<?php

namespace jrosset\EnvReader;

use DateTime;
use DateTimeInterface;
use Exception;
use jrosset\Singleton\TSingleton;
use RangeException;
use UnexpectedValueException;

/**
 * Utility class to get informations from ENV file
 *
 * You should overwrite {@see BaseEnv::PATH_ENV} to set ENV file path<br>
 * Overwrite {@see BaseEnv::initProperties()} to set initial properties
 */
abstract class BaseEnv {
    use TSingleton;

    /**
     * ENV file path
     */
    protected const PATH_ENV = '.env';

    /**
     * @var string[] Current properties, read from ENV file (&lt;property name&gt; => &lt;property value&gt;)<br>
     * <b>NOTE:</b> All properties' name are stored in upper-case
     */
    private array $properties;

    /**
     * Initialize initial properties then read ENV file
     *
     * @throws Exception If ENV can't be read
     */
    protected function __construct () {
        $this->properties = array_change_key_case($this->initProperties(), CASE_UPPER);
        $this->readEnv();
    }
    /**
     * Get all properties
     *
     * @return string[] Get all properties (properties' name are in upper case)
     */
    public function getProperties (): array {
        return $this->properties;
    }
    /**
     * Check if a property id defined
     *
     * @param string $name The property name
     *
     * @return bool Is the property defined ?
     */
    public function hasProperty (string $name): bool {
        return array_key_exists(mb_strtoupper($name), $this->getProperties());
    }
    /**
     * Get a property value
     *
     * @param string      $name    The property name
     * @param string|null $default The default value if property is not set
     *                             Raise an exception if property is not set AND $default is Null
     *
     * @return string The property value
     *
     * @throws UnexpectedValueException If property is not set AND $default is Null
     */
    public function getProperty (string $name, ?string $default = null): string {
        $name = mb_strtoupper($name);
        if (!$this->hasProperty($name)) {
            if ($default === null) {
                throw new UnexpectedValueException('The "' . $name . '" property is not set');
            }
            return $default;
        }

        return $this->properties[$name];
    }
    /**
     * Get a property value as a boolean
     *
     * @param string    $name      The property name
     * @param bool|null $default   The default value if property is not set
     *                             Raise an exception if property is not set AND $default is Null
     *
     * @return bool The property value
     *
     * @throws UnexpectedValueException If property is not set AND $default is Null
     * @throws RangeException If the property can't be cast to a boolean
     *
     * @noinspection PhpUnused
     */
    public function getPropertyAsBool (string $name, ?bool $default = null): bool {
        switch ($value = $this->getProperty($name, $default === null ? null : ($default === true ? '1' : '0'))) {
            case '1':
            case 'true':
                return true;

            case '0':
            case 'false':
                return false;

            default:
                throw new RangeException('The "' . $name . '" property is not a valid boolean : ' . $value);
        }
    }
    /**
     * Get a property value as an integer
     *
     * @param string   $name       The property name
     * @param int|null $default    The default value if property is not set
     *                             Raise an exception if property is not set AND $default is Null
     *
     * @return int The property value
     *
     * @throws UnexpectedValueException If property is not set AND $default is Null
     * @throws RangeException If the property can't be cast to an integer
     *
     * @noinspection PhpUnused
     */
    public function getPropertyAsInt (string $name, ?int $default = null): int {
        $value = $this->getProperty($name, $default === null ? null : (string)$default);
        if (preg_match('#^\s*(?<value>[0-9]+)\s*$#', $value, $match) !== 1) {
            throw new RangeException('The "' . $name . '" property is not a valid integer : ' . $value);
        }
        return (int)$match['value'];
    }
    /**
     * Get a property value as a float value (the decimal separator is dot)
     *
     * @param string     $name     The property name
     * @param float|null $default  The default value if property is not set
     *                             Raise an exception if property is not set AND $default is Null
     *
     * @return float The property value
     *
     * @throws UnexpectedValueException If property is not set AND $default is Null
     * @throws RangeException If the property can't be cast to a float value
     *
     * @noinspection PhpUnused
     */
    public function getPropertyAsReal (string $name, ?float $default = null): float {
        $value = $this->getProperty($name, $default === null ? null : (string)$default);
        if (preg_match('#^\s*(?<value>[0-9]+(?:\.[0-9]+)?)\s*$#', $value, $match) !== 1) {
            throw new RangeException('The "' . $name . '" property is not a valid float value : ' . $value);
        }
        return (float)$match['value'];
    }
    /**
     * Get a property value as a date and time ({@link https://www.php.net/manual/book.datetime.php DateTime})
     *
     * The date <b>must</b> respect {@link https://datatracker.ietf.org/doc/html/rfc3339 RFC339} norm
     *
     * @param string        $name    The property name
     * @param DateTime|null $default The default value if property is not set
     *                               Raise an exception if property is not set AND $default is Null
     *
     * @return DateTime The property value
     *
     * @throws UnexpectedValueException If property is not set AND $default is Null
     * @throws RangeException If the property can't be cast to a date and time
     *
     * @noinspection PhpUnused
     */
    public function getPropertyAsDateTime (string $name, ?DateTime $default = null): DateTime {
        $value = DateTime::createFromFormat(
            DateTimeInterface::RFC3339,
            $this->getProperty($name, $default === null ? null : $default->format(DateTimeInterface::RFC3339))
        );

        $errors = DateTime::getLastErrors();
        if ($errors !== false) {
            $messages = [];

            if (($nb_error = $errors['error_count']) > 0) {
                foreach ($errors['errors'] as $idx => $error) {
                    $messages[] = 'ERREUR #' . $idx . ' : ' . $error;
                }
            }
            if (($nb_warning = $errors['warning_count']) > 0) {
                foreach ($errors['warnings'] as $idx => $warning) {
                    $messages[] = 'ALERTE #' . $idx . ' : ' . $warning;
                }
            }

            if ($nb_error + $nb_warning > 0) {
                throw new RangeException('The "' . $name . '" property is not a valid date and time : ' . $value . "\n\n" . implode("\n", $messages));
            }
        }
        if ($value === false) {
            throw new RangeException('The "' . $name . '" property is not a valid date and time : ' . $value);
        }

        return $value;
    }
    /**
     * Initialize initial properties
     *
     * @return string[] Properties initial values (&lt;property name&gt; => &lt;property value&gt;)
     */
    protected function initProperties (): array {
        return [
            'APP_DEV' => 0,
        ];
    }
    /**
     * Read the ENV file
     *
     * @throws Exception If ENV can't be read
     */
    private function readEnv (): void {
        if (!file_exists(static::PATH_ENV)) {
            return;
        }

        $lines = file(static::PATH_ENV, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
        if ($lines === false) {
            throw new Exception('Unable to read environment file "' . static::PATH_ENV . '"');
        }

        foreach ($lines as $line) {
            if (preg_match('/^\s*(?:(?<comment>#).+|(?<key>[a-zA-Z0-9_-]+)=(?<value>.+))$/i', $line, $match) !== 1) {
                continue;           // Ligne invalide
            }

            if (isset($match['comment']) && trim($match['comment']) !== '') {
                continue;           // Commentaire
            }

            $this->properties[mb_strtoupper($match['key'])] = $match['value'];
        }
    }
}