using System;
using System.Reflection;

namespace FullSerializer.Internal {
    /// <summary>
    /// A property or field on a MetaType. This unifies the FieldInfo and PropertyInfo classes.
    /// </summary>
    public class fsMetaProperty {
        internal fsMetaProperty(fsConfig config, FieldInfo field) {
            _memberInfo = field;
            StorageType = field.FieldType;
            MemberName = field.Name;
            IsPublic = field.IsPublic;
            IsReadOnly = field.IsInitOnly;
            CanRead = true;
            CanWrite = true;

            CommonInitialize(config);
        }

        internal fsMetaProperty(fsConfig config, PropertyInfo property) {
            _memberInfo = property;
            StorageType = property.PropertyType;
            MemberName = property.Name;
            IsPublic = (property.GetGetMethod() != null && property.GetGetMethod().IsPublic) &&
                       (property.GetSetMethod() != null && property.GetSetMethod().IsPublic);
            IsReadOnly = false;
            CanRead = property.CanRead;
            CanWrite = property.CanWrite;

            CommonInitialize(config);
        }

        private void CommonInitialize(fsConfig config) {
            var attr = fsPortableReflection.GetAttribute<fsPropertyAttribute>(_memberInfo);
            if (attr != null) {
                JsonName = attr.Name;
                OverrideConverterType = attr.Converter;
            }

            if (string.IsNullOrEmpty(JsonName)) {
                JsonName = config.GetJsonNameFromMemberName(MemberName, _memberInfo);
            }
        }

        /// <summary>
        /// Internal handle to the reflected member.
        /// </summary>
        private MemberInfo _memberInfo;

        /// <summary>
        /// The type of value that is stored inside of the property. For example, for an int field,
        /// StorageType will be typeof(int).
        /// </summary>
        public Type StorageType {
            get;
            private set;
        }

        /// <summary>
        /// A custom fsBaseConverter instance to use for this field/property, if requested. This will be
        /// null if the default converter selection algorithm should be used. This is specified using the
        /// [fsObject] annotation with the Converter field.
        /// </summary>
        public Type OverrideConverterType {
            get;
            private set;
        }

        /// <summary>
        /// Can this property be read?
        /// </summary>
        public bool CanRead {
            get;
            private set;
        }

        /// <summary>
        /// Can this property be written to?
        /// </summary>
        public bool CanWrite {
            get;
            private set;
        }

        /// <summary>
        /// The serialized name of the property, as it should appear in JSON.
        /// </summary>
        public string JsonName {
            get;
            private set;
        }

        /// <summary>
        /// The name of the actual member.
        /// </summary>
        public string MemberName {
            get;
            private set;
        }

        /// <summary>
        /// Is this member public?
        /// </summary>
        public bool IsPublic {
            get;
            private set;
        }

        /// <summary>
        /// Is this type readonly? We can modify readonly properties using reflection, but not
        /// using generated C#.
        /// </summary>
        public bool IsReadOnly {
            get; private set;
        }

        /// <summary>
        /// Writes a value to the property that this MetaProperty represents, using given object
        /// instance as the context.
        /// </summary>
        public void Write(object context, object value) {
            FieldInfo field = _memberInfo as FieldInfo;
            PropertyInfo property = _memberInfo as PropertyInfo;

            if (field != null) {
                field.SetValue(context, value);
            }

            else if (property != null) {
                MethodInfo setMethod = property.GetSetMethod(/*nonPublic:*/ true);
                if (setMethod != null) {
                    setMethod.Invoke(context, new object[] { value });
                }
            }
        }

        /// <summary>
        /// Reads a value from the property that this MetaProperty represents, using the given
        /// object instance as the context.
        /// </summary>
        public object Read(object context) {
            if (_memberInfo is PropertyInfo) {
                return ((PropertyInfo)_memberInfo).GetValue(context, new object[] { });
            }

            else {
                return ((FieldInfo)_memberInfo).GetValue(context);
            }
        }
    }
}