<?php

namespace App\Services;

use App\Models\RateEntry;
use App\Models\CountryZone;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use PhpOffice\PhpSpreadsheet\IOFactory;
use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
use PhpOffice\PhpSpreadsheet\Cell\Cell;
use Exception;

/**
 * RateImportService
 * ----------------
 * Parses the customer's operational Excel format and stores rates
 * into the rate_entries table (4-quadrant model).
 *
 * ─── معماری ارزی (Currency Architecture) ───
 * ارز مبنا در کل سیستم IFNEX = ریال ایران (IRR).
 * همه نرخ‌ها در دیتابیس به‌صورت ریال ذخیره می‌شوند.
 *
 * هنگام ایمپورت، کاربر «ارز مبدأ» فایل اکسل را انتخاب می‌کند (مثلاً AED، USD، EUR، IRR).
 * سرویس هر نرخ را با نرخ روزِ آن ارز به ریال تبدیل کرده و سپس ذخیره می‌کند.
 * بدین ترتیب نرخ‌ها در زمان ایمپورت «ثبت» می‌شوند و تغییرات نرخ ارز روزانه
 * روی نرخ‌های حمل ذخیره‌شده اثر نمی‌گذارد — فقط ایمپورت‌های بعدی از نرخ جدید استفاده می‌کنند.
 */
class RateImportService
{
    public const SHEET_NAMES = [
        'import' => ['Import Rate', 'ImportRate', 'Import'],
        'export' => ['Export Rate', 'ExportRate', 'Export'],
    ];

    public const SECTION_MARKERS = [
        'document' => ['DOCUMENT', 'DOC', 'DOC NORMAL', 'DOC_NORMAL', 'DOCNORMAL'],
        'parcel'   => ['NON - DOCUMENT', 'NON-DOCUMENT', 'NON DOCUMENT',
                       'NONDOC', 'NON DOC', 'PARCEL', 'NON-DOC', 'NON - DOC'],
    ];

    public array $summary = [
        'imported' => 0,
        'updated'   => 0,
        'skipped'   => 0,
        'errors'    => [],
        'zones_updated' => 0,
    ];

    protected string $sourceCurrency = 'AED';
    protected ExchangeRateService $exchangeRate;

    public function import(string $filePath, string $sourceCurrency = 'AED'): array
    {
        $this->summary = [
            'imported' => 0, 'updated' => 0, 'skipped' => 0,
            'errors' => [], 'zones_updated' => 0,
        ];

        $this->sourceCurrency = strtoupper($sourceCurrency);
        $this->exchangeRate = app(ExchangeRateService::class);

        if (! file_exists($filePath)) {
            throw new Exception("File not found: {$filePath}");
        }

        $spreadsheet = IOFactory::load($filePath);

        foreach (self::SHEET_NAMES['import'] as $name) {
            if ($spreadsheet->sheetNameExists($name)) {
                $this->importRateSheet($spreadsheet->getSheetByName($name), 'import');
                break;
            }
        }

        foreach (self::SHEET_NAMES['export'] as $name) {
            if ($spreadsheet->sheetNameExists($name)) {
                $this->importRateSheet($spreadsheet->getSheetByName($name), 'export');
                break;
            }
        }

        if ($spreadsheet->sheetNameExists('Zone')) {
            $this->importZoneSheet($spreadsheet->getSheetByName('Zone'));
        } elseif ($spreadsheet->sheetNameExists('Zones')) {
            $this->importZoneSheet($spreadsheet->getSheetByName('Zones'));
        }

        return $this->summary;
    }

    protected function importRateSheet(Worksheet $ws, string $direction): void
    {
        $maxRow = $ws->getHighestDataRow();
        $maxCol = $ws->getHighestDataColumn();
        $maxColIdx = \PhpOffice\PhpSpreadsheet\Cell\Coordinate::columnIndexFromString($maxCol);

        $currentSection = null;
        $headerRowIdx = null;

        for ($r = 1; $r <= $maxRow; $r++) {
            $rowValues = [];
            for ($c = 1; $c <= min($maxColIdx, 11); $c++) {
                $rowValues[$c] = $ws->getCellByColumnAndRow($c, $r)->getCalculatedValue();
            }

