/* eslint-disable no-underscore-dangle -- Lexical nodes use protected __ fields by convention. */

import React from "react"
import type { ComponentType, ReactNode } from "react"
import { useLexicalComposerContext } from "@lexical/react/LexicalComposerContext"
import { useLexicalNodeSelection } from "@lexical/react/useLexicalNodeSelection"
import {
  $applyNodeReplacement,
  $getNodeByKey,
  $insertNodes,
  COMMAND_PRIORITY_LOW,
  DecoratorNode,
  KEY_BACKSPACE_COMMAND,
  KEY_DELETE_COMMAND,
  mergeRegister,
} from "lexical"
import type {
  DOMConversionMap,
  DOMExportOutput,
  LexicalEditor,
  NodeKey,
  SerializedLexicalNode,
  Spread,
} from "lexical"
import { cn } from "@workspace/ui/lib/utils"

import type { LexicalActionContext, LexicalActionDefinition } from "./types"

export interface LexicalEmbedPayload {
  id: string
  title: string
  description?: string
  imageUrl?: string
  metadata?: Record<string, unknown>
}

export interface LexicalEmbedRenderProps {
  payload: LexicalEmbedPayload
}

export interface LexicalEmbedDefinition {
  type: string
  render: ComponentType<LexicalEmbedRenderProps>
}

export interface CreateLexicalEmbedActionOptions {
  embed?: LexicalEmbedDefinition
  name: string
  label: LexicalActionDefinition["label"]
  icon?: LexicalActionDefinition["icon"]
  onRequest: (context: LexicalActionContext) => void
}

type SerializedLexicalEmbedNode = Spread<
  {
    embedType: string
    payload: LexicalEmbedPayload
  },
  SerializedLexicalNode
>

const LexicalEmbedContext = React.createContext<
  ReadonlyMap<string, LexicalEmbedDefinition>
>(new Map())

export function LexicalEmbedProvider({
  definitions,
  children,
}: {
  definitions: readonly LexicalEmbedDefinition[]
  children: ReactNode
}) {
  const definitionsByType = React.useMemo(
    () =>
      new Map(
        definitions.map((definition) => [definition.type, definition] as const)
      ),
    [definitions]
  )

  return (
    <LexicalEmbedContext.Provider value={definitionsByType}>
      {children}
    </LexicalEmbedContext.Provider>
  )
}

export function createLexicalEmbedAction({
  name,
  label,
  icon,
  embed,
  onRequest,
}: CreateLexicalEmbedActionOptions): LexicalActionDefinition {
  return {
    name,
    label,
    icon,
    group: "insert",
    nodes: [LexicalEmbedNode],
    embeds: embed ? [embed] : undefined,
    execute: onRequest,
  }
}

export function insertLexicalEmbed(
  editor: LexicalEditor,
  embedType: string,
  payload: LexicalEmbedPayload
) {
  editor.update(() => {
    $insertNodes([$createLexicalEmbedNode(embedType, payload)])
  })
}

export class LexicalEmbedNode extends DecoratorNode<ReactNode> {
  __embedType: string
  __payload: LexicalEmbedPayload

  static getType(): string {
    return "lexical-embed"
  }

  static clone(node: LexicalEmbedNode): LexicalEmbedNode {
    return new LexicalEmbedNode(node.__embedType, node.__payload, node.__key)
  }

  static importJSON(node: SerializedLexicalEmbedNode): LexicalEmbedNode {
    return $createLexicalEmbedNode(node.embedType, node.payload)
  }

  static importDOM(): DOMConversionMap | null {
    const conversion = (element: HTMLElement) => {
      const embedType = element.dataset.lexicalEmbedType
      const serializedPayload = element.dataset.lexicalEmbedPayload
      if (!embedType || !serializedPayload) return null

      try {
        const payload = JSON.parse(serializedPayload) as LexicalEmbedPayload
        if (!isLexicalEmbedPayload(payload)) return null
        return {
          conversion: () => ({
            node: $createLexicalEmbedNode(embedType, payload),
            forChild: () => null,
          }),
          priority: 4 as const,
        }
      } catch {
        return null
      }
    }

    return {
      article: conversion,
      div: conversion,
    }
  }

  constructor(embedType: string, payload: LexicalEmbedPayload, key?: NodeKey) {
    super(key)
    this.__embedType = embedType
    this.__payload = payload
  }

