using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using JD.Kernel.StaticHelpers;
using JD.Reflection.Attributes;
using JD.Reflection.MefImplementations.Metadata;
using JD.Reflection.MefImplementations.Model.Internal;

namespace JD.Reflection.MefImplementations.Model
{
    public class ImportDefinition
    {
        #region Variables

        private readonly PartDefinition m_part;
        private readonly string m_contractName;
        private readonly string m_requiredTypeIdentity;
        private readonly ImportCardinality m_cardinality;
        private readonly LazyMemberInfo m_importingMember;
        private readonly IEnumerable<RequiredMetadataItem> m_requiredMetadata;

        #endregion

        #region Constructor

        public ImportDefinition(PartDefinition part, string contractName, string requiredTypeIdentity, ImportCardinality cardinality, MemberInfo importingMember, IEnumerable<RequiredMetadataItem> requiredMetadata)
            : this(part, contractName, requiredTypeIdentity, cardinality, new LazyMemberInfo(importingMember), requiredMetadata)
        {
        }

        internal ImportDefinition(PartDefinition part, string contractName, string requiredTypeIdentity, ImportCardinality cardinality, LazyMemberInfo importingMember, IEnumerable<RequiredMetadataItem> requiredMetadata)
        {
            Throw.IfNull(part, "part");
            Throw.IfEmpty(contractName, "contractName");
            Throw.IfNull(importingMember, "importingMember");

            m_part = part;
            m_contractName = contractName;
            m_requiredTypeIdentity = requiredTypeIdentity;
            m_cardinality = cardinality;
            m_importingMember = importingMember;
            m_requiredMetadata = requiredMetadata ?? Enumerable.Empty<RequiredMetadataItem>();
        }

        #endregion

        #region Properties

        public PartDefinition Part
        {
            get { return m_part; }
        }

        public string ContractName
        {
            get { return m_contractName; }
        }

        public string RequiredTypeIdentity
        {
            get { return m_requiredTypeIdentity; }
        }

        public ImportCardinality Cardinality
        {
            get { return m_cardinality; }
        }

        public IEnumerable<RequiredMetadataItem> RequiredMetadata
        {
            get { return m_requiredMetadata; }
        }

        #endregion

        #region Methods

        public MemberInfo GetImportingMember()
        {
            return m_importingMember.Member;
        }

        public bool IsSatisfiedBy(ExportDefinition export)
        {
            if (!Equals(ContractName, export.ContractName))
            {
                return false;
            }

            if (!string.IsNullOrEmpty(RequiredTypeIdentity) && !Equals(RequiredTypeIdentity, export.ExportTypeIdentity))
            {
                return false;
            }

            foreach (var requiredMetadata in RequiredMetadata)
            {
                object value;
                if (!export.Metadata.TryGetValue(requiredMetadata.Key, out value) || !requiredMetadata.Type.IsInstanceOfType(value))
                {
                    return false;
                }
            }

            return true;
        }

        public override string ToString()
        {
            return $"{ContractName} [RequiredTypeIdentity: {RequiredTypeIdentity}]";
        }

        #endregion
    }
}