import {
  type Middleware,
  arrow,
  autoPlacement,
  computePosition,
  flip,
  hide,
  inline,
  offset,
  shift,
  size,
} from '@floating-ui/dom'
import type { Editor } from '@tiptap/core'
import { getText, getTextSerializersFromSchema, posToDOMRect } from '@tiptap/core'
import type { Node as ProsemirrorNode } from '@tiptap/pm/model'
import type { EditorState } from '@tiptap/pm/state'
import { Plugin, PluginKey } from '@tiptap/pm/state'
import type { EditorView } from '@tiptap/pm/view'

export interface FloatingMenuPluginProps {
  /**
   * The plugin key for the floating menu.
   * @default 'floatingMenu'
   */
  pluginKey: PluginKey | string

  /**
   * The editor instance.
   * @default null
   */
  editor: Editor

  /**
   * The DOM element that contains your menu.
   * @default null
   */
  element: HTMLElement

  /**
   * A function that determines whether the menu should be shown or not.
   * If this function returns `false`, the menu will be hidden, otherwise it will be shown.
   */
  shouldShow:
    | ((props: {
        editor: Editor
        view: EditorView
        state: EditorState
        oldState?: EditorState
        from: number
        to: number
      }) => boolean)
    | null

  /**
   * FloatingUI options.
   */
  options?: {
    strategy?: 'absolute' | 'fixed'
    placement?:
      | 'top'
      | 'right'
      | 'bottom'
      | 'left'
      | 'top-start'
      | 'top-end'
      | 'right-start'
      | 'right-end'
      | 'bottom-start'
      | 'bottom-end'
      | 'left-start'
      | 'left-end'
    offset?: Parameters<typeof offset>[0] | boolean
    flip?: Parameters<typeof flip>[0] | boolean
    shift?: Parameters<typeof shift>[0] | boolean
    arrow?: Parameters<typeof arrow>[0] | false
    size?: Parameters<typeof size>[0] | boolean
    autoPlacement?: Parameters<typeof autoPlacement>[0] | boolean
    hide?: Parameters<typeof hide>[0] | boolean
    inline?: Parameters<typeof inline>[0] | boolean
  }
}

export type FloatingMenuViewProps = FloatingMenuPluginProps & {
  /**
   * The editor view.
   */
  view: EditorView
}

export class FloatingMenuView {
  public editor: Editor

  public element: HTMLElement

  public view: EditorView

  public preventHide = false

  private getTextContent(node: ProsemirrorNode) {
    return getText(node, { textSerializers: getTextSerializersFromSchema(this.editor.schema) })
  }

  public shouldShow: Exclude<FloatingMenuPluginProps['shouldShow'], null> = ({ view, state }) => {
    const { selection } = state
    const { $anchor, empty } = selection
    const isRootDepth = $anchor.depth === 1

    const isEmptyTextBlock =
      $anchor.parent.isTextblock &&
      !$anchor.parent.type.spec.code &&
      !$anchor.parent.textContent &&
      $anchor.parent.childCount === 0 &&
      !this.getTextContent($anchor.parent)

    if (!view.hasFocus() || !empty || !isRootDepth || !isEmptyTextBlock || !this.editor.isEditable) {
      return false
    }

    return true
  }

  private floatingUIOptions: NonNullable<FloatingMenuPluginProps['options']> = {
    strategy: 'absolute',
    placement: 'right',
    offset: 8,
    flip: {},
    shift: {},
    arrow: false,
    size: false,
    autoPlacement: false,
    hide: false,
    inline: false,
  }

  get middlewares() {
    const middlewares: Middleware[] = []

    if (this.floatingUIOptions.flip) {
      middlewares.push(flip(typeof this.floatingUIOptions.flip !== 'boolean' ? this.floatingUIOptions.flip : undefined))
    }

    if (this.floatingUIOptions.shift) {
      middlewares.push(
        shift(typeof this.floatingUIOptions.shift !== 'boolean' ? this.floatingUIOptions.shift : undefined),
      )
    }

    if (this.floatingUIOptions.offset) {
      middlewares.push(
        offset(typeof this.floatingUIOptions.offset !== 'boolean' ? this.floatingUIOptions.offset : undefined),
      )
    }

    if (this.floatingUIOptions.arrow) {
      middlewares.push(arrow(this.floatingUIOptions.arrow))
    }

    if (this.floatingUIOptions.size) {
      middlewares.push(size(typeof this.floatingUIOptions.size !== 'boolean' ? this.floatingUIOptions.size : undefined))
    }

