<?php

namespace App\Modules\Taxonomy\Application;

use App\Models\User;
use App\Modules\Courses\Domain\CourseVersion;
use App\Modules\Courses\Domain\Enums\CourseVersionStatus;
use App\Modules\Taxonomy\Domain\ContentTaxonomyMapping;
use App\Modules\Taxonomy\Domain\Enums\MappableType;
use App\Modules\Taxonomy\Domain\Enums\MappingConfirmationStatus;
use App\Modules\Taxonomy\Domain\Enums\MappingSource;
use App\Modules\Taxonomy\Domain\Enums\MappingType;
use App\Modules\Taxonomy\Domain\TaxonomyNode;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Validation\ValidationException;

final class ContentMappingService
{
    public function create(
        string $organizationId,
        string $courseVersionId,
        MappableType $mappableType,
        string $mappableId,
        string $taxonomyNodeId,
        MappingType $mappingType,
        ?string $masteryLevel,
        float $weight,
        MappingSource $source,
        ?float $confidence,
        User $actor,
    ): ContentTaxonomyMapping {
        $version = CourseVersion::query()->where('organization_id', $organizationId)->findOrFail($courseVersionId);

        if ($version->status === CourseVersionStatus::Published) {
            $this->invalid('courseVersionId', 'Published course versions cannot receive new mappings.');
        }

        TaxonomyNode::query()->where('organization_id', $organizationId)->findOrFail($taxonomyNodeId);
        $this->resolveTarget($organizationId, $version, $mappableType, $mappableId);

        $confirmation = $source === MappingSource::AiSuggested
            ? MappingConfirmationStatus::Draft
            : MappingConfirmationStatus::Confirmed;

        return ContentTaxonomyMapping::query()->create([
            'organization_id' => $organizationId,
            'course_version_id' => $version->getKey(),
            'mappable_type' => $mappableType,
            'mappable_id' => $mappableId,
            'taxonomy_node_id' => $taxonomyNodeId,
            'mapping_type' => $mappingType,
            'mastery_level' => $masteryLevel,
            'weight' => $weight,
            'source' => $source,
            'confidence' => $confidence,
            'confirmation_status' => $confirmation,
            'confirmed_by' => $confirmation === MappingConfirmationStatus::Confirmed ? $actor->getKey() : null,
            'confirmed_at' => $confirmation === MappingConfirmationStatus::Confirmed ? now() : null,
        ]);
    }

    private function resolveTarget(string $organizationId, CourseVersion $version, MappableType $type, string $id): Model
    {
        $modelClass = $type->modelClass();
        $query = $modelClass::query()->where('organization_id', $organizationId);

        if ($type !== MappableType::Course) {
            $query->where('course_version_id', $version->getKey());
        }

        $target = $query->find($id);

        if (! $target || ($type === MappableType::Course && $target->getKey() !== $version->getKey())) {
            $this->invalid('mappableId', 'The selected content does not belong to this course version.');
        }

        return $target;
    }

    private function invalid(string $field, string $message): never
    {
        throw ValidationException::withMessages([$field => [$message]]);
    }
}