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()
	.min(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) {
			return {ok: false, error: 'password must have at least 8 characters'};
		}
		return {ok: true, error: ''};
	}

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

	stringOf(data, list) {  // String must be in 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: ''};
	}

	stringNin(data, list) {  // String must not be in list
		const {ignore, error} = Joi.string().invalid(...list).validate(data);
		if (error) {
			return {ok: false, error: 'value not allowed'};
		}
		return {ok: true, error: ''};
	}

	stringLength(data, length) {  // String with maximum 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) {  // Number between min and 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) {  // Number above 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) {  // Number below max
		const {ignore, error} = Joi.number().allow('').max(max).validate(data);
		if (error) {
			return {ok: false, error: `must not be above ${max}`};
		}
		return {ok: true, error: ''};
	}

	url(data) {
		const {ignore, error} = Joi.string().uri().validate(data);
		if (error) {
			return {ok: false, error: `must be a valid URL`};
		}
		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: ''};
	}

	equal(data, compare) {
		if (data !== compare) {
			return {ok: false, error: `must be equal`};
		}
		return {ok: true, error: ''};
	}

	parameterName(data) {
		const {ignore, error} = Joi.string()
		.max(128)
		.invalid('condition_template', 'material_template')
		.allow('')
		.pattern(/^[^.]+$/)
		.required()
		.messages({'string.pattern.base': 'name must not contain a dot'})
		.validate(data);
		if (error) {
			return {ok: false, error: error.details[0].message};
		}
		return {ok: true, error: ''};
	}

	parameterRange(data) {
		if (data) {
			try {
				const {ignore, error} = Joi.object({
					values: Joi.array()
					.min(1),

					min: Joi.number(),

					max: Joi.number(),

					type: Joi.string()
					.valid('string', 'number', 'boolean', 'array'),

					required: Joi.boolean()
				})
				.oxor('values', 'min')
				.oxor('values', 'max')
				.required()
				.validate(JSON.parse(data));
				if (error) {
					return {ok: false, error: error.details[0].message};
				}
			}
			catch (e) {
				return {ok: false, error: `no valid JSON`};
			}
			return {ok: true, error: ''};
		}
		else {
			return {ok: false, error: `no valid value`};
		}
	}
}