<?php

namespace SilverStripe\EnvironmentCheck\Checks;

use SilverStripe\EnvironmentCheck\EnvironmentCheck;
use SilverStripe\ORM\Versioning\Versioned;

/**
 * Checks for the accessibility and file type validation of one or more files or folders.
 *
 * Examples:
 * // Checks /assets/calculator_files has .json files and all files are valid json files.
 * EnvironmentCheckSuite::register('check', 'FileAccessibilityAndValidationCheck("' . BASE_PATH . '/assets/calculator_files/*.json",
 *  "jsonValidate", '.FileAccessibilityAndValidationCheck::CHECK_ALL.')', 'Check a json file exist and are all valid json files'
 * );
 *
 * // Checks /assets/calculator_files/calculator.json exists and is valid json file.
 * EnvironmentCheckSuite::register('check', 'FileAccessibilityAndValidationCheck("' . BASE_PATH . '/assets/calculator_files/calculator.json",
 *  "jsonValidate", '.FileAccessibilityAndValidationCheck::CHECK_SINGLE.')', 'Check a calculator.json exists and is valid json file'
 * );
 *
 * // Check only existence
 * EnvironmentCheckSuite::register('check', 'FileAccessibilityAndValidationCheck("' . BASE_PATH . '/assets/calculator_files/calculator.json")',
 * 'Check a calculator.json exists only'
 * );
 *
 * @package environmentcheck
 */
class FileAccessibilityAndValidationCheck implements EnvironmentCheck
{
    /**
     * @var int
     */
    const CHECK_SINGLE = 1;

    /**
     * @var int
     */
    const CHECK_ALL = 2;

    /**
     * Absolute path to a file or folder, compatible with glob().
     *
     * @var string
     */
    protected $path;

    /**
     * Constant, check for a single file to match age criteria, or all of them.
     *
     * @var int
     */
    protected $fileTypeValidateFunc;

    /**
     * Constant, check for a single file to match age criteria, or all of them.
     *
     * @var int
     */
    protected $checkType;

    /**
     * @param string $path
     * @param string $fileTypeValidateFunc
     * @param null|int $checkType
     */
    public function __construct($path, $fileTypeValidateFunc = 'noVidation', $checkType = null)
    {
        $this->path = $path;
        $this->fileTypeValidateFunc = ($fileTypeValidateFunc)? $fileTypeValidateFunc : 'noVidation';
        $this->checkType = ($checkType) ? $checkType : self::CHECK_SINGLE;
    }

    /**
     * {@inheritDoc}
     *
     * @return array
     */
    public function check()
    {
        $origStage = Versioned::get_reading_mode();
        Versioned::set_reading_mode(Versioned::LIVE);

        $files = $this->getFiles();
        if ($files) {
            $fileTypeValidateFunc = $this->fileTypeValidateFunc;
            if (method_exists($this, $fileTypeValidateFunc)) {
                $invalidFiles = [];
                $validFiles = [];

                foreach ($files as $file) {
                    if ($this->$fileTypeValidateFunc($file)) {
                        $validFiles[] = $file;
                    } else {
                        $invalidFiles[] = $file;
                    }
                }

                // If at least one file was valid, count as passed
                if ($this->checkType == self::CHECK_SINGLE && count($invalidFiles) < count($files)) {
                    $validFileList = PHP_EOL;
                    foreach ($validFiles as $vf) {
                        $validFileList .= $vf . PHP_EOL;
                    }
                    if ($fileTypeValidateFunc == 'noVidation') {
                        $checkReturn = [
                            EnvironmentCheck::OK,
                            sprintf('At least these file(s) accessible: %s', $validFileList)
                        ];
                    } else {
                        $checkReturn = [
                            EnvironmentCheck::OK,
                            sprintf(
                                'At least these file(s) passed file type validate function "%s": %s',
                                $fileTypeValidateFunc,
                                $validFileList
                            )
                        ];
                    }
                } else {
                    if (count($invalidFiles) == 0) {
                        $checkReturn = [EnvironmentCheck::OK, 'All files valideted'];
                    } else {
                        $invalidFileList = PHP_EOL;
                        foreach ($invalidFiles as $vf) {
                            $invalidFileList .= $vf . PHP_EOL;
                        }

                        if ($fileTypeValidateFunc == 'noVidation') {
                            $checkReturn = [
                                EnvironmentCheck::ERROR,
                                sprintf('File(s) not accessible: %s', $invalidFileList)
                            ];
                        } else {
                            $checkReturn = [
                                EnvironmentCheck::ERROR,
                                sprintf(
                                    'File(s) not passing the file type validate function "%s": %s',
                                    $fileTypeValidateFunc,
                                    $invalidFileList
                                )
                            ];
                        }
                    }
                }
            } else {
                $checkReturn =  array(
                    EnvironmentCheck::ERROR,
                    sprintf("Invalid file type validation method name passed: %s ", $fileTypeValidateFunc)
                );
            }
        } else {
            $checkReturn = array(
                EnvironmentCheck::ERROR,
                sprintf("No files accessible at path %s", $this->path)
            );
        }

        Versioned::set_reading_mode($origStage);

        return $checkReturn;
    }

    /**
     * @param string $file
     *
     * @return bool
     */
    private function jsonValidate($file)
    {
        $json = json_decode(file_get_contents($file));
        if (!$json) {
            return false;
        }
        return true;
    }

    /**
     * @param string $file
     *
     * @return bool
     */
    protected function noVidation($file)
    {
        return true;
    }

    /**
     * Gets a list of absolute file paths.
     *
     * @return array
     */
    protected function getFiles()
    {
        return glob($this->path);
    }
}