package org.jetbrains.dokka.Model

import org.jetbrains.dokka.KotlinTypeWrapper
import org.jetbrains.dokka.links.DRI
import org.jetbrains.dokka.pages.PlatformData
import org.jetbrains.kotlin.kdoc.psi.impl.KDocTag

class Module(val packages: List<Package>) : DocumentationNode() {
    override val dri: DRI = DRI.topLevel
    override val children: List<Package> = packages
    override val extra: MutableSet<Extra> = mutableSetOf()
}

class Package(
    override val dri: DRI,
    override val functions: List<Function>,
    override val properties: List<Property>,
    override val classes: List<Class>,
    override val extra: MutableSet<Extra> = mutableSetOf()
) : ScopeNode() {
    override val name = dri.packageName.orEmpty()
}

class Class(
    override val dri: DRI,
    override val name: String,
    val kind: ClassKind,
    val constructors: List<Function>,
    override val functions: List<Function>,
    override val properties: List<Property>,
    override val classes: List<Class>,
    override val expected: ClassPlatformInfo?,
    override val actual: List<ClassPlatformInfo>,
    override val extra: MutableSet<Extra> = mutableSetOf()
) : ScopeNode() {
    val inherited by lazy { platformInfo.mapNotNull { (it as? ClassPlatformInfo)?.inherited }.flatten() }
}

class Function(
    override val dri: DRI,
    override val name: String,
    val returnType: TypeWrapper?,
    val isConstructor: Boolean,
    override val receiver: Parameter?,
    val parameters: List<Parameter>,
    override val expected: PlatformInfo?,
    override val actual: List<PlatformInfo>,
    override val extra: MutableSet<Extra> = mutableSetOf()
) : CallableNode() {
    override val children: List<Parameter>
        get() = listOfNotNull(receiver) + parameters
}

class Property(
    override val dri: DRI,
    override val name: String,
    override val receiver: Parameter?,
    override val expected: PlatformInfo?,
    override val actual: List<PlatformInfo>,
    override val extra: MutableSet<Extra> = mutableSetOf()
) : CallableNode() {
    override val children: List<Parameter>
        get() = listOfNotNull(receiver)
}

// TODO: treat named Parameters and receivers differently
class Parameter(
    override val dri: DRI,
    override val name: String?,
    val type: TypeWrapper,
    override val actual: List<PlatformInfo>,
    override val extra: MutableSet<Extra> = mutableSetOf()
) : DocumentationNode() {
    override val children: List<DocumentationNode>
        get() = emptyList()
}

interface PlatformInfo {
    val docTag: KDocTag?
    val links: Map<String, DRI>
    val platformData: List<PlatformData>
}

class BasePlatformInfo(
    override val docTag: KDocTag?,
    override val links: Map<String, DRI>,
    override val platformData: List<PlatformData>) : PlatformInfo {

    override fun equals(other: Any?): Boolean =
        other is PlatformInfo && (
                docTag?.text == other.docTag?.text &&
                        links == other.links)

    override fun hashCode(): Int =
        listOf(docTag?.text, links).hashCode()
}

class ClassPlatformInfo(
    val info: PlatformInfo,
    val inherited: List<DRI>) : PlatformInfo by info

abstract class DocumentationNode {
    open val expected: PlatformInfo? = null
    open val actual: List<PlatformInfo> = emptyList()
    open val name: String? = null
    val platformInfo by lazy { listOfNotNull(expected) + actual }
    val platformData by lazy { platformInfo.flatMap { it.platformData }.toSet() }

    abstract val dri: DRI

    abstract val children: List<DocumentationNode>

    override fun toString(): String {
        return "${javaClass.simpleName}($dri)" + briefDocstring.takeIf { it.isNotBlank() }?.let { " [$it]" }.orEmpty()
    }

    override fun equals(other: Any?) = other is DocumentationNode && this.dri == other.dri

    override fun hashCode() = dri.hashCode()

    val commentsData: List<Pair<String, Map<String, DRI>>>
        get() = platformInfo.mapNotNull { it.docTag?.let { tag -> Pair(tag.getContent(), it.links) } }

    val briefDocstring: String
        get() = platformInfo.firstOrNull()?.docTag?.getContent().orEmpty().shorten(40)

    open val extra: MutableSet<Extra> = mutableSetOf()
}

abstract class ScopeNode : DocumentationNode() {
    abstract val functions: List<Function>
    abstract val properties: List<Property>
    abstract val classes: List<Class>

    override val children: List<DocumentationNode>
        get() = functions + properties + classes
}

abstract class CallableNode : DocumentationNode() {
    abstract val receiver: Parameter?
}

private fun String.shorten(maxLength: Int) = lineSequence().first().let {
    if (it.length != length || it.length > maxLength) it.take(maxLength - 3) + "..." else it
}

interface TypeWrapper {
    val constructorFqName: String?
    val constructorNamePathSegments: List<String>
    val arguments: List<KotlinTypeWrapper>
    val dri: DRI?
}
interface ClassKind

fun DocumentationNode.dfs(predicate: (DocumentationNode) -> Boolean): DocumentationNode? =
    if (predicate(this)) {
        this
    } else {
        this.children.asSequence().mapNotNull { it.dfs(predicate) }.firstOrNull()
    }

interface Extra