using System;
using System.Security.Cryptography;
using FrostFS.SDK.ModelsV2.Enums;

namespace FrostFS.SDK.ModelsV2;

public class FrostFsObject
{
    public FrostFsObject(ObjectId objectId, ObjectHeader header, byte[] payload)
    {
        ObjectId = objectId;
        Payload = payload;
        Header = header;        
    }

    public FrostFsObject(ContainerId container, byte[] payload, ObjectType objectType = ObjectType.Regular)
    {
        Payload = payload;
        Header = new ObjectHeader(containerId: container, type: objectType, attributes: []);        
    }
    
    public ObjectHeader Header { get; set; }
    
    public ObjectId? ObjectId
    {
        get; internal set;
    }
    
    public byte[] Payload { get; set; }

    public IObjectReader? ObjectReader { get; set; }
    
    public Signature? Signature { get; set; }   

    public void SetParent(LargeObject largeObject)
    {
        if (Header?.Split == null)
            throw new Exception("The object is not initialized properly");

        Header.Split.ParentHeader = largeObject.Header;
    }
}

public class LargeObject(ContainerId container) : FrostFsObject(container, [])
{
    private readonly SHA256 payloadHash = SHA256.Create();

    public void AppendBlock(byte[] bytes, int count)
    {
        Header!.PayloadLength += (ulong)count;
        this.payloadHash.TransformBlock(bytes, 0, count, bytes, 0);
    }

    public LargeObject CalculateHash()
    {
        this.payloadHash.TransformFinalBlock([], 0, 0);
        Header!.PayloadCheckSum = this.payloadHash.Hash;
        return this;
    }

    public ulong PayloadLength
    {
        get { return Header!.PayloadLength; }
    }
}

public class LinkObject : FrostFsObject
{
    public LinkObject(ContainerId containerId, SplitId splitId, LargeObject largeObject) : base (containerId, [])
    {
        Header!.Split = new Split(splitId)
        {
            ParentHeader = largeObject.Header
        };
    }
}