/*****************************************************************************
*
* Copyright (c) 2003-2020 by The University of Queensland
* http://www.uq.edu.au
*
* Primary Business: Queensland, Australia
* Licensed under the Apache License, version 2.0
* http://www.apache.org/licenses/LICENSE-2.0
*
* Development until 2012 by Earth Systems Science Computational Center (ESSCC)
* Development 2012-2013 by School of Earth Sciences
* Development from 2014-2017 by Centre for Geoscience Computing (GeoComp)
* Development from 2019 by School of Earth and Environmental Sciences
**
*****************************************************************************/

#include <weipa/EscriptDataset.h>
#include <weipa/DataVar.h>

#ifdef ESYS_HAVE_SILO
#include <silo.h>
#endif

#include <cstring>
#include <fstream>
#include <iostream>
#include <sstream>

using namespace std;
using namespace weipa;

string insertTimestep(const string& fString, int timeStep, int tsMultiplier)
{
    string s(fString);
    size_t pos;
    if ((pos = s.find("%")) != s.npos) {
        size_t endpos = pos+1;
        while (endpos<s.length() && s[endpos] != 'd')
            endpos++;
        string fmtStr = s.substr(pos, endpos-pos+1);
        char ts[255];
        sprintf(ts, fmtStr.c_str(), timeStep*tsMultiplier);
        s.replace(pos, endpos-pos+1, ts);
    }
    return s;
}

int usage()
{
#ifdef ESYS_HAVE_SILO
    cerr << "Usage: escriptconvert {-vtk|-silo} <file.esd>" << endl;
#else
    cerr << "Note: escriptconvert was compiled without Silo support!" << endl;
    cerr << "Usage: escriptconvert [-vtk] <file.esd>" << endl;
#endif
    fflush(stderr);
    return -1;
}

void cleanup()
{
#if HAVE_MPI
    MPI_Finalize();
#endif
}

int main(int argc, char** argv)
{
#if HAVE_MPI
    MPI_Init(&argc, &argv);
#endif

    // turn off for debugging purposes
    bool writeMultiMesh = true;

    // whether time-varying datasets should use the same domain (from T=0)
    // TODO: Add a command line option for this
    bool writeDomainOnce = true;
    bool doVTK = false, doSilo = false;
    string esdFile;

#if ESYS_HAVE_SILO
    if (argc != 3) {
        cleanup();
        return usage();
    }

    if (!strcmp(argv[1], "-vtk")) {
        doVTK = true;
    } else if (!strcmp(argv[1], "-silo")) {
        doSilo = true;
    } else {
        cleanup();
        return usage();
    }
    esdFile = string(argv[2]);
    
#else // !ESYS_HAVE_SILO
    if (argc == 2) {
        esdFile = string(argv[1]);
    } else if (argc == 3) {
        if (strcmp(argv[1], "-vtk")) {
            cleanup();
            return usage();
        }
        esdFile = string(argv[2]);
    } else {
        cleanup();
        return usage();
    }
    doVTK = true;
#endif

    if (!doVTK && !doSilo) {
        cleanup();
        return usage();
    }
    
    ifstream in(esdFile.c_str());
    if (!in.is_open()) {
        cerr << "Could not open " << esdFile << "." << endl;
        cleanup();
        return -1;
    }

    // first line (header) should be "#escript datafile Vx.y"
    char line[256];
    in.getline(line, 256);
    int major, minor;
    if (sscanf(line, "#escript datafile V%d.%d", &major, &minor) != 2) {
        cerr << esdFile << " is not a valid escript datafile." << endl;
        in.close();
        cleanup();
        return -1;
    }

    int nParts=0, nTimesteps=1, tsMultiplier=1;
    string domainFile;
    StringVec varFiles;
    StringVec varNames;

