<?php
/**
 * Validator.php
 *
 * Class to run validations.  Also allows sharing data between ValidationGroups.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * @link       https://www.librenms.org
 *
 * @copyright  2017 Tony Murray
 * @author     Tony Murray <murraytony@gmail.com>
 */

namespace LibreNMS;

use Illuminate\Support\Str;
use LibreNMS\Interfaces\ValidationGroup;
use LibreNMS\Util\Laravel;
use ReflectionClass;
use ReflectionException;

class Validator
{
    /** @var array */
    private $validation_groups = [];
    /** @var array */
    private $results = [];
    /** @var string|null */
    private $username;

    /**
     * Validator constructor.
     */
    public function __construct()
    {
        // load all validations
        $pattern = $this->getBaseDir() . '/LibreNMS/Validations/*.php';

        foreach (glob($pattern) as $file) {
            $class_name = basename($file, '.php');
            $class = '\LibreNMS\Validations\\' . $class_name;

            try {
                $rc = new ReflectionClass($class);

                if (! $rc->isAbstract()) {
                    $validation_name = strtolower($class_name);
                    $this->validation_groups[$validation_name] = new $class();
                    $this->results[$validation_name] = [];
                }
            } catch (ReflectionException $e) {
            }
        }
    }

    /**
     * Run validations. An empty array will run all default validations.
     *
     * @param  array  $validation_groups  selected validation groups to run
     * @param  bool  $print_group_status  print out group status
     */
    public function validate(array $validation_groups = [], bool $print_group_status = false): void
    {
        foreach ($this->validation_groups as $group_name => $group) {
            // only run each group once
            if ($group->isCompleted()) {
                continue;
            }

            if ((empty($validation_groups) && $group->isDefault()) || in_array($group_name, $validation_groups)) {
                if ($print_group_status && Laravel::isCli()) {
                    echo "Checking $group_name:";
                }

                /** @var ValidationGroup $group */
                $group->validate($this);

                if (Laravel::isCli()) {
                    if ($print_group_status) {
                        $status = ValidationResult::getStatusText($this->getGroupStatus($group_name));
                        c_echo(" $status\n");
                    }

                    $this->printResults($group_name);
                }

                // validation is complete for this group
                $group->markCompleted();
            }
        }
    }

    /**
     * Get the overall status of a validation group.
     *
     * @param  string  $validation_group
     * @return int
     */
    public function getGroupStatus(string $validation_group): int
    {
        $results = $this->getResults($validation_group);

        return array_reduce($results, function ($compound, ValidationResult $result) {
            return min($compound, $result->getStatus());
        }, ValidationResult::SUCCESS);
    }

    /**
     * Get overall status
     */
    public function getStatus(): int
    {
        return array_reduce($this->results, function ($compound, array $results) {
            foreach ($results as $result) {
                $compound = min($compound, $result->getStatus());
            }

            return $compound;
        }, ValidationResult::SUCCESS);
    }

    /**
     * Get the ValidationResults for a specific validation group.
     *
     * @param  string|null  $validation_group
     * @return ValidationResult[]
     */
    public function getResults(string $validation_group = null): array
    {
        if (isset($validation_group)) {
            return $this->results[$validation_group] ?? [];
        }

        return array_reduce($this->results, 'array_merge', []);
    }

    /**
     * Get all of the ValidationResults that have been submitted.
     * ValidationResults will be grouped by the validation group.
     *
     * @return ValidationResult[][]
     */
    public function getAllResults(): array
    {
        return $this->results;
    }

    /**
     * Print all ValidationResults or a group of them.
     *
     * @param  string|null  $validation_group
     */
    public function printResults(string $validation_group = null): void
    {
        $results = $this->getResults($validation_group);

        foreach ($results as $result) {
            $result->consolePrint();
            if ($result->hasFixer()) {
                $input = readline('Attempt to fix this issue (y or n)?:');
                if ($input === 'y') {
                    $result = app()->make($result->getFixer())->fix();
                    if ($result) {
                        echo "Attempted to apply fix.\n";
                    } else {
                        echo "Failed to apply fix.\n";
                    }
                }
            }
        }
    }