            $matchedSection = $this->detectSection($rowValues);
            if ($matchedSection !== null) {
                $currentSection = $matchedSection;
                $headerRowIdx = null;
                continue;
            }

            if ($currentSection !== null && $headerRowIdx === null) {
                if ($this->isHeaderRow($rowValues)) {
                    $headerRowIdx = $r;
                    continue;
                }
            }

            if ($currentSection !== null && $headerRowIdx !== null) {
                $parsed = $this->parseRateRow($rowValues);
                if ($parsed === null) {
                    if ($this->isEmptyRow($rowValues)) {
                        $currentSection = null;
                        $headerRowIdx = null;
                    }
                    continue;
                }

                ['weight' => $weight, 'rates' => $rates] = $parsed;

                foreach ($rates as $zone => $rate) {
                    if ($rate === null) {
                        $this->summary['skipped']++;
                        continue;
                    }
                    $this->upsertRate($direction, $currentSection, $weight, $zone, (float) $rate);
                }
            }
        }
    }

    protected function detectSection(array $rowValues): ?string
    {
        foreach ($rowValues as $val) {
            if (! is_string($val) || trim($val) === '') {
                continue;
            }
            $normalized = strtoupper(trim($val));

            foreach (self::SECTION_MARKERS['parcel'] as $marker) {
                if ($normalized === strtoupper($marker)) {
                    return 'parcel';
                }
            }
            foreach (self::SECTION_MARKERS['document'] as $marker) {
                if ($normalized === strtoupper($marker)) {
                    return 'document';
                }
            }
        }
        return null;
    }

    protected function isHeaderRow(array $rowValues): bool
    {
        if (! isset($rowValues[1]) || ! is_string($rowValues[1])) {
            return false;
        }
        $first = strtolower(trim($rowValues[1]));
        if (! in_array($first, ['weight (kg)', 'weight', 'weight(kg)', 'wt', 'wt (kg)'])) {
            return false;
        }
        $zoneCount = 0;
        $expectedInt = 1;
        for ($c = 2; $c <= 11; $c++) {
            $val = $rowValues[$c] ?? null;
            if ($val === null || $val === '') continue;

            if (is_string($val) && preg_match('/^zone\s*(\d+)$/i', trim($val), $m)) {
                $zoneCount++;
                continue;
            }
            if (is_int($val) || (is_string($val) && preg_match('/^\d+$/', trim($val)))) {
                $intVal = (int) $val;
                if ($intVal === $expectedInt) {
                    $zoneCount++;
                    $expectedInt++;
                    continue;
                }
            }
        }
        return $zoneCount >= 3;
    }

    protected function parseRateRow(array $rowValues): ?array
    {
        if (! isset($rowValues[1]) || $rowValues[1] === null || $rowValues[1] === '') {
            return null;
        }
        $weightVal = $rowValues[1];
        if (is_string($weightVal)) {
            $weightVal = trim($weightVal);
            if ($weightVal === '' || ! is_numeric($weightVal)) {
                return null;
            }
            $weightVal = (float) $weightVal;
        } elseif (! is_numeric($weightVal)) {
            return null;
        } else {
            $weightVal = (float) $weightVal;
        }
        $weightVal = round($weightVal, 3);

        $rates = [];
        for ($c = 2; $c <= 11; $c++) {
            $zone = $c - 1;
            $val = $rowValues[$c] ?? null;
            if ($val === null || $val === '' || (is_string($val) && trim($val) === '')) {
                $rates[$zone] = null;
                continue;
            }
            if (is_numeric($val)) {
                $rates[$zone] = (float) $val;
            } else {
                $this->summary['errors'][] = "Non-numeric rate at weight={$weightVal} zone={$zone}: " . substr((string)$val, 0, 40);
                $rates[$zone] = null;
            }
        }
        return ['weight' => $weightVal, 'rates' => $rates];
    }

    protected function isEmptyRow(array $rowValues): bool
    {
        foreach ($rowValues as $v) {
            if ($v !== null && $v !== '' && !(is_string($v) && trim($v) === '')) {
                return false;
            }
        }
        return true;
    }

