// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package io.v.v23.vom;

import com.google.common.base.Strings;
import com.google.common.io.ByteStreams;
import io.v.v23.vdl.GeneratedFromVdl;
import io.v.v23.vdl.Kind;
import io.v.v23.vdl.NativeTypes;
import io.v.v23.vdl.Types;
import io.v.v23.vdl.VdlAny;
import io.v.v23.vdl.VdlArray;
import io.v.v23.vdl.VdlField;
import io.v.v23.vdl.VdlOptional;
import io.v.v23.vdl.VdlStruct;
import io.v.v23.vdl.VdlType;
import io.v.v23.vdl.VdlType.Builder;
import io.v.v23.vdl.VdlType.PendingType;
import io.v.v23.vdl.VdlTypeObject;
import io.v.v23.vdl.VdlUnion;
import io.v.v23.vdl.VdlValue;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * BinaryDecoder reads a VDL value from {@code InputStream} encoded in binary VOM format.
 */
// TODO(sjr): make sure this works for all unexported VDL types.
public class BinaryDecoder {
    private final BufferedInputStream in;
    private final Map<TypeId, VdlType> decodedTypes;
    private final Map<TypeId, WireType> wireTypes;
    private boolean binaryMagicByteRead;
    private Version version;
    private long[] typeIds;
    private static Version[] allowedVersions = {Version.Version80, Version.Version81};

    public BinaryDecoder(InputStream in) {
        this.in = new BufferedInputStream(in);
        this.decodedTypes = new HashMap<TypeId, VdlType>();
        this.wireTypes = new HashMap<TypeId, WireType>();
        this.binaryMagicByteRead = false;
    }

    /**
     * Decodes a VDL value. Returns an instance of provided {@code Type}.
     *
     * @param targetType the type of returned object
     * @return the decoded value
     * @throws IOException
     * @throws ConversionException
     */
    public Object decodeValue(Type targetType) throws IOException, ConversionException {
        if (!binaryMagicByteRead) {
            version = Version.fromByte((byte)in.read());
            binaryMagicByteRead = true;
        }
        VdlType actualType = decodeType();
        assertTypesCompatible(actualType, targetType);
        if (targetType == Object.class) {
            try {
                targetType = Types.getReflectTypeForVdl(actualType);
            } catch (IllegalArgumentException e) {
                throw new ConversionException(e);
            }
        }
        return readValueMessage(actualType, targetType);
    }

    /**
     * Decodes a VDL value.
     * The decoder tries to match named VDL types with Java classes generated from VDL by
     * translating VDL type name to Java class name, initializing class and calling
     * {@code Types.getReflectTypeForVdl}. If the decoder fails to find a matching class for VDL
     * type it will construct a general {@code VdlValue}. Prefer to use {@code decodeValue(Type)}
     * over this method.
     *
     * @return the decoded value
     * @throws IOException
     * @throws ConversionException
     */
    public Object decodeValue() throws IOException, ConversionException {
        return decodeValue(Object.class);
    }

    private void assertTypesCompatible(VdlType actualType, Type targetType)
            throws ConversionException {
        if (targetType != Object.class && targetType != VdlValue.class && !TypeCompatibility.
                compatible(actualType, Types.getVdlTypeFromReflect(targetType))) {
            throw new ConversionException(actualType, targetType, "types are incompatible");
        }
    }

    private Object readValueMessage(VdlType actualType, Type targetType) throws IOException,
            ConversionException {
        if (version != Version.Version80 && (BinaryUtil.hasAny(actualType) || BinaryUtil.hasTypeObject(actualType))) {
            long len = BinaryUtil.decodeUint(in);
            typeIds = new long[(int)len];
            for (int i = 0; i < len; i++) {
                typeIds[i] = BinaryUtil.decodeUint(in);
            }
        }
        if (version != Version.Version80 && BinaryUtil.hasAny(actualType)) {
            long len = BinaryUtil.decodeUint(in);
            for (int i = 0; i < len; i++) {
                BinaryUtil.decodeUint(in); // read anyMsgLen (ignore value -- it is unused)
            }
        }
        if (BinaryUtil.hasBinaryMsgLen(actualType)) {
            // Do nothing with this information for now.
            BinaryUtil.decodeUint(in);
        }
        return readValue(actualType, targetType);
    }

