/* Copyright 2010-2014 MongoDB Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

using System;
using System.Xml;

namespace MongoDB.Bson
{
    /// <summary>
    /// Represents a BSON boolean value.
    /// </summary>
    [Serializable]
    public class BsonBoolean : BsonValue, IComparable<BsonBoolean>, IEquatable<BsonBoolean>
    {
        // private static fields
        private static BsonBoolean __falseInstance = new BsonBoolean(false);
        private static BsonBoolean __trueInstance = new BsonBoolean(true);

        // private fields
        private bool _value;

        // constructors
        /// <summary>
        /// Initializes a new instance of the BsonBoolean class.
        /// </summary>
        /// <param name="value">The value.</param>
        public BsonBoolean(bool value)
            : base(BsonType.Boolean)
        {
            _value = value;
        }

        // public static properties
        /// <summary>
        /// Gets the instance of BsonBoolean that represents false.
        /// </summary>
        public static BsonBoolean False
        {
            get { return __falseInstance; }
        }

        /// <summary>
        /// Gets the instance of BsonBoolean that represents true.
        /// </summary>
        public static BsonBoolean True
        {
            get { return __trueInstance; }
        }

        // public properties
        /// <summary>
        /// Gets the BsonBoolean as a bool.
        /// </summary>
        [Obsolete("Use Value instead.")]
        public override object RawValue
        {
            get { return _value; }
        }

        /// <summary>
        /// Gets the value of this BsonBoolean.
        /// </summary>
        public bool Value
        {
            get { return _value; }
        }

        // public operators
        /// <summary>
        /// Converts a bool to a BsonBoolean.
        /// </summary>
        /// <param name="value">A bool.</param>
        /// <returns>A BsonBoolean.</returns>
        public static implicit operator BsonBoolean(bool value)
        {
            return value ? __trueInstance : __falseInstance;
        }

        /// <summary>
        /// Compares two BsonBoolean values.
        /// </summary>
        /// <param name="lhs">The first BsonBoolean.</param>
        /// <param name="rhs">The other BsonBoolean.</param>
        /// <returns>True if the two BsonBoolean values are not equal according to ==.</returns>
        public static bool operator !=(BsonBoolean lhs, BsonBoolean rhs)
        {
            return !(lhs == rhs);
        }

        /// <summary>
        /// Compares two BsonBoolean values.
        /// </summary>
        /// <param name="lhs">The first BsonBoolean.</param>
        /// <param name="rhs">The other BsonBoolean.</param>
        /// <returns>True if the two BsonBoolean values are equal according to ==.</returns>
        public static bool operator ==(BsonBoolean lhs, BsonBoolean rhs)
        {
            if (object.ReferenceEquals(lhs, null)) { return object.ReferenceEquals(rhs, null); }
            return lhs.Equals(rhs);
        }

        // public static methods
        /// <summary>
        /// Returns one of the two possible BsonBoolean values.
        /// </summary>
        /// <param name="value">The bool value.</param>
        /// <returns>The corresponding BsonBoolean value.</returns>
        [Obsolete("Use implicit conversion to BsonBoolean or new BsonBoolean(bool value) instead.")]
        public static BsonBoolean Create(bool value)
        {
            return value ? __trueInstance : __falseInstance;
        }

        /// <summary>
        /// Returns one of the two possible BsonBoolean values.
        /// </summary>
        /// <param name="value">An object to be mapped to a BsonBoolean.</param>
        /// <returns>A BsonBoolean or null.</returns>
        public new static BsonBoolean Create(object value)
        {
            if (value != null)
            {
                return (BsonBoolean)BsonTypeMapper.MapToBsonValue(value, BsonType.Boolean);
            }
            else
            {
                return null;
            }
        }

        // public methods
        /// <summary>
        /// Compares this BsonBoolean to another BsonBoolean.
        /// </summary>
        /// <param name="other">The other BsonBoolean.</param>
        /// <returns>A 32-bit signed integer that indicates whether this BsonBoolean is less than, equal to, or greather than the other.</returns>
        public int CompareTo(BsonBoolean other)
        {
            if (other == null) { return 1; }
            return (_value ? 1 : 0).CompareTo(other._value ? 1 : 0);
        }

        /// <summary>
        /// Compares the BsonBoolean to another BsonValue.
        /// </summary>
        /// <param name="other">The other BsonValue.</param>
        /// <returns>A 32-bit signed integer that indicates whether this BsonBoolean is less than, equal to, or greather than the other BsonValue.</returns>
        public override int CompareTo(BsonValue other)
        {
            if (other == null) { return 1; }
            var otherBoolean = other as BsonBoolean;
            if (otherBoolean != null)
            {
                return (_value ? 1 : 0).CompareTo(otherBoolean._value ? 1 : 0);
            }
            return CompareTypeTo(other);
        }

        /// <summary>
        /// Compares this BsonBoolean to another BsonBoolean.
        /// </summary>
        /// <param name="rhs">The other BsonBoolean.</param>
        /// <returns>True if the two BsonBoolean values are equal.</returns>
        public bool Equals(BsonBoolean rhs)
        {
            if (object.ReferenceEquals(rhs, null) || GetType() != rhs.GetType()) { return false; }
            return _value == rhs._value;
        }

        /// <summary>
        /// Compares this BsonBoolean to another object.
        /// </summary>
        /// <param name="obj">The other object.</param>
        /// <returns>True if the other object is a BsonBoolean and equal to this one.</returns>
        public override bool Equals(object obj)
        {
            return Equals(obj as BsonBoolean); // works even if obj is null or of a different type
        }

        /// <summary>
        /// Gets the hash code.
        /// </summary>
        /// <returns>The hash code.</returns>
        public override int GetHashCode()
        {
            // see Effective Java by Joshua Bloch
            int hash = 17;
            hash = 37 * hash + BsonType.GetHashCode();
            hash = 37 * hash + _value.GetHashCode();
            return hash;
        }

        /// <summary>
        /// Converts this BsonValue to a Boolean (using the JavaScript definition of truthiness).
        /// </summary>
        /// <returns>A Boolean.</returns>
        public override bool ToBoolean()
        {
            return _value;
        }

        /// <summary>
        /// Returns a string representation of the value.
        /// </summary>
        /// <returns>A string representation of the value.</returns>
        public override string ToString()
        {
            return XmlConvert.ToString(_value);
        }
    }
}