using System;
using System.Diagnostics;
using System.IO;
using Pithos.Interfaces;
using Pithos.Network;

namespace Pithos.Core.Agents
{
    [DebuggerDisplay("{FilePath} C:{C} L:{L} S:{S}")]
    public class StateTuple
    {
        public string FilePath { get; private set; }

        public string MD5
        {
            get
            {
                Debug.Assert(EmptyOrLength(_md5, 32));
                return _md5;
            }
            set
            {
                if (!EmptyOrLength(value, 32))
                    throw new ArgumentException("A proper MD5 hash value should have 32 characters");
                _md5 = value;
            }
        }

        private bool EmptyOrLength(string value, int length)
        {
            return String.IsNullOrWhiteSpace(value) || value.Length == length;
        }

        public string L
        {
            get
            {
                //For the change to Merkle Hash, we need to return the final Merkle Hash
                var hash = FileState.NullSafe(f => f.Checksum);
                //var hash = FileState.NullSafe(f => f.ETag);
                
                //Ensure the hash size matches SHA256
                Debug.Assert(EmptyOrLength(hash, 64));
                
                return String.IsNullOrWhiteSpace(hash) ? null : hash;
            }
        }

        private string _c;
        public string C
        {
            get
            {
                Debug.Assert(EmptyOrLength(_c, 64));
                return _c;
            }
            set {
                if (!EmptyOrLength(value, 64))
                    throw new ArgumentException("A proper hash value should have 64 characters");
                _c = String.IsNullOrWhiteSpace(value) ? null : value;
            }
        }

        public string S
        {
            get
            {
                //The Server hash will be the X-Object-Hash, not the ETag
                var hash= ObjectInfo.NullSafe(o => o.X_Object_Hash);

                Debug.Assert(EmptyOrLength(hash, 64));
                
                return String.IsNullOrWhiteSpace(hash) ? null : hash;
            }
        }

        private FileSystemInfo _fileInfo;
        private TreeHash _merkle;
        private string _md5;

        public FileSystemInfo FileInfo
        {
            get { return _fileInfo; }
            set
            {
                _fileInfo = value;
                FilePath = value.FullName;
            }
        }

        public FileState FileState { get; set; }
        public ObjectInfo ObjectInfo{ get; set; }


        public TreeHash Merkle
        {
            get {
                return _merkle;
            }
            set {
                _merkle = value;
                C = _merkle.TopHash.ToHashString();
            }
        }

        public bool Locked { get; set; }

        public string NewFullPath { get; set; }

        public string OldMD5 { get; set; }

        public string OldFullPath { get; set; }

        public StateTuple() { }

        public StateTuple(FileSystemInfo info)
        {
            FileInfo = info;
        }

        public bool HashesValid()
        {
            return (EmptyOrLength(C, 64)
                  && EmptyOrLength(L, 64)
                  && EmptyOrLength(S, 64)
                );
        }
    }
}