/* Tuplr: A programming language
 * Copyright (C) 2008-2009 David Robillard <dave@drobilla.net>
 *
 * Tuplr is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * Tuplr is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
 * Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Tuplr.  If not, see <http://www.gnu.org/licenses/>.
 */

/** @file
 * @brief Compile AST using generic backend interface
 *
 * Compilation pass functions (lift/compile) that don't require direct use
 * of any specific backend API are implemented here.  Others are implemented
 * in e.g. llvm.cpp.
 */

#include "tuplr.hpp"

using namespace std;

CValue
ASymbol::compile(CEnv& cenv)
{
	return cenv.vals.ref(this);
}

void
AFn::lift(CEnv& cenv)
{
	cenv.push();
	for (const_iterator p = prot()->begin(); p != prot()->end(); ++p)
		cenv.def((*p)->as<ASymbol*>(), *p, NULL, NULL);

	// Lift body
	for (size_t i = 2; i < size(); ++i)
		at(i)->lift(cenv);

	cenv.pop();

	AType* type = cenv.type(this);
	if (impls.find(type) || !type->concrete())
		return;

	AType* protT = type->at(1)->as<AType*>();
	liftCall(cenv, *protT);
}

void
ACall::lift(CEnv& cenv)
{
	AFn* c = cenv.tenv.resolve(at(0))->to<AFn*>();
	AType argsT(loc);

	// Lift arguments
	for (size_t i = 1; i < size(); ++i) {
		at(i)->lift(cenv);
		argsT.push_back(cenv.type(at(i)));
	}

	if (!c) return; // Primitive

	if (c->prot()->size() < size() - 1)
		throw Error(loc, (format("too many arguments to function `%1%'") % at(0)->str()).str());
	if (c->prot()->size() > size() - 1)
		throw Error(loc, (format("too few arguments to function `%1%'") % at(0)->str()).str());

	c->liftCall(cenv, argsT); // Lift called closure
}

CValue
ACall::compile(CEnv& cenv)
{
	AFn* c = cenv.tenv.resolve(at(0))->to<AFn*>();

	if (!c) return NULL; // Primitive

	AType protT(loc);
	for (size_t i = 1; i < size(); ++i)
		protT.push_back(cenv.type(at(i)));

	TEnv::GenericTypes::const_iterator gt = cenv.tenv.genericTypes.find(c);
	assert(gt != cenv.tenv.genericTypes.end());
	AType fnT(loc);
	fnT.push_back(cenv.penv.sym("Fn"));
	fnT.push_back(&protT);
	fnT.push_back(cenv.type(this));

	CFunction f = c->impls.find(&fnT);
	THROW_IF(!f, loc, (format("callee failed to compile for type %1%") % fnT.str()).str());

	vector<CValue> args(size() - 1);
	for (size_t i = 0; i < args.size(); ++i)
		args[i] = cenv.compile(at(i + 1));

	return cenv.engine()->compileCall(cenv, f, args);
}

void
ADef::lift(CEnv& cenv)
{
	// Define stub first for recursion
	cenv.def(sym(), at(2), cenv.type(at(2)), NULL);
	AFn* c = at(2)->to<AFn*>();
	if (c)
		c->name = sym()->str();
	at(2)->lift(cenv);
}

CValue
ADef::compile(CEnv& cenv)
{
	// Define stub first for recursion
	cenv.def(sym(), at(2), cenv.type(at(2)), NULL);
	CValue val = cenv.compile(at(size() - 1));
	cenv.vals.def(sym(), val);
	return val;
}