// ==++==
// 
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
/*============================================================
**
** File:    Version
**
**
** Purpose: 
**
**
===========================================================*/
namespace System {

    using System.Diagnostics.Contracts;
    using CultureInfo = System.Globalization.CultureInfo;
    using NumberStyles = System.Globalization.NumberStyles;

    // A Version object contains four hierarchical numeric components: major, minor,
    // build and revision.  Build and revision may be unspecified, which is represented 
    // internally as a -1.  By definition, an unspecified component matches anything 
    // (both unspecified and specified), and an unspecified component is "less than" any
    // specified component.

    [Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
    public sealed class Version : ICloneable, IComparable
#if GENERICS_WORK
        , IComparable<Version>, IEquatable<Version>
#endif
    {
        // AssemblyName depends on the order staying the same
        private int _Major;
        private int _Minor;
        private int _Build = -1;
        private int _Revision = -1;
    
        public Version(int major, int minor, int build, int revision) {
            if (major < 0) 
              throw new ArgumentOutOfRangeException("major",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            if (minor < 0) 
              throw new ArgumentOutOfRangeException("minor",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            if (build < 0)
              throw new ArgumentOutOfRangeException("build",Environment.GetResourceString("ArgumentOutOfRange_Version"));
            
            if (revision < 0) 
              throw new ArgumentOutOfRangeException("revision",Environment.GetResourceString("ArgumentOutOfRange_Version"));
            Contract.EndContractBlock();
            
            _Major = major;
            _Minor = minor;
            _Build = build;
            _Revision = revision;
        }

        public Version(int major, int minor, int build) {
            if (major < 0) 
                throw new ArgumentOutOfRangeException("major",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            if (minor < 0) 
              throw new ArgumentOutOfRangeException("minor",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            if (build < 0) 
              throw new ArgumentOutOfRangeException("build",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            Contract.EndContractBlock();
            
            _Major = major;
            _Minor = minor;
            _Build = build;
        }
    
        public Version(int major, int minor) {
            if (major < 0) 
                throw new ArgumentOutOfRangeException("major",Environment.GetResourceString("ArgumentOutOfRange_Version"));

            if (minor < 0) 
                throw new ArgumentOutOfRangeException("minor",Environment.GetResourceString("ArgumentOutOfRange_Version"));
            Contract.EndContractBlock();
            
            _Major = major;
            _Minor = minor;
        }

        public Version(String version) {
            Version v = Version.Parse(version);
            _Major = v.Major;
            _Minor = v.Minor;
            _Build = v.Build;
            _Revision = v.Revision;
        }

#if FEATURE_LEGACYNETCF
        //required for Mango AppCompat
        [System.Runtime.CompilerServices.FriendAccessAllowed]
#endif
        public Version() 
        {
            _Major = 0;
            _Minor = 0;
        }

        // Properties for setting and getting version numbers
        public int Major {
            get { return _Major; }
        }
    
        public int Minor {
            get { return _Minor; }
        }
    
        public int Build {
            get { return _Build; }
        }
    
        public int Revision {
            get { return _Revision; }
        }

        public short MajorRevision {
            get { return (short)(_Revision >> 16); }
        }

        public short MinorRevision {
            get { return (short)(_Revision & 0xFFFF); }
        }
     
        public Object Clone() {
            Version v = new Version();
            v._Major = _Major;
            v._Minor = _Minor;
            v._Build = _Build;
            v._Revision = _Revision;
            return(v);
        }

        public int CompareTo(Object version)
        {
            if (version == null)
            {
#if FEATURE_LEGACYNETCF
                if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8) {
                    throw new ArgumentOutOfRangeException();
                } else {
#endif
                    return 1;
#if FEATURE_LEGACYNETCF
                }
#endif
            }

