import React, {
  ComponentType,
  FC,
  memo,
  useEffect,
  useRef,
  useState,
} from 'react'
import ReactDOM from 'react-dom'
import classNames from 'classnames'
import { getTooltip } from '@codemirror/view'
import importOverleafModules from '../../../macros/import-overleaf-module.macro'
import {
  useCodeMirrorStateContext,
  useCodeMirrorViewContext,
} from '@/features/source-editor/components/codemirror-context'
import { reviewTooltipStateField } from '@/features/source-editor/extensions/review-tooltip'
import usePreviousValue from '@/shared/hooks/use-previous-value'
import { useLayoutContext } from '@/shared/context/layout-context'
import { useEditorPropertiesContext } from '@/features/ide-react/context/editor-properties-context'
import AddCommentAction from './components/add-comment-action'
import TrackedChangesActions from './components/tracked-changes-actions'

const TOOLTIP_SHOW_DELAY = 120

// Each default-exports a self-gating component.
const editorFloatingMenuActions = importOverleafModules(
  'editorFloatingMenuActions'
) as { import: { default: ComponentType }; path: string }[]

const EditorFloatingMenu: FC = () => {
  const state = useCodeMirrorStateContext()
  const view = useCodeMirrorViewContext()
  const [show, setShow] = useState(true)
  const tooltipState = state.field(reviewTooltipStateField, false)?.tooltip
  const previousTooltipState = usePreviousValue(tooltipState)

  useEffect(() => {
    if (tooltipState !== null && previousTooltipState === null) {
      setShow(true)
    }
  }, [tooltipState, previousTooltipState])

  useEffect(() => {
    if (!show || !tooltipState) {
      return
    }
    const handleMouseDown = (event: MouseEvent) => {
      const target = event.target as Element | null
      if (
        !view.contentDOM.contains(target) &&
        !target?.closest?.('.review-tooltip-menu-container') &&
        !target?.closest?.('.modal') &&
        !target?.closest?.('.modal-backdrop')
      ) {
        setShow(false)
      }
    }
    document.addEventListener('mousedown', handleMouseDown)
    return () => {
      document.removeEventListener('mousedown', handleMouseDown)
    }
  }, [show, tooltipState, view])

  if (!show || !tooltipState) {
    return null
  }

  const tooltipView = getTooltip(view, tooltipState)

  if (!tooltipView) {
    return null
  }

  return ReactDOM.createPortal(<EditorFloatingMenuContent />, tooltipView.dom)
}

const EditorFloatingMenuContent = memo(function EditorFloatingMenuContent() {
  const view = useCodeMirrorViewContext()
  const { reviewPanelOpen } = useLayoutContext()
  const { wantTrackChanges } = useEditorPropertiesContext()
  const [visible, setVisible] = useState(false)
  const menuRef = useRef<HTMLDivElement>(null)

  useEffect(() => {
    const measure = () => {
      view.requestMeasure({
        key: 'editor-floating-menu-position',
        read(view) {
          const cursorCoords = view.coordsAtPos(view.state.selection.main.head)
          if (!cursorCoords) {
            return
          }

          const menuHeight =
            menuRef.current?.getBoundingClientRect().height ?? 0
          const scrollDomRect = view.scrollDOM.getBoundingClientRect()
          const contentDomRect = view.contentDOM.getBoundingClientRect()
          const cursorCenterY = (cursorCoords.top + cursorCoords.bottom) / 2

          if (
            // Cursor scrolls out of view at the top
            cursorCoords.top < scrollDomRect.top ||
            // Cursor scrolls out of view at the bottom
            cursorCoords.top > scrollDomRect.bottom
          ) {
            return { visibility: 'hidden' as const }
          }

          return {
            position: 'fixed' as const,
            // Align centrally
            top: cursorCenterY - menuHeight / 2,
            right: window.innerWidth - contentDomRect.left,
          }
        },
        // Mutate the DOM directly rather than via state to avoid re-rendering
        // on every scroll frame.
        write(res) {
          const el = menuRef.current
          if (!el || !res) return
          // Only toggle visibility when off-screen
          if (res.visibility === 'hidden') {
            el.style.visibility = 'hidden'
          } else {
            el.style.visibility = ''
            el.style.position = res.position
            el.style.top = `${res.top}px`
            el.style.right = `${res.right}px`
          }
        },
      })
    }

    measure()

    // Re-center when the menu's own height changes (e.g. tracked-change
    // actions appear/disappear).
    const observer = new ResizeObserver(measure)
    if (menuRef.current) {
      observer.observe(menuRef.current)
    }
    // The scroller's box tracks the editor pane, so this catches pane/window
    // resizes. It doesn't fire on scroll, hence the separate scroll listener.
    observer.observe(view.scrollDOM)

    // Track the cursor as the editor scrolls.
    view.scrollDOM.addEventListener('scroll', measure)

    return () => {
      observer.disconnect()
      view.scrollDOM.removeEventListener('scroll', measure)
    }
  }, [view, reviewPanelOpen, wantTrackChanges])

  useEffect(() => {
    setVisible(false)
    const timeout = setTimeout(() => {
      setVisible(true)
    }, TOOLTIP_SHOW_DELAY)

    return () => {
      clearTimeout(timeout)
    }
  }, [])

  return (
    <div
      ref={menuRef}
      className={classNames('editor-floating-menu', {
        'editor-floating-menu-visible': visible,
      })}
    >
      <AddCommentAction />
      <TrackedChangesActions />
      {editorFloatingMenuActions.map(
        ({ import: { default: Component }, path }) => (
          <React.Fragment key={path}>
            <div className="editor-floating-menu-divider" />
            <Component />
          </React.Fragment>
        )
      )}
    </div>
  )
})

export default EditorFloatingMenu