package shark

import com.github.ajalt.clikt.core.CliktCommand
import com.github.ajalt.clikt.core.PrintMessage
import jline.console.ConsoleReader
import jline.console.UserInterruptException
import jline.console.completer.CandidateListCompletionHandler
import jline.console.completer.StringsCompleter
import shark.HeapObject.HeapClass
import shark.HeapObject.HeapInstance
import shark.HeapObject.HeapObjectArray
import shark.HeapObject.HeapPrimitiveArray
import shark.HprofHeapGraph.Companion.openHeapGraph
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.BooleanArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.ByteArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.CharArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.DoubleArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.FloatArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.IntArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.LongArrayDump
import shark.HprofRecord.HeapDumpRecord.ObjectRecord.PrimitiveArrayDumpRecord.ShortArrayDump
import shark.InteractiveCommand.COMMAND.ANALYZE
import shark.InteractiveCommand.COMMAND.ARRAY
import shark.InteractiveCommand.COMMAND.CLASS
import shark.InteractiveCommand.COMMAND.Companion.matchesCommand
import shark.InteractiveCommand.COMMAND.DETAILED_PATH_TO_INSTANCE
import shark.InteractiveCommand.COMMAND.EXIT
import shark.InteractiveCommand.COMMAND.HELP
import shark.InteractiveCommand.COMMAND.INSTANCE
import shark.InteractiveCommand.COMMAND.PATH_TO_INSTANCE
import shark.SharkCliCommand.Companion.echoNewline
import shark.SharkCliCommand.Companion.retrieveHeapDumpFile
import shark.SharkCliCommand.Companion.sharkCliParams
import shark.ValueHolder.BooleanHolder
import shark.ValueHolder.ByteHolder
import shark.ValueHolder.CharHolder
import shark.ValueHolder.DoubleHolder
import shark.ValueHolder.FloatHolder
import shark.ValueHolder.IntHolder
import shark.ValueHolder.LongHolder
import shark.ValueHolder.ReferenceHolder
import shark.ValueHolder.ShortHolder
import java.io.File
import java.util.Locale

class InteractiveCommand : CliktCommand(
  name = "interactive",
  help = "Explore a heap dump."
) {

  enum class COMMAND(
    val commandName: String,
    val suffix: String = "",
    val help: String
  ) {
    ANALYZE(
      commandName = "analyze",
      help = "Analyze the heap dump."
    ),
    CLASS(
      commandName = "class",
      suffix = "NAME@ID",
      help = "Show class with a matching NAME and Object ID."
    ),
    INSTANCE(
      commandName = "instance",
      suffix = "CLASS_NAME@ID",
      help = "Show instance with a matching CLASS_NAME and Object ID."
    ),
    ARRAY(
      commandName = "array",
      suffix = "CLASS_NAME@ID",
      help = "Show array instance with a matching CLASS_NAME and Object ID."
    ),
    PATH_TO_INSTANCE(
      commandName = "->instance",
      suffix = "CLASS_NAME@ID",
      help = "Show path from GC Roots to instance."
    ),
    DETAILED_PATH_TO_INSTANCE(
      commandName = "~>instance",
      suffix = "CLASS_NAME@ID",
      help = "Show path from GC Roots to instance, highlighting suspect references."
    ),
    HELP(
      commandName = "help",
      help = "Show this message."
    ),
    EXIT(
      commandName = "exit",
      help = "Exit this interactive prompt."
    ),
    ;

    val pattern: String
      get() = if (suffix.isEmpty()) commandName else "$commandName "

    val patternHelp: String
      get() = pattern + suffix

    override fun toString() = commandName

    companion object {
      infix fun String.matchesCommand(command: COMMAND): Boolean {
        return if (command.suffix.isEmpty()) {
          this == command.commandName
        } else {
          startsWith(command.pattern)
        }
      }
    }
  }

  override fun run() {
    openHprof { graph, heapDumpFile ->
      val console = setupConsole(graph)
      var exit = false
      while (!exit) {
        val input = console.readCommand()
        exit = handleCommand(input, heapDumpFile, graph)
        echoNewline()
      }
    }
  }

