package org.jetbrains.dokka

import org.jetbrains.dokka.LanguageService.RenderMode
import java.util.*

data class FormatLink(val text: String, val href: String)

enum class ListKind {
    Ordered,
    Unordered
}

abstract class StructuredFormatService(locationService: LocationService,
                                              val languageService: LanguageService,
                                              override val extension: String) : FormatService {
    val locationService: LocationService = locationService.withExtension(extension)

    abstract fun appendBlockCode(to: StringBuilder, line: String, language: String)
    abstract fun appendHeader(to: StringBuilder, text: String, level: Int = 1)
    abstract fun appendParagraph(to: StringBuilder, text: String)
    abstract fun appendLine(to: StringBuilder, text: String)
    abstract fun appendLine(to: StringBuilder)
    abstract fun appendAnchor(to: StringBuilder, anchor: String)

    abstract fun appendTable(to: StringBuilder, body: () -> Unit)
    abstract fun appendTableHeader(to: StringBuilder, body: () -> Unit)
    abstract fun appendTableBody(to: StringBuilder, body: () -> Unit)
    abstract fun appendTableRow(to: StringBuilder, body: () -> Unit)
    abstract fun appendTableCell(to: StringBuilder, body: () -> Unit)

    abstract fun formatText(text: String): String
    abstract fun formatSymbol(text: String): String
    abstract fun formatKeyword(text: String): String
    abstract fun formatIdentifier(text: String, kind: IdentifierKind): String
    fun formatEntity(text: String): String = text
    abstract fun formatLink(text: String, href: String): String
    open fun formatLink(link: FormatLink): String = formatLink(formatText(link.text), link.href)
    abstract fun formatStrong(text: String): String
    abstract fun formatStrikethrough(text: String): String
    abstract fun formatEmphasis(text: String): String
    abstract fun formatCode(code: String): String
    abstract fun formatUnorderedList(text: String): String
    abstract fun formatOrderedList(text: String): String
    abstract fun formatListItem(text: String, kind: ListKind): String
    abstract fun formatBreadcrumbs(items: Iterable<FormatLink>): String
    abstract fun formatNonBreakingSpace(): String
    open fun formatSoftLineBreak(): String = ""
    open fun formatIndentedSoftLineBreak(): String = ""

    open fun formatText(location: Location, nodes: Iterable<ContentNode>, listKind: ListKind = ListKind.Unordered): String {
        return nodes.map { formatText(location, it, listKind) }.joinToString("")
    }

    open fun formatText(location: Location, content: ContentNode, listKind: ListKind = ListKind.Unordered): String {
        return StringBuilder().apply {
            when (content) {
                is ContentText -> append(formatText(content.text))
                is ContentSymbol -> append(formatSymbol(content.text))
                is ContentKeyword -> append(formatKeyword(content.text))
                is ContentIdentifier -> append(formatIdentifier(content.text, content.kind))
                is ContentNonBreakingSpace -> append(formatNonBreakingSpace())
                is ContentSoftLineBreak -> append(formatSoftLineBreak())
                is ContentIndentedSoftLineBreak -> append(formatIndentedSoftLineBreak())
                is ContentEntity -> append(formatEntity(content.text))
                is ContentStrong -> append(formatStrong(formatText(location, content.children)))
                is ContentStrikethrough -> append(formatStrikethrough(formatText(location, content.children)))
                is ContentCode -> append(formatCode(formatText(location, content.children)))
                is ContentEmphasis -> append(formatEmphasis(formatText(location, content.children)))
                is ContentUnorderedList -> append(formatUnorderedList(formatText(location, content.children, ListKind.Unordered)))
                is ContentOrderedList -> append(formatOrderedList(formatText(location, content.children, ListKind.Ordered)))
                is ContentListItem -> append(formatListItem(formatText(location, content.children), listKind))

