import { Injectable } from '@angular/core';
import Joi from '@hapi/joi';
import {AbstractControl} from '@angular/forms';

@Injectable({
  providedIn: 'root'
})
export class ValidationService {

  private vUsername = Joi.string()
    .lowercase()
    .pattern(new RegExp('^[a-z0-9-_.]+$'))
    .min(1)
    .max(128);

  private vPassword = Joi.string()
    .pattern(/^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[!"#%&'()*+,-.\/:;<=>?@[\]^_`{|}~])(?=\S+$)[a-zA-Z0-9!"#%&'()*+,\-.\/:;<=>?@[\]^_`{|}~]{8,}$/)
    .max(128);

  constructor() { }

  generate(method, args) {  // generate a Validator function
    return (control: AbstractControl): {[key: string]: any} | null => {
      let ok;
      let error;
      if (args) {
        ({ok, error} = this[method](control.value, ...args));
      }
      else {
        ({ok, error} = this[method](control.value));
      }
      return ok ? null : { failure: error };
    };
  }

  username(data) {
    const {ignore, error} = this.vUsername.validate(data);
    if (error) {
      return {ok: false, error: 'username must only contain a-z0-9-_.'};
    }
    return {ok: true, error: ''};
  }

  password(data) {
    const {ignore, error} = this.vPassword.validate(data);
    if (error) {
      if (Joi.string().min(8).validate(data).error) {
        return {ok: false, error: 'password must have at least 8 characters'};
      }
      else if (Joi.string().pattern(/[a-z]+/).validate(data).error) {
        return {ok: false, error: 'password must have at least one lowercase character'};
      }
      else if (Joi.string().pattern(/[A-Z]+/).validate(data).error) {
        return {ok: false, error: 'password must have at least one uppercase character'};
      }
      else if (Joi.string().pattern(/[0-9]+/).validate(data).error) {
        return {ok: false, error: 'password must have at least one number'};
      }
      else if (Joi.string().pattern(/[!"#%&'()*+,-.\/:;<=>?@[\]^_`{|}~]+/).validate(data).error) {
        return {ok: false, error: 'password must have at least one of the following characters !"#%&\'()*+,-.\\/:;<=>?@[]^_`{|}~'};
      }
      else {
        return {ok: false, error: 'password must only contain a-zA-Z0-9!"#%&\'()*+,-./:;<=>?@[]^_`{|}~'};
      }
    }
    return {ok: true, error: ''};
  }

  string(data) {
    const {ignore, error} = Joi.string().max(128).allow('').validate(data);
    if (error) {
      return {ok: false, error: 'must contain max 128 characters'};
    }
    return {ok: true, error: ''};
  }

  stringOf(data, list) {
    const {ignore, error} = Joi.string().allow('').valid(...list.map(e => e.toString())).validate(data);
    if (error) {
      return {ok: false, error: 'must be one of ' + list.join(', ')};
    }
    return {ok: true, error: ''};
  }

  stringLength(data, length) {
    const {ignore, error} = Joi.string().max(length).allow('').validate(data);
    if (error) {
      return {ok: false, error: 'must contain max ' + length + ' characters'};
    }
    return {ok: true, error: ''};
  }

  minMax(data, min, max) {
    const {ignore, error} = Joi.number().allow('').min(min).max(max).validate(data);
    if (error) {
      return {ok: false, error: `must be between ${min} and ${max}`};
    }
    return {ok: true, error: ''};
  }

  min(data, min) {
    const {ignore, error} = Joi.number().allow('').min(min).validate(data);
    if (error) {
      return {ok: false, error: `must not be below ${min}`};
    }
    return {ok: true, error: ''};
  }

  max(data, max) {
    const {ignore, error} = Joi.number().allow('').min(max).validate(data);
    if (error) {
      return {ok: false, error: `must not be above ${max}`};
    }
    return {ok: true, error: ''};
  }

  unique(data, list) {
    const {ignore, error} = Joi.string().allow('').invalid(...list.map(e => e.toString())).validate(data);
    if (error) {
      return {ok: false, error: `values must be unique`};
    }
    return {ok: true, error: ''};
  }
}