/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Async.Linux.hpp
    Date: 2022-4-12
    Author: Reece
***/
#pragma once

namespace Aurora::IO::FS
{
    struct LinuxAsyncFileTransaction;

    struct LinuxAsyncFileTransactionLoopSource : Loop::LSEvent
    {
        LinuxAsyncFileTransactionLoopSource(AuSPtr<LinuxAsyncFileTransaction> that);

        virtual bool IsSignaled() override;
        virtual bool OnTrigger(AuUInt handle) override;
        virtual Loop::ELoopSource GetType() override;
    private:
        AuWPtr<LinuxAsyncFileTransaction> caller_;
    };

    struct FileHandle
    {
        ~FileHandle();

        bool Init(const AuString &path, EFileOpenMode openMode, bool directIO, EFileAdvisoryLockLevel lock);
        void Init(int read, int write);

        int readHandle {-1};
        int writeHandle {-1};

        AuString path;
        bool readOnly;
        bool directIO;
    };

    struct LinuxAsyncFileStream : public IAsyncFileStream
    {
        AuSPtr<IAsyncTransaction> NewTransaction() override;
        bool BlockingTruncate(AuUInt64 length) override;
        bool BlockingRead(AuUInt64 offset, const Memory::MemoryViewStreamWrite &parameters) override;
        bool BlockingWrite(AuUInt64 offset, const Memory::MemoryViewStreamRead &parameters) override;

        void Init(const AuSPtr<FileHandle> &handle);

        AuSPtr<FileHandle> GetHandle();

    private:
        AuSPtr<FileHandle> handle_;
    };


    struct LinuxAsyncFileTransaction : IAsyncTransaction, AuEnableSharedFromThis<LinuxAsyncFileTransaction>, Aurora::IO::UNIX::ASubmittable
    {
        ~LinuxAsyncFileTransaction();

        bool Init(const AuSPtr<FileHandle> &handle);

        bool StartRead(AuUInt64 offset, const AuSPtr<AuMemoryViewWrite> &memoryView) override;
        bool StartWrite(AuUInt64 offset, const AuSPtr<AuMemoryViewRead> &memoryView) override;
        
        bool Complete() override;
        AuUInt32 GetLastPacketLength() override;
        
        void SetCallback(const AuSPtr<IAsyncFinishedSubscriber> &sub) override;
        
        bool Wait(AuUInt32 timeout) override;
        AuSPtr<Loop::ILoopSource> NewLoopSource() override;
    
        void Reset() override;

        void DispatchCb();
        AuSPtr<FileHandle> GetFileHandle();

        virtual void LIOS_Process(AuUInt32 read, bool failure, int err, bool mark) override;

    private:
        AuSPtr<FileHandle> handle_;
        AuUInt32 lastAbstractOffset_ {}, lastFinishedStat_{};
        bool latch_ {};
        bool bTxFinished_ {};
        AuSPtr<IAsyncFinishedSubscriber> sub_;
        AuSPtr<LinuxAsyncFileTransactionLoopSource> loopSource_;
    };
}