/*
 * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.graal.loop;

import java.util.*;

import com.oracle.graal.api.meta.*;
import com.oracle.graal.debug.*;
import com.oracle.graal.graph.*;
import com.oracle.graal.graph.iterators.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.nodes.calc.*;
import com.oracle.graal.nodes.cfg.*;

public class LoopEx {

    private final Loop lirLoop;
    private LoopFragmentInside inside;
    private LoopFragmentWhole whole;
    private CountedLoopInfo counted; // TODO (gd) detect
    private LoopsData data;

    LoopEx(Loop lirLoop, LoopsData data) {
        this.lirLoop = lirLoop;
        this.data = data;
    }

    public Loop lirLoop() {
        return lirLoop;
    }

    public LoopFragmentInside inside() {
        if (inside == null) {
            inside = new LoopFragmentInside(this);
        }
        return inside;
    }

    public LoopFragmentWhole whole() {
        if (whole == null) {
            whole = new LoopFragmentWhole(this);
        }
        return whole;
    }

    @SuppressWarnings("unused")
    public LoopFragmentInsideFrom insideFrom(FixedNode point) {
        // TODO (gd)
        return null;
    }

    @SuppressWarnings("unused")
    public LoopFragmentInsideBefore insideBefore(FixedNode point) {
        // TODO (gd)
        return null;
    }

    public boolean isOutsideLoop(Node n) {
        return !whole().contains(n);
    }

    public LoopBeginNode loopBegin() {
        return lirLoop().loopBegin();
    }

    public FixedNode predecessor() {
        return (FixedNode) loopBegin().forwardEnd().predecessor();
    }

    public FixedNode entryPoint() {
        return loopBegin().forwardEnd();
    }

    public boolean isCounted() {
        return counted != null;
    }

    public CountedLoopInfo counted() {
        return counted;
    }

    public LoopEx parent() {
        if (lirLoop.parent == null) {
            return null;
        }
        return data.loop(lirLoop.parent);
    }

    public int size() {
        return whole().nodes().count();
    }

    @Override
    public String toString() {
        return (isCounted() ? "CountedLoop [" + counted() + "] " : "Loop ") + "(depth=" + lirLoop().depth + ") " + loopBegin();
    }

    private class InvariantPredicate extends NodePredicate {

        @Override
        public boolean apply(Node n) {
            return isOutsideLoop(n);
        }
    }

    public void reassociateInvariants() {
        InvariantPredicate invariant = new InvariantPredicate();
        StructuredGraph graph = (StructuredGraph) loopBegin().graph();
        for (BinaryNode binary : whole().nodes().filter(BinaryNode.class)) {
            if (!BinaryNode.canTryReassociate(binary)) {
                continue;
            }
            BinaryNode result = BinaryNode.reassociate(binary, invariant);
            if (result != binary) {
                if (Debug.isLogEnabled()) {
                    Debug.log(MetaUtil.format("%H::%n", Debug.contextLookup(ResolvedJavaMethod.class)) + " : Reassociated %s into %s", binary, result);
                }
                graph.replaceFloating(binary, result);
            }
        }
    }

    public void setCounted(CountedLoopInfo countedLoopInfo) {
        counted = countedLoopInfo;
    }

    public LoopsData loopsData() {
        return data;
    }

    public NodeBitMap nodesInLoopFrom(BeginNode point, BeginNode until) {
        Collection<BeginNode> blocks = new LinkedList<>();
        Collection<BeginNode> exits = new LinkedList<>();
        Queue<Block> work = new LinkedList<>();
        ControlFlowGraph cfg = loopsData().controlFlowGraph();
        work.add(cfg.blockFor(point));
        Block untilBlock = until != null ? cfg.blockFor(until) : null;
        while (!work.isEmpty()) {
            Block b = work.remove();
            if (b == untilBlock) {
                continue;
            }
            if (lirLoop().exits.contains(b)) {
                exits.add(b.getBeginNode());
            } else if (lirLoop().blocks.contains(b)) {
                blocks.add(b.getBeginNode());
                work.addAll(b.getDominated());
            }
        }
        return LoopFragment.computeNodes(point.graph(), blocks, exits);
    }
}