/**
 * 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 kotlinx.coroutines.runBlocking
import kotlinx.coroutines.sync.Semaphore
import org.jsoup.Jsoup
import org.jsoup.nodes.Document
import org.mosad.thecitadelofricks.Lesson
import org.mosad.thecitadelofricks.TimetableWeek
import org.slf4j.LoggerFactory

/**
 * @param timetableURL the URL of the timetable you want to get
 * @param htmlDoc the html document to use (the timetableURL will be ignored if this value is present)
 */
class TimetableParser(timetableURL: String? = null, htmlDoc: Document? = null) {
    private var logger: org.slf4j.Logger = LoggerFactory.getLogger(TimetableParser::class.java)
    private val days = arrayOf("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday")

    companion object {
        val semaphore = Semaphore(3, 0)
    }

    private val htmlDoc: Document? =
        htmlDoc
            ?: if (timetableURL == null) {
                null
            } else {
                runBlocking {
                    try {
                        // Only allow sending a limited amount of requests at the same time
                        semaphore.acquire()
                        Jsoup.connect(timetableURL).get()
                    } catch (gex: Exception) {
                        logger.error("general TimetableParser error", gex)
                        null
                    } finally {
                        semaphore.release()
                    }
                }
            }

    /**
     * parse the timetable from the previously given url
     * the timetable is organised per row not per column;
     * Mon 1, Tue 1, Wed 1, Thur 1, Fri 1, Sat 1, Mon 2 and so on
     */
    fun parseTimeTable(): TimetableWeek? {
        if (htmlDoc == null) {
            return null
        }

        val timetableWeek = TimetableWeek()
        val rows = htmlDoc.select("table.timetable").select("tr[scope=\"row\"]")

        var sDay = -1
        var sRow = -1
        var sLesson = Lesson("", "", "", "", "")

        // get each row with index, reflects 1 timeslot per day
        for ((rowIndex, row) in rows.withIndex()) {
            var day = 0
            var lessonIndexDay = 0 // the index of the lesson per timeslot

            // elements are now all lessons, including empty ones
            row.select("td.lastcol, td[style]").forEach { element ->

                // if there is a lecture with rowspan="2", we need to shift everything by one to the left. This is stupid and ugly there needs to bee an API
                if ((sDay > -1 && sRow > -1) && (sDay == day && ((sRow + 1) == rowIndex))) {
                    // we found a lecture that is longer than 1 lesson
                    timetableWeek.days[day].timeslots[rowIndex].add(sLesson) // this just works if there is one lecture per slot

                    // adjust the following slot
                    sDay++
                    sLesson = Lesson(
                        "$day.$rowIndex.$lessonIndexDay",
                        element.select("div.lesson-subject").text(),
                        element.select("div.lesson-teacher").text(),
                        element.select("div.lesson-room").text(),
                        element.select("div.lesson-remark").text()
                    )

                    // adjust the slot directly as we don't get there anymore
                    if (sDay == 5) {
                        timetableWeek.days[day + 1].timeslots[rowIndex].add(sLesson)
                    }

                } else {
                    timetableWeek.days[day].timeslots[rowIndex].add(
                        Lesson(
                            "$day.$rowIndex.$lessonIndexDay",
                            element.select("div.lesson-subject").text(),
                            element.select("div.lesson-teacher").text(),
                            element.select("div.lesson-room").text(),
                            element.select("div.lesson-remark").text()
                        )
                    )
                }

                // we found a lecture with rowspan="2", save day, row and lesson for later adjustment
                if (element.toString().contains("rowspan=\"2\"")) {
                    sDay = day
                    sRow = rowIndex
                    sLesson = timetableWeek.days[day].timeslots[rowIndex].get(index = 0)
                }

                lessonIndexDay++

                if (element.hasClass("lastcol")) {
                    day++
                    lessonIndexDay = 0
                }
            }

        }

        return timetableWeek
    }

    /**
     * parse the week number of the year for the timetable
     */
    fun parseWeekNumberYear(): Int? {
        if (htmlDoc == null) {
            return null
        }

        return htmlDoc.select("h1.timetable-caption").text().substringAfter("- ")
            .substringBefore(".").replace(" ", "").toInt()
    }

    @Suppress("unused")
    /**
     * print a timetable
     * @param timetable the timetable to print
     */
    fun printTimetableWeek(timetable: TimetableWeek) {
        for (j in 0..5) print(days[j].padEnd(75, ' ') + " | ")
        println()
        for (j in 0..5) print("-".padEnd(76 + (j.toFloat().div(j).toInt()), '-') + "+")
        println()

        // the timeslot
        for (i in 0..5) {

            for (j in 0..5) {
                val ldiff = if (timetable.days[j].timeslots[i].size == 0) 1 else timetable.days[j].timeslots[i].size

                for (lesson in timetable.days[j].timeslots[i]) print(lesson.lessonSubject.padEnd(75 / ldiff, ' '))
                if (ldiff == 2) print(" ")
                print(" | ")
            }
            println()

            for (j in 0..5) {
                val ldiff = if (timetable.days[j].timeslots[i].size == 0) 1 else timetable.days[j].timeslots[i].size

                for (lesson in timetable.days[j].timeslots[i]) print(lesson.lessonTeacher.padEnd(75 / ldiff, ' '))
                if (ldiff == 2) print(" ")
                print(" | ")
            }
            println()

            for (j in 0..5) {
                val ldiff = if (timetable.days[j].timeslots[i].size == 0) 1 else timetable.days[j].timeslots[i].size

                for (lesson in timetable.days[j].timeslots[i]) print(lesson.lessonRoom.padEnd(75 / ldiff, ' '))
                if (ldiff == 2) print(" ")
                print(" | ")
            }
            println()

            for (j in 0..5) print("-".padEnd(76 + (j.toFloat().div(j).toInt()), '-') + "+")
            println()
        }

        println(" \n")
    }

}