<?php

namespace App\Modules\Assessments\Application;

use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\Rule;
use Illuminate\Validation\ValidationException;

final class QuestionSchema
{
    /** @return list<string> */
    public function types(): array
    {
        return ['single_choice', 'multiple_choice', 'true_false', 'matching', 'sorting', 'drag_drop', 'hotspot', 'scenario', 'branching_scenario'];
    }

    /** @param array<string, mixed> $configuration @return array<string, mixed> */
    public function validate(string $type, array $configuration): array
    {
        Validator::make(['type' => $type], ['type' => ['required', Rule::in($this->types())]])->validate();
        $rules = match ($type) {
            'single_choice', 'multiple_choice' => [
                'options' => ['required', 'array', 'min:2', 'max:12'],
                'options.*.id' => ['required', 'string', 'distinct', 'max:80'],
                'options.*.text' => ['required', 'string', 'max:1000'],
                'options.*.correct' => ['required', 'boolean'],
                'options.*.feedback' => ['nullable', 'string', 'max:2000'],
            ],
            'true_false' => ['answer' => ['required', 'boolean'], 'feedback' => ['nullable', 'string', 'max:2000']],
            'matching' => [
                'pairs' => ['required', 'array', 'min:2', 'max:12'],
                'pairs.*.left' => ['required', 'string', 'max:500'],
                'pairs.*.right' => ['required', 'string', 'max:500'],
            ],
            'sorting' => ['items' => ['required', 'array', 'min:2', 'max:12'], 'items.*' => ['required', 'string', 'distinct', 'max:500']],
            'drag_drop' => [
                'items' => ['required', 'array', 'min:2', 'max:16'],
                'items.*.text' => ['required', 'string', 'max:500'],
                'items.*.target' => ['required', 'string', 'max:160'],
            ],
            'hotspot' => [
                'imageAssetId' => ['required', 'string'],
                'hotspots' => ['required', 'array', 'min:1', 'max:12'],
                'hotspots.*.x' => ['required', 'numeric', 'between:0,100'],
                'hotspots.*.y' => ['required', 'numeric', 'between:0,100'],
                'hotspots.*.radius' => ['required', 'numeric', 'between:1,40'],
                'hotspots.*.label' => ['required', 'string', 'max:160'],
                'hotspots.*.correct' => ['required', 'boolean'],
            ],
            'scenario' => [
                'context' => ['required', 'string', 'max:5000'],
                'choices' => ['required', 'array', 'min:2', 'max:8'],
                'choices.*.text' => ['required', 'string', 'max:1000'],
                'choices.*.score' => ['required', 'numeric', 'between:0,1'],
                'choices.*.feedback' => ['required', 'string', 'max:3000'],
            ],
            'branching_scenario' => [
                'startNodeId' => ['required', 'string'],
                'nodes' => ['required', 'array', 'min:2', 'max:80'],
                'nodes.*.id' => ['required', 'string', 'distinct', 'max:80'],
                'nodes.*.type' => ['required', Rule::in(['scene', 'question', 'result'])],
                'nodes.*.title' => ['required', 'string', 'max:240'],
                'nodes.*.body' => ['nullable', 'string', 'max:5000'],
                'nodes.*.choices' => ['nullable', 'array', 'max:12'],
                'nodes.*.choices.*.text' => ['required_with:nodes.*.choices', 'string', 'max:1000'],
                'nodes.*.choices.*.targetNodeId' => ['required_with:nodes.*.choices', 'string'],
            ],
        };
        $validated = Validator::make($configuration, $rules)->validate();
        if (in_array($type, ['single_choice', 'multiple_choice'], true)) {
            $correct = collect($validated['options'])->where('correct', true)->count();
            if (($type === 'single_choice' && $correct !== 1) || ($type === 'multiple_choice' && $correct < 1)) {
                throw ValidationException::withMessages(['configuration.options' => [$type === 'single_choice' ? 'دقیقاً یک گزینه باید صحیح باشد.' : 'حداقل یک گزینه باید صحیح باشد.']]);
            }
        }
        if ($type === 'branching_scenario') {
            $this->validateGraph($validated);
        }

        return $validated;
    }

    /** @param array<string, mixed> $graph */
    private function validateGraph(array $graph): void
    {
        $nodes = collect($graph['nodes'])->keyBy('id');
        if (! $nodes->has($graph['startNodeId'])) {
            throw ValidationException::withMessages(['configuration.startNodeId' => ['گره شروع وجود ندارد.']]);
        }
        foreach ($nodes as $node) {
            foreach ($node['choices'] ?? [] as $choice) {
                if (! $nodes->has($choice['targetNodeId'])) {
                    throw ValidationException::withMessages(['configuration.nodes' => ["مسیر به گره ناموجود {$choice['targetNodeId']} اشاره می‌کند."]]);
                }
            }
        }
        $reachable = [];
        $queue = [$graph['startNodeId']];
        while ($queue !== []) {
            $id = array_shift($queue);
            if (isset($reachable[$id])) {
                continue;
            }
            $reachable[$id] = true;
            foreach (($nodes[$id]['choices'] ?? []) as $choice) {
                $queue[] = $choice['targetNodeId'];
            }
        }
        $unreachable = $nodes->keys()->reject(fn (string $id): bool => isset($reachable[$id]))->values();
        if ($unreachable->isNotEmpty()) {
            throw ValidationException::withMessages(['configuration.nodes' => ['گره‌های غیرقابل‌دسترسی: '.$unreachable->implode('، ')]]);
        }
        if (! $nodes->contains(fn (array $node): bool => $node['type'] === 'result')) {
            throw ValidationException::withMessages(['configuration.nodes' => ['سناریو باید حداقل یک گره نتیجه داشته باشد.']]);
        }
    }
}