/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Registry.cpp
    Date: 2021-6-13
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Registry.hpp"

#include <nlohmann/json.hpp>
using json = nlohmann::json;

namespace Aurora::Registry
{
    class FSRegistry : public IRegistry
    {
    public:

        bool Init();
        
        void OpenReadWriteback(const AuString &path) override;
        void OpenRead(const AuString &path) override;
        bool Read(const AuString &path, EReadType read) override;
        void SetWriteModeNone() override;
        void SetWriteModeCache() override;
        void SetWriteModeStream(const AuOptional<AuString> &path) override;
        void SetWriteModeBuffered(const AuOptional<AuString> &path) override;
        void WriteAllCacheBack() override; 
        void SaveBuffered() override;
        void SaveAll(const AuOptional<AuString> &path) override;
        void OpenSave(const AuString &path, bool buffered = false) override;
        void CloseSave() override;
        bool KeyExists(const AuString &key, RegistryType &type) override;
        bool GetOrCreateKey(const AuString &key, const RegistryValue &def, RegistryValue &value) override;
        bool SetKey(const AuString &key, const RegistryValue &value) override;
        bool GetKey(const AuString &key, RegistryValue &value) override;
        void LockKey(const AuString &str) override;
        void UnlockKey(const AuString &str) override;
        
        bool SetKeyLocked(const AuString &key, const RegistryValue &value);
        bool GetKeyLocked(const AuString &key, RegistryValue &value);
        bool Save();

    private:
        AuThreadPrimitives::RWLockUnique_t lock_;
        EWriteMode writeMode_;
        json currentStreamDocument_;
        json cacheDocument_;
        AuOptional<AuString> lastPath_;
        AuList<AuString> restrictedKeys_;
        AuList<AuString> changes_;
    };

    bool FSRegistry::Init()
    {
        lock_ = AuThreadPrimitives::RWLockUnique();
        return lock_ ? true : false;
    }

    void FSRegistry::SetWriteModeNone()
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        writeMode_ = EWriteMode::eWriteModeLocked;
        changes_.clear();
    }

    void FSRegistry::SetWriteModeCache()
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        writeMode_ = EWriteMode::eWriteModeFileBuffer;
        //lastPath_.reset();
        changes_.clear();
    }

    void FSRegistry::SetWriteModeStream(const AuOptional<AuString> &path)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        writeMode_ = EWriteMode::eWriteModeFileStream;
        if (path) lastPath_ = path;
        changes_.clear();
    }

    void FSRegistry::SetWriteModeBuffered(const AuOptional<AuString> &path)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        writeMode_ = EWriteMode::eWriteModeFileBuffer;
        if (path) lastPath_ = path;
        changes_.clear();
    }

    bool FSRegistry::Read(const AuString &path, EReadType read)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        this->lastPath_ = path;
        try
        {
            AuString file;

            currentStreamDocument_ = {};

            if (read == EReadType::eClearCacheAndStore)
            {
                cacheDocument_ = {};
            }

            if (!IO::FS::ReadString(path, file))
            {
                return IO::FS::WriteString(path, "{}");
            }

            currentStreamDocument_ = json::parse(file);
            
            for (const auto &[key, value] : currentStreamDocument_.items())
            {
                if (read == EReadType::eStoreNew)
                {
                    if (cacheDocument_.find(key) != cacheDocument_.end())
                    {
                        continue;
                    }
                }
                cacheDocument_[key] = value;
            }

        }
        catch (...)
        {
            return false;
        }
        return true;
    }

    bool FSRegistry::KeyExists(const AuString &key, RegistryType &type)
    {
        AU_LOCK_GUARD(lock_->AsReadable());

        auto itrObject = cacheDocument_.find(key);
        if (itrObject == cacheDocument_.end())
        {
            return false;
        }

        auto itrType = itrObject->find("type");
        if (itrType == itrObject->end())
        {
            return false;
        }

        auto itrValue = itrObject->find("value");
        if (itrValue == itrObject->end())
        {
            return false;
        }

        return true;
    }

    bool FSRegistry::GetOrCreateKey(const AuString &key, const RegistryValue &ref, RegistryValue &value)
    {
        AU_LOCK_GUARD(lock_->AsWritable());

        if (GetKeyLocked(key, value))
        {
            return true;
        }

        value = ref;
        return SetKeyLocked(key, ref);
    }

    bool FSRegistry::GetKey(const AuString &key, RegistryValue &value)
    {
        AU_LOCK_GUARD(lock_->AsReadable());
        return SetKeyLocked(key, value);
    }

    bool FSRegistry::GetKeyLocked(const AuString &key, RegistryValue &value)
    {    
        auto itrObject = cacheDocument_.find(key);
        if (itrObject == cacheDocument_.end())
        {
            return false;
        }
            
        auto itrType = itrObject->find("type");
        auto itrValue = itrObject->find("value");

        if ((itrType == itrObject->end()) ||
            (itrValue == itrObject->end()))
        {
            return false;
        }
            
        if (!itrValue->is_string())
        {
            return false;
        }

        if (!itrType->is_number_integer())
        {
            return false;
        }

        Parse::ParsableTag type     = *itrType;
        AuString           strValue = *itrValue;

