<?php

namespace App\Config\Validation;

use App\Models\Employee;
use CodeIgniter\HTTP\IncomingRequest;
use Config\OSPOS;
use Config\Services;
use DirectoryIterator;
use IntlChar;

/**
 * @property Employee employee
 * @property IncomingRequest request
 */
class OSPOSRules
{
    private IncomingRequest $request;
    private array $config;

    /**
     * Validates the username and password sent to the login view. User is logged in on successful validation.
     *
     * @param string $username Username to check against.
     * @param string $fields Comma separated string of the fields for validation.
     * @param array $data Data sent to the view.
     * @param string|null $error The error sent back to the validation handler on failure.
     * @return bool True if validation passes or false if there are errors.
     * @noinspection PhpUnused
     */
    public function login_check(string $username, string $fields, array $data, ?string &$error = null): bool
    {
        $employee = model(Employee::class);
        $this->request = Services::request();
        $this->config = config(OSPOS::class)->settings;

        // Installation Check
        if (!$this->installation_check()) {
            $error = lang('Login.invalid_installation');

            return false;
        }

        $gcaptcha_enabled = array_key_exists('gcaptcha_enable', $this->config) && $this->config['gcaptcha_enable'];
        if ($gcaptcha_enabled) {
            $g_recaptcha_response = $this->request->getPost('g-recaptcha-response');

            if (!$this->gcaptcha_check($g_recaptcha_response)) {
                $error = lang('Login.invalid_gcaptcha');

                return false;
            }
        }

        $password = $data['password'];
        if (!$employee->login($username, $password)) {
            $error = lang('Login.invalid_username_and_password');

            return false;
        }

        return true;
    }

    /**
     * Checks to see if GCaptcha verification was successful.
     *
     * @param $response
     * @return bool true on successful GCaptcha verification or false if GCaptcha failed.
     */
    protected function gcaptcha_check($response): bool
    {
        if (!empty($response)) {
            $check = [
                'secret'   => $this->config['gcaptcha_secret_key'],
                'response' => $response,
                'remoteip' => $this->request->getIPAddress()
            ];

            $ch = curl_init();

            curl_setopt($ch, CURLOPT_URL, "https://www.google.com/recaptcha/api/siteverify");
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($check));
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

            $result = curl_exec($ch);

            curl_close($ch);

            $status = json_decode($result, true);

            if (!empty($status['success'])) {
                return true;
            }
        }

        return false;
    }

    /**
     * Checks to make sure dependency PHP extensions are installed
     *
     * @return bool
     */
    private function installation_check(): bool
    {
        $installed_extensions = implode(', ', get_loaded_extensions());
        $required_extensions = ['bcmath', 'intl', 'gd', 'openssl', 'mbstring', 'curl', 'xml', 'json'];
        $pattern = '/';

        foreach ($required_extensions as $extension) {
            $pattern .= '(?=.*\b' . preg_quote($extension, '/') . '\b)';
        }

        $pattern .= '/i';
        $is_installed = preg_match($pattern, $installed_extensions);

        if (!$is_installed) {
            log_message('error', '[ERROR] Check your php.ini.');
            log_message('error', "PHP installed extensions: $installed_extensions");
            log_message('error', 'PHP required extensions: ' . implode(', ', $required_extensions));
        }

        return $is_installed;
    }

    /**
     * Validates the candidate as a decimal number. Takes the locale into account. Used in validation rule calls.
     *
     * @param string $candidate
     * @param string|null $error
     * @return bool
     * @noinspection PhpUnused
     */
    public function decimal_locale(string $candidate, ?string &$error = null): bool
    {
        return parse_decimals($candidate) !== false;
    }

    /**
     * Validates that a locale-aware decimal value is non-negative (>= 0).
     *
     * @param string $candidate
     * @param string|null $error
     * @return bool
     * @noinspection PhpUnused
     */
    public function nonNegativeDecimal(string $candidate, ?string &$error = null): bool
    {
        $value = parse_decimals($candidate);

        return $value !== false && $value >= 0;
    }

    /**
     * Validates that the candidate value is greater than or equal to another
     * field in the same request (proper cross-field comparison).
     *
     * CI4's built-in greater_than_equal_to[field] rule does not resolve the
     * [field] token to that field's value, so this rule performs the real
     * comparison and sets a human-readable error on failure.
     *
     * @param string $candidate The value being validated (e.g. max).
     * @param string $otherField The field to compare against (e.g. min).
     * @param array $data The full set of data being validated.
     * @param string|null $error Error message set on failure.
     * @return bool
     * @noinspection PhpUnused
     */
    public function gte_field(string $candidate, string $otherField, array $data, ?string &$error = null): bool
    {
        $other = $data[$otherField] ?? null;

