function dateFromListRow(string $value): ?CarbonInterface
    {
        if (! preg_match('#(\d{2})/(\d{2})/(\d{2,4})#', $value, $m)) {
            return null;
        }

        $year = strlen($m[3]) === 2 ? '20'.$m[3] : $m[3];

        return Carbon::createFromDate((int) $year, (int) $m[2], (int) $m[1])->startOfDay();
    }

    /**
     * The station ELTA needs when issuing a voucher: configured
     * (ELTA_ORIGIN_STATION_CODE), or read from the login response once —
     * ELTA returns the account's user_station there even though our
     * account's login password is rejected.
     */
    private function senderStation(): string
    {
        if (filled(config('elta.origin_station_code'))) {
            return (string) config('elta.origin_station_code');
        }

        return (string) Cache::rememberForever('elta.user_station', fn () => $this->client->login([
            'pel_code' => config('elta.apost_code'),
            'user_code' => config('elta.user_code'),
            'user_pass' => config('elta.user_pass'),
        ])->data['user_station'] ?? '');
    }

    /**
     * web_status_name is free text with no structured status code — same
     * limitation Acs\AcsFulfillmentService::guessStatusFromAction() has.
     * Live-confirmed text seen so far: "ΔΗΜΙΟΥΡΓΙΑ ΣΥ.ΔΕ.ΤΑ. ΑΠΟ ΠΕΛΑΤΗ"
     * (voucher created) — matched via a Pending-ish fallback below since
     * it isn't yet in transit. Other statuses are best-guess substring
     * matches to refine as more real tracking text is observed.
     */
    /**
     * ELTA's status texts come in unaccented capitals ("ΠΑΡΑΔΟΘΗΚΕ"), so
     * they're lowercased and stripped of accents before matching.
     */
    private function guessStatusFromTitle(string $title): TrackingStatus
    {
        $title = strtr(mb_strtolower($title), [
            'ά' => 'α', 'έ' => 'ε', 'ή' => 'η', 'ί' => 'ι', 'ό' => 'ο', 'ύ' => 'υ', 'ώ' => 'ω',
            'ϊ' => 'ι', 'ϋ' => 'υ', 'ΐ' => 'ι', 'ΰ' => 'υ',
        ]);

        return match (true) {
            str_contains($title, 'επιστροφ') => TrackingStatus::Returned,
            str_contains($title, 'παραδοθηκε') => TrackingStatus::Delivered,
            str_contains($title, 'διανομη') => TrackingStatus::OutForDelivery,
            str_contains($title, 'παραλαβη') => TrackingStatus::CollectedFromSender,
            str_contains($title, 'μεταφορα') || str_contains($title, 'διαμετακομιση') || str_contains($title, 'διακινηση') => TrackingStatus::InTransit,
            default => TrackingStatus::Pending,
        };
    }
}