                is ContentNodeLink -> {
                    val node = content.node
                    val linkTo = if (node != null) locationHref(location, node) else "#"
                    val linkText = formatText(location, content.children)
                    if (linkTo == ".") {
                        append(linkText)
                    } else {
                        append(formatLink(linkText, linkTo))
                    }
                }
                is ContentExternalLink -> {
                    val linkText = formatText(location, content.children)
                    if (content.href == ".") {
                        append(linkText)
                    } else {
                        append(formatLink(linkText, content.href))
                    }
                }
                is ContentParagraph -> appendParagraph(this, formatText(location, content.children))
                is ContentBlockCode -> appendBlockCode(this, formatText(location, content.children), content.language)
                is ContentHeading -> appendHeader(this, formatText(location, content.children), content.level)
                is ContentBlock -> append(formatText(location, content.children))
            }
        }.toString()
    }

    open fun link(from: DocumentationNode, to: DocumentationNode): FormatLink = link(from, to, extension)

    open fun link(from: DocumentationNode, to: DocumentationNode, extension: String): FormatLink {
        return FormatLink(to.name, locationService.relativePathToLocation(from, to))
    }

    fun locationHref(from: Location, to: DocumentationNode): String {
        val topLevelPage = to.references(DocumentationReference.Kind.TopLevelPage).singleOrNull()?.to
        if (topLevelPage != null) {
            return from.relativePathTo(locationService.location(topLevelPage), to.name)
        }
        return from.relativePathTo(locationService.location(to))
    }

    fun appendDocumentation(location: Location, to: StringBuilder, overloads: Iterable<DocumentationNode>) {
        val breakdownBySummary = overloads.groupByTo(LinkedHashMap()) { node -> node.content }

        for ((summary, items) in breakdownBySummary) {
            appendAsOverloadGroup(to) {
                items.forEach {
                    val rendered = languageService.render(it)
                    appendAsSignature(to, rendered) {
                        to.append(formatCode(formatText(location, rendered)))
                        it.appendSourceLink(to)
                    }
                    it.appendOverrides(to)
                    it.appendDeprecation(location, to)
                }
                // All items have exactly the same documentation, so we can use any item to render it
                val item = items.first()
                item.details(DocumentationNode.Kind.OverloadGroupNote).forEach {
                    to.append(formatText(location, it.content))
                }
                to.append(formatText(location, item.content.summary))
                appendDescription(location, to, item)
                appendLine(to)
                appendLine(to)
            }
        }
    }

    private fun DocumentationNode.isModuleOrPackage(): Boolean =
        kind == DocumentationNode.Kind.Module || kind == DocumentationNode.Kind.Package

    protected open fun appendAsSignature(to: StringBuilder, node: ContentNode, block: () -> Unit) {
        block()
    }

    protected open fun appendAsOverloadGroup(to: StringBuilder, block: () -> Unit) {
        block()
    }

    fun appendDescription(location: Location, to: StringBuilder, node: DocumentationNode) {
        if (node.content.description != ContentEmpty) {
            appendLine(to, formatText(location, node.content.description))
            appendLine(to)
        }
        node.content.getSectionsWithSubjects().forEach {
            appendSectionWithSubject(it.key, location, it.value, to)
        }

        for (section in node.content.sections.filter { it.subjectName == null }) {
            appendLine(to, formatStrong(formatText(section.tag)))
            appendLine(to, formatText(location, section))
        }
    }

    fun Content.getSectionsWithSubjects(): Map<String, List<ContentSection>> =
            sections.filter { it.subjectName != null }.groupBy { it.tag }

    fun appendSectionWithSubject(title: String, location: Location, subjectSections: List<ContentSection>, to: StringBuilder) {
        appendHeader(to, title, 3)
        subjectSections.forEach {
            val subjectName = it.subjectName
            if (subjectName != null) {
                appendAnchor(to, subjectName)
                to.append(formatCode(subjectName)).append(" - ")
                to.append(formatText(location, it))
                appendLine(to)
            }
        }
    }