    while (in.good()) {
        in.getline(line, 256);
        if (line[0] == '#' || strlen(line) == 0)
            continue;
        int iVal;
        char sVal[256];
        if (sscanf(line, "N=%d", &iVal) == 1)
            nParts = iVal;
        else if (sscanf(line, "T=%d", &iVal) == 1)
            nTimesteps = iVal;
        else if (sscanf(line, "DT=%d", &iVal) == 1)
            tsMultiplier = iVal;
        else if (sscanf(line, "M=%s", sVal) == 1)
            domainFile = sVal;
        else if (sscanf(line, "V=%s", sVal) == 1 && strchr(sVal, ':')) {
            // split into filename and variable name
            char* colon = strchr(sVal, ':');
            *colon = 0;
            varFiles.push_back(sVal);
            varNames.push_back(colon+1);
        } else {
            cerr << esdFile << " is not a valid escript datafile." << endl;
            in.close();
            cleanup();
            return -1;
        }
    }

    in.close();
    
    if (nParts < 1 || domainFile == "" || nTimesteps < 1 || tsMultiplier < 1) {
        cerr << esdFile << " is not a valid escript datafile." << endl;
        cleanup();
        return -1;
    }

    cout << "Converting " << esdFile << "..." << endl;

    DomainChunks domainFromTzero;

    // load and save all timesteps
    for (int timeStep = 0; timeStep < nTimesteps; timeStep++) {
        StringVec varFilesTS;
        StringVec::const_iterator it;

        // look for "%d" in filename and replace by timestep*multiplier if found
        for (it=varFiles.begin(); it!=varFiles.end(); it++) {
            string v = insertTimestep(*it, timeStep, tsMultiplier);
            if (nParts > 1)
                v.append(".nc.%04d");
            else
                v.append(".nc");
            varFilesTS.push_back(v);
        }

        if (nTimesteps > 1)
            cout << "T = " << timeStep << endl;

        EscriptDataset* ds;
#if HAVE_MPI
        ds = new EscriptDataset(MPI_COMM_WORLD);
#else
        ds = new EscriptDataset();
#endif

        if (writeDomainOnce && timeStep > 0) {
            if (!ds->loadNetCDF(domainFromTzero, varFilesTS, varNames)) {
                delete ds;
                break;
            }
        } else {
            string domainTS = insertTimestep(domainFile, timeStep, tsMultiplier);
            if (nParts > 1)
                domainTS.append(".nc.%04d");
            else
                domainTS.append(".nc");

            if (!ds->loadNetCDF(domainTS, varFilesTS, varNames, nParts)) {
                delete ds;
                break;
            }
        }

        string baseName(esdFile);
        size_t dot = baseName.rfind('.');
        if (dot != baseName.npos)
            baseName.erase(dot, baseName.length()-dot);

        ds->setCycleAndTime(timeStep, (double)timeStep);

        ostringstream outFilename;
        outFilename << baseName;
        if (nTimesteps > 1)
            outFilename << "." << timeStep;
        if (doSilo) {
            outFilename << ".silo";
            ds->saveSilo(outFilename.str(), writeMultiMesh);
        } else {
            outFilename << ".vtu";
            ds->saveVTK(outFilename.str());
        }

        // keep domain from first timestep if it should be reused
        if (writeDomainOnce && nTimesteps > 1 && timeStep == 0) {
            domainFromTzero = ds->getConvertedDomain();
            domainFile = outFilename.str();
            DomainChunks::iterator domIt;
            if (doSilo) {
                for (domIt = domainFromTzero.begin();
                        domIt != domainFromTzero.end();
                        domIt++)
                {
                    // Prepend Silo mesh paths with the filename of the mesh
                    // to be used
                    string fullSiloPath = domainFile + string(":");
                    fullSiloPath += (*domIt)->getSiloPath();
                    (*domIt)->setSiloPath(fullSiloPath);
                }
            }
        }

        delete ds;
    }
    
    cout << "All done." << endl;
    cleanup();

    return 0;
}