Add text-to-rule parsing functionality

[FabianoLothor]

• Create TextParser class with natural language processing
• Add Rule::createFromText() static method
• Support common patterns: frequencies, intervals, counts, weekdays, months
• Compatible with existing Rule infrastructure and TextTransformer

[FabianoLothor]

#222

[FabianoLothor]

@simshaun I don't know how to trigger phpstan check in the PR.

[simshaun]

Shouldn't be necessary with Composer's autoloader

[FabianoLothor]

Removed

[simshaun]

Thank you! At initial glance, looks good. I'll fully review when I get some downtime.

Couple things:

1. A comprehensive test suite will be necessary. I can work on it while reviewing if you don't beat me to it.
2. Multi-lingual support would be nice. This isn't a blocker and can be added later.

[FabianoLothor]

1. A comprehensive test suite will be necessary. I can work on it while reviewing if you don't beat me to it.

I won't be able to write unit-tests until the weekend, but this snippet might be helpful if you decide to write them properly:

<?php

require_once 'src/Recurr/Exception.php';
require_once 'src/Recurr/Exception/InvalidRRule.php';
require_once 'src/Recurr/Exception/InvalidArgument.php';
require_once 'src/Recurr/Exception/InvalidWeekday.php';
require_once 'src/Recurr/TextParser.php';
require_once 'src/Recurr/Rule.php';

use Recurr\Rule;
use Recurr\TextParser;

echo "Testing Text-to-Rule functionality\n";
echo "==================================\n\n";

// Test cases similar to rrule.js examples
$testCases = [
    'every day',
    'every 2 days', 
    'every week',
    'every 3 weeks',
    'every month',
    'every year',
    'every day for 3 times',
    'every 2 weeks for 5 times',
    'every Monday',
    'every Friday', 
    'every weekdays',
    'every January',
    'every December'
];

foreach ($testCases as $text) {
    echo "Testing: '$text'\n";
    
    try {
        $rule = Rule::createFromText($text);
        $rruleString = $rule->getString();
        echo "  Result: $rruleString\n";
        echo "  Frequency: " . $rule->getFreqAsText() . "\n";
        if ($rule->getInterval() > 1) {
            echo "  Interval: " . $rule->getInterval() . "\n";
        }
        if ($rule->getCount()) {
            echo "  Count: " . $rule->getCount() . "\n";
        }
        if ($rule->getByDay()) {
            echo "  ByDay: " . implode(',', $rule->getByDay()) . "\n";
        }
        if ($rule->getByMonth()) {
            echo "  ByMonth: " . implode(',', $rule->getByMonth()) . "\n";
        }
    } catch (Exception $e) {
        echo "  Error: " . $e->getMessage() . "\n";
    }
    
    echo "\n";
}

echo "Testing completed!\n";

2. Multi-lingual support would be nice. This isn't a blocker and can be added later.

I really like the multi-lingual support suggestion, certainly doable and likely not too complicated to implement.

That said, I'm not aware of a similar feature in other libraries that supports internationalization. It would be a really nice and welcome novelty.

todoist for example is an app that supports multi-lingual support for recurring tasks.