<?php
namespace App\Importer;

use App\Models\CustomField;
use App\Models\Setting;
use App\Models\User;
use ForceUTF8\Encoding;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;
use League\Csv\Reader;

abstract class Importer
{
    protected $csv;
    /**
     * Id of User performing import
     * @var
     */
    protected $user_id;
    /**
     * Are we updating items in the import
     * @var bool
     */
    protected $updating;
    /**
     * Default Map of item fields->csv names
     * @var array
     */
    private $defaultFieldMap = [
        'asset_tag' => 'asset tag',
        'category' => 'category',
        'checkout_class' => 'checkout type', // Supports Location or User for assets.  Using checkout_class instead of checkout_type because type exists on asset already.
        'checkout_location' => 'checkout location',
        'company' => 'company',
        'item_name' => 'item name',
        'item_number' => "item number",
        'image' => 'image',
        'expiration_date' => 'expiration date',
        'location' => 'location',
        'notes' => 'notes',
        'license_email' => 'licensed to email',
        'license_name' => "licensed to name",
        'maintained' => 'maintained',
        'manufacturer' => 'manufacturer',
        'asset_model' => "model name",
        'model_number' => 'model number',
        'order_number' => 'order number',
        'purchase_cost' => 'purchase cost',
        'purchase_date' => 'purchase date',
        'purchase_order' => 'purchase order',
        'qty' => 'quantity',
        'reassignable' => 'reassignable',
        'requestable' => 'requestable',
        'seats' => 'seats',
        'serial_number' => 'serial number',
        'status' => 'status',
        'supplier' => 'supplier',
        'termination_date' => 'termination date',
        'warranty_months' => 'warranty',
        'full_name' => 'full name',
        'email' => 'email',
        'username' => 'username',
        'jobtitle' => 'job title',
        'employee_num' => 'employee number',
        'phone_number' => 'phone number',
        'first_name' => 'first name',
        'last_name' => 'last name',
    ];
    /**
     * Map of item fields->csv names
     * @var array
     */
    protected $fieldMap = [];
    /**
     * @var callable
     */
    protected $logCallback;
    protected $tempPassword;
    /**
     * @var callable
     */
    protected $progressCallback;
    /**
     * @var null
     */
    protected $usernameFormat;
    /**
     * @var callable
     */
    protected $errorCallback;

    /**
     * ObjectImporter constructor.
     * @param string $file
     */
    public function __construct($file)
    {
        $this->fieldMap = $this->defaultFieldMap;
        if (! ini_get("auto_detect_line_endings")) {
            ini_set("auto_detect_line_endings", '1');
        }
        // By default the importer passes a url to the file.
        // However, for testing we also support passing a string directly
        if (is_file($file)) {
            $this->csv = Reader::createFromPath($file);
        } else {
            $this->csv = Reader::createFromString($file);
        }
        $this->tempPassword = substr(str_shuffle("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 20);
    }
    // Cached Values for import lookups
    protected $customFields;

    public function import()
    {
        $headerRow = $this->csv->fetchOne();
        $this->csv->setHeaderOffset(0);
        $results = $this->normalizeInputArray($this->csv->getRecords());

        $this->populateCustomFields($headerRow);

        DB::transaction(function () use (&$results) {
            Model::unguard();
            $resultsCount = sizeof($results);
            foreach ($results as $row) {
                $this->handle($row);
                if ($this->progressCallback) {
                    call_user_func($this->progressCallback, $resultsCount);
                }

                $this->log('------------- Action Summary ----------------');
            }
        });
    }


    abstract protected function handle($row);

    /**
     * Fetch custom fields from database and translate/parse them into a format
     * appropriate for use in the importer.
     * @return void
     * @author Daniel Meltzer
     * @since  5.0
     */
    protected function populateCustomFields($headerRow)
    {
        // Stolen From https://adamwathan.me/2016/07/14/customizing-keys-when-mapping-collections/
        // This 'inverts' the fields such that we have a collection of fields indexed by name.
        $this->customFields = CustomField::All()->reduce(function ($nameLookup, $field) {
            $nameLookup[$field['name']] = $field;
            return $nameLookup; 
        });
        // Remove any custom fields that do not exist in the header row.  This prevents nulling out values that shouldn't exist.
        // In detail, we compare the lower case name of custom fields (indexed by name) to the keys in the header row.  This
        // results in an array with only custom fields that are in the file.
        if ($this->customFields) {
            $this->customFields = array_intersect_key(
                array_change_key_case($this->customFields),
                array_change_key_case(array_flip($headerRow))
            );
        }

    }
    /**
     * Check to see if the given key exists in the array, and trim excess white space before returning it
     *
     * @author Daniel Melzter
     * @since 3.0
     * @param $array array
     * @param $key string
     * @param $default string
     * @return string
     */
    public function findCsvMatch(array $array, $key, $default = null)
    {

        $val = $default;

        $key = $this->lookupCustomKey($key);

        $this->log("Custom Key: ${key}");
        if (array_key_exists($key, $array)) {
            $val = Encoding::toUTF8(trim($array[ $key ]));
        }
        // $this->log("${key}: ${val}");
        return $val;
    }

    /**
     * Looks up A custom key in the custom field map
     *
     * @author Daniel Melzter
     * @since 4.0
     * @param $key string
     * @return string|null
     */
    public function lookupCustomKey($key)
    {
        if (array_key_exists($key, $this->fieldMap)) {
            // $this->log("Found a match in our custom map: {$key} is " . $this->fieldMap[$key]);
            return $this->fieldMap[$key];
        }
        // Otherwise no custom key, return original.
        return $key;
    }

