<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed.');

/* ----------------------------------------------------------------------------
 * Easy!Appointments - Open Source Web Scheduler
 *
 * @package     EasyAppointments
 * @author      A.Tselegidis <alextselegidis@gmail.com>
 * @copyright   Copyright (c) 2013 - 2017, Alex Tselegidis
 * @license     http://opensource.org/licenses/GPL-3.0 - GPLv3
 * @link        http://easyappointments.org
 * @since       v1.0.0
 * ---------------------------------------------------------------------------- */

/**
 * Providers_Model Class
 *
 * Contains the database operations for the service provider users of
 * Easy!Appointments.
 *
 * Data Structure:
 *      'fist_name'
 *      'last_name' (required)
 *      'email' (required)
 *      'mobile_number'
 *      'phone_number' (required)
 *      'address'
 *      'city'
 *      'state'
 *      'zip_code'
 *      'notes'
 *      'id_roles'
 *      'services' >> array that contains the ids that the provider can provide
 *      'settings'
 *          'username'
 *          'password'
 *          'notifications'
 *          'working_plan'
 *          'google_sync'
 *          'google_token'
 *          'google_calendar'
 *          'sync_past_days'
 *          'sync_future_days',
 *          'calendar_view'
 *
 * @package Models
 */
class Providers_Model extends CI_Model {
    /**
     * Add (insert - update) a service provider record.
     *
     * If the record already exists (id value provided) then it is going to be updated,
     * otherwise inserted into the database.
     *
     * @param array $provider Contains the service provider data.
     * @return int Returns the record id.
     * @throws Exception When the record data validation fails.
     */
    public function add($provider) {
        $this->validate($provider);

        if ($this->exists($provider) && !isset($provider['id'])) {
            $provider['id'] = $this->find_record_id($provider);
        }

        if (!isset($provider['id'])) {
            $provider['id'] = $this->_insert($provider);
        } else {
            $provider['id'] = $this->_update($provider);
        }

        return (int)$provider['id'];
    }

    /**
     * Check whether a particular provider record already exists in the database.
     *
     * @param array $provider Contains the provider data. The 'email' value is required
     * in order to check for a provider.
     * @return bool Returns whether the provider record exists or not.
     * @throws Exception When the 'email' value is not provided.
     */
    public function exists($provider) {
        if (!isset($provider['email'])) {
            throw new Exception('Provider email is not provided:' . print_r($provider, TRUE));
        }

        // This method shouldn't depend on another method of this class.
        $num_rows = $this->db
                ->select('*')
                ->from('ea_users')
                ->join('ea_roles', 'ea_roles.id = ea_users.id_roles', 'inner')
                ->where('ea_users.email', $provider['email'])
                ->where('ea_roles.slug', DB_SLUG_PROVIDER)
                ->get()->num_rows();

        return ($num_rows > 0) ? TRUE : FALSE;
    }

    /**
     * Insert a new provider record into the database.
     *
     * @param array $provider Contains the provider data (must be already validated).
     * @return int Returns the new record id.
     * @throws Exception When the insert operation fails.
     */
    protected function _insert($provider) {
        $this->load->helper('general');

        // Get provider role id.
        $provider['id_roles'] = $this->get_providers_role_id();

        // Store provider settings and services (must not be present on the $provider array).
        $services = $provider['services'];
        unset($provider['services']);
        $settings = $provider['settings'];
        unset($provider['settings']);

        // Insert provider record and save settings.
        if (!$this->db->insert('ea_users', $provider)) {
            throw new Exception('Could not insert provider into the database');
        }

        $settings['salt'] = generate_salt();
        $settings['password'] = hash_password($settings['salt'], $settings['password']);

        $provider['id'] = $this->db->insert_id();
        $this->save_settings($settings, $provider['id']);
        $this->save_services($services, $provider['id']);

        // Return the new record id.
        return (int)$provider['id'];
    }

    /**
     * Update an existing provider record in the database.
     *
     * @param array $provider Contains the provider data.
     * @return int Returns the record id.
     * @throws Exception When the update operation fails.
     */
    protected function _update($provider) {
        $this->load->helper('general');

        // Store service and settings (must not be present on the $provider array).
        $services = $provider['services'];
        unset($provider['services']);
        $settings = $provider['settings'];
        unset($provider['settings']);

        if (isset($settings['password'])) {
            $salt = $this->db->get_where('ea_user_settings', array('id_users' => $provider['id']))->row()->salt;
            $settings['password'] = hash_password($salt, $settings['password']);
        }

