<?php

namespace App\Imports;

use App\Models\Item;
use App\Models\Plant;
use App\Models\ProductionCalendar;
use App\Models\ProductionPlan;
use App\Models\ProductionPlanTarget;
use Illuminate\Support\Collection;
use Maatwebsite\Excel\Concerns\ToCollection;
use Maatwebsite\Excel\Concerns\WithHeadingRow;
use Maatwebsite\Excel\Concerns\WithCalculatedFormulas;
use Illuminate\Support\Facades\DB;
use Exception;
use Carbon\Carbon;

class DayPlanTargetImport implements ToCollection, WithHeadingRow, WithCalculatedFormulas
{
    protected $plantId;
    protected $lineId;
    protected $year;
    protected $month;
    protected $week;

    public function __construct($plantId, $lineId, $year, $month, $week)
    {
        $this->plantId = $plantId;
        $this->lineId = $lineId;
        $this->year = $year;
        $this->month = $month;
        $this->week = strtolower($week);
    }


    public function collection(Collection $rows)
    {
        $weekMapping = [
            'week_1' => 1,
            'week_2' => 8,
            'week_3' => 15,
            'week_4' => 22,
            'week_5' => 29,
        ];

        if (!isset($weekMapping[$this->week])) {
            throw new Exception('Invalid week selected.');
        }

        $startDay = $weekMapping[$this->week];

        $daysInMonth = cal_days_in_month(
            CAL_GREGORIAN,
            (int) $this->month,
            (int) $this->year
        );

        $maxDays = min(7, $daysInMonth - $startDay + 1);

        if ($maxDays <= 0) {
            throw new Exception('Selected week is outside the selected month.');
        }

        DB::transaction(function () use ($rows, $startDay, $maxDays) {

            // Get calendar leave dates
            $calendar = ProductionCalendar::where('plant_id', $this->plantId)
                ->whereMonth('created_at', $this->month)
                ->whereYear('created_at', $this->year)
                ->first();

            $leaveDates = $calendar->leave_dates ?? [];

            if (is_string($leaveDates)) {
                $leaveDates = explode(',', $leaveDates);
            }

            $leaveDates = collect($leaveDates)
                ->map(fn ($date) => trim((string) $date))
                ->filter()
                ->map(fn ($date) => Carbon::parse($date)->format('Y-m-d'))
                ->toArray();

            foreach ($rows as $index => $row) {

                $excelValues = array_values($row->toArray());

                // First two columns
                $plantCode = trim((string) ($excelValues[0] ?? ''));
                $itemCode = trim((string) ($excelValues[1] ?? ''));

                if ($plantCode === '' || $itemCode === '') {
                    throw new Exception(
                        'Plant Code or Item Code missing in Excel row ' . ($index + 2)
                    );
                }

                $plant = Plant::where('code', $plantCode)->first();

                if (!$plant) {
                    throw new Exception("Plant Code {$plantCode} not found.");
                }

                $item = Item::where('code', $itemCode)
                    ->where('plant_id', $plant->id)
                    ->first();

                if (!$item) {
                    throw new Exception(
                        "Item Code {$itemCode} not found for Plant Code {$plantCode}."
                    );
                }

                $plan = ProductionPlan::where('plant_id', $plant->id)
                    ->where('item_id', $item->id)
                    ->whereMonth('created_at', $this->month)
                    ->whereYear('created_at', $this->year)
                    ->first();

                if (!$plan) {
                    throw new Exception(
                        "Production plan not found for Item Code: {$itemCode}"
                    );
                }

                // Remaining columns contain daily quantities
                $dayValues = array_slice($excelValues, 2);

                $updateData = [];

                for ($i = 0; $i < $maxDays; $i++) {

                    $databaseDay = $startDay + $i;

                    $date = Carbon::create(
                        $this->year,
                        $this->month,
                        $databaseDay
                    )->format('Y-m-d');

                    // Leave date: always zero
                    if (in_array($date, $leaveDates)) {
                        $updateData["day_{$databaseDay}"] = 0;
                        continue;
                    }

                    $quantity = $dayValues[$i] ?? null;

                    // Blank quantity: do not update
                    if ($quantity === null || trim((string) $quantity) === '') {
                        continue;
                    }

                    if (!is_numeric($quantity) || $quantity < 0) {
                        throw new Exception(
                            "Invalid quantity for Plant {$plantCode}, Item {$itemCode}, Day {$databaseDay}."
                        );
                    }

                    $updateData["day_{$databaseDay}"] = $quantity;
                }

                if (!empty($updateData)) {
                    $plan->update($updateData);

                    // Refresh the latest database values
                    $plan->refresh();

                    // Calculate total of day_1 to day_31
                    $totalPlanQuantity = 0;

                    for ($day = 1; $day <= 31; $day++) {

                        $totalPlanQuantity += (float) (
                            $plan->{"day_{$day}"} ?? 0
                        );
                    }

                    // Update monthly plan quantity
                    $plan->update([
                        'plan_quantity' => $totalPlanQuantity,
                    ]);
                }
            }
        });
    }

}