    /**
     * Upsert a rate row — همیشه به ریال ذخیره می‌شود.
     */
    protected function upsertRate(string $direction, string $serviceType, float $weight, int $zone, float $rate): void
    {
        $rateInIrr = $this->exchangeRate->convertToIrr($rate, $this->sourceCurrency);

        try {
            $existing = RateEntry::where([
                'direction'    => $direction,
                'service_type' => $serviceType,
                'weight'       => $weight,
                'zone'         => $zone,
                'currency'     => 'IRR',
            ])->where('effective_at', '>=', now()->startOfDay())
              ->first();

            if ($existing) {
                $existing->update(['rate' => $rateInIrr]);
                $this->summary['updated']++;
            } else {
                RateEntry::create([
                    'direction'    => $direction,
                    'service_type' => $serviceType,
                    'weight'       => $weight,
                    'zone'         => $zone,
                    'rate'         => $rateInIrr,
                    'currency'     => 'IRR',
                    'effective_at' => now(),
                ]);
                $this->summary['imported']++;
            }
        } catch (Exception $e) {
            $this->summary['errors'][] = "DB error: {$direction}×{$serviceType} w={$weight} z={$zone}: " . $e->getMessage();
            Log::warning('RateImport: ' . $e->getMessage());
        }
    }

    protected function importZoneSheet(Worksheet $ws): void
    {
        $maxRow = $ws->getHighestDataRow();

        $headerRow = null;
        for ($r = 1; $r <= min(20, $maxRow); $r++) {
            $b = $ws->getCellByColumnAndRow(2, $r)->getCalculatedValue();
            $f = $ws->getCellByColumnAndRow(6, $r)->getCalculatedValue();
            if ((is_string($b) && stripos($b, 'country') !== false) ||
                (is_string($f) && stripos($f, 'country') !== false)) {
                $headerRow = $r;
                break;
            }
        }
        if ($headerRow === null) {
            $headerRow = 3;
        }

        for ($r = $headerRow + 1; $r <= $maxRow; $r++) {
            $parcelCountry   = $ws->getCellByColumnAndRow(2, $r)->getCalculatedValue();
            $parcelZone      = $ws->getCellByColumnAndRow(3, $r)->getCalculatedValue();
            $documentCountry = $ws->getCellByColumnAndRow(6, $r)->getCalculatedValue();
            $documentZone    = $ws->getCellByColumnAndRow(7, $r)->getCalculatedValue();

            if (is_string($parcelCountry) && trim($parcelCountry) !== '' &&
                $parcelZone !== null && $parcelZone !== '' && (int)$parcelZone > 0) {
                $this->upsertCountryZone(trim($parcelCountry), parcelZone: (int)$parcelZone);
            }

            if (is_string($documentCountry) && trim($documentCountry) !== '' &&
                $documentZone !== null && $documentZone !== '' && (int)$documentZone > 0) {
                $this->upsertCountryZone(trim($documentCountry), documentZone: (int)$documentZone);
            }
        }
    }

    protected function upsertCountryZone(string $country, ?int $parcelZone = null, ?int $documentZone = null): void
    {
        try {
            $row = CountryZone::where('country_name', $country)->first();
            if ($row) {
                $update = [];
                if ($parcelZone !== null)   $update['parcel_zone']   = $parcelZone;
                if ($documentZone !== null) $update['document_zone'] = $documentZone;
                if (! empty($update)) {
                    $row->update($update);
                    $this->summary['zones_updated']++;
                }
            } else {
                CountryZone::create([
                    'country_name'  => $country,
                    'parcel_zone'   => $parcelZone,
                    'document_zone' => $documentZone,
                ]);
                $this->summary['zones_updated']++;
            }
        } catch (Exception $e) {
            $this->summary['errors'][] = "Country zone error ({$country}): " . $e->getMessage();
        }
    }
}