package org.jetbrains.dokka

import com.intellij.openapi.vfs.VirtualFileManager
import com.intellij.psi.PsiJavaFile
import com.intellij.psi.PsiManager
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.runBlocking
import org.jetbrains.dokka.analysis.AnalysisEnvironment
import org.jetbrains.dokka.analysis.DokkaResolutionFacade
import org.jetbrains.dokka.model.DModule
import org.jetbrains.dokka.pages.PlatformData
import org.jetbrains.dokka.pages.RootPageNode
import org.jetbrains.dokka.plugability.DokkaContext
import org.jetbrains.dokka.plugability.DokkaPlugin
import org.jetbrains.dokka.utilities.DokkaLogger
import org.jetbrains.kotlin.cli.common.CLIConfigurationKeys
import org.jetbrains.kotlin.cli.common.messages.CompilerMessageLocation
import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
import org.jetbrains.kotlin.cli.common.messages.MessageCollector
import org.jetbrains.kotlin.cli.common.messages.MessageRenderer
import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
import org.jetbrains.kotlin.cli.jvm.config.JavaSourceRoot
import org.jetbrains.kotlin.utils.PathUtil
import java.io.File

/**
 * DokkaGenerator is the main entry point for generating documentation
 * [generate] method has been split into submethods for test reasons
 */
class DokkaGenerator(
    private val configuration: DokkaConfiguration,
    private val logger: DokkaLogger
) {
    fun generate() = timed {
        report("Setting up analysis environments")
        val platforms: Map<PlatformData, EnvironmentAndFacade> = setUpAnalysis(configuration)

        report("Initializing plugins")
        val context = initializePlugins(configuration, logger, platforms)

        report("Creating documentation models")
        val modulesFromPlatforms = createDocumentationModels(platforms, context)

        report("Transforming documentation model before merging")
        val transformedDocumentationBeforeMerge = transformDocumentationModelBeforeMerge(modulesFromPlatforms, context)

        report("Merging documentation models")
        val documentationModel = mergeDocumentationModels(transformedDocumentationBeforeMerge, context)

        report("Transforming documentation model after merging")
        val transformedDocumentation = transformDocumentationModelAfterMerge(documentationModel, context)

        report("Creating pages")
        val pages = createPages(transformedDocumentation, context)

        report("Transforming pages")
        val transformedPages = transformPages(pages, context)

        report("Rendering")
        render(transformedPages, context)

        context.unusedPoints.takeIf { it.isNotEmpty() }
            ?.also { logger.warn("Unused extension points found: ${it.joinToString(", ")}") }
        logger.report()
    }.dump("\n\n === TIME MEASUREMENT ===\n")

    fun setUpAnalysis(configuration: DokkaConfiguration): Map<PlatformData, EnvironmentAndFacade> =
        configuration.passesConfigurations.map {
            it.platformData to createEnvironmentAndFacade(it)
        }.toMap()

    fun initializePlugins(
        configuration: DokkaConfiguration,
        logger: DokkaLogger,
        platforms: Map<PlatformData, EnvironmentAndFacade>,
        pluginOverrides: List<DokkaPlugin> = emptyList()
    ) = DokkaContext.create(configuration, logger, platforms, pluginOverrides)

    fun createDocumentationModels(
        platforms: Map<PlatformData, EnvironmentAndFacade>,
        context: DokkaContext
    ) = platforms.flatMap { (pdata, _) -> translateSources(pdata, context) }

    fun transformDocumentationModelBeforeMerge(
        modulesFromPlatforms: List<DModule>,
        context: DokkaContext
    ) = context[CoreExtensions.preMergeDocumentableTransformer].fold(modulesFromPlatforms) { acc, t -> t(acc, context) }

    fun mergeDocumentationModels(
        modulesFromPlatforms: List<DModule>,
        context: DokkaContext
    ) = context.single(CoreExtensions.documentableMerger).invoke(modulesFromPlatforms, context)

    fun transformDocumentationModelAfterMerge(
        documentationModel: DModule,
        context: DokkaContext
    ) = context[CoreExtensions.documentableTransformer].fold(documentationModel) { acc, t -> t(acc, context) }

    fun createPages(
        transformedDocumentation: DModule,
        context: DokkaContext
    ) = context.single(CoreExtensions.documentableToPageTranslator).invoke(transformedDocumentation)

    fun transformPages(
        pages: RootPageNode,
        context: DokkaContext
    ) = context[CoreExtensions.pageTransformer].fold(pages) { acc, t -> t(acc) }

    fun render(
        transformedPages: RootPageNode,
        context: DokkaContext
    ) {
        val renderer = context.single(CoreExtensions.renderer)
        runBlocking {
            val scope = this
            with(renderer) {
                scope.render(transformedPages).join()
            }
        }
    }

    private fun createEnvironmentAndFacade(pass: DokkaConfiguration.PassConfiguration): EnvironmentAndFacade =
        AnalysisEnvironment(DokkaMessageCollector(logger), pass.analysisPlatform).run {
            if (analysisPlatform == Platform.jvm) {
                addClasspath(PathUtil.getJdkClassesRootsFromCurrentJre())
            }
            pass.classpath.forEach { addClasspath(File(it)) }

            addSources(pass.sourceRoots.map { it.path })

            loadLanguageVersionSettings(pass.languageVersion, pass.apiVersion)

            val environment = createCoreEnvironment()
            val (facade, _) = createResolutionFacade(environment)
            EnvironmentAndFacade(environment, facade)
        }

    private fun translateSources(platformData: PlatformData, context: DokkaContext) =
        context[CoreExtensions.sourceToDocumentableTranslator].map {
            it.invoke(platformData, context)
        }

    class DokkaMessageCollector(private val logger: DokkaLogger) : MessageCollector {
        override fun clear() {
            seenErrors = false
        }

        private var seenErrors = false

        override fun report(severity: CompilerMessageSeverity, message: String, location: CompilerMessageLocation?) {
            if (severity == CompilerMessageSeverity.ERROR) {
                seenErrors = true
            }
            logger.info(MessageRenderer.PLAIN_FULL_PATHS.render(severity, message, location))
        }

        override fun hasErrors() = seenErrors
    }
}

// It is not data class due to ill-defined equals
class EnvironmentAndFacade(val environment: KotlinCoreEnvironment, val facade: DokkaResolutionFacade) {
    operator fun component1() = environment
    operator fun component2() = facade
}

private class Timer(startTime: Long, private val logger: DokkaLogger?) {
    private val steps = mutableListOf("" to startTime)

    fun report(name: String) {
        logger?.progress(name)
        steps += (name to System.currentTimeMillis())
    }

    fun dump(prefix: String = "") {
        println(prefix)
        val namePad = steps.map { it.first.length }.max() ?: 0
        val timePad = steps.windowed(2).map { (p1, p2) -> p2.second - p1.second }.max()?.toString()?.length ?: 0
        steps.windowed(2).forEach { (p1, p2) ->
            if (p1.first.isNotBlank()) {
                println("${p1.first.padStart(namePad)}: ${(p2.second - p1.second).toString().padStart(timePad)}")
            }
        }
    }
}

private fun timed(logger: DokkaLogger? = null, block: Timer.() -> Unit): Timer =
    Timer(System.currentTimeMillis(), logger).apply(block).apply { report("") }