  private fun openHprof(block: (HeapGraph, File) -> Unit) {
    val params = context.sharkCliParams
    val heapDumpFile = retrieveHeapDumpFile(params)
    val obfuscationMappingPath = params.obfuscationMappingPath

    val proguardMapping = obfuscationMappingPath?.let {
      ProguardMappingReader(it.inputStream()).readProguardMapping()
    }

    heapDumpFile.openHeapGraph().use { graph ->
      block(graph, heapDumpFile)
    }
  }

  private fun setupConsole(graph: HeapGraph): ConsoleReader {
    val console = ConsoleReader()
    console.handleUserInterrupt = true

    console.addCompleter(StringsCompleter(COMMAND.values().map { it.pattern }))
    console.addCompleter { buffer, _, candidates ->
      if (buffer != null) {
        when {
          buffer matchesCommand CLASS -> {
            val matchingObjects = findMatchingObjects(buffer, graph.classes) {
              it.name
            }
            candidates.addAll(matchingObjects.map { renderHeapObject(it) })
          }
          buffer matchesCommand INSTANCE -> {
            val matchingObjects = findMatchingObjects(buffer, graph.instances) {
              it.instanceClassSimpleName
            }
            candidates.addAll(matchingObjects.map { renderHeapObject(it) })
          }
          buffer matchesCommand PATH_TO_INSTANCE -> {
            val matchingObjects = findMatchingObjects(buffer, graph.instances) {
              it.instanceClassSimpleName
            }
            candidates.addAll(matchingObjects.map { "->${renderHeapObject(it)}" })
          }
          buffer matchesCommand DETAILED_PATH_TO_INSTANCE -> {
            val matchingObjects = findMatchingObjects(buffer, graph.instances) {
              it.instanceClassSimpleName
            }
            candidates.addAll(matchingObjects.map { "~>${renderHeapObject(it)}" })
          }
          buffer matchesCommand ARRAY -> {
            val matchingObjects =
              findMatchingObjects(buffer, graph.primitiveArrays + graph.objectArrays) {
                if (it is HeapPrimitiveArray) {
                  it.arrayClassName
                } else {
                  (it as HeapObjectArray).arrayClassSimpleName
                }
              }
            candidates.addAll(matchingObjects.map { renderHeapObject(it) })
          }
        }
      }
      if (candidates.isEmpty()) -1 else 0
    }
    val completionHandler = CandidateListCompletionHandler()
    completionHandler.printSpaceAfterFullCompletion = false
    console.completionHandler = completionHandler
    console.prompt = "Enter command [help]:\n"
    return console
  }

  private fun ConsoleReader.readCommand(): String? {
    val input = try {
      readLine()
    } catch (ignored: UserInterruptException) {
      throw PrintMessage("Program interrupted by user")
    }
    echoNewline()
    return input
  }

  private fun handleCommand(
    input: String?,
    heapDumpFile: File,
    graph: HeapGraph
  ): Boolean {
    when {
      input == null -> throw PrintMessage("End Of File was encountered")
      input.isBlank() || input matchesCommand HELP -> echoHelp()
      input matchesCommand EXIT -> return true
      input matchesCommand ANALYZE -> analyze(heapDumpFile, graph)
      input matchesCommand PATH_TO_INSTANCE -> {
        analyzeMatchingObjects(heapDumpFile, input, graph.instances, false) {
          it.instanceClassSimpleName
        }
      }
      input matchesCommand DETAILED_PATH_TO_INSTANCE -> {
        analyzeMatchingObjects(heapDumpFile, input, graph.instances, true) {
          it.instanceClassSimpleName
        }
      }
      input matchesCommand CLASS -> {
        renderMatchingObjects(input, graph.classes) {
          it.name
        }
      }
      input matchesCommand INSTANCE -> {
        renderMatchingObjects(input, graph.instances) {
          it.instanceClassSimpleName
        }
      }
      input matchesCommand ARRAY -> {
        renderMatchingObjects(input, graph.primitiveArrays + graph.objectArrays) {
          if (it is HeapPrimitiveArray) {
            it.arrayClassName
          } else {
            (it as HeapObjectArray).arrayClassSimpleName
          }
        }
      }
      else -> {
        echo("Unknown command [$input].\n")
        echoHelp()
      }
    }
    return false
  }

