<?php

namespace App\Services\Addons;

use App\Models\Event;
use App\Models\EventPackage;
use App\Models\EventPackageAddon;
use App\Models\Package;
use Carbon\CarbonImmutable;
use Illuminate\Support\Arr;

class EventFeatureEntitlementService
{
    /**
     * @param  array<int, string>  $addonKeys
     * @return array{
     *   allowed: bool,
     *   granted_by: 'package'|'addon'|null,
     *   required_feature: string,
     *   addon_keys: array<int, string>
     * }
     */
    public function resolveForEvent(Event $event, string $requiredFeature, array $addonKeys = []): array
    {
        $eventPackage = $this->resolveEventPackage($event);

        if (! $eventPackage) {
            return [
                'allowed' => false,
                'granted_by' => null,
                'required_feature' => $requiredFeature,
                'addon_keys' => $addonKeys,
            ];
        }

        if ($this->packageGrantsFeature($eventPackage->package, $requiredFeature)) {
            return [
                'allowed' => true,
                'granted_by' => 'package',
                'required_feature' => $requiredFeature,
                'addon_keys' => $addonKeys,
            ];
        }

        if ($this->addonGrantsFeature($eventPackage, $addonKeys, $requiredFeature)) {
            return [
                'allowed' => true,
                'granted_by' => 'addon',
                'required_feature' => $requiredFeature,
                'addon_keys' => $addonKeys,
            ];
        }

        return [
            'allowed' => false,
            'granted_by' => null,
            'required_feature' => $requiredFeature,
            'addon_keys' => $addonKeys,
        ];
    }

    private function resolveEventPackage(Event $event): ?EventPackage
    {
        $event->loadMissing('eventPackage.package', 'eventPackage.addons');

        if ($event->eventPackage) {
            return $event->eventPackage;
        }

        return $event->eventPackages()
            ->with(['package', 'addons'])
            ->orderByDesc('purchased_at')
            ->orderByDesc('id')
            ->first();
    }

    private function packageGrantsFeature(?Package $package, string $requiredFeature): bool
    {
        if (! $package) {
            return false;
        }

        return in_array($requiredFeature, $this->normalizeFeatureList($package->features), true);
    }

    /**
     * @param  array<int, string>  $addonKeys
     */
    private function addonGrantsFeature(EventPackage $eventPackage, array $addonKeys, string $requiredFeature): bool
    {
        $addons = $eventPackage->relationLoaded('addons')
            ? $eventPackage->addons
            : $eventPackage->addons()
                ->where('status', 'completed')
                ->get();

        return $addons->contains(function (EventPackageAddon $addon) use ($addonKeys, $requiredFeature): bool {
            if (! $this->addonIsActive($addon)) {
                return false;
            }

            if ($addonKeys !== [] && in_array((string) $addon->addon_key, $addonKeys, true)) {
                return true;
            }

            $metadataFeatures = $this->normalizeFeatureList(
                Arr::get($addon->metadata ?? [], 'entitlements.features', Arr::get($addon->metadata ?? [], 'features', []))
            );

            return in_array($requiredFeature, $metadataFeatures, true);
        });
    }

    private function addonIsActive(EventPackageAddon $addon): bool
    {
        if ($addon->status !== 'completed') {
            return false;
        }

        $expiryCandidates = [
            Arr::get($addon->metadata ?? [], 'entitlements.expires_at'),
            Arr::get($addon->metadata ?? [], 'expires_at'),
            Arr::get($addon->metadata ?? [], 'valid_until'),
        ];

        foreach ($expiryCandidates as $candidate) {
            if (! is_string($candidate) || trim($candidate) === '') {
                continue;
            }

            try {
                $expiresAt = CarbonImmutable::parse($candidate);
            } catch (\Throwable) {
                continue;
            }

            if ($expiresAt->isPast()) {
                return false;
            }
        }

        return true;
    }

    /**
     * @return array<int, string>
     */
    private function normalizeFeatureList(mixed $value): array
    {
        if (is_string($value)) {
            $decoded = json_decode($value, true);

            if (json_last_error() === JSON_ERROR_NONE) {
                $value = $decoded;
            }
        }

        if (! is_array($value)) {
            return [];
        }

        if (array_is_list($value)) {
            return array_values(array_filter(array_map(
                static fn (mixed $feature): string => trim((string) $feature),
                $value
            )));
        }

        return array_values(array_filter(array_map(
            static fn (mixed $feature): string => trim((string) $feature),
            array_keys(array_filter($value, static fn (mixed $enabled): bool => (bool) $enabled))
        )));
    }
}