using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Utils;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text;
using System.Text.RegularExpressions;

namespace Sarand.Net.Standard.Base.Helpers
{
	//=======================================================================
	public static class SacsDataValidationHelper
	{
		//-------------------------------------------------------------------
		// Email address.
		//-------------------------------------------------------------------
		/// <summary>
		/// Validate the email address.
		/// <para>Ref. https://stackoverflow.com/questions/1365407/c-sharp-code-to-validate-email-address</para>
		/// </summary>
		public static bool IsValidEmailAddress(String value)
		{
			if (StringUtil.IsEmpty(value)) return false;
			if (!new EmailAddressAttribute().IsValid(value)) return false;

			// Exclude spaces.
			if (Regex.Matches(value, " ").Count > 0) return false;

			// Exclude consecutive dots.
			if (Regex.Matches(value, "\\.\\.").Count > 0) return false;

			// Check for at least one dot after @ [to ensure john@smith is invalid].
			if (Regex.Matches(value, "@[^@.]+\\.").Count < 1) return false;

			return true;
		}

		//-------------------------------------------------------------------
		// URL.
		//-------------------------------------------------------------------
		/// <summary>
		/// Validate the URL, including protocol and leading slashes ('//').
		/// </summary>
		public static bool IsCompleteUrl(String value)
		{
			if (StringUtil.IsEmpty(value)) return false;
			if (!new UrlAttribute().IsValid(value))
				return false;
			return true;
		}

		/// <summary>
		/// Validate the URL.
		/// <para>NB AllowsURL to start with leading slashes ('//'), ie. no protocol ('https:') or to start with the domain (no protocol or slashes).</para>
		/// <para>NB Use IsCompleteUrl to validate that protocol and slashes are also present.</para>
		/// </summary>
		public static bool IsValidUrl(String value)
		{
			if (StringUtil.IsEmpty((value ?? "").Trim())) return false;

			// Ensure that value has at least one dot.
			if (Regex.Matches(value, "\\.").Count == 0) return false;

			// Ensure that value has no '@ symbols (unless encoded).
			if (Regex.Matches(value, "\\@").Count > 0) return false;

			// URL validation.
			if (!new UrlAttribute().IsValid(value))
			{
				// URL validation insists on the full URL.
				if (!new UrlAttribute().IsValid("//" + value))
				{
					if (!new UrlAttribute().IsValid("http://" + value))
						return false;
				}
			}
			return true;
		}

		// Wikipedia URLs. [[https:]//]xx.wikipedia.org...
		private static readonly Regex reWikipediaUrl = new Regex("^(?:(?:http(?:s)?:)?//)?\\w{2}" + Regex.Escape(".wikipedia.org/wiki/") + ".+", RegexOptions.IgnoreCase);
		private static readonly Regex reWikipediaUrl_Alt = new Regex("^(?:(?:http(?:s)?:)?//)?\\w{2}" + Regex.Escape(".wikipedia.org/w/index.php?") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidWikipediaUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reWikipediaUrl.Matches(value).Count > 0) return true;
			if (reWikipediaUrl_Alt.Matches(value).Count > 0) return true;
			return false;
		}

		// LinkedIn URLs. [[https:]//][www|xx].linkedin.com/in...
		private static readonly Regex reLinkedInUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:(?:www|\\w{2})\\.)?" + Regex.Escape("linkedin.com/in/") + ".+", RegexOptions.IgnoreCase);
		private static readonly Regex reLinkedInUrl_Company = new Regex("^(?:(?:http(?:s)?:)?//)?(?:(?:www|\\w{2})\\.)?" + Regex.Escape("linkedin.com/company/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidLinkedInUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reLinkedInUrl.Matches(value).Count > 0) return true;
			if (reLinkedInUrl_Company.Matches(value).Count > 0) return true;
			return false;
		}

		// Twitter URLs. [[http[s]:]//][wwww.]twitter.com/...
		private static readonly Regex reTwitterUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:www\\.)?" + Regex.Escape("twitter.com/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidTwitterUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reTwitterUrl.Matches(value).Count > 0) return true;
			return false;
		}

		// Facebook URLs. [[https:]//][www.|xx.|xx-xx.]facebook.com/in...
		private static readonly Regex reFacebookUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:(?:www|\\w{2}|\\w{2}-\\w{2})\\.)?" + Regex.Escape("facebook.com/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidFacebookUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reFacebookUrl.Matches(value).Count > 0) return true;
			return false;
		}

		// Instagram URLs. [[https:]//][www.]instagram.com/...
		private static readonly Regex reInstagramUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:www\\.)?" + Regex.Escape("instagram.com/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidInstagramUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reInstagramUrl.Matches(value).Count > 0) return true;
			return false;
		}

		// YouTube URLs. [[https:]//][www.]youtube.com/...
		private static readonly Regex reYouTubeUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:www\\.)?" + Regex.Escape("youtube.com/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidYouTubeUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reYouTubeUrl.Matches(value).Count > 0) return true;
			return false;
		}

		// Twitch URLs. [[https:]//][www.]twitch.com/...
		private static readonly Regex reTwitchUrl = new Regex("^(?:(?:http(?:s)?:)?//)?(?:www\\.)?" + Regex.Escape("twitch.tv/") + ".+", RegexOptions.IgnoreCase);
		public static bool IsValidTwitchUrl(String value)
		{
			if (!IsValidUrl(value)) return false;
			if (reTwitchUrl.Matches(value).Count > 0) return true;
			return false;
		}

		//-------------------------------------------------------------------
		/// <summary>
		/// Ensure that the website address is a valid URL, ie. at least starts with '//'.
		/// <para>To allow the value to be used in an anchor element href attribute.</para>
		/// </summary>
		public static String QualifyAbsoluteUrl(String url)
		{
			if (!IsValidUrl(url)) return url;
			if (IsCompleteUrl(url)) return url;
			if (IsCompleteUrl("https:" + url)) return url;
			return "//" + url;
		}

		//-------------------------------------------------------------------
		// Phone number.
		//-------------------------------------------------------------------
		/// <summary>
		/// Validate the phone number.
		/// <para>Ref. https://www.twilio.com/blog/validating-phone-numbers-effectively-with-c-and-the-net-frameworks</para>
		/// </summary>
		public static bool IsValidPhone(String value)
		{
			if (StringUtil.IsEmpty(value)) return false;
			if (!new PhoneAttribute().IsValid(value)) return false;

			// Apply minimum length.
			if (StringUtil.GetLength(value) < 8) return false;

			return true;
		}

		//-------------------------------------------------------------------
		// Tax identification number.
		// European country Tax Identification Numbers:
		//   https://ec.europa.eu/taxation_customs/vies/faqvies.do#item_11
		//-------------------------------------------------------------------
		/// <summary>
		/// Validate the tax identification number.
		/// </summary>
		public static bool IsValidTaxIdentificationNumber(String countryCode, String value)
		{
			if (StringUtil.IsEmpty(value)) return false;

			//---------------------------------------------------------------
			// GB, United Kingdom.
			//   Standard:
			//      GB999 9999 99            block of 3 digits, block of 4 digits and block of 2 digits [00-96]
			//   Branch:
			//      GB999 9999 99 9995       as above followed by block of 3 digits
			//   Government departments:
			//      GBGD9996                 'GD' followed by block of 3 or 4 digits
			//   Health Authoritites:
			//      GBHA9997                 'HA' followed by block of 3 or 4 digits
			//---------------------------------------------------------------
			// Apply minimum length.
			if (StringUtil.GetLength(value) < 8) return false;

			// Country prefix.
			if (!value.StartsWith("GB")) return false;

			return true;
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}