    private VdlType decodeType() throws IOException, ConversionException {
        while (true) {
            in.mark(1);
            int firstByte = in.read();
            if ((byte)firstByte == Constants.WIRE_CTRL_TYPE_INCOMPLETE) {
                // skip for now, it isn't needed because types are built when used as opposed
                // to building when they are received in go.
            } else {
                in.reset();
            }
            long typeId = BinaryUtil.decodeInt(in);
            if (typeId == 0) {
                throw new CorruptVomStreamException("Unexpected zero type ID");
            } else if (typeId > 0) {
                return getType(new TypeId(typeId));
            } else {
                WireType wireType = (WireType) readValueMessage(WireType.VDL_TYPE, WireType.class);
                wireTypes.put(new TypeId(-typeId), wireType);
            }
        }
    }

    private VdlType lookupType(TypeId typeId) {
        VdlType type = BootstrapType.getBootstrapType(typeId);
        if (type != null) {
            return type;
        } else if (decodedTypes.containsKey(typeId)) {
            return decodedTypes.get(typeId);
        } else {
            return null;
        }
    }

    private VdlType getType(TypeId typeId) throws CorruptVomStreamException {
        VdlType type = lookupType(typeId);
        if (type != null) {
            return type;
        } else {
            WireToVdlTypeBuilder builder = new WireToVdlTypeBuilder();
            PendingType pendingType = builder.lookupOrBuildPending(typeId);
            builder.build();
            return pendingType.built();
        }
    }

    private Object readValue(VdlType actualType, Type targetType)
            throws IOException, ConversionException {
        ConversionTarget target;
        if (targetType == VdlValue.class) {
            target = new ConversionTarget(actualType);
        } else if (targetType == Object.class) {
            // This can happen only inside VDL Any, as top-level type is constructed
            // Outside of readValue().
            try {
                targetType = Types.getReflectTypeForVdl(actualType);
                target = new ConversionTarget(targetType, actualType);
            } catch (IllegalArgumentException e) {
                target = new ConversionTarget(actualType);
            }
        } else {
            target = new ConversionTarget(targetType);
        }

        // Solve any/optional case.
        if (actualType.getKind() != Kind.ANY && actualType.getKind() != Kind.OPTIONAL) {
            if (target.getKind() == Kind.ANY) {
                return new VdlAny(actualType, (Serializable) readValue(actualType, Object.class));
            } else if (target.getKind() == Kind.OPTIONAL) {
                Type elemType = ReflectUtil.getElementType(target.getTargetType(), 0);
                return VdlOptional.of((VdlValue) readValue(actualType, elemType));
            }
        }

        // Convert native value.
        NativeTypes.Converter converter = Types.getNativeTypeConverter(target.getTargetType());
        if (converter != null) {
            VdlValue value = (VdlValue) readValue(actualType, converter.getWireType());
            return converter.nativeFromVdlValue(value);
        }
        switch (actualType.getKind()) {
            case ANY:
                return readVdlAny(target);
            case ARRAY:
            case LIST:
                return readVdlArrayOrVdlList(actualType, target);
            case BOOL:
                return readVdlBool(target);
            case BYTE:
                return readVdlByte(target);
            case ENUM:
                return readVdlEnum(actualType, target);
            case FLOAT32:
            case FLOAT64:
                return readVdlFloat(target);
            case INT8:
                if (version == Version.Version80) {
                    throw new RuntimeException("int8 is unsupported in VOM version 0x80");
                }
                // fallthrough
            case INT16:
            case INT32:
            case INT64:
                return readVdlInt(target);
            case MAP:
            case SET:
                return readVdlMapOrSet(actualType, target);
            case STRUCT:
                return readVdlStruct(actualType, target);
            case UNION:
                return readVdlUnion(actualType, target);
            case OPTIONAL:
                return readVdlOptional(actualType, target);
            case STRING:
                return readVdlString(target);
            case TYPEOBJECT:
                return readVdlTypeObject();
            case UINT16:
            case UINT32:
            case UINT64:
                return readVdlUint(target);
            default:
                throw new ConversionException(actualType, targetType);
        }
    }