  private fun echoHelp() {
    echo("Available commands:")
    val longestPatternHelp = COMMAND.values()
      .map { it.patternHelp }.maxBy { it.length }!!.length
    COMMAND.values()
      .forEach { command ->
        val patternHelp = command.patternHelp
        val extraSpaceCount = (longestPatternHelp - patternHelp.length)
        val extraSpaces = " ".repeat(extraSpaceCount)
        println("  $patternHelp$extraSpaces  ${command.help}")
      }
  }

  private fun <T : HeapObject> renderMatchingObjects(
    pattern: String,
    objects: Sequence<T>,
    namer: (T) -> String
  ) {
    val matchingObjects = findMatchingObjects(pattern, objects, namer)
    when {
      matchingObjects.size == 1 -> {
        matchingObjects.first()
          .show()
      }
      matchingObjects.isNotEmpty() -> {
        matchingObjects.forEach { heapObject ->
          echo(renderHeapObject(heapObject))
        }
      }
      else -> {
        echo("No object found matching [$pattern]")
      }
    }
  }

  private fun <T : HeapObject> analyzeMatchingObjects(
    heapDumpFile: File,
    pattern: String,
    objects: Sequence<T>,
    showDetails: Boolean,
    namer: (T) -> String
  ) {
    val matchingObjects = findMatchingObjects(pattern, objects, namer)
    when {
      matchingObjects.size == 1 -> {
        val heapObject = matchingObjects.first()
        analyze(heapDumpFile, heapObject.graph, showDetails, heapObject.objectId)
      }
      matchingObjects.isNotEmpty() -> {
        matchingObjects.forEach { heapObject ->
          echo(if (showDetails) "~>" else "->" + renderHeapObject(heapObject))
        }
      }
      else -> {
        echo("No object found matching [$pattern]")
      }
    }
  }

  private fun <T : HeapObject> findMatchingObjects(
    pattern: String,
    objects: Sequence<T>,
    namer: (T) -> String
  ): List<T> {
    val firstSpaceIndex = pattern.indexOf(' ')
    val contentStartIndex = firstSpaceIndex + 1
    val nextSpaceIndex = pattern.indexOf(' ', contentStartIndex)
    val endIndex = if (nextSpaceIndex != -1) nextSpaceIndex else pattern.length
    val content = pattern.substring(contentStartIndex, endIndex)
    val identifierIndex = content.indexOf('@')
    val (classNamePart, objectIdStart) = if (identifierIndex == -1) {
      content to null
    } else {
      content.substring(0, identifierIndex) to
        content.substring(identifierIndex + 1)
    }

    val objectId = objectIdStart?.toLongOrNull()
    val checkObjectId = objectId != null
    val matchingObjects = objects
      .filter {
        classNamePart in namer(it) &&
          (!checkObjectId ||
            it.objectId.toString().startsWith(objectIdStart!!))
      }
      .toList()

    if (objectIdStart != null) {
      val exactMatchingByObjectId = matchingObjects.firstOrNull { objectId == it.objectId }
      if (exactMatchingByObjectId != null) {
        return listOf(exactMatchingByObjectId)
      }
    }

    val exactMatchingByName = matchingObjects.filter { classNamePart == namer(it) }

    return exactMatchingByName.ifEmpty {
      matchingObjects
    }
  }

  private fun HeapObject.show() {
    when (this) {
      is HeapInstance -> showInstance()
      is HeapClass -> showClass()
      is HeapObjectArray -> showObjectArray()
      is HeapPrimitiveArray -> showPrimitiveArray()
    }
  }

  private fun HeapInstance.showInstance() {
    echo(renderHeapObject(this))
    echo("  Instance of ${renderHeapObject(instanceClass)}")

    val fieldsPerClass = readFields()
      .toList()
      .groupBy { it.declaringClass }
      .toList()
      .filter { it.first.name != "java.lang.Object" }
      .reversed()