    private fun DocumentationNode.appendOverrides(to: StringBuilder) {
        overrides.forEach {
            to.append("Overrides ")
            val location = locationService.relativePathToLocation(this, it)
            appendLine(to, formatLink(FormatLink(it.owner!!.name + "." + it.name, location)))
        }
    }

    private fun DocumentationNode.appendDeprecation(location: Location, to: StringBuilder) {
        if (deprecation != null) {
            val deprecationParameter = deprecation!!.details(DocumentationNode.Kind.Parameter).firstOrNull()
            val deprecationValue = deprecationParameter?.details(DocumentationNode.Kind.Value)?.firstOrNull()
            if (deprecationValue != null) {
                to.append(formatStrong("Deprecated:")).append(" ")
                appendLine(to, formatText(deprecationValue.name.removeSurrounding("\"")))
                appendLine(to)
            } else if (deprecation?.content != Content.Empty) {
                to.append(formatStrong("Deprecated:")).append(" ")
                to.append(formatText(location, deprecation!!.content))
            } else {
                appendLine(to, formatStrong("Deprecated"))
                appendLine(to)
            }
        }
    }

    private fun DocumentationNode.appendSourceLink(to: StringBuilder) {
        val sourceUrl = details(DocumentationNode.Kind.SourceUrl).firstOrNull()
        if (sourceUrl != null) {
            to.append(" ")
            appendLine(to, formatLink("(source)", sourceUrl.name))
        } else {
            appendLine(to)
        }
    }

    fun appendLocation(location: Location, to: StringBuilder, nodes: Iterable<DocumentationNode>) {
        val singleNode = nodes.singleOrNull()
        if (singleNode != null && singleNode.isModuleOrPackage()) {
            if (singleNode.kind == DocumentationNode.Kind.Package) {
                appendHeader(to, "Package " + formatText(singleNode.name), 2)
            }
            to.append(formatText(location, singleNode.content))
        } else {
            val breakdownByName = nodes.groupBy { node -> node.name }
            for ((name, items) in breakdownByName) {
                appendHeader(to, formatText(name))
                appendDocumentation(location, to, items)
            }
        }
    }

    private fun appendSection(location: Location, caption: String, nodes: List<DocumentationNode>, node: DocumentationNode, to: StringBuilder) {
        if (nodes.any()) {
            appendHeader(to, caption, 3)

            val children = nodes.sortedBy { it.name }
            val membersMap = children.groupBy { link(node, it) }

            appendTable(to) {
                appendTableBody(to) {
                    for ((memberLocation, members) in membersMap) {
                        appendTableRow(to) {
                            appendTableCell(to) {
                                to.append(formatLink(memberLocation))
                            }
                            appendTableCell(to) {
                                val breakdownBySummary = members.groupBy { formatText(location, it.summary) }
                                for ((summary, items) in breakdownBySummary) {
                                    appendSummarySignatures(items, location, to)
                                    if (!summary.isEmpty()) {
                                        to.append(summary)
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    private fun appendSummarySignatures(items: List<DocumentationNode>, location: Location, to: StringBuilder) {
        val summarySignature = languageService.summarizeSignatures(items)
        if (summarySignature != null) {
            appendAsSignature(to, summarySignature) {
                appendLine(to, summarySignature.signatureToText(location))
            }
            return
        }
        val renderedSignatures = items.map { languageService.render(it, RenderMode.SUMMARY) }
        renderedSignatures.subList(0, renderedSignatures.size - 1).forEach {
            appendAsSignature(to, it) {
                appendLine(to, it.signatureToText(location))
            }
        }
        appendAsSignature(to, renderedSignatures.last()) {
            to.append(renderedSignatures.last().signatureToText(location))
        }
    }

    private fun ContentNode.signatureToText(location: Location): String {
        return if (this is ContentBlock && this.isEmpty()) {
            ""
        } else {
            val signatureAsCode = ContentCode()
            signatureAsCode.append(this)
            formatText(location, signatureAsCode)
        }
    }

