/*
 * (C) Copyright 2010-2015 SAP SE.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 */

package com.logicalhacking.dasca.crosslanguage.builder

import com.ibm.wala.cast.js.html.DefaultSourceExtractor
import com.ibm.wala.cast.js.html.DefaultSourceExtractor.HtmlCallBack
import com.ibm.wala.cast.js.html.IUrlResolver
import java.net.URL
import com.ibm.wala.cast.js.html.ITag
import org.apache.commons.io.input.BOMInputStream
import org.apache.commons.io.ByteOrderMark
import java.io.InputStreamReader
import scala.io.Source
import java.io.File
import org.apache.commons.io.IOUtils
import java.io.BufferedInputStream
import scala.collection.JavaConverters._
import com.typesafe.scalalogging.Logger
import java.io.IOException
import org.slf4j.LoggerFactory
import org.apache.commons.io.FileUtils
import scala.collection.mutable.MutableList

class AllScriptsExtractor(apkUnzipDir: File) extends DefaultSourceExtractor {
  val logger = Logger(LoggerFactory.getLogger(getClass.toString))
  val extractedScripts = MutableList[URL]()

  override def createHtmlCallback(entrypoint: URL, urlResolver: IUrlResolver) = new HtmlCallBack(entrypoint, urlResolver)

  class HtmlCallBack(entrypoint: URL, urlResolver: IUrlResolver) extends DefaultSourceExtractor.HtmlCallBack(entrypoint, urlResolver) {

    val AbsolutePathRegex = """.+android_asset/(.+)""".r
    val RemotePathRegex = """(https?://.+)""".r

    override def handleScript(tag: ITag) = {
      val content = tag.getAttributeByName("src");
      if (content != null) {
        val urlString = content.fst
        try {
          // For some reason, some people use absolute script paths in their Cordova apps...
          val scriptSrc = urlString match {
            case AbsolutePathRegex(rel) => new File(new File(apkUnzipDir, "assets"), rel).toURI().toURL()
            case RemotePathRegex(urlString) => {
              val url = new URL(urlString)
              logger.debug(s"Downloading $urlString...")
              val dest = new File(new File(apkUnzipDir, "downloaded"), url.getFile)
              dest.getParentFile.mkdirs()
              val stream = url.openStream()
              FileUtils.copyInputStreamToFile(stream, dest)
              IOUtils.closeQuietly(stream)
              dest.toURI().toURL()
            }
            case _ => new URL(entrypoint, urlString)
          }
          if (!new File(scriptSrc.getFile).isFile()) {
            // Try again with all lower-case letter, otherwise files may be missed on case-sensitive file systems
            if (!new File(scriptSrc.getFile.toLowerCase()).isFile()) {
              throw new IOException(s"$scriptSrc does not exist on the file system!")
            }
          }
          extractedScripts += scriptSrc
        } catch {
          case ioe: IOException => logger.warn(s"Could not fetch script $urlString!", ioe)
        }
      }
    }

  }

}