// Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package com.intellij.util.indexing

import com.intellij.ide.plugins.loadExtensionWithText
import com.intellij.openapi.application.PathManager
import com.intellij.openapi.extensions.InternalIgnoreDependencyViolation
import com.intellij.openapi.project.Project
import com.intellij.openapi.util.Disposer
import com.intellij.psi.stubs.StubIndexKey
import com.intellij.testFramework.fixtures.LightJavaCodeInsightFixtureTestCase
import com.intellij.util.io.lastModified
import org.junit.Assert
import java.nio.file.Files
import kotlin.streams.toList

class IndexInfrastructureExtensionTest : LightJavaCodeInsightFixtureTestCase() {
  fun `test infrastructure extension drops all indexes when it requires invalidation`() {
    val text = "<fileBasedIndexInfrastructureExtension implementation=\"" + TestIndexInfrastructureExtension::class.java.name + "\"/>"
    Disposer.register(testRootDisposable, loadExtensionWithText(text, TestIndexInfrastructureExtension::class.java.classLoader))

    val before = Files.list(PathManager.getIndexRoot()).use {
      it.toList().associate { p -> p.fileName.toString() to p.lastModified().toMillis() }.toSortedMap()
    }

    val switcher = FileBasedIndexSwitcher()
    switcher.turnOff()
    switcher.turnOn()

    val after = Files.list(PathManager.getIndexRoot()).use {
      it.toList().associate { p -> p.fileName.toString() to p.lastModified().toMillis() }.toSortedMap()
    }

    var containsExtensionCaches = false
    for ((b, a) in (before.entries zip after.entries)) {
      Assert.assertEquals(b.key, a.key)
      Assert.assertTrue(a.value > b.value)
      if (a.key.endsWith(testInfraExtensionFile)) {
        containsExtensionCaches = true
      }
    }
    Assert.assertTrue(containsExtensionCaches)
  }
}

const val testInfraExtensionFile = "_test_extension"

@InternalIgnoreDependencyViolation
class TestIndexInfrastructureExtension : FileBasedIndexInfrastructureExtension {
  override fun createFileIndexingStatusProcessor(project: Project): FileBasedIndexInfrastructureExtension.FileIndexingStatusProcessor? =
    null

  override fun <K : Any?, V : Any?> combineIndex(indexExtension: FileBasedIndexExtension<K, V>,
                                                 baseIndex: UpdatableIndex<K, V, FileContent>): UpdatableIndex<K, V, FileContent>? {
    Files.createFile(PathManager.getIndexRoot().resolve(indexExtension.name.name + testInfraExtensionFile))
    return null
  }

  override fun onFileBasedIndexVersionChanged(indexId: ID<*, *>) = Unit

  override fun onStubIndexVersionChanged(indexId: StubIndexKey<*, *>) = Unit

  override fun initialize(indexLayoutId: String?): FileBasedIndexInfrastructureExtension.InitializationResult
  = FileBasedIndexInfrastructureExtension.InitializationResult.INDEX_REBUILD_REQUIRED

  override fun resetPersistentState() = Unit

  override fun resetPersistentState(indexId: ID<*, *>) = Unit

  override fun shutdown() = Unit

  override fun getVersion(): Int = 0

}