    fieldsPerClass.forEach { (heapClass, fields) ->
      echo("  Fields from ${renderHeapObject(heapClass)}")
      fields.forEach { field ->
        echo("    ${field.name} = ${renderHeapValue(field.value)}")
      }
    }
  }

  private fun HeapClass.showClass() {
    echo(this@InteractiveCommand.renderHeapObject(this))
    val superclass = superclass
    if (superclass != null) {
      echo("  Extends ${renderHeapObject(superclass)}")
    }

    val staticFields = readStaticFields()
      .filter { field ->
        !field.name.startsWith(
          "\$class\$"
        ) && field.name != "\$classOverhead"
      }
      .toList()
    if (staticFields.isNotEmpty()) {
      echo("  Static fields")
      staticFields
        .forEach { field ->
          echo("    static ${field.name} = ${renderHeapValue(field.value)}")
        }
    }

    val instances = when {
      isPrimitiveArrayClass -> primitiveArrayInstances
      isObjectArrayClass -> objectArrayInstances
      else -> instances
    }.toList()
    if (instances.isNotEmpty()) {
      echo("  ${instances.size} instance" + if (instances.size != 1) "s" else "")
      instances.forEach { arrayOrInstance ->
        echo("    ${renderHeapObject(arrayOrInstance)}")
      }
    }
  }

  private fun HeapObjectArray.showObjectArray() {
    val elements = readElements()
    echo(renderHeapObject(this))
    echo("  Instance of ${renderHeapObject(arrayClass)}")
    var repeatedValue: HeapValue? = null
    var repeatStartIndex = 0
    var lastIndex = 0
    elements.forEachIndexed { index, element ->
      lastIndex = index
      if (repeatedValue == null) {
        repeatedValue = element
        repeatStartIndex = index
      } else if (repeatedValue != element) {
        val repeatEndIndex = index - 1
        if (repeatStartIndex == repeatEndIndex) {
          echo("  $repeatStartIndex = ${renderHeapValue(repeatedValue!!)}")
        } else {
          echo("  $repeatStartIndex..$repeatEndIndex = ${renderHeapValue(repeatedValue!!)}")
        }
        repeatedValue = element
        repeatStartIndex = index
      }
    }
    if (repeatedValue != null) {
      if (repeatStartIndex == lastIndex) {
        echo("  $repeatStartIndex = ${renderHeapValue(repeatedValue!!)}")
      } else {
        echo("  $repeatStartIndex..$lastIndex = ${renderHeapValue(repeatedValue!!)}")
      }
    }
  }

  private fun HeapPrimitiveArray.showPrimitiveArray() {
    val record = readRecord()
    echo(renderHeapObject(this))
    echo("  Instance of ${renderHeapObject(arrayClass)}")

    var repeatedValue: Any? = null
    var repeatStartIndex = 0
    var lastIndex = 0
    val action: (Int, Any) -> Unit = { index, value ->
      lastIndex = index
      if (repeatedValue == null) {
        repeatedValue = value
        repeatStartIndex = index
      } else if (repeatedValue != value) {
        val repeatEndIndex = index - 1
        if (repeatStartIndex == repeatEndIndex) {
          echo("  $repeatStartIndex = $repeatedValue")
        } else {
          echo("  $repeatStartIndex..$repeatEndIndex = $repeatedValue")
        }
        repeatedValue = value
        repeatStartIndex = index
      }
    }

    when (record) {
      is BooleanArrayDump -> record.array.forEachIndexed(action)
      is CharArrayDump -> record.array.forEachIndexed(action)
      is FloatArrayDump -> record.array.forEachIndexed(action)
      is DoubleArrayDump -> record.array.forEachIndexed(action)
      is ByteArrayDump -> record.array.forEachIndexed(action)
      is ShortArrayDump -> record.array.forEachIndexed(action)
      is IntArrayDump -> record.array.forEachIndexed(action)
      is LongArrayDump -> record.array.forEachIndexed(action)
    }
    if (repeatedValue != null) {
      if (repeatStartIndex == lastIndex) {
        echo("  $repeatStartIndex = $repeatedValue")
      } else {
        echo("  $repeatStartIndex..$lastIndex = $repeatedValue")
      }
    }
  }