    /**
     * Used to lowercase header values to ensure we're comparing values properly.
     * 
     * @param $results
     * @return array
     */
    public function normalizeInputArray($results)
    {
        $newArray = [];
        foreach ($results as $index => $arrayToNormalize) {
            $newArray[$index] = array_change_key_case($arrayToNormalize);
        }
        return $newArray;
    }
    /**
     * Figure out the fieldname of the custom field
     *
     * @author A. Gianotto <snipe@snipe.net>
     * @since 3.0
     * @param $array array
     * @return string
     */
    public function array_smart_custom_field_fetch(array $array, $key)
    {
        $index_name = strtolower($key->name);
        return array_key_exists($index_name, $array) ? trim($array[$index_name]) : false;
    }

    protected function log($string)
    {
        if ($this->logCallback) {
            call_user_func($this->logCallback, $string);
        }
    }

    protected function logError($item, $field)
    {
        if ($this->errorCallback) {
            call_user_func($this->errorCallback, $item, $field, $item->getErrors());
        }
    }

    /**
     * Finds the user matching given data, or creates a new one if there is no match
     *
     * @author Daniel Melzter
     * @since 3.0
     * @param $row array
     * @return User Model w/ matching name
     * @internal param array $user_array User details parsed from csv
     */
    protected function createOrFetchUser($row)
    {
        $user_array = [
            'full_name' => $this->findCsvMatch($row, "full_name"),
            'email'     => $this->findCsvMatch($row, "email"),
            'username'  => $this->findCsvMatch($row, "username")
        ];
        // If the full name is empty, bail out--we need this to extract first name (at the very least)
        if(empty($user_array['full_name'])) {
            $this->log('Insufficient user data provided (Full name is required)- skipping user creation, just adding asset');
            return false;
        }

        // Is the user actually an ID?
        if($user = $this->findUserByNumber($user_array['full_name'])) {
            return $user;
        }
        $this->log('User does not appear to be an id with number: '.$user_array['full_name'].'.  Continuing through our processes');

        // Populate email if it does not exist.
        if(empty($user_array['email'])) {
            $user_array['email'] = User::generateEmailFromFullName($user_array['full_name']);
        }

        $user_formatted_array = User::generateFormattedNameFromFullName($user_array['full_name'], Setting::getSettings()->username_format);
        $user_array['first_name'] = $user_formatted_array['first_name'];
        $user_array['last_name'] = $user_formatted_array['last_name'];
        if (empty($user_array['username'])) {
            $user_array['username'] = $user_formatted_array['username'];
            if ($this->usernameFormat =='email') {
                $user_array['username'] = $user_array['email'];
            }
        }

        // Check for a matching user after trying to guess username.
        if($user = User::where('username', $user_array['username'])->first()) {
            $this->log('User '.$user_array['username'].' already exists');
            return $user;
        }

        // If at this point we have not found a username or first name, bail out in shame.
        if(empty($user_array['username']) || empty($user_array['first_name'])) {
            return false;
        }

        // No Luck, let's create one.
        $user = new User;
        $user->first_name = $user_array['first_name'];
        $user->last_name = $user_array['last_name'];
        $user->username = $user_array['username'];
        $user->email = $user_array['email'];
        $user->activated = 1;
        $user->password = $this->tempPassword;

        if ($user->save()) {
            $this->log('User '.$user_array['username'].' created');
            return $user;
        }
        $this->logError($user, 'User "' . $user_array['username'] . '" was not able to be created.');
        return false;
    }

    /**
     * Matches a user by user_id if user_name provided is a number
     * @param  string $user_name users full name from csv
     * @return User           User Matching ID
     */
    protected function findUserByNumber($user_name)
    {
        // A number was given instead of a name
        if (is_numeric($user_name)) {
            $this->log('User '.$user_name.' is a number - lets see if it matches a user id');
            return User::find($user_name);
        }
    }

    /**
     * Sets the Id of User performing import.
     *
     * @param mixed $user_id the user id
     *
     * @return self
     */
    public function setUserId($user_id)
    {
        $this->user_id = $user_id;

        return $this;
    }

    /**
     * Sets the Are we updating items in the import.
     *
     * @param bool $updating the updating
     *
     * @return self
     */
    public function setUpdating($updating)
    {
        $this->updating = $updating;

        return $this;
    }

    /**
     * Defines mappings of csv fields
     *
     * @param bool $updating the updating
     *
     * @return self
     */
    public function setFieldMappings($fields)
    {
        // Some initial sanitization.
        $fields = array_map('strtolower', $fields);
        $this->fieldMap = array_merge($this->defaultFieldMap, $fields);

        // $this->log($this->fieldMap);
        return $this;
    }

    /**
     * Sets the callbacks for the import
     *
     * @param callable $logCallback Function to call when we have data to log
     * @param callable $progressCallback Function to call to display progress
     * @param callable $errorCallback Function to call when we have errors
     *
     * @return self
     */
    public function setCallbacks(callable $logCallback, callable $progressCallback, callable $errorCallback)
    {
        $this->logCallback = $logCallback;
        $this->progressCallback = $progressCallback;
        $this->errorCallback = $errorCallback;

        return $this;
    }
    /**
     * Sets the value of usernameFormat.
     *
     * @param string $usernameFormat the username format
     *
     * @return self
     */
    public function setUsernameFormat($usernameFormat)
    {
        $this->usernameFormat = $usernameFormat;

        return $this;
    }
}