    /**
     * Submit a validation result.
     * This allows customizing ValidationResults before submitting.
     *
     * @param  ValidationResult  $result
     * @param  string|null  $group  manually specify the group, otherwise this will be inferred from the callers class name
     */
    public function result(ValidationResult $result, string $group = null): void
    {
        // get the name of the validation that submitted this result
        if (empty($group)) {
            $group = 'unknown';
            $bt = debug_backtrace();
            foreach ($bt as $entry) {
                if (Str::startsWith($entry['class'], 'LibreNMS\Validations')) {
                    $group = str_replace('LibreNMS\Validations\\', '', $entry['class']);
                    break;
                }
            }
        }

        $this->results[strtolower($group)][] = $result;
    }

    /**
     * Submit an ok validation result.
     *
     * @param  string  $message
     * @param  string|null  $fix
     * @param  string|null  $group  manually specify the group, otherwise this will be inferred from the callers class name
     */
    public function ok(string $message, string $fix = null, string $group = null): void
    {
        $this->result(new ValidationResult($message, ValidationResult::SUCCESS, $fix), $group);
    }

    /**
     * Submit a warning validation result.
     *
     * @param  string  $message
     * @param  string|null  $fix
     * @param  string|null  $group  manually specify the group, otherwise this will be inferred from the callers class name
     */
    public function warn(string $message, string $fix = null, string $group = null): void
    {
        $this->result(new ValidationResult($message, ValidationResult::WARNING, $fix), $group);
    }

    /**
     * Submit a failed validation result.
     *
     * @param  string  $message
     * @param  string|null  $fix
     * @param  string|null  $group  manually specify the group, otherwise this will be inferred from the callers class name
     */
    public function fail(string $message, string $fix = null, string $group = null): void
    {
        $this->result(new ValidationResult($message, ValidationResult::FAILURE, $fix), $group);
    }

    /**
     * Submit an informational validation result.
     *
     * @param  string  $message
     * @param  string|null  $group  manually specify the group, otherwise this will be inferred from the callers class name
     */
    public function info(string $message, string $group = null): void
    {
        $this->result(new ValidationResult($message, ValidationResult::INFO), $group);
    }

    /**
     * Execute a command, but don't run it as root.  If we are root, run as the LibreNMS user.
     * Arguments match exec()
     *
     * @param  string  $command  the command to run
     * @param  array|null  $output  will hold the output of the command
     * @param  int|null  $code  will hold the return code from the command
     */
    public function execAsUser(string $command, array &$output = null, int &$code = null): void
    {
        if (self::getUsername() === 'root') {
            $command = 'su ' . \config('librenms.user') . ' -s /bin/sh -c "' . $command . '"';
        }
        exec($command, $output, $code);
    }

    /**
     * Get the username of the user running this and cache it for future requests.
     *
     * @return string
     */
    public function getUsername(): string
    {
        if (! isset($this->username)) {
            if (function_exists('posix_getpwuid')) {
                $userinfo = posix_getpwuid(posix_geteuid());
                $this->username = $userinfo['name'];
            } else {
                $this->username = getenv('USERNAME') ?: getenv('USER');
            }
        }

        return $this->username;
    }

    /**
     * Get the base url for this LibreNMS install, this will only work from web pages.
     * (unless base_url is set)
     *
     * @return string the base url without a trailing /
     */
    public function getBaseURL(): string
    {
        $url = function_exists('get_url') ? get_url() : Config::get('base_url');

        return rtrim(str_replace('validate', '', $url), '/');  // get base_url from current url
    }

    public function getBaseDir(): string
    {
        return realpath(__DIR__ . '/..');
    }

    public function getStatusText(int $status): string
    {
        switch ($status) {
            case ValidationResult::SUCCESS:
                return 'Ok';
            case ValidationResult::FAILURE:
                return 'Failure';
            case ValidationResult::WARNING:
                return 'Warning';
            case ValidationResult::INFO:
                return 'Info';
            default:
                return '';
        }
    }

    public function toArray(): array
    {
        return array_map(function (array $results, string $group) {
            $groupStatus = $this->getGroupStatus($group);

            return [
                'group' => $group,
                'name' => ucfirst($group),
                'status' => $groupStatus,
                'statusText' => $this->getStatusText($groupStatus),
                'results' => array_map(function (ValidationResult $result) {
                    return $result->toArray();
                }, $results),
            ];
        }, $this->getAllResults(), array_keys($this->getAllResults()));
    }
}
