// ==========================================================================
//                         Mason - A Read Simulator
// ==========================================================================
// Copyright (c) 2006-2026, Knut Reinert, FU Berlin
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of Knut Reinert or the FU Berlin nor the names of
//       its contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL KNUT REINERT OR THE FU BERLIN BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
// DAMAGE.
//
// ==========================================================================
// Author: Manuel Holtgrewe <manuel.holtgrewe@fu-berlin.de>
// ==========================================================================

#include "external_split_merge.h"

// ---------------------------------------------------------------------------
// Function IdSplitter::open()
// ---------------------------------------------------------------------------

void IdSplitter::open()
{
    close();
    for (unsigned i = 0; i < numContigs; ++i)
    {
#if defined(STDLIB_VS)
        char fileNameBuffer[1000];
        char filePathBuffer[1000];
        //  Gets the temp path env string (no guarantee it's a valid path).
        DWORD dwRetVal = 0;
        dwRetVal = GetTempPath(1000,            // length of the buffer
                               filePathBuffer); // buffer for path
        if (dwRetVal > 1000 || (dwRetVal == 0))
        {
            std::cerr << "GetTempPath failed" << std::endl;
            exit(1);
        }

        UINT uRetVal   = 0;
        uRetVal = GetTempFileName(filePathBuffer,   // directory for tmp files
                                  TEXT("MASON_"),   // temp file name prefix
                                  0,                // create unique name
                                  fileNameBuffer);  // buffer for name

        if (uRetVal == 0)
        {
            std::cerr << "GetTempFileName failed" << std::endl;
            exit(1);
        }

        // The file exists now and is already closed.
        DeleteFile(fileNameBuffer);
        files.push_back(new std::fstream(&fileNameBuffer[0], std::ios::binary | std::ios::in | std::ios::out));
        // TODO: Deleting the file here will not actually remove it on windows.
        fileNames.push_back(fileNameBuffer);
#else  // POSIX (Linux/Mac)
        // Create temporary file using POSIX API, open with <cstdio>, delete, close POSIX.
        char const * tmpdir = 0;
        if ((tmpdir = getenv("TMPDIR")) == NULL)
            tmpdir = "/tmp";
        std::string pathTpl = tmpdir;
        pathTpl += "/MASON_XXXXXX";

        mode_t cur_umask = umask(S_IRWXO | S_IRWXG);  // to silence Coverity warning
        int fd = mkstemp(&pathTpl[0]);
        files.push_back(new std::fstream(pathTpl.c_str(), std::ios::binary | std::ios::in | std::ios::out));
        umask(cur_umask);
        remove(pathTpl.c_str());
        ::close(fd);
#endif

        if (!files.back())
        {
            std::cerr << "ERROR: Could not open temporary file!\n";
            exit(1);
        }
    }
}

// ---------------------------------------------------------------------------
// Function IdSplitter::reset()
// ---------------------------------------------------------------------------

void IdSplitter::reset()
{
    for (unsigned i = 0; i < files.size(); ++i)
        if (files[i] != 0)
        {
            SEQAN_ASSERT(files[i]->good());
            files[i]->flush();
            files[i]->seekg(0);
            SEQAN_ASSERT(files[i]->good());
        }
}

// ---------------------------------------------------------------------------
// Function IdSplitter::close()
// ---------------------------------------------------------------------------

void IdSplitter::close()
{
    for (unsigned i = 0; i < files.size(); ++i)
        if (files[i])
        {
            delete files[i];
#ifdef STDLIB_VS
            DeleteFile(fileNames[i].c_str());
#endif  // #ifdef STDLIB_VS
            files[i] = 0;
        }
    files.clear();
    fileNames.clear();
}

// ---------------------------------------------------------------------------
// Function SamJoiner::init()
// ---------------------------------------------------------------------------

void SamJoiner::init(seqan2::BamFileOut * outPtr)
{
    resize(records, splitter->files.size());
    active.resize(splitter->files.size());

    for (unsigned i = 0; i < splitter->files.size(); ++i)
    {
        if (i == 0u && outPtr)
            bamFileIns.push_back(new seqan2::BamFileIn(*outPtr, *splitter->files[i]));
        else
            bamFileIns.push_back(new seqan2::BamFileIn(*splitter->files[i]));

        // We use a separate header structure and name stores and caches.  Since the headers of all files are equal, we
        // will write out the first one only.
        seqan2::BamHeader tmpHeader;
        readHeader(tmpHeader, *bamFileIns[i]);
        if (i == 0u)
            header = tmpHeader;

        active[i] = _loadNext(records[i], i);
        numActive += (active[i] != false);
    }
}

// ---------------------------------------------------------------------------
// Function SamJoiner::_loadNext()
// ---------------------------------------------------------------------------

bool SamJoiner::_loadNext(seqan2::BamAlignmentRecord & record, unsigned idx)
{
    if (seqan2::atEnd(*bamFileIns[idx]))
        return false;
    readRecord(record, *bamFileIns[idx]);
    return true;
}

// ---------------------------------------------------------------------------
// Function SamJoiner::get()
// ---------------------------------------------------------------------------

int SamJoiner::get(seqan2::BamAlignmentRecord & record)
{
    unsigned idx = std::numeric_limits<unsigned>::max();
    for (unsigned i = 0; i < length(records); ++i)
    {
        if (!active[i])
            continue;
        if (idx == std::numeric_limits<unsigned>::max() || ltBamAlignmentRecord(records[i], records[idx]))
            idx = i;
    }
    if (idx == std::numeric_limits<unsigned>::max())
        return 1;

    // We use double-buffering and the input parameters as buffers.
    using std::swap;
    active[idx] = _loadNext(record, idx);
    swap(record, records[idx]);
    numActive -= !active[idx];

    return 0;
}

// ---------------------------------------------------------------------------
// Function ContigPicker::pick()
// ---------------------------------------------------------------------------

std::pair<int, int> ContigPicker::pick()
{
    // Pick reference id.
    int rID = 0;
    if (lengthSums.size() > 1u)
    {
        std::uniform_int_distribution<int64_t> dist(0, lengthSums.back() - 1);
        int64_t x = dist(rng);
        for (unsigned i = 0; i < lengthSums.size(); ++i)
        {
            if (x >= lengthSums[i])
                rID = i + 1;
            if (x < lengthSums[i])
                break;
        }
    }

    // Pick haplotype id.
    std::uniform_int_distribution<int> dist2(0, numHaplotypes - 1);
    int hID = dist2(rng);

    return std::make_pair(rID, hID);
}
