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

    File: FSRecursion.cpp
    Date: 2022-11-06
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "FS.hpp"

namespace Aurora::IO::FS
{
    struct RecursiveDirIterator : IReadDir
    {
        AuSPtr<IReadDir> pDir;
        AuList<AuString> nextLevel;
        AuString curPath;
        AuString curSubDir;
        bool bSymlinkTraversal { true };
        AuUInt32 uErrorCount {};
        AuList<AuString> failedPaths;

        virtual AuUInt32 GetErrorCount() override
        {
            return this->uErrorCount;
        }

        virtual AuList<AuString> GetErrorPaths() override
        {
            return this->failedPaths;
        }

        bool OpenDir(const AuROString &str)
        {
            curPath = str;
            pDir = ReadDir(str);
            return bool(pDir);
        }

        bool OpenNext(const AuROString &str)
        {
            curPath = str;
            pDir = ReadDir(str);
            return bool(pDir);
        }

        void DoNext()
        {
            if (this->pDir)
            {
                if (auto uCount = this->pDir->GetErrorCount())
                {
                    this->failedPaths.push_back(this->curPath + AuString(1, AuFS::kPathSplitter) + this->curSubDir);
                    this->uErrorCount += uCount;
                }
            }

            this->pDir.reset();

            if (!nextLevel.size())
            {
                return;
            }

            auto a = nextLevel[0];
            nextLevel.erase(nextLevel.begin());
            pDir = ReadDir(curPath + "/" + a);
            curSubDir = a;
        }

        virtual StatEx *Next() override
        {
            AU_DEBUG_MEMCRUNCH;

            StatEx *pNext {};
            if (!this->pDir)
            {
                return {};
            }

            do
            {
                try
                {
                    pNext = this->pDir->Next();

                    while (!pNext)
                    {
                        DoNext();
                        if (!this->pDir)
                        {
                            return {};
                        }

                        pNext = this->pDir->Next();
                    }

                    if (curSubDir.size())
                    {
                        pNext->fileName.insert(pNext->fileName.begin(), curSubDir.begin(), curSubDir.end());
                    }

                    if (!this->bSymlinkTraversal && pNext->bSymLink)
                    {
                        continue;
                    }

                    if (pNext->bExistsDirectory)
                    {
                        nextLevel.push_back(pNext->fileName + "/");
                    }
                }
                catch (...)
                {
                    SysPushErrorCatch();
                }
            }
            while (false);
            
            return pNext;
        }
    };

    AUKN_SYM AuSPtr<IReadDir> ReadDirRecursive(const AuROString &string, AuOptional<bool> bTraverseSymlinks)
    {
        auto pObj = AuMakeShared<RecursiveDirIterator>();
        if (!pObj)
        {
            SysPushErrorMem();
            return {};
        }

        pObj->bSymlinkTraversal = bTraverseSymlinks.ValueOr(true);

        try
        {
            if (!pObj->OpenDir(string))
            {
                return {};
            }
        }
        catch (...)
        {
            SysPushErrorCatch();
        }

        return pObj;
    }
}