<?php

namespace App\Http\Controllers;

use App\Models\Post;
use App\Models\Thread;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class PostController extends Controller
{
    public function index(Request $request): JsonResponse
    {
        $query = Post::query();

        $threadParam = $request->query('thread');
        if (is_string($threadParam)) {
            $threadId = $this->parseIriId($threadParam);
            if ($threadId !== null) {
                $query->where('thread_id', $threadId);
            }
        }

        $posts = $query
            ->oldest('created_at')
            ->get()
            ->map(fn (Post $post) => $this->serializePost($post));

        return response()->json($posts);
    }

    public function store(Request $request): JsonResponse
    {
        $data = $request->validate([
            'body' => ['required', 'string'],
            'thread' => ['required', 'string'],
        ]);

        $threadId = $this->parseIriId($data['thread']);
        $thread = Thread::findOrFail($threadId);

        $post = Post::create([
            'thread_id' => $thread->id,
            'user_id' => $request->user()?->id,
            'body' => $data['body'],
        ]);

        return response()->json($this->serializePost($post), 201);
    }

    public function destroy(Post $post): JsonResponse
    {
        $post->delete();

        return response()->json(null, 204);
    }

    private function parseIriId(?string $value): ?int
    {
        if (!$value) {
            return null;
        }

        if (preg_match('#/threads/(\d+)$#', $value, $matches)) {
            return (int) $matches[1];
        }

        if (is_numeric($value)) {
            return (int) $value;
        }

        return null;
    }

    private function serializePost(Post $post): array
    {
        return [
            'id' => $post->id,
            'body' => $post->body,
            'thread' => "/api/threads/{$post->thread_id}",
            'user_id' => $post->user_id,
            'created_at' => $post->created_at?->toIso8601String(),
            'updated_at' => $post->updated_at?->toIso8601String(),
        ];
    }
}