// Copyright (c) 2009-2010 Satoshi Nakamoto

// Copyright (c) 2009-2022 The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <stdexcept>

#include <flatfile.h>

#include <logging.h>

#include <tinyformat.h>

#include <util/fs_helpers.h>

FlatFileSeq::FlatFileSeq(fs::path dir, const char* prefix, size_t chunk_size) :

    m_dir(std::move(dir)),

    m_prefix(prefix),

    m_chunk_size(chunk_size)

{

    if (chunk_size == 0) {

        throw std::invalid_argument("chunk_size must be positive");

    }

}

std::string FlatFilePos::ToString() const

{

    return strprintf("FlatFilePos(nFile=%i, nPos=%i)", nFile, nPos);

}

fs::path FlatFileSeq::FileName(const FlatFilePos& pos) const

{

    return m_dir / fs::u8path(strprintf("%s%05u.dat", m_prefix, pos.nFile));

}

FILE* FlatFileSeq::Open(const FlatFilePos& pos, bool read_only) const

{

    if (pos.IsNull()) {

        return nullptr;

    }

    fs::path path = FileName(pos);

    fs::create_directories(path.parent_path());

    FILE* file = fsbridge::fopen(path, read_only ? "rb": "rb+");

    if (!file && !read_only)

        file = fsbridge::fopen(path, "wb+");

    if (!file) {

        LogPrintf("Unable to open file %s\n", fs::PathToString(path));

        return nullptr;

    }

    if (pos.nPos && fseek(file, pos.nPos, SEEK_SET)) {

        LogPrintf("Unable to seek to position %u of %s\n", pos.nPos, fs::PathToString(path));

        if (fclose(file) != 0) {

            LogError("Unable to close file %s", fs::PathToString(path));

        }

        return nullptr;

    }

    return file;

}

size_t FlatFileSeq::Allocate(const FlatFilePos& pos, size_t add_size, bool& out_of_space) const

{

    out_of_space = false;

    unsigned int n_old_chunks = (pos.nPos + m_chunk_size - 1) / m_chunk_size;

    unsigned int n_new_chunks = (pos.nPos + add_size + m_chunk_size - 1) / m_chunk_size;

    if (n_new_chunks > n_old_chunks) {

        size_t old_size = pos.nPos;

        size_t new_size = n_new_chunks * m_chunk_size;

        size_t inc_size = new_size - old_size;

        if (CheckDiskSpace(m_dir, inc_size)) {

            FILE *file = Open(pos);

            if (file) {

                LogDebug(BCLog::VALIDATION, "Pre-allocating up to position 0x%x in %s%05u.dat\n", new_size, m_prefix, pos.nFile);

                AllocateFileRange(file, pos.nPos, inc_size);

                if (fclose(file) != 0) {

                    LogError("Cannot close file %s%05u.dat after extending it with %u bytes", m_prefix, pos.nFile, new_size);

                    return 0;

                }

                return inc_size;

            }

        } else {

            out_of_space = true;

        }

    }

    return 0;

}

bool FlatFileSeq::Flush(const FlatFilePos& pos, bool finalize) const

{

    FILE* file = Open(FlatFilePos(pos.nFile, 0)); // Avoid fseek to nPos

    if (!file) {

        LogError("%s: failed to open file %d\n", __func__, pos.nFile);

        return false;

    }

    if (finalize && !TruncateFile(file, pos.nPos)) {

        LogError("%s: failed to truncate file %d\n", __func__, pos.nFile);

        if (fclose(file) != 0) {

            LogError("Failed to close file %d", pos.nFile);

        }

        return false;

    }

    if (!FileCommit(file)) {

        LogError("%s: failed to commit file %d\n", __func__, pos.nFile);

        if (fclose(file) != 0) {

            LogError("Failed to close file %d", pos.nFile);

        }

        return false;

    }

    DirectoryCommit(m_dir);

    if (fclose(file) != 0) {

        LogError("Failed to close file %d after flush", pos.nFile);

        return false;

    }

    return true;

}