/*
 * Copyright (C) 2024 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.systemui.lifecycle

import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.filters.SmallTest
import com.android.systemui.SysuiTestCase
import com.android.systemui.kosmos.testScope
import com.android.systemui.testKosmos
import com.google.common.truth.Truth.assertThat
import kotlinx.coroutines.Job
import kotlinx.coroutines.test.runCurrent
import kotlinx.coroutines.test.runTest
import org.junit.Assert.assertThrows
import org.junit.Test
import org.junit.runner.RunWith

@SmallTest
@RunWith(AndroidJUnit4::class)
class ExclusiveActivatableTest : SysuiTestCase() {

    private val kosmos = testKosmos()
    private val testScope = kosmos.testScope

    private val underTest = FakeActivatable()

    @Test
    fun activate() =
        testScope.runTest {
            assertThat(underTest.activationCount).isEqualTo(0)
            assertThat(underTest.cancellationCount).isEqualTo(0)

            underTest.activateIn(testScope)
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(1)
            assertThat(underTest.cancellationCount).isEqualTo(0)
        }

    @Test
    fun activate_andCancel() =
        testScope.runTest {
            assertThat(underTest.activationCount).isEqualTo(0)
            assertThat(underTest.cancellationCount).isEqualTo(0)

            val job = Job()
            underTest.activateIn(testScope, context = job)
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(1)
            assertThat(underTest.cancellationCount).isEqualTo(0)

            job.cancel()
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(1)
            assertThat(underTest.cancellationCount).isEqualTo(1)
        }

    @Test
    fun activate_afterCancellation() =
        testScope.runTest {
            assertThat(underTest.activationCount).isEqualTo(0)
            assertThat(underTest.cancellationCount).isEqualTo(0)

            val job = Job()
            underTest.activateIn(testScope, context = job)
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(1)
            assertThat(underTest.cancellationCount).isEqualTo(0)

            job.cancel()
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(1)
            assertThat(underTest.cancellationCount).isEqualTo(1)

            underTest.activateIn(testScope)
            runCurrent()
            assertThat(underTest.activationCount).isEqualTo(2)
            assertThat(underTest.cancellationCount).isEqualTo(1)
        }

    @Test
    fun activate_whileActive_throws() {
        assertThrows(IllegalStateException::class.java) {
            testScope.runTest {
                assertThat(underTest.activationCount).isEqualTo(0)
                assertThat(underTest.cancellationCount).isEqualTo(0)

                underTest.activateIn(testScope)
                runCurrent()
                assertThat(underTest.activationCount).isEqualTo(1)
                assertThat(underTest.cancellationCount).isEqualTo(0)

                underTest.activateIn(testScope)
                runCurrent()
            }
      }
    }
}