    private Object createNullValue(ConversionTarget target) throws ConversionException {
        if (target.getKind() == Kind.ANY) {
            return new VdlAny();
        } else if (target.getKind() == Kind.OPTIONAL) {
            return new VdlOptional<VdlValue>(target.getVdlType());
        } else {
            throw new ConversionException("Can't create a null value of " + target.getTargetType());
        }
    }

    private Object readVdlAny(ConversionTarget target) throws IOException, ConversionException {
        if (peekFlag() == Constants.WIRE_CTRL_NIL) {
            ByteStreams.skipFully(in, 1);
            return createNullValue(target);
        }
        long typeId;
        if (version == Version.Version80) {
            typeId = BinaryUtil.decodeUint(in);
        } else {
            typeId = typeIds[(int)BinaryUtil.decodeUint(in)];
            BinaryUtil.decodeUint(in); // read anyLen index (ignore for now -- unused)
        }
        VdlType actualType = getType(new TypeId(typeId));
        if (target.getKind() == Kind.ANY) {
            return new VdlAny(actualType, (Serializable) readValue(actualType, Object.class));
        } else {
            Type targetType = target.getTargetType();
            assertTypesCompatible(actualType, targetType);
            return readValue(actualType, targetType);
        }
    }

    private Object readVdlBytes(int len, ConversionTarget target) throws IOException, ConversionException {
        byte[] buf = new byte[len];
        int numRead = 0;
        while (numRead < len) {
            int result = in.read(buf, numRead, buf.length - numRead);
            if (result == -1) {
                throw new CorruptVomStreamException("stream ended before full vdl bytes received");
            }
            numRead += result;
        }
        if (numRead > len) {
            throw new RuntimeException("too many bytes returned from read()");
        }
        return ConvertUtil.convertFromBytes(buf, target);
    }

    private Object readVdlArrayOrVdlList(VdlType actualType, ConversionTarget target)
            throws IOException, ConversionException {
        int len;
        if (actualType.getKind() == Kind.LIST) {
            len = (int) BinaryUtil.decodeUint(in);
        } else {
            long uint = BinaryUtil.decodeUint(in);
            if (uint != 0) {
                throw new CorruptVomStreamException(
                        "Array length should be encoded as 0, but it is " + uint);
            }
            len = actualType.getLength();
        }
        if (actualType.getElem().getKind() == Kind.BYTE) {
            return readVdlBytes(len, target);
        }

        Class<?> targetClass = target.getTargetClass();
        if (!List.class.isAssignableFrom(targetClass)) {
            if (BinaryUtil.isBytes(actualType) && targetClass.equals(byte[].class)) {
                return BinaryUtil.decodeBytes(in, len);
            } else if (!targetClass.isArray()) {
                return ConvertUtil.convertFromBytes(BinaryUtil.decodeBytes(in, len), target);
            }
        }

