/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.daffodil.runtime1.infoset

import javax.xml.parsers.DocumentBuilderFactory

import org.apache.daffodil.lib.exceptions.Assert
import org.apache.daffodil.lib.util.MStackOf
import org.apache.daffodil.lib.util.Maybe
import org.apache.daffodil.lib.xml.XMLUtils
import org.apache.daffodil.runtime1.api.DFDLPrimType
import org.apache.daffodil.runtime1.api.InfosetArray
import org.apache.daffodil.runtime1.api.InfosetComplexElement
import org.apache.daffodil.runtime1.api.InfosetElement
import org.apache.daffodil.runtime1.api.InfosetSimpleElement

import org.w3c.dom.Document
import org.w3c.dom.Element
import org.w3c.dom.Node

class W3CDOMInfosetOutputter extends InfosetOutputter {

  private var document: Document = null
  private val stack = new MStackOf[Node]
  private var result: Maybe[Document] = Maybe.Nope

  def reset()
    : Unit = { // call to reuse these. When first constructed no reset call is necessary.
    result = Maybe.Nope
    document = null
    stack.clear
  }

  def startDocument(): Unit = {
    val factory: DocumentBuilderFactory = DocumentBuilderFactory.newInstance()
    factory.setNamespaceAware(true)
    document = factory.newDocumentBuilder().newDocument()
    stack.push(document)
  }

  def endDocument(): Unit = {
    val root = stack.pop
    assert(stack.isEmpty)
    assert(root.isInstanceOf[Document])
    result = Maybe(root.asInstanceOf[Document])
  }

  override def startSimple(se: InfosetSimpleElement): Unit = {

    val elem = createElement(se)

    if (!se.isNilled) {
      val text =
        if (se.metadata.dfdlType == DFDLPrimType.String) {
          XMLUtils.remapXMLIllegalCharactersToPUA(se.getText)
        } else {
          se.getText
        }
      elem.appendChild(document.createTextNode(text))
    }

    stack.top.appendChild(elem)
  }

  override def endSimple(se: InfosetSimpleElement): Unit = {}

  override def startComplex(diComplex: InfosetComplexElement): Unit = {
    val elem = createElement(diComplex)
    stack.top.appendChild(elem)
    stack.push(elem)
  }

  override def endComplex(ce: InfosetComplexElement): Unit = {
    stack.pop
  }

  override def startArray(ar: InfosetArray): Unit = {}
  def endArray(ar: InfosetArray): Unit = {}

  def getResult(): Document = {
    Assert.usage(
      result.isDefined,
      "No result to get. Must check isError parse result before calling getResult"
    )
    result.get
  }

  private def createElement(ie: InfosetElement): Element = {

    assert(document != null)

    val elem: Element =
      if (ie.metadata.namespace eq null) {
        document.createElementNS(null, ie.metadata.name)
      } else {
        document.createElementNS(
          ie.metadata.namespace,
          ie.metadata.toQName
        )
      }

    if (ie.isNilled) {
      elem.setAttributeNS(XMLUtils.XSI_NAMESPACE.toString, "xsi:nil", "true")
    }

    elem
  }

}