        // Update provider record.
        $this->db->where('id', $provider['id']);
        if (!$this->db->update('ea_users', $provider)) {
            throw new Exception('Could not update provider record.');
        }

        $this->save_services($services, $provider['id']);
        $this->save_settings($settings, $provider['id']);

        // Return record id.
        return (int)$provider['id'];
    }

    /**
     * Find the database record id of a provider.
     *
     * @param array $provider Contains the provider data. The 'email' value is required
     * in order to find the record id.
     * @return int Returns the record id.
     * @throws Exception When the provider's email value is not provided.
     */
    public function find_record_id($provider) {
        if (!isset($provider['email'])) {
            throw new Exception('Provider email was not provided:' . print_r($provider, TRUE));
        }

        $result = $this->db
                ->select('ea_users.id')
                ->from('ea_users')
                ->join('ea_roles', 'ea_roles.id = ea_users.id_roles', 'inner')
                ->where('ea_users.email', $provider['email'])
                ->where('ea_roles.slug', DB_SLUG_PROVIDER)
                ->get();

        if ($result->num_rows() == 0) {
            throw new Exception('Could not find provider record id.');
        }

        return (int)$result->row()->id;
    }

    /**
     * Validate provider data before the insert or  update operation is executed.
     *
     * @param array $provider Contains the provider data.
     * @return bool Returns the validation result.
     */
    public function validate($provider) {
        $this->load->helper('data_validation');

        // If a provider id is present, check whether the record exist in the database.
        if (isset($provider['id'])) {
            $num_rows = $this->db->get_where('ea_users',
                    array('id' => $provider['id']))->num_rows();
            if ($num_rows == 0) {
                throw new Exception('Provided record id does not exist in the database.');
            }
        }

        // Validate required fields.
        if (!isset($provider['last_name'])
                || !isset($provider['email'])
                || !isset($provider['phone_number'])) {
            throw new Exception('Not all required fields are provided: ' . print_r($provider, TRUE));
        }

        // Validate provider email address.
        if (!filter_var($provider['email'], FILTER_VALIDATE_EMAIL)) {
            throw new Exception('Invalid email address provided: ' . $provider['email']);
        }

        // Validate provider services.
        if (!isset($provider['services']) || !is_array($provider['services'])) {
            throw new Exception('Invalid provider services given: ' . print_r($provider, TRUE));
        } else { // Check if services are valid numeric values.
            foreach($provider['services'] as $service_id) {
                if (!is_numeric($service_id)) {
                    throw new Exception('A provider service with invalid id was found: '
                            . print_r($provider, TRUE));
                }
            }
        }

        // Validate provider settings.
        if (!isset($provider['settings']) || count($provider['settings']) == 0
                || !is_array($provider['settings'])) {
            throw new Exception('Invalid provider settings given: ' . print_r($provider, TRUE));
        }

        // Check if username exists.
        if (isset($provider['settings']['username'])) {
            $user_id = (isset($provider['id'])) ? $provider['id'] : '';
            if (!$this->validate_username($provider['settings']['username'], $user_id)) {
                throw new Exception ('Username already exists. Please select a different '
                        . 'username for this record.');
            }
        }

        // Validate provider password
        if (isset($provider['settings']['password'])) {
            if (strlen($provider['settings']['password']) < MIN_PASSWORD_LENGTH) {
                throw new Exception('The user password must be at least '
                        . MIN_PASSWORD_LENGTH . ' characters long.');
            }
        }

        // Validate calendar view mode. 
        if (isset($provider['settings']['calendar_view']) && ($provider['settings']['calendar_view'] !== CALENDAR_VIEW_DEFAULT 
                && $provider['settings']['calendar_view'] !== CALENDAR_VIEW_TABLE)) {
             throw new Exception('The calendar view setting must be either "' . CALENDAR_VIEW_DEFAULT 
                    . '" or "' . CALENDAR_VIEW_TABLE . '", given: ' .  $provider['settings']['calendar_view']);
        }

        // When inserting a record the email address must be unique.
        $provider_id = (isset($provider['id'])) ? $provider['id'] : '';