        Type elementType = ReflectUtil.getElementType(target.getTargetType(), 0);
        if (targetClass.isArray() || VdlArray.class.isAssignableFrom(targetClass)) {
            int targetLen = len;
            if (target.getKind() == Kind.ARRAY) {
                if (len > target.getVdlType().getLength()) {
                    throw new ConversionException(actualType, target.getTargetType(),
                            "target array is too short");
                }
                targetLen = target.getVdlType().getLength();
            }
            Class<?> elementClass = ReflectUtil.getRawClass(elementType);
            Object array = Array.newInstance(elementClass, targetLen);
            for (int i = 0; i < len; i++) {
                ReflectUtil.setArrayValue(array, i, readValue(actualType.getElem(), elementType), elementClass);
            }
            return ReflectUtil.createGeneric(target, array);
        } else {
            List<Object> list = new ArrayList<Object>();
            for (int i = 0; i < len; i++) {
                list.add(readValue(actualType.getElem(), elementType));
            }
            return ReflectUtil.createGeneric(target, list);
        }
    }

    private Object readVdlBool(ConversionTarget target) throws IOException, ConversionException {
        byte b;
        if (version == Version.Version80) {
           b = BinaryUtil.decodeBytes(in, 1)[0];
        } else {
           b = (byte)BinaryUtil.decodeUint(in);
        }
        return ReflectUtil.createPrimitive(target, b != 0, Boolean.TYPE);
    }

    private Object readVdlByte(ConversionTarget target) throws IOException, ConversionException {
        byte b;
        if (version == Version.Version80) {
            b = BinaryUtil.decodeBytes(in, 1)[0];
        } else {
            b = (byte)BinaryUtil.decodeUint(in);
        }
        return ConvertUtil.convertFromByte(b, target);
    }

    private Object readVdlEnum(VdlType actualType, ConversionTarget target) throws IOException,
            ConversionException {
        int enumIndex = (int) BinaryUtil.decodeUint(in);
        byte[] bytes = actualType.getLabels().get(enumIndex).getBytes(BinaryUtil.UTF8_CHARSET);
        return ConvertUtil.convertFromBytes(bytes, target);
    }

    private Object readVdlFloat(ConversionTarget target) throws IOException, ConversionException {
        return ConvertUtil.convertFromDouble(BinaryUtil.decodeDouble(in), target);
    }

    private Object readVdlInt(ConversionTarget target) throws IOException, ConversionException {
        return ConvertUtil.convertFromInt(BinaryUtil.decodeInt(in), target);
    }

    private Type getMapElemOrStructFieldType(ConversionTarget target, Object key)
            throws ConversionException {
        Class<?> targetClass = target.getTargetClass();
        if (target.getKind() == Kind.MAP) {
            return ReflectUtil.getElementType(target.getTargetType(), 1);
        } else if (target.getKind() == Kind.SET) {
            return Boolean.class;
        } else if (targetClass == VdlStruct.class) {
            return VdlValue.class;
        } else {
            String fieldName = (String) key;
            try {
                Field field = targetClass.getDeclaredField(BinaryUtil.firstCharToLower(fieldName));
                return field.getGenericType();
            } catch (NoSuchFieldException e) {
                // OK, we'll try to look at annotations.
            }
            for (Field field : targetClass.getDeclaredFields()) {
                GeneratedFromVdl annotation = field.getAnnotation(GeneratedFromVdl.class);
                if (annotation != null && annotation.name().equals(fieldName)) {
                    return field.getGenericType();
                }
            }
            return Object.class;
        }
    }

    @SuppressWarnings("unchecked")
    private void setMapElemOrStructField(ConversionTarget target, Object data, Object key,
            Object elem, Type elemType) throws ConversionException {
        if (target.getKind() == Kind.MAP) {
            ((Map<Object, Object>) data).put(key, elem);
        } else if (target.getKind() == Kind.SET) {
            if ((Boolean) elem) {
                ((Set<Object>) data).add(key);
            }
        } else if (data instanceof VdlStruct) {
            ((VdlStruct) data).assignField((String) key, (VdlValue) elem);
        } else {
            if (elemType == Object.class) {
                // no such field, just skip it
                return;
            }
            try {
                Field f = data.getClass().getDeclaredField(
                        BinaryUtil.firstCharToLower((String) key));
                f.setAccessible(true);
                f.set(data, elem);
            } catch (Exception e) {
                throw new ConversionException("Can't set field " + key + " to " + elem + " of "
                        + target.getTargetType(), e);
            }
        }
    }