            Version v = version as Version;
            if (v == null)
            {
#if FEATURE_LEGACYNETCF
                if (CompatibilitySwitches.IsAppEarlierThanWindowsPhone8) {
                    throw new InvalidCastException(Environment.GetResourceString("Arg_MustBeVersion"));
                } else {
#endif
                    throw new ArgumentException(Environment.GetResourceString("Arg_MustBeVersion"));
#if FEATURE_LEGACYNETCF
                }
#endif                
            }

            if (this._Major != v._Major)
                if (this._Major > v._Major)
                    return 1;
                else
                    return -1;

            if (this._Minor != v._Minor)
                if (this._Minor > v._Minor)
                    return 1;
                else
                    return -1;

            if (this._Build != v._Build)
                if (this._Build > v._Build)
                    return 1;
                else
                    return -1;

            if (this._Revision != v._Revision)
                if (this._Revision > v._Revision)
                    return 1;
                else
                    return -1;

            return 0;
        }

#if GENERICS_WORK
        public int CompareTo(Version value)
        {
            if (value == null)
                return 1;

            if (this._Major != value._Major)
                if (this._Major > value._Major)
                    return 1;
                else
                    return -1;

            if (this._Minor != value._Minor)
                if (this._Minor > value._Minor)
                    return 1;
                else
                    return -1;

            if (this._Build != value._Build)
                if (this._Build > value._Build)
                    return 1;
                else
                    return -1;

            if (this._Revision != value._Revision)
                if (this._Revision > value._Revision)
                    return 1;
                else
                    return -1;

            return 0;
        }
#endif

        public override bool Equals(Object obj) {
            Version v = obj as Version;
            if (v == null)
                return false;

            // check that major, minor, build & revision numbers match
            if ((this._Major != v._Major) || 
                (this._Minor != v._Minor) || 
                (this._Build != v._Build) ||
                (this._Revision != v._Revision))
                return false;

            return true;
        }

        public bool Equals(Version obj)
        {
            if (obj == null)
                return false;

            // check that major, minor, build & revision numbers match
            if ((this._Major != obj._Major) || 
                (this._Minor != obj._Minor) || 
                (this._Build != obj._Build) ||
                (this._Revision != obj._Revision))
                return false;

            return true;
        }

        public override int GetHashCode()
        {
            // Let's assume that most version numbers will be pretty small and just
            // OR some lower order bits together.

            int accumulator = 0;

            accumulator |= (this._Major & 0x0000000F) << 28;
            accumulator |= (this._Minor & 0x000000FF) << 20;
            accumulator |= (this._Build & 0x000000FF) << 12;
            accumulator |= (this._Revision & 0x00000FFF);

            return accumulator;
        }

        public override String ToString() {
            if (_Build == -1) return(ToString(2));
            if (_Revision == -1) return(ToString(3));
            return(ToString(4));
        }
        
        public String ToString(int fieldCount) {
            switch (fieldCount) {
            case 0: 
                return(String.Empty);
            case 1: 
                return(String.Concat(_Major));
            case 2: 
                return(String.Concat(_Major,".",_Minor));
            default:
                if (_Build == -1)
                    throw new ArgumentException(Environment.GetResourceString("ArgumentOutOfRange_Bounds_Lower_Upper", "0", "2"), "fieldCount");
                if (fieldCount == 3)
                    return( _Major + "." + _Minor + "." + _Build );

                if (_Revision == -1)
                    throw new ArgumentException(Environment.GetResourceString("ArgumentOutOfRange_Bounds_Lower_Upper", "0", "3"), "fieldCount");

                if (fieldCount == 4)
                    return( Major + "." + _Minor + "." + _Build + "." + _Revision );

                throw new ArgumentException(Environment.GetResourceString("ArgumentOutOfRange_Bounds_Lower_Upper", "0", "4"), "fieldCount");
            }
        }

        public static Version Parse(string input) {
            if (input == null) {
                throw new ArgumentNullException("input");
            }
            Contract.EndContractBlock();

            VersionResult r = new VersionResult();
            r.Init("input", true);
            if (!TryParseVersion(input, ref r)) {
                throw r.GetVersionParseException();
            }
            return r.m_parsedVersion;
        }

        public static bool TryParse(string input, out Version result) {
            VersionResult r = new VersionResult();
            r.Init("input", false);
            bool b = TryParseVersion(input, ref r);
            result = r.m_parsedVersion;
            return b;
        }
  
        private static bool TryParseVersion(string version, ref VersionResult result) {
            int major, minor, build, revision;

            if ((Object)version == null) {
                result.SetFailure(ParseFailureKind.ArgumentNullException);
                return false;
            }