        $num_rows = $this->db
                ->select('*')
                ->from('ea_users')
                ->join('ea_roles', 'ea_roles.id = ea_users.id_roles', 'inner')
                ->where('ea_roles.slug', DB_SLUG_PROVIDER)
                ->where('ea_users.email', $provider['email'])
                ->where('ea_users.id <>', $provider_id)
                ->get()
                ->num_rows();

        if ($num_rows > 0) {
            throw new Exception('Given email address belongs to another provider record. '
                    . 'Please use a different email.');
        }

        return TRUE;
    }

    /**
     * Delete an existing provider record from the database.
     *
     * @param numeric $customer_id The record id to be deleted.
     * @return bool Returns the delete operation result.
     * @throws Exception When the provider id value is not numeric.
     */
    public function delete($provider_id) {
        if (!is_numeric($provider_id)) {
            throw new Exception('Invalid argument type $provider_id: ' . $provider_id);
        }

        $num_rows = $this->db->get_where('ea_users', array('id' => $provider_id))->num_rows();
        if ($num_rows == 0) {
            return FALSE; // Record does not exist in database.
        }

        return $this->db->delete('ea_users', array('id' => $provider_id));
    }

    /**
     * Get a specific provider record from the database.
     *
     * @param int $provider_id The id of the record to be returned.
     * @return array Returns an associative array with the selected record's data. Each key
     * has the same name as the database field names.
     * @throws Exception When the selected record does not exist in database.
     */
    public function get_row($provider_id) {
        if (!is_numeric($provider_id)) {
            throw new Exception('$provider_id argument is not a valid numeric value: ' . $provider_id);
        }

        // Check if selected record exists on database.
        if ($this->db->get_where('ea_users', array('id' => $provider_id))->num_rows() == 0) {
            throw new Exception('Selected record does not exist in the database.');
        }

        // Get provider data.
        $provider = $this->db->get_where('ea_users', array('id' => $provider_id))->row_array();


        // Include provider services.
        $services = $this->db->get_where('ea_services_providers',
                array('id_users' => $provider_id))->result_array();
        $provider['services'] = array();
        foreach($services as $service) {
            $provider['services'][] = $service['id_services'];
        }

        // Include provider settings.
        $provider['settings'] = $this->db->get_where('ea_user_settings',
                array('id_users' => $provider_id))->row_array();
        unset($provider['settings']['id_users']);

        // Return provider data array.
        return $provider;
    }

    /**
     * Get a specific field value from the database.
     *
     * @param string $field_name The field name of the value to be returned.
     * @param numeric $provider_id Record id of the value to be returned.
     * @return string Returns the selected record value from the database.
     * 
     * @throws Exception When the $field_name argument is not a valid string.
     * @throws Exception When the $provider_id is not a valid numeric.
     * @throws Exception When the provider record does not exist in the database.
     * @throws Exception When the selected field value is not present on database.
     */
    public function get_value($field_name, $provider_id) {
        if (!is_numeric($provider_id)) {
            throw new Exception('Invalid argument provided as $provider_id: ' . $provider_id);
        }

        if (!is_string($field_name)) {
            throw new Exception('$field_name argument is not a string: ' . $field_name);
        }

        // Check whether the provider record exists in database.
        $result = $this->db->get_where('ea_users', array('id' => $provider_id));
        if ($result->num_rows() == 0) {
            throw new Exception('The record with the $provider_id argument does not exist in '
                    . 'the database: ' . $provider_id);
        }

        $provider = $result->row_array();
        if (!isset($provider[$field_name])) {
            throw new Exception('The given $field_name argument does not exist in the '
                    . 'database: ' . $field_name);
        }

        return $provider[$field_name];
    }

    /**
     * Get all, or specific records from provider's table.
     *
     * @example $this->Model->get_batch('id = ' . $recordId);
     *
     * @param mixed $where_clause (OPTIONAL) The WHERE clause of the query to be executed.
     *
     * NOTICE: DO NOT INCLUDE 'WHERE' KEYWORD.
     *
     * @return array Returns the rows from the database.
     */
    public function get_batch($where_clause = '') {
        // CI db class may confuse two where clauses made in the same time, so
        // get the role id first and then apply the get_batch() where clause.
        $role_id = $this->get_providers_role_id();

        if ($where_clause != '') {
            $this->db->where($where_clause);
        }

        $batch = $this->db->get_where('ea_users',
                array('id_roles' => $role_id))->result_array();

        // Include each provider services and settings.
        foreach($batch as &$provider) {
            // Services
            $services = $this->db->get_where('ea_services_providers',
                    array('id_users' => $provider['id']))->result_array();
            $provider['services'] = array();
            foreach($services as $service) {
                $provider['services'][] = $service['id_services'];
            }

            // Settings
            $provider['settings'] = $this->db->get_where('ea_user_settings',
                    array('id_users' => $provider['id']))->row_array();
            unset($provider['settings']['id_users']);
        }