    private Object createMapOrSetOrStruct(ConversionTarget target) throws ConversionException {
        if (target.getKind() == Kind.MAP) {
            return ReflectUtil.createGeneric(target, new HashMap<Object, Object>());
        } else if (target.getKind() == Kind.SET) {
            return ReflectUtil.createGeneric(target, new HashSet<Object>());
        } else {
            return ReflectUtil.createStruct(target);
        }
    }

    private Type getTargetKeyType(ConversionTarget target) throws ConversionException {
        if (target.getKind() == Kind.MAP || target.getKind() == Kind.SET) {
            return ReflectUtil.getElementType(target.getTargetType(), 0);
        } else {
            return String.class;
        }
    }

    private Object readVdlMapOrSet(VdlType actualType, ConversionTarget target)
            throws IOException, ConversionException {
        Object data = createMapOrSetOrStruct(target);
        Type targetKeyType = getTargetKeyType(target);
        int len = (int) BinaryUtil.decodeUint(in);
        for (int i = 0; i < len; i++) {
            Object key = readValue(actualType.getKey(), targetKeyType);
            Type targetElemType = getMapElemOrStructFieldType(target, key);
            Object elem;
            if (actualType.getKind() == Kind.SET) {
                if (targetElemType == VdlAny.class) {
                    elem = new VdlAny(Boolean.class, true);
                } else {
                    elem = ReflectUtil.createPrimitive(new ConversionTarget(targetElemType),
                            true, Boolean.TYPE);
                }
            } else {
                elem = readValue(actualType.getElem(), targetElemType);
            }
            setMapElemOrStructField(target, data, key, elem, targetElemType);
        }
        return data;
    }

    private Object readVdlStruct(VdlType actualType, ConversionTarget target)
            throws IOException, ConversionException {
        Object data = createMapOrSetOrStruct(target);
        Type targetKeyType = getTargetKeyType(target);
        boolean[] seen = new boolean[actualType.getFields().size()];
        Arrays.fill(seen, false);
        while (true) {
            if (peekFlag() == Constants.WIRE_CTRL_END) {
                ByteStreams.skipFully(in, 1);
                break;
            }
            int index = (int) BinaryUtil.decodeUint(in);
            seen[index] = true;
            VdlField field = actualType.getFields().get(index);
            Type targetElemType = getMapElemOrStructFieldType(target, field.getName());
            Object key = ConvertUtil.convertFromBytes(BinaryUtil.getBytes(field.getName()),
                    new ConversionTarget(targetKeyType));
            Object elem = readValue(field.getType(), targetElemType);
            setMapElemOrStructField(target, data, key, elem, targetElemType);
        }
        // Now we need to fill zero values of struct if target is a map.
        if (target.getKind() != Kind.MAP) {
            return data;
        }
        for (int i = 0; i < actualType.getFields().size(); i++) {
            if (seen[i]) {
                continue;
            }
            VdlField field = actualType.getFields().get(i);
            Type elemType = getMapElemOrStructFieldType(target, field.getName());
            Object key = ConvertUtil.convertFromBytes(BinaryUtil.getBytes(field.getName()),
                    new ConversionTarget(targetKeyType));
            VdlType elemVdlType = target.getVdlType().getElem();
            Object elem;
            // All user-defined types and java primitives have a default constructor that returns
            // a zero value. For lists, maps and sets it's OK to return a zero vdl.Value because
            // it will be an empty list, map or set. In other cases we need to return a zero
            // vdl.Value.
            if (elemType instanceof Class
                    && ((Class<?>) elemType).getSuperclass() != VdlValue.class) {
                try {
                    elem = ((Class<?>) elemType).newInstance();
                } catch (Exception e) {
                    throw new ConversionException(field.getType(), elemType);
                }
            } else {
                elem = VdlValue.zeroValue(elemVdlType);
            }
            setMapElemOrStructField(target, data, key, elem, elemType);
        }
        return data;
    }