    if (this.floatingUIOptions.autoPlacement) {
      middlewares.push(
        autoPlacement(
          typeof this.floatingUIOptions.autoPlacement !== 'boolean' ? this.floatingUIOptions.autoPlacement : undefined,
        ),
      )
    }

    if (this.floatingUIOptions.hide) {
      middlewares.push(hide(typeof this.floatingUIOptions.hide !== 'boolean' ? this.floatingUIOptions.hide : undefined))
    }

    if (this.floatingUIOptions.inline) {
      middlewares.push(
        inline(typeof this.floatingUIOptions.inline !== 'boolean' ? this.floatingUIOptions.inline : undefined),
      )
    }

    return middlewares
  }

  constructor({ editor, element, view, options, shouldShow }: FloatingMenuViewProps) {
    this.editor = editor
    this.element = element
    this.view = view

    this.floatingUIOptions = {
      ...this.floatingUIOptions,
      ...options,
    }

    if (shouldShow) {
      this.shouldShow = shouldShow
    }

    this.element.addEventListener('mousedown', this.mousedownHandler, { capture: true })
    this.editor.on('focus', this.focusHandler)
    this.editor.on('blur', this.blurHandler)

    this.update(view, view.state)

    if (this.getShouldShow()) {
      this.show()
    }
  }

  getShouldShow(oldState?: EditorState) {
    const { state } = this.view
    const { selection } = state

    const { ranges } = selection
    const from = Math.min(...ranges.map(range => range.$from.pos))
    const to = Math.max(...ranges.map(range => range.$to.pos))

    const shouldShow = this.shouldShow?.({
      editor: this.editor,
      view: this.view,
      state,
      oldState,
      from,
      to,
    })

    return shouldShow
  }

  updateHandler = (view: EditorView, selectionChanged: boolean, docChanged: boolean, oldState?: EditorState) => {
    const { composing } = view

    const isSame = !selectionChanged && !docChanged

    if (composing || isSame) {
      return
    }

    const shouldShow = this.getShouldShow(oldState)

    if (!shouldShow) {
      this.hide()

      return
    }

    this.updatePosition()
    this.show()
  }

  mousedownHandler = () => {
    this.preventHide = true
  }

  focusHandler = () => {
    // we use `setTimeout` to make sure `selection` is already updated
    setTimeout(() => this.update(this.editor.view))
  }

  blurHandler = ({ event }: { event: FocusEvent }) => {
    if (this.preventHide) {
      this.preventHide = false

      return
    }

    if (event?.relatedTarget && this.element.parentNode?.contains(event.relatedTarget as Node)) {
      return
    }

    if (event?.relatedTarget === this.editor.view.dom) {
      return
    }

    this.hide()
  }

  updatePosition() {
    const { selection } = this.editor.state

    const virtualElement = {
      getBoundingClientRect: () => posToDOMRect(this.view, selection.from, selection.to),
    }

    computePosition(virtualElement, this.element, {
      placement: this.floatingUIOptions.placement,
      strategy: this.floatingUIOptions.strategy,
      middleware: this.middlewares,
    }).then(({ x, y, strategy }) => {
      this.element.style.width = 'max-content'
      this.element.style.position = strategy
      this.element.style.left = `${x}px`
      this.element.style.top = `${y}px`
    })
  }

  update(view: EditorView, oldState?: EditorState) {
    const selectionChanged = !oldState?.selection.eq(view.state.selection)
    const docChanged = !oldState?.doc.eq(view.state.doc)

    this.updateHandler(view, selectionChanged, docChanged, oldState)
  }

  show() {
    this.element.style.visibility = 'visible'
    this.element.style.opacity = '1'
    // attach to editor's parent element
    this.view.dom.parentElement?.appendChild(this.element)
  }

  hide() {
    this.element.style.visibility = 'hidden'
    this.element.style.opacity = '0'
    // remove from the parent element
    this.element.remove()
  }

  destroy() {
    this.hide()
    this.element.removeEventListener('mousedown', this.mousedownHandler, { capture: true })
    this.editor.off('focus', this.focusHandler)
    this.editor.off('blur', this.blurHandler)
  }
}

export const FloatingMenuPlugin = (options: FloatingMenuPluginProps) => {
  return new Plugin({
    key: typeof options.pluginKey === 'string' ? new PluginKey(options.pluginKey) : options.pluginKey,
    view: view => new FloatingMenuView({ view, ...options }),
  })
}