Search PDF files for text in Kotlin

//---------------------------------------------------------------------------------------
// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
// Consult legal.txt regarding legal and license information.
//---------------------------------------------------------------------------------------

package com.pdftron.android.pdfnetsdksamples.samples

import com.pdftron.android.pdfnetsdksamples.OutputListener
import com.pdftron.android.pdfnetsdksamples.PDFNetSample
import com.pdftron.android.pdfnetsdksamples.R
import com.pdftron.android.pdfnetsdksamples.util.Utils
import com.pdftron.common.PDFNetException
import com.pdftron.pdf.*
import com.pdftron.sdf.SDFDoc
import java.util.*

class TextSearchTest : PDFNetSample() {
    init {
        setTitle(R.string.sample_textsearch_title)
        setDescription(R.string.sample_textsearch_description)
    }

    override fun run(outputListener: OutputListener?) {
        super.run(outputListener)
        mOutputListener = outputListener
        mFileList.clear()
        printHeader(outputListener!!)

        try {
            val doc = PDFDoc(Utils.getAssetTempFile(PDFNetSample.INPUT_PATH + "credit card numbers.pdf")!!.absolutePath)
            doc.initSecurityHandler()

            val txt_search = TextSearch()
            var mode = TextSearch.e_whole_word or TextSearch.e_page_stop

            val pattern = "joHn sMiTh"

            //PDFDoc doesn't allow simultaneous access from different threads. If this
            //document could be used from other threads (e.g., the rendering thread inside
            //PDFView/PDFViewCtrl, if used), it is good practice to lock it.
            //Notice: don't forget to call doc.Unlock() to avoid deadlock.
            doc.lock()

            //call Begin() method to initialize the text search.
            txt_search.begin(doc, pattern, mode, -1, -1)

            var step = 0

            //call Run() method iteratively to find all matching instances.
            while (true) {
                val result = txt_search.run()

                if (result.code == TextSearchResult.e_found) {
                    if (step == 0) {
                        //step 0: found "John Smith"
                        //note that, here, 'ambient_string' and 'hlts' are not written to,
                        //as 'e_ambient_string' and 'e_highlight' are not set.
                        mOutputListener!!.println(result.resultStr + "'s credit card number is: ")

                        //now switch to using regular expressions to find John's credit card number
                        mode = txt_search.mode
                        mode = mode or (TextSearch.e_reg_expression or TextSearch.e_highlight)
                        txt_search.mode = mode
                        val new_pattern = "\\d{4}-\\d{4}-\\d{4}-\\d{4}" //or "(\\d{4}-){3}\\d{4}"
                        txt_search.setPattern(new_pattern)

                        step = step + 1
                    } else if (step == 1) {
                        //step 1: found John's credit card number
                        mOutputListener!!.println("  " + result.resultStr)

                        //note that, here, 'hlts' is written to, as 'e_highlight' has been set.
                        //output the highlight info of the credit card number
                        val hlts = result.highlights
                        hlts.begin(doc)
                        while (hlts.hasNext()) {
                            mOutputListener!!.println("The current highlight is from page: " + hlts.currentPageNumber)
                            hlts.next()
                        }

                        //see if there is an AMEX card number
                        val new_pattern = "\\d{4}-\\d{6}-\\d{5}"
                        txt_search.setPattern(new_pattern)

                        step = step + 1
                    } else if (step == 2) {
                        //found an AMEX card number
                        mOutputListener!!.println("\nThere is an AMEX card number:")
                        mOutputListener!!.println("  " + result.resultStr)

                        //change mode to find the owner of the credit card; supposedly, the owner's
                        //name proceeds the number
                        mode = txt_search.mode
                        mode = mode or TextSearch.e_search_up
                        txt_search.mode = mode
                        val new_pattern = "[A-z]++ [A-z]++"
                        txt_search.setPattern(new_pattern)

                        step = step + 1
                    } else if (step == 3) {
                        //found the owner's name of the AMEX card
                        mOutputListener!!.println("Is the owner's name:")
                        mOutputListener!!.println("  " + result.resultStr + "?")

                        //add a link annotation based on the location of the found instance
                        val hlts = result.highlights
                        hlts.begin(doc)
                        while (hlts.hasNext()) {
                            val cur_page = doc.getPage(hlts.currentPageNumber)
                            val q = hlts.currentQuads
                            val quad_count = q.size / 8
                            for (i in 0 until quad_count) {
                                //assume each quad is an axis-aligned rectangle
                                val offset = 8 * i
                                val x1 = Math.min(Math.min(Math.min(q[offset + 0], q[offset + 2]), q[offset + 4]), q[offset + 6])
                                val x2 = Math.max(Math.max(Math.max(q[offset + 0], q[offset + 2]), q[offset + 4]), q[offset + 6])
                                val y1 = Math.min(Math.min(Math.min(q[offset + 1], q[offset + 3]), q[offset + 5]), q[offset + 7])
                                val y2 = Math.max(Math.max(Math.max(q[offset + 1], q[offset + 3]), q[offset + 5]), q[offset + 7])
                                val hyper_link = com.pdftron.pdf.annots.Link.create(doc, Rect(x1, y1, x2, y2), Action.createURI(doc, "http://www.pdftron.com"))
                                cur_page.annotPushBack(hyper_link)
                            }
                            hlts.next()
                        }
                        doc.save(Utils.createExternalFile("credit card numbers_linked.pdf", mFileList).absolutePath, SDFDoc.SaveMode.LINEARIZED, null)
                        break
                    }
                } else if (result.code == TextSearchResult.e_page) {
                    //you can update your UI here, if needed
                } else {
                    break
                }
            }

            doc.unlock()
            doc.close()
        } catch (e: PDFNetException) {
            mOutputListener!!.printError(e.stackTrace)
        }

        for (file in mFileList) {
            addToFileList(file)
        }
        printFooter(outputListener)
    }

    companion object {

        private var mOutputListener: OutputListener? = null

        private val mFileList = ArrayList<String>()
    }

}