<?php

namespace App\Services;

use App\Models\ClassPackage;
use App\Models\ClassPackageUnit;
use App\Models\IrrecusableProposal;
use App\Models\IrrecusableProposalProduct;
use App\Models\PavaoProposal;
use App\Models\PavaoProposalProduct;
use App\Models\Unit;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Support\Facades\DB;

class ClassPackageService
{
    private const EAGER_LOAD = [
        'unitPackages',
        'groups',
        'pavaoProposal.products.product',
        'irrecusableProposal.products.product',
    ];

    public function __construct(
        protected ClassPackageUnitService $unitService,
        protected ProposalPricingService $pricingService,
    ) {}

    public function getAll(): Collection
    {
        return ClassPackage::with(['pavaoProposal', 'irrecusableProposal'])->orderBy('created_at', 'desc')->get();
    }

    public function findById(int $id): ?ClassPackage
    {
        return ClassPackage::with(self::EAGER_LOAD)->find($id);
    }

    public function create(array $data): ClassPackage
    {
        $unitVisibilities = $data['unit_visibilities'] ?? null;
        $groupIds         = $data['group_ids'] ?? [];
        $pavao            = array_key_exists('pavao', $data) ? $data['pavao'] : null;
        $irrecusavel      = array_key_exists('irrecusavel', $data) ? $data['irrecusavel'] : null;
        unset($data['unit_visibilities'], $data['group_ids'], $data['pavao'], $data['irrecusavel']);

        $package = ClassPackage::create($data);

        if ($pavao !== null) {
            $this->pricingService->upsert(PavaoProposal::class, PavaoProposalProduct::class, 'class_package_id', $package->id, $pavao);
        }

        if ($irrecusavel !== null) {
            $this->pricingService->upsert(IrrecusableProposal::class, IrrecusableProposalProduct::class, 'class_package_id', $package->id, $irrecusavel, withCondition: true);
        }

        // Replicate to all units (all start visible = true)
        $this->replicateToAllUnits($package->load(['pavaoProposal.products', 'irrecusableProposal.products']));

        // Sync selected groups
        if (!empty($groupIds)) {
            $package->groups()->sync($groupIds);
        }

        // Apply visibility overrides
        $this->applyVisibilityOverrides($package, $unitVisibilities, $groupIds);

        return $package->load(self::EAGER_LOAD);
    }

    public function update(int $id, array $data): ?ClassPackage
    {
        $package = $this->findById($id);
        if (!$package) return null;

        $unitVisibilities = $data['unit_visibilities'] ?? null;
        $groupIds         = array_key_exists('group_ids', $data) ? ($data['group_ids'] ?? []) : null;
        $pavaoProvided       = array_key_exists('pavao', $data);
        $irrecusavelProvided = array_key_exists('irrecusavel', $data);
        $pavao       = $data['pavao'] ?? null;
        $irrecusavel = $data['irrecusavel'] ?? null;
        unset($data['unit_visibilities'], $data['group_ids'], $data['pavao'], $data['irrecusavel']);

        $package->update($data);

        $scheduleFields = array_intersect_key($data, array_flip([
            'class_duration_minutes',
            'weekday',
            'start_time',
            'second_weekday',
            'second_start_time',
        ]));
        if (!empty($scheduleFields)) {
            ClassPackageUnit::where('class_package_id', $package->id)->update($scheduleFields);
        }

        // Pavão/Irrecusável updates never propagate to already-cloned unit copies.
        if ($pavaoProvided) {
            if ($pavao !== null) {
                $this->pricingService->upsert(PavaoProposal::class, PavaoProposalProduct::class, 'class_package_id', $package->id, $pavao);
            } else {
                $this->pricingService->deleteFor(PavaoProposal::class, 'class_package_id', $package->id);
            }
        }

        if ($irrecusavelProvided) {
            if ($irrecusavel !== null) {
                $this->pricingService->upsert(IrrecusableProposal::class, IrrecusableProposalProduct::class, 'class_package_id', $package->id, $irrecusavel, withCondition: true);
            } else {
                $this->pricingService->deleteFor(IrrecusableProposal::class, 'class_package_id', $package->id);
            }
        }

        if ($groupIds !== null) {
            $package->groups()->sync($groupIds);
        }

        // Determine current group IDs (after sync)
        $currentGroupIds = $package->groups()->pluck('groups.id')->toArray();

        if ($unitVisibilities !== null || $groupIds !== null) {
            $this->applyVisibilityOverrides($package, $unitVisibilities, $currentGroupIds);
        }

        return $package->fresh(self::EAGER_LOAD);
    }

    public function delete(int $id): bool
    {
        $package = ClassPackage::find($id);
        if (!$package) return false;

        return $package->delete();
    }

    public function replicateToAllUnits(ClassPackage $package): void
    {
        Unit::all()->each(function (Unit $unit) use ($package) {
            // Skip if ClassPackageUnit already exists for this package/unit combo
            $exists = ClassPackageUnit::withTrashed()
                ->where('class_package_id', $package->id)
                ->where('unit_id', $unit->id)
                ->exists();

            if (!$exists) {
                $this->unitService->replicateFromBasePackage($unit->id, $package);
            }
        });
    }

    /**
     * Apply visibility overrides:
     * - Units in selected groups → forced visible = true
     * - Other units → use explicit unit_visibilities (if provided)
     */
    private function applyVisibilityOverrides(ClassPackage $package, ?array $unitVisibilities, array $groupIds): void
    {
        // Get all unit IDs that belong to the selected groups
        $groupUnitIds = [];
        if (!empty($groupIds)) {
            $groupUnitIds = DB::table('group_units')
                ->whereIn('group_id', $groupIds)
                ->pluck('unit_id')
                ->unique()
                ->toArray();
        }

        // Force group units to visible = true
        if (!empty($groupUnitIds)) {
            ClassPackageUnit::where('class_package_id', $package->id)
                ->whereIn('unit_id', $groupUnitIds)
                ->update(['visible' => true]);
        }

        // Apply explicit visibility for non-group units
        if (!empty($unitVisibilities)) {
            foreach ($unitVisibilities as $uv) {
                if (in_array($uv['unit_id'], $groupUnitIds)) {
                    continue; // group units cannot be hidden
                }

                ClassPackageUnit::where('class_package_id', $package->id)
                    ->where('unit_id', $uv['unit_id'])
                    ->update(['visible' => $uv['visible']]);
            }
        }
    }
}