<?php

declare(strict_types=1);

namespace App\Http\Controllers;

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

/**
 * CRUD for the authenticated user's projects. A project is only ever visible to
 * its owner; anything else responds 404.
 */
final class ProjectController extends Controller
{
    private const TITLE_MAX = 255;
    private const DESCRIPTION_MAX = 2000;
    private const MAX_PROJECTS_PER_OWNER = 100;

    public function __construct(private readonly ProjectRepository $projects)
    {
    }

    /**
     * GET /api/projects
     */
    public function index(Request $request, Response $response): Response
    {
        $projects = $this->projects->allForOwner($this->user($request)['id']);

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

    /**
     * POST /api/projects
     */
    public function store(Request $request, Response $response): Response
    {
        $ownerId = $this->user($request)['id'];

        $validator = new Validator($this->body($request));
        $title = $validator->requiredString('title', self::TITLE_MAX);
        $description = $validator->optionalString('description', self::DESCRIPTION_MAX) ?? '';
        $validator->assert();

        if ($this->projects->countForOwner($ownerId) >= self::MAX_PROJECTS_PER_OWNER) {
            throw new ApiException(
                sprintf('You have reached the maximum of %d projects.', self::MAX_PROJECTS_PER_OWNER),
                409,
            );
        }

        $project = $this->projects->create($ownerId, $title, $description);

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

    /**
     * GET /api/projects/{projectId}
     */
    public function show(Request $request, Response $response, array $args): Response
    {
        return $this->json($response, ['project' => $this->present($this->requireOwnedProject($request, $args))]);
    }

    /**
     * PATCH /api/projects/{projectId}
     */
    public function update(Request $request, Response $response, array $args): Response
    {
        $project = $this->requireOwnedProject($request, $args);

        $validator = new Validator($this->body($request));
        $fields = [];
        if ($validator->has('title')) {
            $fields['title'] = $validator->requiredString('title', self::TITLE_MAX);
        }
        if ($validator->has('description')) {
            $fields['description'] = $validator->optionalString('description', self::DESCRIPTION_MAX) ?? '';
        }
        if ($fields === [] && !$validator->failed()) {
            $validator->add('title', 'Provide at least one of: title, description.');
        }
        $validator->assert();

        $updated = $this->projects->update($project['id'], $project['owner_id'], $fields);

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

    /**
     * DELETE /api/projects/{projectId}
     */
    public function destroy(Request $request, Response $response, array $args): Response
    {
        $this->projects->delete($this->requireOwnedProject($request, $args)['id']);

        return $response->withStatus(204);
    }

    /**
     * Load the project named in the route, or 404 if it is missing or not owned
     * by the authenticated user.
     *
     * @param array<string, string> $args
     * @return array{id: int, owner_id: int, title: string, description: string, card_count: int, completed_count: int, created_at: string, updated_at: string}
     */
    private function requireOwnedProject(Request $request, array $args): array
    {
        $project = $this->projects->findOwnedBy((int) $args['projectId'], $this->user($request)['id']);

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

        return $project;
    }

    /**
     * @param array{id: int, owner_id: int, title: string, description: string, card_count: int, completed_count: int, created_at: string, updated_at: string} $project
     * @return array<string, mixed>
     */
    private function present(array $project): array
    {
        return [
            'id' => $project['id'],
            'title' => $project['title'],
            'description' => $project['description'],
            'owner_id' => $project['owner_id'],
            'card_count' => $project['card_count'],
            'completed_count' => $project['completed_count'],
            'created_at' => $project['created_at'],
            'updated_at' => $project['updated_at'],
        ];
    }
}