  private fun renderHeapValue(heapValue: HeapValue): String {
    return when (val holder = heapValue.holder) {
      is ReferenceHolder -> {
        when {
          holder.isNull -> "null"
          !heapValue.graph.objectExists(holder.value) -> "@${holder.value} object not found"
          else -> {
            val heapObject = heapValue.asObject!!
            renderHeapObject(heapObject)
          }
        }
      }
      is BooleanHolder -> holder.value.toString()
      is CharHolder -> holder.value.toString()
      is FloatHolder -> holder.value.toString()
      is DoubleHolder -> holder.value.toString()
      is ByteHolder -> holder.value.toString()
      is ShortHolder -> holder.value.toString()
      is IntHolder -> holder.value.toString()
      is LongHolder -> holder.value.toString()
    }
  }

  private fun renderHeapObject(heapObject: HeapObject): String {
    return when (heapObject) {
      is HeapClass -> {
        val instanceCount = when {
          heapObject.isPrimitiveArrayClass -> heapObject.primitiveArrayInstances
          heapObject.isObjectArrayClass -> heapObject.objectArrayInstances
          else -> heapObject.instances
        }.count()
        val plural = if (instanceCount != 1) "s" else ""
        "$CLASS ${heapObject.name}@${heapObject.objectId} (${instanceCount} instance$plural)"
      }
      is HeapInstance -> {
        val asJavaString = heapObject.readAsJavaString()

        val value =
          if (asJavaString != null) {
            " \"${asJavaString}\""
          } else ""

        "$INSTANCE ${heapObject.instanceClassSimpleName}@${heapObject.objectId}$value"
      }
      is HeapObjectArray -> {
        val className = heapObject.arrayClassSimpleName.removeSuffix("[]")
        "$ARRAY $className[${heapObject.readElements().count()}]@${heapObject.objectId}"
      }
      is HeapPrimitiveArray -> {
        val record = heapObject.readRecord()
        val primitiveName = heapObject.primitiveType.name.toLowerCase(Locale.US)
        "$ARRAY $primitiveName[${record.size}]@${heapObject.objectId}"
      }
    }
  }

  private fun analyze(
    heapDumpFile: File,
    graph: HeapGraph,
    showDetails: Boolean = true,
    leakingObjectId: Long? = null
  ) {
    if (leakingObjectId != null) {
      if (!graph.objectExists(leakingObjectId)) {
        echo("@$leakingObjectId not found")
        return
      } else {
        val heapObject = graph.findObjectById(leakingObjectId)
        if (heapObject !is HeapInstance) {
          echo("${renderHeapObject(heapObject)} is not an instance")
          return
        }
      }
    }

    val objectInspectors =
      if (showDetails) AndroidObjectInspectors.appDefaults.toMutableList() else mutableListOf()

    objectInspectors += ObjectInspector {
      it.labels += renderHeapObject(it.heapObject)
    }

    val leakingObjectFinder = if (leakingObjectId == null) {
      FilteringLeakingObjectFinder(
        AndroidObjectInspectors.appLeakingObjectFilters
      )
    } else {
      LeakingObjectFinder {
        setOf(leakingObjectId)
      }
    }

    val listener = OnAnalysisProgressListener { step ->
      SharkLog.d { "Analysis in progress, working on: ${step.name}" }
    }

    val heapAnalyzer = HeapAnalyzer(listener)
    SharkLog.d { "Analyzing heap dump $heapDumpFile" }

    val heapAnalysis = heapAnalyzer.analyze(
      heapDumpFile = heapDumpFile,
      graph = graph,
      leakingObjectFinder = leakingObjectFinder,
      referenceMatchers = AndroidReferenceMatchers.appDefaults,
      computeRetainedHeapSize = true,
      objectInspectors = objectInspectors,
      metadataExtractor = AndroidMetadataExtractor
    )

    if (leakingObjectId == null || heapAnalysis is HeapAnalysisFailure) {
      echo(heapAnalysis)
    } else {
      val leakTrace = (heapAnalysis as HeapAnalysisSuccess).allLeaks.first()
        .leakTraces.first()
      echo(if (showDetails) leakTrace else leakTrace.toSimplePathString())
    }
  }
}