/*
 * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

package kotlinx.coroutines.experimental.swing

import kotlinx.coroutines.experimental.CancellableContinuation
import kotlinx.coroutines.experimental.CoroutineDispatcher
import kotlinx.coroutines.experimental.Delay
import kotlinx.coroutines.experimental.DisposableHandle
import kotlinx.coroutines.experimental.swing.Swing.delay
import java.awt.event.ActionListener
import java.util.concurrent.TimeUnit
import javax.swing.SwingUtilities
import javax.swing.Timer
import kotlin.coroutines.experimental.CoroutineContext

/**
 * Dispatches execution onto Swing event dispatching thread and provides native [delay] support.
 */
object Swing : CoroutineDispatcher(), Delay {
    override fun dispatch(context: CoroutineContext, block: Runnable) = SwingUtilities.invokeLater(block)

    override fun scheduleResumeAfterDelay(time: Long, unit: TimeUnit, continuation: CancellableContinuation<Unit>) {
        val timer = schedule(time, unit, ActionListener {
            with(continuation) { resumeUndispatched(Unit) }
        })
        continuation.invokeOnCancellation { timer.stop() }
    }

    override fun invokeOnTimeout(time: Long, unit: TimeUnit, block: Runnable): DisposableHandle {
        val timer = schedule(time, unit, ActionListener {
            block.run()
        })
        return object : DisposableHandle {
            override fun dispose() {
                timer.stop()
            }
        }
    }

    private fun schedule(time: Long, unit: TimeUnit, action: ActionListener): Timer =
        Timer(unit.toMillis(time).coerceAtMost(Int.MAX_VALUE.toLong()).toInt(), action).apply {
            isRepeats = false
            start()
        }

    override fun toString() = "Swing"
}