/**
 * General Trainsmart package.
 */

package com.trainsmart {

	/**
	 * Management of the pointer to the patch.
	 */

	public class Pointer {

		// Some useful strings:
		private static const lineFeed:String = '\n';
		private static const carriageReturn:String = '\r';
		private static const equal:String = '=';
		private static const dot:String = '.';
		private static const space:String = ' ';
		private static const bytes:String = 'B';
		private static const kilobytes:String = 'KB';
		private static const megabytes:String = 'MB';
		private static const kilo:Number = 1024;
		private static const URLField:String = 'patch';
		private static const sizeField:String = 'size';
		private static const majorField:String = 'major';
		private static const minorField:String = 'minor';
		private static const revisionField:String = 'revision';
		private static const requiredField:String = 'required';

		/**
		 * URL for the patch.
		 */

		private static var URL:String = null;

		/**
		 * Size of the patch, in bytes.
		 */

		private static var size:int = -1;

		/**
		 * New version (major number).
		 */

		private static var major:int = -1;

		/**
		 * New version (minor number).
		 */

		private static var minor:int = -1;

		/**
		 * New version (revision number).
		 */

		private static var revision:int = -1;

		/**
		 * Whether this patch is compulsory or not (since version 0.9.5).
		 */

		private static var required:Boolean = false;

		/**
		 * Main constructor.
		 */

		function Pointer (pointerContent:String) {

			var exception:Error = new Error ();

			if (pointerContent.length < 1) {
				exception.name = 'The pointer to the patch seems empty';
				throw exception;
			}

			var lines:Array = pointerContent.substring (0, pointerContent.length - 1).split (lineFeed);
			var pair:Array = null;
			var i:String = null;
			var fieldNames:Array = [URLField, sizeField, majorField, minorField, revisionField, requiredField];
			var foundValues:Array = [false, false, false, false, false, false];

			if (lines.length != fieldNames.length) {
				exception.name = 'Wrong number of lines (' + lines.length + ') in the pointer to the patch';
				throw exception;
			}

			for each (var j:String in lines) {
				i = j;
				
				while (lineFeed == i.charAt (i.length - 1) || carriageReturn == i.charAt (i.length - 1))
					i = i.substring (0, i.length - 1);

				pair = i.split (equal);

				if (pair.length != 2) {
					exception.name = 'Wrong line ("' + i + '") in the pointer to the patch';
					throw exception;
				}

				if (-1 == fieldNames.indexOf (pair [0].toString ().toLowerCase ())) {
					exception.name = 'Wrong field name ("' + pair [0].toString () + '") in the pointer to the patch';
					throw exception;
				}

				if (foundValues [fieldNames.indexOf (pair [0].toString ().toLowerCase ())]) {
					exception.name = 'The field "' + pair [0].toString () + '" is repeated in the pointer to the patch';
					throw exception;
				}

				foundValues [fieldNames.indexOf (pair [0].toString ().toLowerCase ())] = true;

				switch (pair [0].toString ().toLowerCase ()) {

					case URLField:
						URL = pair [1];
						break;

					case sizeField:
						size = pair [1];
						break;

					case majorField:
						major = pair [1];
						break;

					case minorField:
						minor = pair [1];
						break;

					case revisionField:
						revision = pair [1];
						break;

					case requiredField:

						switch (pair [1]) {

							case '0':
								required = false;
								break;

							case '1':
								required = true;
								break;

							default:
								exception.name = 'Wrong value ("' + pair [1].toString () + '") in field "required"';
								throw exception;
								break;

						}

						break;

				}

			}

		}

		/**
		 * Get the URL for the patch.
		 */

		public function getURL (): String {

			return URL;

		}

		/**
		 * Get the size of the patch, nicely formatted (e.g. "2.34 MB").
		 */

		public function getSize (): String {

			var result:String = null;

			if (size < kilo)
				result = size + space + bytes;
			else {

				if (size < kilo * kilo) {
					result = (size / kilo).toString ();

					if (-1 != result.indexOf (dot))
						result = result.substring (0, result.indexOf (dot) + 2);

					result += space + kilobytes;
				} else {
					result = (size / (kilo * kilo)).toString ();

					if (-1 != result.indexOf (dot))
						result = result.substring (0, result.indexOf (dot) + 2);

					result += space + megabytes;
				}

			}

			return result;

		}

		/**
		 * Get the major version.
		 */

		public function getMajor (): int {

			return major;

		}

		/**
		 * Get the minor version.
		 */

		public function getMinor (): int {

			return minor;

		}

		/**
		 * Get the revision version.
		 */

		public function getRevision (): int {

			return revision;

		}

		/**
		 * Get the "required" property.
		 */

		public function getRequired (): Boolean {

			return required;

		}

		/**
		 * Get a software version, nicely formatted (e.g. "2.3.14").
		 */

		public static function formatVersion (major:int, minor:int, revision:int): String {

			return major + dot + minor + dot + revision;

		}

	}

}

// EOF