            String[] parsedComponents = version.Split(new char[] { '.' });
            int parsedComponentsLength = parsedComponents.Length;
            if ((parsedComponentsLength < 2) || (parsedComponentsLength > 4)) {
                result.SetFailure(ParseFailureKind.ArgumentException);
                return false;
            }

            if (!TryParseComponent(parsedComponents[0], "version", ref result, out major)) {
                return false;
            }

            if (!TryParseComponent(parsedComponents[1], "version", ref result, out minor)) {
                return false;
            }

            parsedComponentsLength -= 2;

            if (parsedComponentsLength > 0) {
                if (!TryParseComponent(parsedComponents[2], "build", ref result, out build)) {
                    return false;
                }

                parsedComponentsLength--;

                if (parsedComponentsLength > 0) {
                    if (!TryParseComponent(parsedComponents[3], "revision", ref result, out revision)) {
                        return false;
                    } else {
                        result.m_parsedVersion = new Version(major, minor, build, revision);
                    }
                } else {
                    result.m_parsedVersion = new Version(major, minor, build);
                }
            } else {
                result.m_parsedVersion = new Version(major, minor);
            }

            return true;
        }

        private static bool TryParseComponent(string component, string componentName, ref VersionResult result, out int parsedComponent) {
            if (!Int32.TryParse(component, NumberStyles.Integer, CultureInfo.InvariantCulture, out parsedComponent)) {
                result.SetFailure(ParseFailureKind.FormatException, component);
                return false;
            }

            if (parsedComponent < 0) {
                result.SetFailure(ParseFailureKind.ArgumentOutOfRangeException, componentName);
                return false;
            }

            return true;
        }

        public static bool operator ==(Version v1, Version v2) {
            if (Object.ReferenceEquals(v1, null)) {
                return Object.ReferenceEquals(v2, null);
            }

            return v1.Equals(v2);
        }

        public static bool operator !=(Version v1, Version v2) {
            return !(v1 == v2);
        }

        public static bool operator <(Version v1, Version v2) {
            if ((Object) v1 == null)
                throw new ArgumentNullException("v1");
            Contract.EndContractBlock();
            return (v1.CompareTo(v2) < 0);
        }
        
        public static bool operator <=(Version v1, Version v2) {
            if ((Object) v1 == null)
                throw new ArgumentNullException("v1");
            Contract.EndContractBlock();
            return (v1.CompareTo(v2) <= 0);
        }
        
        public static bool operator >(Version v1, Version v2) {
            return (v2 < v1);
        }
        
        public static bool operator >=(Version v1, Version v2) {
            return (v2 <= v1);
        }

        internal enum ParseFailureKind { 
            ArgumentNullException, 
            ArgumentException, 
            ArgumentOutOfRangeException, 
            FormatException 
        }

        internal struct VersionResult {
            internal Version m_parsedVersion;
            internal ParseFailureKind m_failure;
            internal string m_exceptionArgument;
            internal string m_argumentName;
            internal bool m_canThrow;

            internal void Init(string argumentName, bool canThrow) {
                m_canThrow = canThrow;
                m_argumentName = argumentName;
            }

            internal void SetFailure(ParseFailureKind failure) {
                SetFailure(failure, String.Empty);
            }

            internal void SetFailure(ParseFailureKind failure, string argument) {
                m_failure = failure;
                m_exceptionArgument = argument;
                if (m_canThrow) {
                    throw GetVersionParseException();
                }
            }

            internal Exception GetVersionParseException() {
                switch (m_failure) {
                    case ParseFailureKind.ArgumentNullException:
                        return new ArgumentNullException(m_argumentName);
                    case ParseFailureKind.ArgumentException:
                        return new ArgumentException(Environment.GetResourceString("Arg_VersionString"));
                    case ParseFailureKind.ArgumentOutOfRangeException:
                        return new ArgumentOutOfRangeException(m_exceptionArgument, Environment.GetResourceString("ArgumentOutOfRange_Version"));
                    case ParseFailureKind.FormatException:
                        // Regenerate the FormatException as would be thrown by Int32.Parse()
                        try {
                            Int32.Parse(m_exceptionArgument, CultureInfo.InvariantCulture);
                        } catch (FormatException e) {
                            return e;
                        } catch (OverflowException e) {
                            return e;
                        }
                        Contract.Assert(false, "Int32.Parse() did not throw exception but TryParse failed: " + m_exceptionArgument);
                        return new FormatException(Environment.GetResourceString("Format_InvalidString"));
                    default:
                        Contract.Assert(false, "Unmatched case in Version.GetVersionParseException() for value: " + m_failure);
                        return new ArgumentException(Environment.GetResourceString("Arg_VersionString"));
                }
            }
 
        }
    }
}