    private Object readVdlUnion(VdlType actualType, ConversionTarget target) throws IOException,
            ConversionException {
        int index = (int) BinaryUtil.decodeUint(in);
        if (index < 0 || index >= actualType.getFields().size()) {
            throw new CorruptVomStreamException("Union index " + index + " is out of range " + 1 +
                    "..." + actualType.getFields().size());
        }
        VdlField actualField = actualType.getFields().get(index);
        VdlType actualElemType = actualField.getType();
        // Solve vdl.Value case.
        if (target.getTargetClass() == VdlUnion.class) {
            return new VdlUnion(actualType, index, actualElemType,
                    readValue(actualElemType, Object.class));
        }
        Class<?> targetClass = target.getTargetClass();
        // This can happen if targetClass is NamedUnion.A.
        if (targetClass.getSuperclass() != VdlUnion.class) {
            targetClass = targetClass.getSuperclass();
        }
        // Look-up field class in target.
        Class<?> fieldClass = null;
        for (Class<?> klass : targetClass.getDeclaredClasses()) {
            if (klass.getName().equals(targetClass.getName() + "$" + actualField.getName())) {
                fieldClass = klass;
                break;
            }
        }
        if (fieldClass == null) {
            throw new ConversionException(actualType, target.getTargetType());
        }
        try {
            Type elemType = fieldClass.getDeclaredField("elem").getGenericType();
            return fieldClass.getConstructor(ReflectUtil.getRawClass(elemType)).newInstance(
                    readValue(actualElemType, elemType));
        } catch (Exception e) {
            throw new ConversionException(actualType, target.getTargetType(), e);
        }
    }

    private Object readVdlOptional(VdlType actualType, ConversionTarget target) throws IOException,
            ConversionException {
        if (peekFlag() == Constants.WIRE_CTRL_NIL) {
            ByteStreams.skipFully(in, 1);
            return createNullValue(target);
        } else {
            Type type = target.getTargetType();
            if (target.getKind() == Kind.OPTIONAL) {
                type = ReflectUtil.getElementType(target.getTargetType(), 0);
                return VdlOptional.of((VdlValue) readValue(actualType.getElem(), type));
            } else {
                return readValue(actualType.getElem(), type);
            }
        }
    }

    private Object readVdlString(ConversionTarget target) throws IOException, ConversionException {
        int len = (int) BinaryUtil.decodeUint(in);
        byte[] bytes = BinaryUtil.decodeBytes(in, len);
        return ConvertUtil.convertFromBytes(bytes, target);
    }

    private Object readVdlUint(ConversionTarget target) throws IOException, ConversionException {
        return ConvertUtil.convertFromUint(BinaryUtil.decodeUint(in), target);
    }

    private Object readVdlTypeObject() throws IOException {
        long typeId;
        if (version == Version.Version80) {
            typeId = BinaryUtil.decodeUint(in);
        } else {
            typeId = typeIds[(int)BinaryUtil.decodeUint(in)];
        }
        return new VdlTypeObject(getType(new TypeId(typeId)));
    }

    private byte peekFlag() throws IOException {
        in.mark(1);
        byte flag = (byte) in.read();
        in.reset();
        return flag;
    }

    /**
     * Builds VdlType from wire type.
     */
    private final class WireToVdlTypeBuilder {
        private final Builder builder;
        private final Map<TypeId, PendingType> pendingTypes;

        public WireToVdlTypeBuilder() {
            builder = new Builder();
            pendingTypes = new HashMap<TypeId, PendingType>();
        }

        public void build() {
            builder.build();
            for (Map.Entry<TypeId, PendingType> entry : pendingTypes.entrySet()) {
                VdlType vdlType = entry.getValue().built();
                if (!Strings.isNullOrEmpty(vdlType.getName())) {
                    Types.loadClassForVdlName(vdlType.getName());
                }
                BinaryDecoder.this.decodedTypes.put(entry.getKey(), vdlType);
            }
        }

