session-android/app/src/main/java/org/thoughtcrime/securesms/home/PathStatusView.kt

package org.thoughtcrime.securesms.home

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.graphics.Canvas
import android.graphics.Paint
import android.util.AttributeSet
import android.view.View
import androidx.annotation.ColorInt
import androidx.lifecycle.coroutineScope
import androidx.localbroadcastmanager.content.LocalBroadcastManager
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.withContext
import network.loki.messenger.R
import org.session.libsession.snode.OnionRequestAPI
import org.thoughtcrime.securesms.conversation.v2.ViewUtil
import org.thoughtcrime.securesms.util.getColorWithID
import org.thoughtcrime.securesms.util.toPx

class PathStatusView : View {
    private val broadcastReceivers = mutableListOf<BroadcastReceiver>()
    @ColorInt var mainColor: Int = 0
        set(newValue) { field = newValue; paint.color = newValue }
    @ColorInt var sessionShadowColor: Int = 0
        set(newValue) { field = newValue; paint.setShadowLayer(toPx(8, resources).toFloat(), 0.0f, 0.0f, newValue) }

    private val paint: Paint by lazy {
        val result = Paint()
        result.style = Paint.Style.FILL
        result.isAntiAlias = true
        result
    }

    private var updateJob: Job? = null

    constructor(context: Context) : super(context) {
        initialize()
    }

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        initialize()
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        initialize()
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {
        initialize()
    }

    private fun initialize() {
        if (!isInEditMode) {
            update()
        }
        setWillNotDraw(false)
    }

    override fun onAttachedToWindow() {
        super.onAttachedToWindow()
        registerObservers()
    }

    private fun registerObservers() {
        val buildingPathsReceiver: BroadcastReceiver = object : BroadcastReceiver() {

            override fun onReceive(context: Context, intent: Intent) {
                handleBuildingPathsEvent()
            }
        }
        broadcastReceivers.add(buildingPathsReceiver)
        LocalBroadcastManager.getInstance(context).registerReceiver(buildingPathsReceiver, IntentFilter("buildingPaths"))
        val pathsBuiltReceiver: BroadcastReceiver = object : BroadcastReceiver() {

            override fun onReceive(context: Context, intent: Intent) {
                handlePathsBuiltEvent()
            }
        }
        broadcastReceivers.add(pathsBuiltReceiver)
        LocalBroadcastManager.getInstance(context).registerReceiver(pathsBuiltReceiver, IntentFilter("pathsBuilt"))
    }

    override fun onDetachedFromWindow() {
        for (receiver in broadcastReceivers) {
            LocalBroadcastManager.getInstance(context).unregisterReceiver(receiver)
        }
        super.onDetachedFromWindow()
    }

    private fun handleBuildingPathsEvent() { update() }
    private fun handlePathsBuiltEvent() { update() }

    private fun update() {
        if (updateJob?.isActive != true) { // false or null
            updateJob = ViewUtil.getActivityLifecycle(this)?.coroutineScope?.launchWhenStarted {
                val paths = withContext(Dispatchers.IO) { OnionRequestAPI.paths }
                if (paths.isNotEmpty()) {
                    setBackgroundResource(R.drawable.accent_dot)
                    val hasPathsColor = context.getColor(R.color.accent_green)
                    mainColor = hasPathsColor
                    sessionShadowColor = hasPathsColor
                } else {
                    setBackgroundResource(R.drawable.paths_building_dot)
                    val pathsBuildingColor = resources.getColorWithID(R.color.paths_building, context.theme)
                    mainColor = pathsBuildingColor
                    sessionShadowColor = pathsBuildingColor
                }
            }
        }
    }

    override fun onDraw(c: Canvas) {
        val w = width.toFloat()
        val h = height.toFloat()
        c.drawCircle(w / 2, h / 2, w / 2, paint)
        super.onDraw(c)
    }
}