        if (is_numeric($candidate) && is_numeric($other) && (float) $candidate < (float) $other) {
            $error = 'The value must be a number greater than or equal to the ' . $otherField . ' field.';
            return false;
        }

        return true;
    }

    /**
     * Validates that the candidate theme name matches an installed bootswatch theme directory.
     *
     * @param string $theme
     * @param string|null $error
     * @return bool
     * @noinspection PhpUnused
     */
    public function themeExists(string $theme, ?string &$error = null): bool
    {
        $dir = new DirectoryIterator('resources/bootswatch');

        foreach ($dir as $fileInfo) {
            if (
                $fileInfo->isDir()
                && !$fileInfo->isDot()
                && $fileInfo->getFilename() !== 'fonts'
                && $fileInfo->getFilename() === $theme
            ) {
                return true;
            }
        }

        return false;
    }

    /**
     * Unicode-aware version of CodeIgniter's built-in `alpha_numeric_punct` rule, which only
     * matches ASCII (`preg_match('\A[A-Z0-9 ~!#$%\&\*\-_+=|:.]+\z/i', ...)`) and so rejects
     * legitimate non-English text (e.g. accented or CJK characters). Allows unicode letters,
     * combining marks (so base+diacritic sequences pass), and digits in place of `A-Z0-9`, and
     * reuses the exact same punctuation set as the original rule (`~!#$%&*-_+=|:.` plus space),
     * extended with `'` and `,` to accommodate real-world tax names (e.g. "O'Brien's Tax",
     * "Impôt, incl."). `<` and `>` are deliberately absent from the punctuation set, same as in
     * the original rule, so this also serves as a defense-in-depth backstop against HTML
     * injection (the primary fix is escaping at render time).
     *
     * @param string $candidate
     * @param string|null $error
     * @return bool
     * @noinspection PhpUnused
     */
    public function unicode_alpha_numeric_punct(string $candidate, ?string &$error = null): bool
    {
        $allowedPunctuation = ['~', '!', '#', '$', '%', '&', '*', '-', '_', '+', '=', '|', ':', '.', ' ', "'", ','];

        $allowedCategories = [
            IntlChar::CHAR_CATEGORY_UPPERCASE_LETTER,
            IntlChar::CHAR_CATEGORY_LOWERCASE_LETTER,
            IntlChar::CHAR_CATEGORY_TITLECASE_LETTER,
            IntlChar::CHAR_CATEGORY_MODIFIER_LETTER,
            IntlChar::CHAR_CATEGORY_OTHER_LETTER,
            IntlChar::CHAR_CATEGORY_NON_SPACING_MARK,
            IntlChar::CHAR_CATEGORY_COMBINING_SPACING_MARK,
            IntlChar::CHAR_CATEGORY_ENCLOSING_MARK,
            IntlChar::CHAR_CATEGORY_DECIMAL_DIGIT_NUMBER,
            IntlChar::CHAR_CATEGORY_LETTER_NUMBER,
            IntlChar::CHAR_CATEGORY_OTHER_NUMBER,
        ];

        foreach (mb_str_split($candidate) as $character) {
            if (in_array($character, $allowedPunctuation, true)) {
                continue;
            }

            if (!in_array(IntlChar::charType($character), $allowedCategories, true)) {
                return false;
            }
        }

        return true;
    }

    /**
     * Validates that the candidate is a plain filesystem path: only letters, digits,
     * underscore, dash, dot and forward slash. Uses \A...\z (not ^...$) because PCRE's $
     * also matches immediately before a single trailing newline, which would let a
     * value like "/usr/bin/php\n" slip through — the bug behind GHSA-jc56-j8m6-q627.
     *
     * @param string $candidate
     * @param string|null $error
     * @return bool
     * @noinspection PhpUnused
     */
    public function valid_path_strict(string $candidate, ?string &$error = null): bool
    {
        if ($candidate === '') {
            return false;
        }

        return (bool) preg_match('/\A[a-zA-Z0-9_\-\/.]+\z/', $candidate);
    }
}