/*
 * Copyright (c) 2013, 2016 Oracle and/or its affiliates. All rights reserved. This
 * code is released under a tri EPL/GPL/LGPL license. You can use it,
 * redistribute it and/or modify it under the terms of the:
 *
 * Eclipse Public License version 1.0
 * GNU General Public License version 2
 * GNU Lesser General Public License version 2.1
 */
package org.jruby.truffle.core.hash;

import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.NodeChildren;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.ExplodeLoop;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.profiles.BranchProfile;
import com.oracle.truffle.api.profiles.ConditionProfile;
import com.oracle.truffle.api.source.SourceSection;
import org.jruby.truffle.Layouts;
import org.jruby.truffle.RubyContext;
import org.jruby.truffle.core.basicobject.BasicObjectNodes;
import org.jruby.truffle.core.basicobject.BasicObjectNodesFactory;
import org.jruby.truffle.language.RubyNode;
import org.jruby.truffle.language.dispatch.CallDispatchHeadNode;
import org.jruby.truffle.language.dispatch.DispatchHeadNodeFactory;
import org.jruby.truffle.language.objects.IsFrozenNode;
import org.jruby.truffle.language.objects.IsFrozenNodeGen;

@ImportStatic(HashGuards.class)
@NodeChildren({
        @NodeChild(value = "hash", type = RubyNode.class),
        @NodeChild(value = "key", type = RubyNode.class),
        @NodeChild(value = "value", type = RubyNode.class),
        @NodeChild(value = "byIdentity", type = RubyNode.class)
})
public abstract class SetNode extends RubyNode {

    @Child private HashNode hashNode;
    @Child private CallDispatchHeadNode eqlNode;
    @Child private BasicObjectNodes.ReferenceEqualNode equalNode;
    @Child private LookupEntryNode lookupEntryNode;

    private final ConditionProfile byIdentityProfile = ConditionProfile.createBinaryProfile();

    private final BranchProfile extendProfile = BranchProfile.create();
    private final ConditionProfile strategyProfile = ConditionProfile.createBinaryProfile();

    @Child private IsFrozenNode isFrozenNode;
    @Child private CallDispatchHeadNode dupNode;
    @Child private CallDispatchHeadNode freezeNode;

    private final ConditionProfile frozenProfile = ConditionProfile.createBinaryProfile();

    public SetNode(RubyContext context, SourceSection sourceSection) {
        super(context, sourceSection);
        hashNode = new HashNode(context, sourceSection);
        eqlNode = DispatchHeadNodeFactory.createMethodCall(context);
        equalNode = BasicObjectNodesFactory.ReferenceEqualNodeFactory.create(null);
    }

    public abstract Object executeSet(VirtualFrame frame, DynamicObject hash, Object key, Object value, boolean byIdentity);

    @Specialization(guards = { "isNullHash(hash)", "!isRubyString(key)" })
    public Object setNull(VirtualFrame frame, DynamicObject hash, Object key, Object value, boolean byIdentity) {
        int hashed = 0;
        if (!byIdentityProfile.profile(byIdentity)) {
            hashed = hashNode.hash(frame, key);
        }

        Object store = PackedArrayStrategy.createStore(getContext(), hashed, key, value);
        assert HashOperations.verifyStore(getContext(), store, 1, null, null);
        Layouts.HASH.setStore(hash, store);
        Layouts.HASH.setSize(hash, 1);
        Layouts.HASH.setFirstInSequence(hash, null);
        Layouts.HASH.setLastInSequence(hash, null);

        assert HashOperations.verifyStore(getContext(), hash);
        return value;
    }

    @Specialization(guards = {"isNullHash(hash)", "byIdentity", "isRubyString(key)"})
    public Object setNullByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setNull(frame, hash, key, value, byIdentity);
    }

    @Specialization(guards = {"isNullHash(hash)", "!byIdentity", "isRubyString(key)"})
    public Object setNullNotByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setNull(frame, hash, freezeAndDupIfNeeded(frame, key), value, byIdentity);
    }

    @ExplodeLoop
    @Specialization(guards = {"isPackedHash(hash)", "!isRubyString(key)"})
    public Object setPackedArray(VirtualFrame frame, DynamicObject hash, Object key, Object value, boolean byIdentity) {
        assert HashOperations.verifyStore(getContext(), hash);

        boolean profiledByIdentity = byIdentityProfile.profile(byIdentity);

        int hashed = 0;
        if (!profiledByIdentity) {
            hashed = hashNode.hash(frame, key);
        }

        final Object[] store = (Object[]) Layouts.HASH.getStore(hash);
        final int size = Layouts.HASH.getSize(hash);

        for (int n = 0; n < getContext().getOptions().HASH_PACKED_ARRAY_MAX; n++) {
            if (n < size) {
                final boolean equal;
                if (profiledByIdentity) {
                    equal = equalNode.executeReferenceEqual(key, PackedArrayStrategy.getKey(store, n));
                } else {
                    equal = hashed == PackedArrayStrategy.getHashed(store, n) &&
                            eqlNode.callBoolean(frame, key, "eql?", null, PackedArrayStrategy.getKey(store, n));
                }

