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** General Public License version 3 as published by the Free Software
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#pragma once

#include "filepathexceptions.h"
#include "filepathid.h"
#include "filepath.h"
#include "filepathview.h"
#include "stringcache.h"

#include <algorithm>

namespace ClangBackEnd {

template <typename FilePathStorage>
class CLANGSUPPORT_GCCEXPORT FilePathCache
{
    class FileNameView
    {
    public:
        friend bool operator==(const FileNameView &first, const FileNameView &second)
        {
            return first.directoryId == second.directoryId
                && first.fileName == second.fileName;
        }

        static
        int compare(FileNameView first, FileNameView second) noexcept
        {
            int directoryDifference = first.directoryId - second.directoryId;

            if (directoryDifference)
                return directoryDifference;

            return Utils::compare(first.fileName, second.fileName);
        }

    public:
        Utils::SmallStringView fileName;
        int directoryId;
    };

    class FileNameEntry
    {
    public:
        FileNameEntry(Utils::SmallStringView fileName, int directoryId)
            : fileName(fileName),
              directoryId(directoryId)
        {}

        FileNameEntry(FileNameView view)
            : fileName(view.fileName),
              directoryId(view.directoryId)
        {}

        friend bool operator==(const FileNameEntry &first, const FileNameEntry &second)
        {
            return first.directoryId == second.directoryId
                && first.fileName == second.fileName;
        }

        operator FileNameView() const
        {
            return {fileName, directoryId};
        }

        operator Utils::SmallString() &&
        {
            return std::move(fileName);
        }

    public:
        Utils::SmallString fileName;
        int directoryId;
    };

    using DirectoryPathCache = StringCache<Utils::PathString,
                                           Utils::SmallStringView,
                                           int,
                                           SharedMutex,
                                           decltype(&Utils::reverseCompare),
                                           Utils::reverseCompare>;
    using FileNameCache = StringCache<FileNameEntry,
                                      FileNameView,
                                      int,
                                      SharedMutex,
                                      decltype(&FileNameView::compare),
                                      FileNameView::compare>;
public:
    FilePathCache(FilePathStorage &filePathStorage)
        : m_filePathStorage(filePathStorage)
    {}

    FilePathCache(const FilePathCache &) = delete;
    FilePathCache &operator=(const FilePathCache &) = delete;

    FilePathId filePathId(FilePathView filePath) const
    {
        Utils::SmallStringView directoryPath = filePath.directory();

        int directoryId = m_directyPathCache.stringId(directoryPath,
                                                      [&] (const Utils::SmallStringView) {
            return m_filePathStorage.fetchDirectoryId(directoryPath);
        });

        Utils::SmallStringView fileName = filePath.name();

        int fileNameId = m_fileNameCache.stringId({fileName, directoryId},
                                                  [&] (const FileNameView) {
            return m_filePathStorage.fetchSourceId(directoryId, fileName);
        });

        return {directoryId, fileNameId};
    }

    FilePath filePath(FilePathId filePathId) const
    {
        if (Q_UNLIKELY(!filePathId.isValid()))
            throw NoFilePathForInvalidFilePathId();

        auto fetchFilePath = [&] (int id) { return m_filePathStorage.fetchDirectoryPath(id); };

        Utils::PathString directoryPath = m_directyPathCache.string(filePathId.directoryId,
                                                                    fetchFilePath);


        auto fetchSoureName = [&] (int id) {
            return FileNameEntry{m_filePathStorage.fetchSourceName(id), filePathId.directoryId};
        };

        Utils::SmallString fileName = m_fileNameCache.string(filePathId.filePathId,
                                                             fetchSoureName);

        return FilePath{directoryPath, fileName};
    }

private:
    mutable DirectoryPathCache m_directyPathCache;
    mutable FileNameCache m_fileNameCache;
    FilePathStorage &m_filePathStorage;
};

} // namespace ClangBackEnd