/*
 * Copyright (c) 2015, 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.cast;

import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.profiles.BranchProfile;
import com.oracle.truffle.api.source.SourceSection;
import org.jruby.truffle.Layouts;
import org.jruby.truffle.RubyContext;
import org.jruby.truffle.language.RubyNode;
import org.jruby.truffle.language.control.RaiseException;
import org.jruby.truffle.language.dispatch.CallDispatchHeadNode;
import org.jruby.truffle.language.dispatch.DispatchHeadNodeFactory;

@NodeChild(value = "child", type = RubyNode.class)
public abstract class ToFNode extends RubyNode {

    @Child private CallDispatchHeadNode toFNode;

    private final BranchProfile errorProfile = BranchProfile.create();

    public ToFNode(RubyContext context, SourceSection sourceSection) {
        super(context, sourceSection);
    }

    public double doDouble(VirtualFrame frame, Object value) {
        final Object doubleObject = executeDouble(frame, value);

        if (doubleObject instanceof Double) {
            return (double) doubleObject;
        }

        errorProfile.enter();
        throw new UnsupportedOperationException("executeDouble must return a double, instead it returned a " + doubleObject.getClass().getName());
    }

    public abstract Object executeDouble(VirtualFrame frame, Object value);

    @Specialization
    public double coerceInt(int value) {
        return value;
    }

    @Specialization
    public double coerceLong(long value) {
        return value;
    }

    @Specialization
    public double coerceDouble(double value) {
        return value;
    }

    @Specialization
    public double coerceBoolean(VirtualFrame frame, boolean value,
            @Cached("create()") BranchProfile errorProfile) {
        return coerceObject(frame, value, errorProfile);
    }

    @Specialization
    public double coerceDynamicObject(VirtualFrame frame, DynamicObject object,
            @Cached("create()") BranchProfile errorProfile) {
        return coerceObject(frame, object, errorProfile);
    }

    private double coerceObject(VirtualFrame frame, Object object, BranchProfile errorProfile) {
        if (toFNode == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            toFNode = insert(DispatchHeadNodeFactory.createMethodCall(getContext(), true));
        }

        final Object coerced;
        try {
            coerced = toFNode.call(frame, object, "to_f");
        } catch (RaiseException e) {
            if (Layouts.BASIC_OBJECT.getLogicalClass(e.getException()) == coreLibrary().getNoMethodErrorClass()) {
                errorProfile.enter();
                throw new RaiseException(coreExceptions().typeErrorNoImplicitConversion(object, "Float", this));
            } else {
                throw e;
            }
        }

        if (coreLibrary().getLogicalClass(coerced) == coreLibrary().getFloatClass()) {
            return (double) coerced;
        } else {
            errorProfile.enter();
            throw new RaiseException(coreExceptions().typeErrorBadCoercion(object, "Float", "to_f", coerced, this));
        }
    }

}
