namespace Sernatur {
	namespace Person {

		public errordomain InvalidRut {
			INVALID,
			TOOLARGE,
			INVALIDVERIFIER
		}

		public class Rut : GLib.Object {
			private string clean_rut;
			private string pretty_rut;
			private unichar verifier;

			public enum Type {
				RUN,
				RUT
			}

			public Rut (string rut) throws InvalidRut {
				parse (rut);
			}

			private void parse (string rut) throws InvalidRut {
				try {
					var regex = new Regex ("^[ ]*([0-9.]{0,11}[\\-]?[0-9kK])?[ ]*$");
					if (!regex.match (rut)) {
						throw new InvalidRut.INVALID (dgettext (null, "The RUT %s has an invalid character!"), rut);
					}
				}
				catch (Error e) {
					#if DEBUG
						error (e.message);
					#else
						warning (e.message);
					#endif
				}
				try {
					var regex = new Regex ("([.-])");
					string new_rut = rut.up ();
					new_rut = new_rut.strip ();
					rut = regex.replace (new_rut, new_rut.length, 0, "");
					if (int.parse (rut.substring (0, rut.length - 1)) > 100000000) {
						throw new InvalidRut.TOOLARGE (dgettext (null, "The RUT %s is too big!"), rut);
					}
					this.verifier = rut.get_char (rut.length - 1);
					this.clean_rut = rut.substring (0, rut.length - 1);
					if (generate_verfifier (this.clean_rut) != this.verifier) {
						throw new InvalidRut.INVALIDVERIFIER (dgettext (null, "The verifier %C is invalid!"), this.verifier);
					}
					pretty();
				}
				catch (Error e) {
					#if DEBUG
						error (e.message);
					#else
						warning (e.message);
					#endif
				}
			}

			private void pretty () {
				string new_rut = "";
				string temp_rut = this.clean_rut.reverse ();
				int rut_length = this.clean_rut.length;
				for (int i = 0; i < rut_length; i++) {
					new_rut = new_rut + temp_rut.get_char(i).to_string ();
					if ((i + 1) % 3 == 0) {
						new_rut = new_rut + ".";
					}
				}
				new_rut = new_rut.reverse ();
				this.pretty_rut = new_rut + "-" + this.verifier.to_string ();
			}

			private unichar generate_verfifier (string rut) {
				/**
				 * 1. Multiply each digit of the RUT by 2, 3, ..., 7, 2, 3, ... from the end of the RUT moving forward.
				 * 2. Add the partial multiplications.
				 * 3. Calculate the remainder of the division by 11.
				 * 4. The verifier is 11 minus the previous result. If the result is 10, change it to K.
				 */
				int multiplier = 2;
				int sum = 0;
				int remainder;
				int division;
				int rut_length = rut.length;

				// Steps 1 and 2
				for (int i = rut_length - 1; i >= 0; i--) {
					sum = sum + (int.parse (rut.substring(i, 1)) * multiplier);
					multiplier++;
					if (multiplier == 8) {
						multiplier = 2;
					}
				}

				// Step 3
				division = sum / 11;
				division = division * 11;
				remainder = sum - division;

				// Step 4
				if (remainder != 0) {
					remainder = 11 - remainder;
				}

				// Let's return their verifier
				if (remainder == 10) {
					// Their verifier is 10 so let's return K.
					return 'K';
				}
				else {
					return (unichar) remainder + '0';
				}
			}

			public string get_clean_rut () {
				return this.clean_rut + this.verifier.to_string ();
			}

			public string get_rut () {
				return this.pretty_rut;
			}

			public Type type () {
				uint rut = int.parse (this.clean_rut);
				if (rut < 100000000 && rut > 50000000) {
					// Company
					return Type.RUT;
				}
				else {
					// Person
					return Type.RUN;
				}
			}
		}
	}
}