/*
 * Copyright 2017 Christian Basler
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License 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 ch.dissem.msgpack

import ch.dissem.msgpack.types.*
import java.io.IOException
import java.io.InputStream

/**
 * Reads MPType object from an [InputStream].
 */
object Reader {
    private val unpackers = mutableListOf<MPType.Unpacker<*>>()

    init {
        unpackers.add(MPNil.Unpacker())
        unpackers.add(MPBoolean.Unpacker())
        unpackers.add(MPInteger.Unpacker())
        unpackers.add(MPFloat.Unpacker())
        unpackers.add(MPString.Unpacker())
        unpackers.add(MPBinary.Unpacker())
        unpackers.add(MPMap.Unpacker(this))
        unpackers.add(MPArray.Unpacker(this))
    }

    /**
     * Register your own extensions. The last registered unpacker always takes precedence.
     */
    fun register(unpacker: MPType.Unpacker<*>) {
        unpackers.add(0, unpacker)
    }

    @Throws(IOException::class)
    fun read(input: InputStream): MPType<*> {
        val firstByte = input.read()
        unpackers
                .firstOrNull { it.doesUnpack(firstByte) }
                ?.let {
                    return it.unpack(firstByte, input)
                }
        throw IOException(String.format("Unsupported input, no reader for 0x%02x", firstByte))
    }
}