        // Return provider records in an array.
        return $batch;
    }

    /**
     * Get the available system providers.
     *
     * This method returns the available providers and the services that can
     * provide.
     *
     * @return array Returns an array with the providers data.
     */
    public function get_available_providers() {
        // Get provider records from database.
        $this->db
                ->select('ea_users.*')
                ->from('ea_users')
                ->join('ea_roles', 'ea_roles.id = ea_users.id_roles', 'inner')
                ->where('ea_roles.slug', DB_SLUG_PROVIDER);

        $providers = $this->db->get()->result_array();

        // Include each provider services and settings.
        foreach($providers as &$provider) {
            // Services
            $services = $this->db->get_where('ea_services_providers',
                    array('id_users' => $provider['id']))->result_array();

            $provider['services'] = array();
            foreach($services as $service) {
                $provider['services'][] = $service['id_services'];
            }

            // Settings
            $provider['settings'] = $this->db->get_where('ea_user_settings',
                    array('id_users' => $provider['id']))->row_array();
            unset($provider['settings']['username']);
            unset($provider['settings']['password']);
            unset($provider['settings']['salt']);
        }

        // Return provider records.
        return $providers;
    }

    /**
     * Get the providers role id from the database.
     *
     * @return int Returns the role id for the provider records.
     */
    public function get_providers_role_id() {
        return $this->db->get_where('ea_roles', array('slug' => DB_SLUG_PROVIDER))->row()->id;
    }

    /**
     * Get a providers setting from the database.
     *
     * @param string $setting_name The setting name that is going to be
     * returned.
     * @param int $provider_id The selected provider id.
     * @return string Returns the value of the selected user setting.
     */
    public function get_setting($setting_name, $provider_id) {
        $provider_settings = $this->db->get_where('ea_user_settings',
                array('id_users' => $provider_id))->row_array();
        return $provider_settings[$setting_name];
    }

    /**
     * Set a provider's setting value in the database.
     *
     * The provider and settings record must already exist.
     *
     * @param string $setting_name The setting's name.
     * @param string $value The setting's value.
     * @param numeric $provider_id The selected provider id.
     */
    public function set_setting($setting_name, $value, $provider_id) {
        $this->db->where(array('id_users' => $provider_id));
        return $this->db->update('ea_user_settings', array($setting_name => $value));
    }

    /**
     * Save the provider settings (used from insert or update operation).
     *
     * @param array $settings Contains the setting values.
     * @param numeric $provider_id Record id of the provider.
     */
    protected function save_settings($settings, $provider_id) {
        if (!is_numeric($provider_id)) {
            throw new Exception('Invalid $provider_id argument given:' . $provider_id);
        }

        if (count($settings) == 0 || !is_array($settings)) {
            throw new Exception('Invalid $settings argument given:' . print_r($settings, TRUE));
        }

        // Check if the setting record exists in db.
        if ($this->db->get_where('ea_user_settings', array('id_users' => $provider_id))
                ->num_rows() == 0) {
            $this->db->insert('ea_user_settings', array('id_users' => $provider_id));
        }

        foreach($settings as $name=>$value) {
            $this->set_setting($name, $value, $provider_id);
        }
    }

    /**
     * Save the provider services in the database (use on both insert and update operation).
     *
     * @param array $services Contains the service ids that the selected provider can provide.
     * @param numeric $provider_id The selected provider record id.
     * @throws Exception When the $services argument type is not array.
     * @throws Exception When the $provider_id argument type is not numeric.
     */
    protected function save_services($services, $provider_id) {
        // Validate method arguments.
        if (!is_array($services)) {
            throw new Exception('Invalid argument type $services: ' . $services);
        }

        if (!is_numeric($provider_id)) {
            throw new Exception('Invalid argument type $provider_id: ' . $provider_id);
        }

        // Save provider services in the database (delete old records and add new).
        $this->db->delete('ea_services_providers', array('id_users' => $provider_id));
        foreach($services as $service_id) {
            $service_provider = array(
                'id_users' => $provider_id,
                'id_services' => $service_id
            );
            $this->db->insert('ea_services_providers', $service_provider);
        }
    }

    /**
     * Validate Records Username
     *
     * @param string $username The provider records username.
     * @param numeric $user_id The user record id.
     * @return bool Returns the validation result.
     */
    public function validate_username($username, $user_id) {
        $num_rows = $this->db->get_where('ea_user_settings',
                array('username' => $username, 'id_users <> ' => $user_id))->num_rows();
        return ($num_rows > 0) ? FALSE : TRUE;
    }
}