                if (equal) {
                    PackedArrayStrategy.setValue(store, n, value);
                    assert HashOperations.verifyStore(getContext(), hash);
                    return value;
                }
            }
        }

        extendProfile.enter();

        if (strategyProfile.profile(size + 1 <= getContext().getOptions().HASH_PACKED_ARRAY_MAX)) {
            PackedArrayStrategy.setHashedKeyValue(store, size, hashed, key, value);
            Layouts.HASH.setSize(hash, size + 1);
            return value;
        } else {
            PackedArrayStrategy.promoteToBuckets(getContext(), hash, store, size);
            BucketsStrategy.addNewEntry(getContext(), hash, hashed, key, value);
        }

        assert HashOperations.verifyStore(getContext(), hash);

        return value;
    }

    @Specialization(guards = {"isPackedHash(hash)", "byIdentity", "isRubyString(key)"})
    public Object setPackedArrayByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setPackedArray(frame, hash, key, value, byIdentity);
    }

    @Specialization(guards = {"isPackedHash(hash)", "!byIdentity", "isRubyString(key)"})
    public Object setPackedArrayNotByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setPackedArray(frame, hash, freezeAndDupIfNeeded(frame, key), value, byIdentity);
    }

    // Can't be @Cached yet as we call from the RubyString specialisation
    private final ConditionProfile foundProfile = ConditionProfile.createBinaryProfile();
    private final ConditionProfile bucketCollisionProfile = ConditionProfile.createBinaryProfile();
    private final ConditionProfile appendingProfile = ConditionProfile.createBinaryProfile();
    private final ConditionProfile resizeProfile = ConditionProfile.createBinaryProfile();

    @Specialization(guards = {"isBucketHash(hash)", "!isRubyString(key)"})
    public Object setBuckets(VirtualFrame frame, DynamicObject hash, Object key, Object value, boolean byIdentity) {
        assert HashOperations.verifyStore(getContext(), hash);

        final HashLookupResult result = lookup(frame, hash, key);
        final Entry entry = result.getEntry();

        if (foundProfile.profile(entry == null)) {
            final Entry[] entries = (Entry[]) Layouts.HASH.getStore(hash);

            final Entry newEntry = new Entry(result.getHashed(), key, value);

            if (bucketCollisionProfile.profile(result.getPreviousEntry() == null)) {
                entries[result.getIndex()] = newEntry;
            } else {
                result.getPreviousEntry().setNextInLookup(newEntry);
            }

            final Entry lastInSequence = Layouts.HASH.getLastInSequence(hash);

            if (appendingProfile.profile(lastInSequence == null)) {
                Layouts.HASH.setFirstInSequence(hash, newEntry);
            } else {
                lastInSequence.setNextInSequence(newEntry);
                newEntry.setPreviousInSequence(lastInSequence);
            }

            Layouts.HASH.setLastInSequence(hash, newEntry);

            final int newSize = Layouts.HASH.getSize(hash) + 1;

            Layouts.HASH.setSize(hash, newSize);

            // TODO CS 11-May-15 could store the next size for resize instead of doing a float operation each time

            if (resizeProfile.profile(newSize / (double) entries.length > BucketsStrategy.LOAD_FACTOR)) {
                BucketsStrategy.resize(getContext(), hash);
            }
        } else {
            entry.setKeyValue(result.getHashed(), key, value);
        }

        assert HashOperations.verifyStore(getContext(), hash);

        return value;
    }

    private HashLookupResult lookup(VirtualFrame frame, DynamicObject hash, Object key) {
        if (lookupEntryNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            lookupEntryNode = insert(new LookupEntryNode(getContext(), getEncapsulatingSourceSection()));
        }
        return lookupEntryNode.lookup(frame, hash, key);
    }

    @Specialization(guards = {"isBucketHash(hash)", "byIdentity", "isRubyString(key)"})
    public Object setBucketsByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setBuckets(frame, hash, key, value, byIdentity);
    }

    @Specialization(guards = {"isBucketHash(hash)", "!byIdentity", "isRubyString(key)"})
    public Object setBucketsNotByIdentity(VirtualFrame frame, DynamicObject hash, DynamicObject key, Object value, boolean byIdentity) {
        return setBuckets(frame, hash, freezeAndDupIfNeeded(frame, key), value, byIdentity);
    }

    private Object freezeAndDupIfNeeded(VirtualFrame frame, DynamicObject key) {
        if (!frozenProfile.profile(isFrozen(key))) {
            return freeze(frame, dup(frame, key));
        } else {
            return key;
        }
    }

    private boolean isFrozen(Object value) {
        if (isFrozenNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            isFrozenNode = insert(IsFrozenNodeGen.create(getContext(), getSourceSection(), null));
        }
        return isFrozenNode.executeIsFrozen(value);
    }

    private Object dup(VirtualFrame frame, Object value) {
        if (dupNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            dupNode = insert(DispatchHeadNodeFactory.createMethodCall(getContext()));
        }
        return dupNode.call(frame, value, "dup", null);
    }

    private Object freeze(VirtualFrame frame, Object value) {
        if (freezeNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            freezeNode = insert(DispatchHeadNodeFactory.createMethodCall(getContext()));
        }
        return freezeNode.call(frame, value, "freeze", null);
    }

}