    override fun appendNodes(location: Location, to: StringBuilder, nodes: Iterable<DocumentationNode>) {
        val breakdownByLocation = nodes.groupBy { node ->
            formatBreadcrumbs(node.path.filterNot { it.name.isEmpty() }.map { link(node, it) })
        }

        for ((breadcrumbs, items) in breakdownByLocation) {
            appendLine(to, breadcrumbs)
            appendLine(to)
            appendLocation(location, to, items.filter { it.kind != DocumentationNode.Kind.ExternalClass })
        }

        for (node in nodes) {
            if (node.kind == DocumentationNode.Kind.ExternalClass) {
                appendSection(location, "Extensions for ${node.name}", node.members, node, to)
                continue
            }

            appendSection(location, "Packages", node.members(DocumentationNode.Kind.Package), node, to)
            appendSection(location, "Types", node.members.filter { it.kind in DocumentationNode.Kind.classLike }, node, to)
            appendSection(location, "Extensions for External Classes", node.members(DocumentationNode.Kind.ExternalClass), node, to)
            appendSection(location, "Enum Values", node.members(DocumentationNode.Kind.EnumItem), node, to)
            appendSection(location, "Constructors", node.members(DocumentationNode.Kind.Constructor), node, to)
            appendSection(location, "Properties", node.members(DocumentationNode.Kind.Property), node, to)
            appendSection(location, "Inherited Properties", node.inheritedMembers(DocumentationNode.Kind.Property), node, to)
            appendSection(location, "Functions", node.members(DocumentationNode.Kind.Function), node, to)
            appendSection(location, "Inherited Functions", node.inheritedMembers(DocumentationNode.Kind.Function), node, to)
            appendSection(location, "Companion Object Properties", node.members(DocumentationNode.Kind.CompanionObjectProperty), node, to)
            appendSection(location, "Companion Object Functions", node.members(DocumentationNode.Kind.CompanionObjectFunction), node, to)
            appendSection(location, "Other members", node.members.filter {
                it.kind !in setOf(
                        DocumentationNode.Kind.Class,
                        DocumentationNode.Kind.Interface,
                        DocumentationNode.Kind.Enum,
                        DocumentationNode.Kind.Object,
                        DocumentationNode.Kind.AnnotationClass,
                        DocumentationNode.Kind.Constructor,
                        DocumentationNode.Kind.Property,
                        DocumentationNode.Kind.Package,
                        DocumentationNode.Kind.Function,
                        DocumentationNode.Kind.CompanionObjectProperty,
                        DocumentationNode.Kind.CompanionObjectFunction,
                        DocumentationNode.Kind.ExternalClass,
                        DocumentationNode.Kind.EnumItem
                        )
            }, node, to)

            val allExtensions = collectAllExtensions(node)
            appendSection(location, "Extension Properties", allExtensions.filter { it.kind == DocumentationNode.Kind.Property }, node, to)
            appendSection(location, "Extension Functions", allExtensions.filter { it.kind == DocumentationNode.Kind.Function }, node, to)
            appendSection(location, "Companion Object Extension Properties", allExtensions.filter { it.kind == DocumentationNode.Kind.CompanionObjectProperty }, node, to)
            appendSection(location, "Companion Object Extension Functions", allExtensions.filter { it.kind == DocumentationNode.Kind.CompanionObjectFunction }, node, to)
            appendSection(location, "Inheritors",
                    node.inheritors.filter { it.kind != DocumentationNode.Kind.EnumItem }, node, to)
            appendSection(location, "Links", node.links, node, to)

        }
    }

    private fun collectAllExtensions(node: DocumentationNode): Collection<DocumentationNode> {
        val result = LinkedHashSet<DocumentationNode>()
        val visited = hashSetOf<DocumentationNode>()

        fun collect(node: DocumentationNode) {
            if (!visited.add(node)) return
            result.addAll(node.extensions)
            node.references(DocumentationReference.Kind.Superclass).forEach { collect(it.to) }
        }

        collect(node)

        return result

    }
}