conventionschedule-android/app/src/main/java/com/adlerosn/brasilfurfest/schedule/managers/ScheduleManager.kt

package com.adlerosn.brasilfurfest.schedule.managers

import android.content.Context
import android.os.FileObserver
import android.util.Log
import com.adlerosn.brasilfurfest.helper.*
import com.adlerosn.brasilfurfest.helper.observables.Observable
import com.adlerosn.brasilfurfest.helper.observables.Observer
import com.adlerosn.brasilfurfest.notification.NotificationFirer
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.convention.Announcement
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.convention.Convention
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.convention.ConventionSeries
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.convention.Event
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.managed.AttendeeConFavorites
import com.adlerosn.brasilfurfest.schedule.abstractDataTypes.managed.AttendeeConsFavorites
import com.google.gson.GsonBuilder
import org.jetbrains.anko.doAsync
import java.io.File
import java.io.Serializable
import java.util.*

class ScheduleManager(context: Context) : UncomplicatedObservable<Any?>(), Observer<Observable<Any?>, Any?>, Serializable {
    override fun update(observable: Observable<Any?>, args: Any?) = onAttendeeIntentionsChanged()

    private val uniqueIdentifierFile = File(context.filesDir, "rduid.txt")
    val uniqueIdentifier: String

    val cacheManager = CacheManager(context)
    private val cachedChoices = File(context.filesDir, "schedule_choices.json")
    private val cachedChoicesCanonicalPath = cachedChoices.canonicalPath

    private val fireNotificationsClosure = { NotificationFirer().fire(context) }

    private inner class InnerFileObserver(path: String, private val closure: ()->Any?) : FixedFileObserver(path){
        override fun onEvent(event: Int, path: String) {
            val mask = FileObserver.CLOSE_WRITE
            if ((event and mask) != 0) {
                closure()
            }
        }
    }

    private var diskChangesToNotLoad: Int = 0
    private fun incrementDiskChangesToNotLoad(howMany: Int = 1){
        synchronized(::diskChangesToNotLoad) {
            diskChangesToNotLoad+=howMany
        }
    }
    private fun notifyDiskChanges() {
        synchronized(::diskChangesToNotLoad) {
            if(diskChangesToNotLoad > 0)
                diskChangesToNotLoad-=1
            else
                loadFromDisk()
        }
        setChanged()
        notifyObservers()
    }

    private val fileObserver: InnerFileObserver
    private val scheduleObserver: InnerFileObserver

    fun updateConventionSeries() =
            cacheManager[RemoteAssets.json.lastPathPart()]!!.first
                    .let { ConventionJsonReader.readFromInputStream(it) }
                    .also { conventionSeries = it }

    var conventionSeries: ConventionSeries = updateConventionSeries()
    val convention get() = conventionSeries.featured
    val attendeeConventionsFavorites = AttendeeConsFavorites()
    val attendeeFavorites
        get(): AttendeeConFavorites {
            lateinit var favorites: AttendeeConFavorites
            synchronized(::attendeeConventionsFavorites) {
                favorites = attendeeConventionsFavorites[convention]
            }
            return favorites
        }
    val conventionTime get() = GregorianCalendar().apply { timeInMillis = System.currentTimeMillis() } // .GregorianCalendar(2018,7,19,13,15)
    private val jsonSerializer get() = GsonBuilder()
            //.setExclusionStrategies(ObservableFieldsExclusionStrategy())
            .registerTypeAdapter(Convention::class.java, ConventionInstanceCreator(convention))
            .create()
//    val nextNotificationTime: Long get(){
//        val early: Long = convention.notificationFireMinutesBefore*60*1000.toLong()
//        val now = conventionTime
//        val thisRange = now.dayRange.split(convention.splitDayIn).first { conventionTime in it }
//        val diff = thisRange.finish.timeInMillis - thisRange.start.timeInMillis
//        val nextEnd = thisRange.start.timeInMillis+(1*diff)
//        val nextNextEnd = thisRange.start.timeInMillis+(2*diff)
//        val earlyNextEnd = nextEnd-early
//        val earlyNextNextEnd = nextNextEnd-early
//        return if(now.timeInMillis < earlyNextEnd) earlyNextEnd else earlyNextNextEnd
//    }

    init {
        loadFromDisk()
        if(!cachedChoices.exists())
            saveToDisk(false)
        uniqueIdentifier = initUniqueIdentifierFile()
        fileObserver = (InnerFileObserver(cachedChoicesCanonicalPath) {notifyDiskChanges()}).apply { startWatching() }
        scheduleObserver = (InnerFileObserver(cacheManager.getFileFor(RemoteAssets.json).absolutePath) {notifyScheduleChanged()}).apply { startWatching() }
    }