        Parse::ParseValueEx parsedValue;
        if (!Parse::ConsumeToken(type, strValue , parsedValue))
        {
            return false;
        }

        value.type = static_cast<Data::EDataType>(type);
        value.value = parsedValue;
        return true;
    }
    
    bool FSRegistry::SetKey(const AuString &key, const RegistryValue &value)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        return SetKeyLocked(key, value);
    }

    bool FSRegistry::SetKeyLocked(const AuString &key, const RegistryValue &value)
    {
        json object {};
        AuString stringified;

        if (std::find(restrictedKeys_.begin(), restrictedKeys_.end(), key) != restrictedKeys_.end())
        {
            return false;
        }

        if (writeMode_ == EWriteMode::eWriteModeLocked)
        {
            return false;
        }

        auto oldValueItr = cacheDocument_.find(key);
        bool hasOldValue = oldValueItr == cacheDocument_.end();
        json oldValue =  hasOldValue ? json{} : *oldValueItr;

        object["type"] = value.type;
        Parse::SerializeToken(static_cast<Parse::ParsableTag>(value.type), value.value, stringified);
        object["value"] = stringified;

        AuTryInsert(changes_, key);

        switch (writeMode_)
        {
        case EWriteMode::eWriteModeFileBuffer:
            cacheDocument_[key] = object;
            break;
        case EWriteMode::eWriteModeFileStream:
            cacheDocument_[key] = object;
            currentStreamDocument_[key] = object;
            Save();
            break;
        }

        return true;
    }

    void FSRegistry::SaveBuffered()
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        {
            AU_LOCK_GUARD(lock_->AsWritable());

            for (const auto &change : changes_)
            {
                currentStreamDocument_[change] = cacheDocument_[change];
            }
        }
        Save();
    }

    void FSRegistry::WriteAllCacheBack()
    {
        AU_LOCK_GUARD(lock_->AsWritable());

        for (const auto &[key, val] : cacheDocument_.items())
        {
            AuTryInsert(changes_, key);
        }
    }

    void FSRegistry::SaveAll(const AuOptional<AuString>& path)
    {
        OpenSave(path.value_or(lastPath_.value_or(AuString())), true);
        WriteAllCacheBack();
        SaveBuffered();
        CloseSave();
    }

   
   void FSRegistry::OpenRead(const AuString &path)
   {
       Read(path, EReadType::eClearCacheAndStore);
   }

   void FSRegistry::OpenReadWriteback(const AuString &path)
   {
       Read(path, EReadType::eClearCacheAndStore);
       OpenSave(path, false);
   }

    void FSRegistry::OpenSave(const AuString &path, bool buffered) 
    {
        if (buffered)
        {
            SetWriteModeBuffered(path);
        }
        else
        {
            SetWriteModeStream(path);
        }
    }
    
    void FSRegistry::CloseSave()
    {
        SetWriteModeNone();
    }

    void FSRegistry::LockKey(const AuString &str)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        AuTryInsert(restrictedKeys_, str);
    }

    void FSRegistry::UnlockKey(const AuString &str)
    {
        AU_LOCK_GUARD(lock_->AsWritable());
        AuTryDeleteList(restrictedKeys_, str);
    }

    bool FSRegistry::Save()
    {
        bool ret {};

        if (!lastPath_.has_value())
        {
            return false;
        }

        if (!IO::FS::WriteString(lastPath_.value(), currentStreamDocument_.dump(4)))
        {
            SysPushErrorIO("Couldn't write registry to {}", lastPath_.value());
            return false;
        }

        return true;
    }

    AUKN_SYM IRegistry *RegistryNew(ERegistrySource source)
    {
        SysAssert(source == ERegistrySource::eFS, "Unknown registry type");
        
        auto registry = _new FSRegistry();
        if (!registry)
        {
            return nullptr;
        }

        if (!registry->Init())
        {
            delete registry;
            return nullptr;
        }
        
        return registry;
    }

    AUKN_SYM void RegistryRelease(IRegistry *registry)
    {
        SafeDelete<FSRegistry *>(registry);
    }
}