#include <map>
#include <iostream>

#include <gc/gc_allocator.h>

#include "shared.hh"
#include "store-api.hh"
#include "eval.hh"
#include "util.hh"
#include "xml-writer.hh"
#include "get-drvs.hh"

using namespace nix;


void printHelp()
{
    std::cout << "Syntax: eval-jobs <expr>\n";
}


static Path gcRootsDir;


typedef std::map<Symbol, std::pair<unsigned int, Value *> > ArgsUsed;
typedef std::list<Value *, traceable_allocator<Value *> > ValueList;
typedef std::map<Symbol, ValueList> AutoArgs;


static void findJobs(EvalState & state, XMLWriter & doc,
    const ArgsUsed & argsUsed, const AutoArgs & argsLeft,
    Value & v, const string & attrPath);


static void tryJobAlts(EvalState & state, XMLWriter & doc,
    const ArgsUsed & argsUsed, const AutoArgs & argsLeft,
    const string & attrPath, Value & fun,
    Formals::Formals_::iterator cur,
    Formals::Formals_::iterator last,
    const Bindings & actualArgs)
{
    if (cur == last) {
        Value v, * arg = state.allocValue();
        state.mkAttrs(*arg, 0);
        *arg->attrs = actualArgs;
        mkApp(v, fun, *arg);
        findJobs(state, doc, argsUsed, argsLeft, v, attrPath);
        return;
    }

    AutoArgs::const_iterator a = argsLeft.find(cur->name);

    if (a == argsLeft.end())
        throw TypeError(format("job `%1%' requires an argument named `%2%'")
            % attrPath % cur->name);

    Formals::Formals_::iterator next = cur; ++next;

    int n = 0;
    foreach (ValueList::const_iterator, i, a->second) {
        Bindings actualArgs2(actualArgs); // !!! inefficient
        ArgsUsed argsUsed2(argsUsed);
        AutoArgs argsLeft2(argsLeft);
        actualArgs2.push_back(Attr(cur->name, *i));
        actualArgs2.sort(); // !!! inefficient
        argsUsed2[cur->name] = std::pair<unsigned int, Value *>(n, *i);
        argsLeft2.erase(cur->name);
        tryJobAlts(state, doc, argsUsed2, argsLeft2, attrPath, fun, next, last, actualArgs2);
        ++n;
    }
}


static void showArgsUsed(XMLWriter & doc, const ArgsUsed & argsUsed)
{
    foreach (ArgsUsed::const_iterator, i, argsUsed) {
        XMLAttrs xmlAttrs2;
        xmlAttrs2["name"] = i->first;
        xmlAttrs2["value"] = (format("%1%") % *i->second.second).str();
        xmlAttrs2["altnr"] = int2String(i->second.first);
        doc.writeEmptyElement("arg", xmlAttrs2);
    }
}


static string queryMetaFieldString(MetaInfo & meta, const string & name)
{
    MetaValue value = meta[name];
    if (value.type != MetaValue::tpString) return "";
    return value.stringValue;
}

    
static int queryMetaFieldInt(MetaInfo & meta, const string & name, int def)
{
    MetaValue value = meta[name];
    if (value.type == MetaValue::tpInt) return value.intValue;
    if (value.type == MetaValue::tpString) {
        int n;
        if (string2Int(value.stringValue, n)) return n;
    }
    return def;
}


static void findJobsWrapped(EvalState & state, XMLWriter & doc,
    const ArgsUsed & argsUsed, const AutoArgs & argsLeft,
    Value & v, const string & attrPath)
{
    debug(format("at path `%1%'") % attrPath);

    state.forceValue(v);

    if (v.type == tAttrs) {

        DrvInfo drv;
        
        if (getDerivation(state, v, drv)) {
            XMLAttrs xmlAttrs;
            Path drvPath;

            xmlAttrs["jobName"] = attrPath;
            xmlAttrs["nixName"] = drv.name;
            xmlAttrs["system"] = drv.system;
            xmlAttrs["drvPath"] = drvPath = drv.queryDrvPath(state);
            xmlAttrs["outPath"] = drv.queryOutPath(state);
            MetaInfo meta = drv.queryMetaInfo(state);
            xmlAttrs["description"] = queryMetaFieldString(meta, "description");
            xmlAttrs["longDescription"] = queryMetaFieldString(meta, "longDescription");
            xmlAttrs["license"] = queryMetaFieldString(meta, "license");
            xmlAttrs["homepage"] = queryMetaFieldString(meta, "homepage");