    private fun notifyScheduleChanged() {
        conventionSeries = updateConventionSeries()
        setChanged()
        notifyObservers()
        fireNotificationsClosure()
    }

    private val readAnnouncementsFile = File(context.filesDir, "announcements_read.txt")
    val unreadAnnouncements: List<Announcement> get() {
        if(!readAnnouncementsFile.exists())
            return listOf()
        val readAnnouncementUUIDs = readAnnouncementsFile.readLines()
        return conventionSeries.announcements.filter { it.uuid !in readAnnouncementUUIDs }
    }
    fun setAnnouncementsRead() {
        readAnnouncementsFile.writeText(
                conventionSeries.announcements.map {
                    it.uuid
                }.joinToString(separator = "\n")
        )
    }


    private fun initUniqueIdentifierFile(): String{
        if(!uniqueIdentifierFile.exists())
            uniqueIdentifierFile.writeText(UUID.randomUUID().toString())
        return uniqueIdentifierFile.readText()
    }

    private fun readObject(ois: java.io.ObjectInputStream){
        ois.defaultReadObject()
        fileObserver.stopWatching()
        fileObserver.startWatching()
        scheduleObserver.stopWatching()
        scheduleObserver.startWatching()
        loadFromDisk()
    }

    private fun loadFromDisk() {
        if (cachedChoices.exists()) {
            synchronized(::attendeeConventionsFavorites) {
                val json = cachedChoices.readText()
                val stateFromDisk = try {
                    jsonSerializer.fromJson(json, attendeeConventionsFavorites::class.java)
                } catch (e: com.google.gson.JsonSyntaxException) {
                    Log.e("Schedule manager", "Malformed JSON", e)
                    AttendeeConsFavorites()
                }
                if (stateFromDisk != null) {
                    stateFromDisk.recursivelyRemoveObservers()
                    attendeeConventionsFavorites.recursivelyRemoveObservers()
                    attendeeConventionsFavorites.clear()
                    attendeeConventionsFavorites.putAll(stateFromDisk)
                    attendeeConventionsFavorites.observeAllChildren()
                    attendeeConventionsFavorites.addObserver(this)
            }
            }
        }
    }


    private fun saveToDisk(async: Boolean = true) {
        synchronized(::attendeeConventionsFavorites) {
            attendeeConventionsFavorites.recursivelyRemoveObservers()
            val json = jsonSerializer.toJson(attendeeConventionsFavorites)
            attendeeConventionsFavorites.observeAllChildren()
            attendeeConventionsFavorites.addObserver(this)
            incrementDiskChangesToNotLoad()
            val closure = { cachedChoices.bufferedWriter().use { it.write(json) } }
            if(async)
                doAsync { closure() }
            else
                closure()
        }
    }

    fun onAttendeeIntentionsChanged() {
        saveToDisk()
    }

    fun clearIntentions() {
        attendeeConventionsFavorites.clear()
        saveToDisk()
    }

    val currentSplashAsset: String get() = (
                    conventionSeries.banners.firstOrNull { conventionTime in it.lifetime }?.banner
                    ?: conventionSeries.defaultBanner
            ).solved!!

    val editionHasStarted: Boolean get() = conventionTime.timeInMillis > convention.officialLifespan.start.timeInMillis
    val editionHasEnded: Boolean get() = conventionTime.timeInMillis > convention.officialLifespan.finish.timeInMillis

    val nextEditionStartTime : Long? get(){
        val currentTime = conventionTime.timeInMillis
        val timeUntilThis = convention.officialLifespan.start.timeInMillis - currentTime
        val timeUntilNext = (convention.nextEdition?.timeInMillis ?: Long.MAX_VALUE) - currentTime
        val stillHappening = editionHasStarted and !editionHasEnded
        return when {
            timeUntilThis > 0 -> convention.officialLifespan.start.timeInMillis
            stillHappening -> null
            timeUntilNext > 0 -> convention.nextEdition?.timeInMillis
            else -> null
        }
    }

    val nextEditionStartCountdown : Triple<Int, Int, Int>?
        get() = nextEditionStartTime?.let { buildDayHourMinuteCountdownTriple(it - conventionTime.timeInMillis) }

    private fun buildDayHourMinuteCountdownTriple(millisUntil: Long): Triple<Int, Int, Int>{
        return (millisUntil/1000).let {
            Triple((it/(3600*24)).toInt(), ((it/3600)%24).toInt(), ((it/60)%60).toInt())
        }
    }

    fun canAttend(event: Event) = attendeeFavorites.canAttend(event)
}