<?php

namespace App\Config;

use Symfony\Component\Yaml\Yaml;

/**
 * Reads the delivered wording of the admin-editable mails from config/email_texts.yaml.
 *
 * That wording is the fallback used whenever no email_text row exists for a key, so the
 * mails keep working on a fresh database and "reset to default" needs nothing but deleting
 * the row.
 *
 * The file is parsed lazily and memoised: a request that sends no mail and opens no admin
 * screen never touches it, and one that does reads it once. Nothing here is validated at
 * compile time, so a missing entry surfaces as an error the first time the catalogue is
 * built - EmailTextCatalogTest builds all of them.
 */
class EmailTextCatalog
{
    /**
     * @var array<string, EmailTextDefinition>|null
     */
    private ?array $definitions = null;

    public function __construct(
        private readonly string $emailTextsFile,
    ) {
    }

    /**
     * @return array<string, EmailTextDefinition> keyed by EmailTextKey value
     */
    public function all(): array
    {
        return $this->definitions ??= $this->build();
    }

    public function get(EmailTextKey $key): EmailTextDefinition
    {
        return $this->all()[$key->value];
    }

    /**
     * @return array<string, EmailTextDefinition>
     */
    private function build(): array
    {
        $config = Yaml::parseFile($this->emailTextsFile);
        $descriptions = $config['placeholders'];

        $definitions = [];

        foreach (EmailTextKey::cases() as $key) {
            $text = $config['texts'][$key->value];

            $placeholders = [];

            foreach ($text['placeholders'] as $name) {
                $placeholders[$name] = $descriptions[$name];
            }

            $definitions[$key->value] = new EmailTextDefinition(
                $key,
                $text['label'],
                $placeholders,
                $text['subject'],
                $text['headline'],
                $text['body'],
            );
        }

        return $definitions;
    }
}