<?php

declare(strict_types=1);

namespace App\Http\Controllers;

use App\Exception\ApiException;
use App\Repository\TodoItemRepository;
use App\Repository\TodoListRepository;
use App\Support\Validator;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;

/**
 * CRUD for the items within one todo list. Every route first checks that the
 * parent list is owned by the authenticated user; otherwise it responds 404.
 */
final class TodoItemController extends Controller
{
    private const TEXT_MAX = 1000;

    public function __construct(
        private readonly TodoListRepository $lists,
        private readonly TodoItemRepository $items,
    ) {
    }

    /**
     * GET /api/lists/{listId}/items
     */
    public function index(Request $request, Response $response, array $args): Response
    {
        $listId = $this->requireOwnedListId($request, $args);

        return $this->json($response, [
            'items' => array_map($this->present(...), $this->items->allForList($listId)),
        ]);
    }

    /**
     * POST /api/lists/{listId}/items
     */
    public function store(Request $request, Response $response, array $args): Response
    {
        $listId = $this->requireOwnedListId($request, $args);

        $validator = new Validator($this->body($request));
        $text = $validator->requiredString('text', self::TEXT_MAX);
        $complete = $validator->optionalBool('complete') ?? false;
        $position = $validator->optionalInt('position', 0);
        $validator->assert();

        $item = $this->items->create($listId, $text, $complete, $position);
        $this->lists->touch($listId);

        return $this->json($response, ['item' => $this->present($item)], 201);
    }

    /**
     * GET /api/lists/{listId}/items/{itemId}
     */
    public function show(Request $request, Response $response, array $args): Response
    {
        $listId = $this->requireOwnedListId($request, $args);

        return $this->json($response, ['item' => $this->present($this->requireItem($listId, $args))]);
    }

    /**
     * PATCH /api/lists/{listId}/items/{itemId}
     */
    public function update(Request $request, Response $response, array $args): Response
    {
        $listId = $this->requireOwnedListId($request, $args);
        $item = $this->requireItem($listId, $args);

        $validator = new Validator($this->body($request));
        $fields = [];
        if ($validator->has('text')) {
            $fields['text'] = $validator->requiredString('text', self::TEXT_MAX);
        }
        if ($validator->has('complete')) {
            $fields['complete'] = $validator->optionalBool('complete');
        }
        if ($validator->has('position')) {
            $fields['position'] = $validator->optionalInt('position', 0);
        }
        if ($fields === [] && !$validator->failed()) {
            $validator->add('text', 'Provide at least one of: text, complete, position.');
        }
        $validator->assert();

        $updated = $this->items->update($item['id'], $listId, $fields);
        $this->lists->touch($listId);

        return $this->json($response, ['item' => $this->present($updated)]);
    }

    /**
     * DELETE /api/lists/{listId}/items/{itemId}
     */
    public function destroy(Request $request, Response $response, array $args): Response
    {
        $listId = $this->requireOwnedListId($request, $args);
        $this->items->delete($this->requireItem($listId, $args)['id']);
        $this->lists->touch($listId);

        return $response->withStatus(204);
    }

    /**
     * @param array<string, string> $args
     */
    private function requireOwnedListId(Request $request, array $args): int
    {
        $list = $this->lists->findOwnedBy((int) $args['listId'], $this->user($request)['id']);

        if ($list === null) {
            throw new ApiException('List not found.', 404);
        }

        return $list['id'];
    }

    /**
     * @param array<string, string> $args
     * @return array{id: int, list_id: int, text: string, complete: bool, position: int, created_at: string, updated_at: string}
     */
    private function requireItem(int $listId, array $args): array
    {
        $item = $this->items->findInList((int) $args['itemId'], $listId);

        if ($item === null) {
            throw new ApiException('Item not found.', 404);
        }

        return $item;
    }

    /**
     * @param array{id: int, list_id: int, text: string, complete: bool, position: int, created_at: string, updated_at: string} $item
     * @return array<string, mixed>
     */
    private function present(array $item): array
    {
        return [
            'id' => $item['id'],
            'list_id' => $item['list_id'],
            'text' => $item['text'],
            'complete' => $item['complete'],
            'position' => $item['position'],
            'created_at' => $item['created_at'],
            'updated_at' => $item['updated_at'],
        ];
    }
}