<?php

declare(strict_types=1);

namespace App\Actions\Projects;

use App\Models\Project;
use App\Models\User;
use App\Services\TaskStream\TaskStreamClient;
use App\Services\TaskStream\TaskStreamException;
use Illuminate\Support\Str;
use Illuminate\Validation\ValidationException;
use Symfony\Component\HttpKernel\Exception\HttpException;

/**
 * Opens a board in TaskStream for a project, new or one without a board
 * yet, and points the project at it.
 *
 * It runs before the project is saved: if TaskStream says no, nothing is
 * saved here either, and the caller gets the reason to fix and retry.
 * The board is public, like the project it tracks is meant to be.
 */
class OpenInTaskStream
{
    /** TaskStream's rule for a project key. */
    public const KEY_PATTERN = '/^[A-Z][A-Z0-9]{1,9}$/';

    public function __construct(protected TaskStreamClient $client) {}

    /**
     * @param  string|null  $bearer  The token the caller presented here.
     * @param  string|null  $key  The key asked for; derived from the slug when null.
     *
     * @throws ValidationException when the caller can fix the request
     */
    public function handle(Project $project, User $user, ?string $bearer, ?string $key = null): void
    {
        $locale = (string) config('locales.default');
        $key = $key !== null ? Str::upper($key) : $this->keyFrom((string) $project->getTranslation('slug', $locale, false));

        if ($key === null) {
            throw ValidationException::withMessages(['taskstream_key' => __('rules.taskstream.key_needed')]);
        }

        try {
            $created = $this->client->createProject(
                token: $this->token($user, $bearer),
                key: $key,
                name: Str::limit((string) $project->getTranslation('title', $locale, false), 80, '…'),
                description: $project->getTranslation('tagline', $locale, false) ?: null,
                public: true,
            );
        } catch (TaskStreamException $e) {
            throw $this->explain($e);
        }

        $project->forceFill([
            'taskstream_project_id' => $created['id'],
            'taskstream_key' => $created['key'],
        ]);
    }

    /**
     * A Pireon token is passed on, so the board belongs to whoever asked. A
     * machine token is this application's alone and means nothing there.
     */
    protected function token(User $user, ?string $bearer): string
    {
        $token = $user->currentAccessToken() === null ? $bearer : $this->client->serviceToken();

        if (blank($token)) {
            throw ValidationException::withMessages(['taskstream' => __('rules.taskstream.machine')]);
        }

        return $token;
    }

    /**
     * A key in TaskStream's style: one word gives its first ten characters
     * ("catalogo" → CATALOGO), several give their initials ("mi-web-nueva"
     * → MWN). Null when nothing usable is left.
     */
    public function keyFrom(string $slug): ?string
    {
        $words = array_values(array_filter(preg_split('/[^A-Z0-9]+/', Str::upper(Str::ascii($slug))) ?: []));

        $key = count($words) === 1
            ? $words[0]
            : implode('', array_map(fn (string $word) => $word[0], $words));

        // It must start with a letter.
        $key = substr((string) preg_replace('/^[0-9]+/', '', $key), 0, 10);

        return preg_match(self::KEY_PATTERN, $key) === 1 ? $key : null;
    }

    protected function explain(TaskStreamException $e): ValidationException|HttpException
    {
        if ($e->isRefusal()) {
            return ValidationException::withMessages([
                'taskstream_key' => __('rules.taskstream.refused', ['reason' => $e->getMessage()]),
            ]);
        }

        if ($e->isUnauthorised()) {
            return ValidationException::withMessages(['taskstream' => __('rules.taskstream.unauthorised')]);
        }

        return new HttpException(502, __('rules.taskstream.unavailable'), $e);
    }
}