            int prio = queryMetaFieldInt(meta, "schedulingPriority", 100);
            xmlAttrs["schedulingPriority"] = int2String(prio);

            int timeout = queryMetaFieldInt(meta, "timeout", 36000);
            xmlAttrs["timeout"] = int2String(timeout);

            int maxsilent = queryMetaFieldInt(meta, "maxSilent", 3600);
            xmlAttrs["maxSilent"] = int2String(maxsilent);

            string maintainers;
            MetaValue value = meta["maintainers"];
            if (value.type == MetaValue::tpString)
                maintainers = value.stringValue;
            else if (value.type == MetaValue::tpStrings) {
                foreach (Strings::const_iterator, i, value.stringValues) {
                    if (maintainers.size() != 0) maintainers += ", ";
                    maintainers += *i;
                }
            }
            xmlAttrs["maintainers"] = maintainers;

            /* Register the derivation as a GC root.  !!! This
               registers roots for jobs that we may have already
               done. */
            if (gcRootsDir != "") {
                Path root = gcRootsDir + "/" + baseNameOf(drvPath);
                if (!pathExists(root)) addPermRoot(*store, drvPath, root, false);
            }
            
            XMLOpenElement _(doc, "job", xmlAttrs);
            showArgsUsed(doc, argsUsed);
        }

        else {
            foreach (Bindings::iterator, i, *v.attrs)
                findJobs(state, doc, argsUsed, argsLeft, *i->value,
                    (attrPath.empty() ? "" : attrPath + ".") + (string) i->name);
        }
    }

    else if (v.type == tLambda && v.lambda.fun->matchAttrs) {
        tryJobAlts(state, doc, argsUsed, argsLeft, attrPath, v,
            v.lambda.fun->formals->formals.begin(),
            v.lambda.fun->formals->formals.end(),
            Bindings());
    }

    else
        throw TypeError(format("unsupported value: %1%") % v);
}


static void findJobs(EvalState & state, XMLWriter & doc,
    const ArgsUsed & argsUsed, const AutoArgs & argsLeft,
    Value & v, const string & attrPath)
{
    try {
        findJobsWrapped(state, doc, argsUsed, argsLeft, v, attrPath);
    } catch (EvalError & e) {
        XMLAttrs xmlAttrs;
        xmlAttrs["location"] = attrPath;
        xmlAttrs["msg"] = e.msg();
        XMLOpenElement _(doc, "error", xmlAttrs);
        showArgsUsed(doc, argsUsed);
    }
}


void run(Strings args)
{
    EvalState state;
    Path releaseExpr;
    AutoArgs autoArgs;
    
    for (Strings::iterator i = args.begin(); i != args.end(); ) {
        string arg = *i++;
        if (arg == "--arg" || arg == "--argstr") {
            /* This is like --arg in nix-instantiate, except that it
               supports multiple versions for the same argument.
               That is, autoArgs is a mapping from variable names to
               *lists* of values. */
            if (i == args.end()) throw UsageError("missing argument");
            string name = *i++;
            if (i == args.end()) throw UsageError("missing argument");
            string value = *i++;
            Value * v = state.allocValue();
            if (arg == "--arg")
                state.eval(state.parseExprFromString(value, absPath(".")), *v);
            else
                mkString(*v, value);
            autoArgs[state.symbols.create(name)].push_back(v);
        }
        else if (arg == "--gc-roots-dir") {
            if (i == args.end()) throw UsageError("missing argument");
            gcRootsDir = *i++;
        }
        else if (arg[0] == '-')
            throw UsageError(format("unknown flag `%1%'") % arg);
        else
            releaseExpr = arg;
    }

    if (releaseExpr == "") throw UsageError("no expression specified");
    
    if (gcRootsDir == "") printMsg(lvlError, "warning: `--gc-roots-dir' not specified");
    
    store = openStore();

    Expr * e = state.parseExprFromFile(releaseExpr);
    Value v;
    state.mkThunk_(v, e);

    std::cout.setf(std::ios::unitbuf);
    XMLWriter doc(true, std::cout);
    XMLOpenElement root(doc, "jobs");
    findJobs(state, doc, ArgsUsed(), autoArgs, v, "");

    state.printStats();
}


string programId = "eval-jobs";