/**
 * TheCitadelofRicks
 *
 * Copyright 2019-2020  <seil0@mosad.xyz>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 *
 */

package org.mosad.thecitadelofricks.hsoparser

import org.jsoup.Jsoup
import org.mosad.thecitadelofricks.Course
import org.slf4j.LoggerFactory
import java.net.SocketTimeoutException
import java.security.KeyManagementException
import java.security.cert.CertificateException
import java.security.cert.X509Certificate
import javax.net.ssl.SSLContext
import javax.net.ssl.SSLSocketFactory
import javax.net.ssl.TrustManager
import javax.net.ssl.X509TrustManager

class CourseListParser {

    private var logger: org.slf4j.Logger = LoggerFactory.getLogger(MensaParser::class.java)

    /**
     * return a list of all courses at courseListURL
     * @param courseListURL the url to the course list page
     * @return a ArrayList<Course> with all courses or null if the request was not successful
     */
    fun getCourseLinks(courseListURL: String): HashMap<String, Course>? {
        val courseLinkList = HashMap<String, Course>()
        try {
            val courseHTML = Jsoup.connect(courseListURL).sslSocketFactory(socketFactory()).get()

            courseHTML.select("ul.index-group").select("li.Class").select("a[href]").forEachIndexed { _, element ->
                courseLinkList[element.text()] = Course(
                    element.text(),
                    element.attr("href").replace("http", "https")
                )
            }
        } catch (ex: SocketTimeoutException) {
            logger.warn("timeout from hs-offenburg.de, updating on next attempt!")
            return null
        } catch (gex: Exception) {
            logger.error("general CourseListParser error", gex)
            return null
        }

        return courseLinkList
    }

    // Hack to ignore ssl errors while reading
    private fun socketFactory(): SSLSocketFactory {
        val trustAllCerts = arrayOf<TrustManager>(object : X509TrustManager {
            @Throws(CertificateException::class)
            override fun checkClientTrusted(chain: Array<X509Certificate>, authType: String) {
            }

            @Throws(CertificateException::class)
            override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {
            }

            override fun getAcceptedIssuers(): Array<X509Certificate> {
                return arrayOf()
            }
        })

        try {
            val sslContext = SSLContext.getInstance("TLS")
            sslContext.init(null, trustAllCerts, java.security.SecureRandom())
            return sslContext.socketFactory
        } catch (e: Exception) {
            when (e) {
                is RuntimeException, is KeyManagementException -> {
                    throw RuntimeException("Failed to create a SSL socket factory", e)
                }
                else -> throw e
            }
        }
    }
}