        public PendingType lookupOrBuildPending(TypeId typeId) throws CorruptVomStreamException {
            PendingType vdlType = lookupType(typeId);
            if (vdlType != null) {
                return vdlType;
            }
            return buildPendingType(typeId);
        }

        private PendingType lookupType(TypeId typeId) {
            VdlType type = BinaryDecoder.this.lookupType(typeId);
            if (type != null) {
                return builder.builtPendingFromType(type);
            } else if (pendingTypes.containsKey(typeId)) {
                return pendingTypes.get(typeId);
            }
            return null;
        }

        private PendingType buildPendingType(TypeId typeId) throws CorruptVomStreamException {
            WireType wireType = BinaryDecoder.this.wireTypes.get(typeId);
            if (wireType == null) {
                throw new CorruptVomStreamException("Unknown wire type " + typeId);
            }
            PendingType pending = builder.newPending();
            pendingTypes.put(typeId, pending);

            switch (wireType.getIndex()) {
                // The mapping is defined in wireType.vdl and is not going to change.
                case 0: // "NameT"
                    WireNamed wireNamed = (WireNamed) wireType.getElem();
                    return pending.setName(wireNamed.getName())
                            .assignBase(lookupOrBuildPending(wireNamed.getBase()));
                case 1: // "EnumT"
                    WireEnum wireEnum = (WireEnum) wireType.getElem();
                    pending.setName(wireEnum.getName()).setKind(Kind.ENUM);
                    for (String label : wireEnum.getLabels()) {
                        pending.addLabel(label);
                    }
                    return pending;
                case 2: // "ArrayT"
                    WireArray wireArray = (WireArray) wireType.getElem();
                    return pending.setName(wireArray.getName()).setKind(Kind.ARRAY)
                            .setLength((int) wireArray.getLen().getValue())
                            .setElem(lookupOrBuildPending(wireArray.getElem()));
                case 3: // "ListT"
                    WireList wireList = (WireList) wireType.getElem();
                    return pending.setName(wireList.getName()).setKind(Kind.LIST)
                            .setElem(lookupOrBuildPending(wireList.getElem()));
                case 4: // "SetT"
                    WireSet wireSet = (WireSet) wireType.getElem();
                    return pending.setName(wireSet.getName()).setKind(Kind.SET)
                            .setKey(lookupOrBuildPending(wireSet.getKey()));
                case 5: // "MapT"
                    WireMap wireMap = (WireMap) wireType.getElem();
                    return pending.setName(wireMap.getName()).setKind(Kind.MAP)
                            .setKey(lookupOrBuildPending(wireMap.getKey()))
                            .setElem(lookupOrBuildPending(wireMap.getElem()));
                case 6: // "StructT"
                    WireStruct wireStruct = (WireStruct) wireType.getElem();
                    pending.setName(wireStruct.getName()).setKind(Kind.STRUCT);
                    for (WireField field : wireStruct.getFields()) {
                        pending.addField(field.getName(), lookupOrBuildPending(field.getType()));
                    }
                    return pending;
                case 7: // "UnionT"
                    WireUnion wireUnion = (WireUnion) wireType.getElem();
                    pending.setName(wireUnion.getName()).setKind(Kind.UNION);
                    for (WireField field : wireUnion.getFields()) {
                        pending.addField(field.getName(), lookupOrBuildPending(field.getType()));
                    }
                    return pending;
                case 8: // "OptionalT"
                    WireOptional wireOptional = (WireOptional) wireType.getElem();
                    return pending.setName(wireOptional.getName()).setKind(Kind.OPTIONAL)
                            .setElem(lookupOrBuildPending(wireOptional.getElem()));
                default:
                    throw new CorruptVomStreamException("Unknown wire type: " + wireType.vdlType());
            }
        }
    }
}