/*
 * Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at:
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 */

package com.fasterxml.jackson.dataformat.ion;

import com.fasterxml.jackson.core.json.DupDetector;
import com.fasterxml.jackson.core.json.JsonWriteContext;

Extension of JsonWriteContexts that recognizes sexps

The JsonWriteContext is used by the pretty printer for handling of the whitespace between tokens,
and by the generator for verifying whether it's valid to write a given token. The writeStartSexp
method in the IonGenerator will enter a "sexp context", so we need a new state in the write
context to track that. Sexp handling is modeled after arrays.
/**
 * Extension of JsonWriteContexts that recognizes sexps
 * <p>
 * The JsonWriteContext is used by the pretty printer for handling of the whitespace between tokens,
 * and by the generator for verifying whether it's valid to write a given token. The writeStartSexp
 * method in the IonGenerator will enter a "sexp context", so we need a new state in the write
 * context to track that. Sexp handling is modeled after arrays.
 */
public class IonWriteContext extends JsonWriteContext {
    // Both contstants are in the tens instead of the ones to avoid conflict with the native
    // Jackson ones

    // Ion-specific contexts
    protected final static int TYPE_SEXP = 30;

    // Ion-specific statuses
    public final static int STATUS_OK_AFTER_SEXP_SEPARATOR = 60;

    protected IonWriteContext(int type, IonWriteContext parent, DupDetector dups) {
        super(type, parent, dups);
    }

    public static IonWriteContext createRootContext(DupDetector dd) {
        return new IonWriteContext(TYPE_ROOT, null, dd);
    }

    public IonWriteContext createChildSexpContext() {
        IonWriteContext ctxt = (IonWriteContext) _child;

        if(ctxt == null) {
            // same assignment as in createChildObjectContext, createChildArrayContext
            _child = ctxt = new IonWriteContext(TYPE_SEXP, this, (_dups == null) ? null : _dups.child());
        }

        // reset returns this, OK to cast
        return (IonWriteContext) ctxt.reset(TYPE_SEXP);
    }

    public final boolean inSexp() {
        return _type == TYPE_SEXP;
    }

    // // Overrides

    // We have to override the two createChild*Context methods to return a IonWriteContext
    // instead of a JsonWriteContext so sexps can be arbitrarily embedded in ion. Otherwise we
    // would only be able to create them as top level values.
    // Two methods below are copied from JsonWriteContext

    @Override
    public IonWriteContext createChildArrayContext() {
        IonWriteContext ctxt = (IonWriteContext) _child;

        if (ctxt == null) {
            _child = ctxt = new IonWriteContext(TYPE_ARRAY, this, (_dups == null) ? null : _dups.child());
            return ctxt;
        }

        return (IonWriteContext) ctxt.reset(TYPE_ARRAY);
    }

    @Override
    public IonWriteContext createChildObjectContext() {
        IonWriteContext ctxt = (IonWriteContext) _child;

        if (ctxt == null) {
            _child = ctxt = new IonWriteContext(TYPE_OBJECT, this, (_dups == null) ? null : _dups.child());
            return ctxt;
        }
        return (IonWriteContext) ctxt.reset(TYPE_OBJECT);
    }

    @Override
    public int writeValue() {
        // Add special handling for sexp separator
        if(_type == TYPE_SEXP) {
            int ix = _index;
            ++_index;
            return (ix < 0) ? STATUS_OK_AS_IS : STATUS_OK_AFTER_SEXP_SEPARATOR;
        }

        return super.writeValue();
    }
}