// Copyright 2021 DeepMind Technologies Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "mujoco.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>


// help
const char helpstring[] =
    "\n Usage:  compile infile outfile\n"
    "   infile can be in mjcf, urdf, mjb format\n"
    "   outfile can be in mjcf, mjb, txt format\n\n"
    " Example:  compile model.xml model.mjb\n";


// deallocate and print message
int finish(const char* msg = 0, mjModel* m = 0)
{
    // deallocated everything
    if( m )
        mj_deleteModel(m);

    // print message
    if( msg )
        printf("%s\n", msg);

    return 0;
}


// possible file types
enum
{
    typeUNKNOWN = 0,
    typeXML,
    typeMJB,
    typeTXT
};


// determine file type
int filetype(const char* filename)
{
    // convert to lower case for string comparison
    char lower[1000];
    size_t i=0;
    while( i<strlen(filename) && i<999 )
    {
        lower[i] = (char)tolower(filename[i]);
        i++;
    }
    lower[i] = 0;

    // find last dot
    int dot = (int)strlen(lower);
    while( dot>=0 && lower[dot]!='.' )
        dot--;

    // no dot found
    if( dot<0 )
        return typeUNKNOWN;

    // check extension
    if( !strcmp(lower+dot, ".xml") || !strcmp(lower+dot, ".urdf") )
        return typeXML;
    else if( !strcmp(lower+dot, ".mjb") )
        return typeMJB;
    else if( !strcmp(lower+dot, ".txt") )
        return typeTXT;
    else
        return typeUNKNOWN;
}



// main function
int main(int argc, const char** argv)
{
    // model and error
    mjModel* m = 0;
    char error[1000];

    // print help if arguments are missing
    if( argc!=3 )
        return finish(helpstring);

    // determine file types
    int type1 = filetype(argv[1]);
    int type2 = filetype(argv[2]);

    // check types
    if( type1==typeUNKNOWN || type1==typeTXT ||
        type2==typeUNKNOWN || (type1==typeMJB && type2==typeXML) )
        return finish("Illegal combination of file formats");

    // make sure output file does not exist
    FILE* fp = fopen(argv[2], "r");
    if( fp )
    {
        fclose(fp);
        return finish("Output file already exists");
    }

    // load model
    if( type1==typeXML )
        m = mj_loadXML(argv[1], 0, error, 1000);
    else
        m = mj_loadModel(argv[1], 0);

    // check error
    if( !m )
    {
        if( type1==typeXML )
            return finish(error, 0);
        else
            return finish("Could not load model", 0);
    }

    // save model
    if( type2==typeXML )
    {
        if( mj_saveLastXML(argv[2], m, error, 1000) )
            return finish(error, m);
    }
    else if( type2==typeMJB )
        mj_saveModel(m, argv[2], 0, 0);
    else
        mj_printModel(m, argv[2]);

    // finalize
    return finish("Done", m);
}