  createDOM(): HTMLElement {
    return document.createElement("div")
  }

  updateDOM(): false {
    return false
  }

  exportDOM(): DOMExportOutput {
    const element = document.createElement("article")
    element.dataset.lexicalEmbedType = this.__embedType
    element.dataset.lexicalEmbedPayload = JSON.stringify(this.__payload)

    if (this.__payload.imageUrl) {
      const image = document.createElement("img")
      image.setAttribute("src", this.__payload.imageUrl)
      image.setAttribute("alt", "")
      element.append(image)
    }

    const title = document.createElement("strong")
    title.textContent = this.__payload.title
    element.append(title)

    if (this.__payload.description) {
      const description = document.createElement("p")
      description.textContent = this.__payload.description
      element.append(description)
    }

    return { element }
  }

  exportJSON(): SerializedLexicalEmbedNode {
    return {
      ...super.exportJSON(),
      embedType: this.__embedType,
      payload: this.__payload,
      type: "lexical-embed",
      version: 1,
    }
  }

  decorate(): ReactNode {
    return (
      <LexicalEmbed
        embedType={this.__embedType}
        payload={this.__payload}
        nodeKey={this.__key}
      />
    )
  }
}

function LexicalEmbed({
  embedType,
  payload,
  nodeKey,
}: {
  embedType: string
  payload: LexicalEmbedPayload
  nodeKey: NodeKey
}) {
  const definitions = React.useContext(LexicalEmbedContext)
  const [editor] = useLexicalComposerContext()
  const [isSelected, setSelected, clearSelection] =
    useLexicalNodeSelection(nodeKey)
  const definition = definitions.get(embedType)
  const Render = definition?.render

  React.useEffect(
    () =>
      mergeRegister(
        editor.registerCommand(
          KEY_DELETE_COMMAND,
          (event) => {
            if (!isSelected) return false
            event.preventDefault()
            editor.update(() => {
              const node = $getNodeByKey(nodeKey)
              if ($isLexicalEmbedNode(node)) node.remove()
            })
            return true
          },
          COMMAND_PRIORITY_LOW
        ),
        editor.registerCommand(
          KEY_BACKSPACE_COMMAND,
          (event) => {
            if (!isSelected) return false
            event.preventDefault()
            editor.update(() => {
              const node = $getNodeByKey(nodeKey)
              if ($isLexicalEmbedNode(node)) node.remove()
            })
            return true
          },
          COMMAND_PRIORITY_LOW
        )
      ),
    [editor, isSelected, nodeKey]
  )

  return (
    <div
      contentEditable={false}
      data-lexical-embed-type={embedType}
      className={cn(
        "my-3 rounded-xl",
        isSelected && "ring-2 ring-primary ring-offset-2 ring-offset-background"
      )}
      onClick={(event) => {
        if (!event.shiftKey) clearSelection()
        setSelected(event.shiftKey ? !isSelected : true)
      }}
    >
      {Render ? <Render payload={payload} /> : <EmbedFallback {...payload} />}
    </div>
  )
}

function EmbedFallback({ title, description, imageUrl }: LexicalEmbedPayload) {
  return (
    <div className="flex items-center gap-3 rounded-xl border bg-muted/30 p-3">
      {imageUrl && (
        <img
          src={imageUrl}
          alt=""
          className="size-12 shrink-0 rounded-lg object-cover"
        />
      )}
      <div className="min-w-0">
        <p className="truncate font-medium">{title}</p>
        {description && (
          <p className="truncate text-sm text-muted-foreground">
            {description}
          </p>
        )}
      </div>
    </div>
  )
}

function isLexicalEmbedPayload(value: unknown): value is LexicalEmbedPayload {
  if (!value || typeof value !== "object") return false
  const payload = value as Partial<LexicalEmbedPayload>
  return typeof payload.id === "string" && typeof payload.title === "string"
}

export function $createLexicalEmbedNode(
  embedType: string,
  payload: LexicalEmbedPayload
) {
  return $applyNodeReplacement(new LexicalEmbedNode(embedType, payload))
}

export function $isLexicalEmbedNode(node: unknown): node is LexicalEmbedNode {
  return node instanceof LexicalEmbedNode
}