#include "derivations.hh"
#include "globals.hh"
#include "store.hh"

#include "derivations-ast.hh"
#include "derivations-ast.cc"


Hash hashTerm(ATerm t)
{
    return hashString(htSHA256, atPrint(t));
}


Path writeDerivation(const Derivation & drv, const string & name)
{
    return addTextToStore(name + drvExtension,
        atPrint(unparseDerivation(drv)));
}


static void checkPath(const string & s)
{
    if (s.size() == 0 || s[0] != '/')
        throw Error(format("bad path `%1%' in store expression") % s);
}
    

static void parseStrings(ATermList paths, StringSet & out, bool arePaths)
{
    for (ATermIterator i(paths); i; ++i) {
        if (ATgetType(*i) != AT_APPL)
            throw badTerm("not a path", *i);
        string s = aterm2String(*i);
        if (arePaths) checkPath(s);
        out.insert(s);
    }
}


void throwBadDrv(ATerm t)
{
    throw badTerm("not a valid derivation", t);
}


Derivation parseDerivation(ATerm t)
{
    Derivation drv;
    ATermList outs, inDrvs, inSrcs, args, bnds;
    ATerm builder, platform;

    if (!matchDerive(t, outs, inDrvs, inSrcs, platform, builder, args, bnds))
        throwBadDrv(t);

    for (ATermIterator i(outs); i; ++i) {
        ATerm id, path, hashAlgo, hash;
        if (!matchDerivationOutput(*i, id, path, hashAlgo, hash))
            throwBadDrv(t);
        DerivationOutput out;
        out.path = aterm2String(path);
        checkPath(out.path);
        out.hashAlgo = aterm2String(hashAlgo);
        out.hash = aterm2String(hash);
        drv.outputs[aterm2String(id)] = out;
    }

    for (ATermIterator i(inDrvs); i; ++i) {
        ATerm drvPath;
        ATermList ids;
        if (!matchDerivationInput(*i, drvPath, ids))
            throwBadDrv(t);
        Path drvPath2 = aterm2String(drvPath);
        checkPath(drvPath2);
        StringSet ids2;
        parseStrings(ids, ids2, false);
        drv.inputDrvs[drvPath2] = ids2;
    }
    
    parseStrings(inSrcs, drv.inputSrcs, true);

    drv.builder = aterm2String(builder);
    drv.platform = aterm2String(platform);
    
    for (ATermIterator i(args); i; ++i) {
        if (ATgetType(*i) != AT_APPL)
            throw badTerm("string expected", *i);
        drv.args.push_back(aterm2String(*i));
    }

    for (ATermIterator i(bnds); i; ++i) {
        ATerm s1, s2;
        if (!matchEnvBinding(*i, s1, s2))
            throw badTerm("tuple of strings expected", *i);
        drv.env[aterm2String(s1)] = aterm2String(s2);
    }

    return drv;
}


static ATermList unparseStrings(const StringSet & paths)
{
    ATermList l = ATempty;
    for (PathSet::const_iterator i = paths.begin();
         i != paths.end(); ++i)
        l = ATinsert(l, toATerm(*i));
    return ATreverse(l);
}


ATerm unparseDerivation(const Derivation & drv)
{
    ATermList outputs = ATempty;
    for (DerivationOutputs::const_iterator i = drv.outputs.begin();
         i != drv.outputs.end(); ++i)
        outputs = ATinsert(outputs,
            makeDerivationOutput(
                toATerm(i->first),
                toATerm(i->second.path),
                toATerm(i->second.hashAlgo),
                toATerm(i->second.hash)));

    ATermList inDrvs = ATempty;
    for (DerivationInputs::const_iterator i = drv.inputDrvs.begin();
         i != drv.inputDrvs.end(); ++i)
        inDrvs = ATinsert(inDrvs,
            makeDerivationInput(
                toATerm(i->first),
                unparseStrings(i->second)));
    
    ATermList args = ATempty;
    for (Strings::const_iterator i = drv.args.begin();
         i != drv.args.end(); ++i)
        args = ATinsert(args, toATerm(*i));

    ATermList env = ATempty;
    for (StringPairs::const_iterator i = drv.env.begin();
         i != drv.env.end(); ++i)
        env = ATinsert(env,
            makeEnvBinding(
                toATerm(i->first),
                toATerm(i->second)));

    return makeDerive(
        ATreverse(outputs),
        ATreverse(inDrvs),
        unparseStrings(drv.inputSrcs),
        toATerm(drv.platform),
        toATerm(drv.builder),
        ATreverse(args),
        ATreverse(env));
}


bool isDerivation(const string & fileName)
{
    return
        fileName.size() >= drvExtension.size() &&
        string(fileName, fileName.size() - drvExtension.size()) == drvExtension;
}