package com.fasterxml.jackson.dataformat.avro.deser;

import java.io.IOException;
import java.util.List;

import com.fasterxml.jackson.core.JsonToken;

Default-providing AvroFieldReader implementations for structured types. Built solely based on JSON default values, for now, so only two variants needed. In future may need to tie to Avro type hierarchy more closely. /**
 * Default-providing {@link AvroFieldReader} implementations for
 * structured types. Built solely based on JSON default values,
 * for now, so only two variants needed. In future may need to
 * tie to Avro type hierarchy more closely.
 */
public class StructDefaults
{
    public static AvroFieldReader createObjectDefaults(String name,
            List<AvroFieldReader> fieldReaders) {
        
        return AvroFieldReader.construct(name, new ObjectDefaults(
                null, null,
                fieldReaders.toArray(new AvroFieldReader[fieldReaders.size()])));
    }

    public static AvroFieldReader createArrayDefaults(String name,
            List<AvroFieldReader> fieldReaders) {
        
        return AvroFieldReader.construct(name, new ArrayDefaults(
                null, null,
                fieldReaders.toArray(new AvroFieldReader[fieldReaders.size()])));
    }

    protected static class ObjectDefaults extends MapReader
    {
        protected final AvroFieldReader[] _fieldReaders;

        public ObjectDefaults(AvroReadContext parent,
                AvroParserImpl parser, AvroFieldReader[] fieldReaders)
        {
            super(parent, parser, null, null, null);
            _fieldReaders = fieldReaders;
        }

        @Override
        public long getRemainingElements() {
            return _fieldReaders.length - _index;
        }

        @Override
        public MapReader newReader(AvroReadContext parent,
                AvroParserImpl parser) {
            return new ObjectDefaults(parent, parser, _fieldReaders);
        }

        @Override
        public JsonToken nextToken() throws IOException
        {
            switch (_state) {
            case STATE_START:
                _parser.setAvroContext(this);
                _state = STATE_NAME;
                return (_currToken = JsonToken.START_OBJECT);
            case STATE_NAME:
                if (_index < _fieldReaders.length) {
                    _state = STATE_VALUE;
                    _currentName = _fieldReaders[_index].getName();
                    return (_currToken = JsonToken.FIELD_NAME);
                }
                final AvroReadContext parent = getParent();
                _state = STATE_DONE;
                _parser.setAvroContext(parent);
                return (_currToken = JsonToken.END_OBJECT);
            case STATE_VALUE:
                _state = STATE_NAME;
                AvroFieldReader r = _fieldReaders[_index++];
                return (_currToken = r.readValue(this, _parser));
            default:
            }
            throwIllegalState(_state);
            return null;
        }

        @Override
        public void skipValue(AvroParserImpl parser) throws IOException {
            // never called defaults
        }
    }

    protected static class ArrayDefaults extends ArrayReader
    {
        protected final AvroFieldReader[] _valueReaders;

        public ArrayDefaults(AvroReadContext parent,
                AvroParserImpl parser, AvroFieldReader[] valueReaders)
        {
            super(parent, parser, null, null);
            _valueReaders = valueReaders;
        }

        @Override
        public ArrayReader newReader(AvroReadContext parent,
                AvroParserImpl parser) {
            return new ArrayDefaults(parent, parser, _valueReaders);
        }

        @Override
        public JsonToken nextToken() throws IOException
        {
            switch (_state) {
            case STATE_START:
                _parser.setAvroContext(this);
                _state = STATE_ELEMENTS;
                return (_currToken = JsonToken.START_ARRAY);
            case STATE_ELEMENTS:
                if (_index < _valueReaders.length) {
                    AvroFieldReader r = _valueReaders[_index++];
                    return (_currToken = r.readValue(this, _parser));
                }
                final AvroReadContext parent = getParent();
                _state = STATE_DONE;
                _parser.setAvroContext(parent);
                return (_currToken = JsonToken.END_ARRAY);
            default:
            }
            throwIllegalState(_state);
            return null;
        }

        @Override
        public void skipValue(AvroParserImpl parser) throws IOException {
            // never called defaults
        }
    }

}