import { useEffect, useId, useRef, useState } from "react"
import { $isLinkNode, $toggleLink } from "@lexical/link"
import { useLexicalComposerContext } from "@lexical/react/LexicalComposerContext"
import { Check, Pencil, Trash2 } from "@workspace/ui/components/icon"
import {
  $findMatchingParent,
  $getNearestNodeFromDOMNode,
  $getNodeByKey,
  $getSelection,
  $isRangeSelection,
  $setSelection,
  COMMAND_PRIORITY_EDITOR,
  createCommand,
} from "lexical"
import type { NodeKey, RangeSelection } from "lexical"
import { Button } from "@workspace/ui/components/button"
import {
  InputGroup,
  InputGroupButton,
  InputGroupTextarea,
} from "@workspace/ui/components/input-group"
import {
  Popover,
  PopoverContent,
  PopoverTitle,
} from "@workspace/ui/components/popover"

import { useLexicalMessage } from "../i18n"
import { lexicalMessages } from "../messages"
import { createSelectionAnchor, type SelectionAnchor } from "./selection-anchor"

interface SelectedTextLink {
  anchor: HTMLElement | SelectionAnchor
  kind: "selection"
  selection: RangeSelection
  url: string
}

interface ExistingLink {
  anchor: HTMLAnchorElement
  key: NodeKey
  kind: "existing"
  url: string
}

type ActiveLink = ExistingLink | SelectedTextLink

export const OPEN_LINK_POPOVER_COMMAND = createCommand<void>(
  "OPEN_LINK_POPOVER_COMMAND"
)

export function LexicalLinkPopoverPlugin() {
  const [editor] = useLexicalComposerContext()
  const [activeLink, setActiveLink] = useState<ActiveLink | null>(null)
  const [draftUrl, setDraftUrl] = useState("")
  const [isEditing, setEditing] = useState(false)
  const inputId = useId()
  const inputRef = useRef<HTMLTextAreaElement>(null)
  const insertLinkLabel = useLexicalMessage(lexicalMessages.insertLink)
  const linkDetailsLabel = useLexicalMessage(lexicalMessages.linkDetails)
  const linkAddressLabel = useLexicalMessage(lexicalMessages.linkAddress)
  const applyLinkLabel = useLexicalMessage(lexicalMessages.applyLink)
  const removeLinkLabel = useLexicalMessage(lexicalMessages.removeLink)
  const editLinkLabel = useLexicalMessage(lexicalMessages.editLink)

  useEffect(() => {
    const rootElement = editor.getRootElement()

    const unregisterOpenCommand = editor.registerCommand(
      OPEN_LINK_POPOVER_COMMAND,
      () => {
        if (!rootElement) return false

        const selectionLink = editor.getEditorState().read(() => {
          const selection = $getSelection()
          if (!$isRangeSelection(selection)) return null

          const linkNode = $findMatchingParent(
            selection.anchor.getNode(),
            $isLinkNode
          )

          return {
            anchor: createSelectionAnchor(rootElement),
            kind: "selection" as const,
            selection: selection.clone(),
            url: linkNode?.getURL() ?? "https://",
          }
        })

        if (!selectionLink) return false

        setActiveLink(selectionLink)
        setDraftUrl(selectionLink.url)
        setEditing(true)
        return true
      },
      COMMAND_PRIORITY_EDITOR
    )

    if (!rootElement) return unregisterOpenCommand

    const handleEditorClick = (event: MouseEvent) => {
      const target = event.target instanceof Element ? event.target : null
      const anchor = target?.closest("a")

      if (
        !(anchor instanceof HTMLAnchorElement) ||
        !rootElement.contains(anchor)
      ) {
        setActiveLink(null)
        setEditing(false)
        return
      }

      event.preventDefault()
      const editorState = editor.getEditorState()
      const link = editorState.read(
        () => {
          const node = $getNearestNodeFromDOMNode(anchor, editorState)
          return $isLinkNode(node)
            ? { key: node.getKey(), url: node.getURL() }
            : null
        },
        { editor }
      )

      if (!link) return

      setActiveLink({
        anchor,
        key: link.key,
        kind: "existing",
        url: link.url,
      })
      setDraftUrl(link.url)
      setEditing(false)
    }

    rootElement.addEventListener("click", handleEditorClick)

    return () => {
      unregisterOpenCommand()
      rootElement.removeEventListener("click", handleEditorClick)
    }
  }, [editor])

  useEffect(() => {
    if (isEditing) inputRef.current?.focus()
  }, [isEditing])

  if (!activeLink) return null

  const closePopover = () => {
    setActiveLink(null)
    setEditing(false)
  }

  const startEditing = () => {
    setDraftUrl(activeLink.url)
    setEditing(true)
  }

  const saveLink = () => {
    const normalizedUrl = draftUrl.trim().replace(/[\r\n]+/g, "")

    if (activeLink.kind === "selection") {
      if (normalizedUrl) {
        editor.update(() => {
          $setSelection(activeLink.selection.clone())
          $toggleLink(normalizedUrl)
        })
      }

      closePopover()
      editor.focus()
      return
    }

    editor.update(() => {
      const node = $getNodeByKey(activeLink.key)
      if (!$isLinkNode(node)) return

      if (normalizedUrl) {
        node.setURL(normalizedUrl)
      } else {
        const children = node.getChildren()
        children.forEach((child) => node.insertBefore(child))
        node.remove()
      }
    })

    if (normalizedUrl) {
      setActiveLink((current) =>
        current ? { ...current, url: normalizedUrl } : null
      )
      setEditing(false)
    } else {
      closePopover()
    }
  }

  const removeLink = () => {
    if (activeLink.kind !== "existing") return

    editor.update(() => {
      const node = $getNodeByKey(activeLink.key)
      if (!$isLinkNode(node)) return
      const children = node.getChildren()
      children.forEach((child) => node.insertBefore(child))
      node.remove()
    })
    closePopover()
  }

  const showEditor = activeLink.kind === "selection" || isEditing

  return (
    <Popover
      open
      onOpenChange={(open) => {
        if (!open) closePopover()
      }}
    >
      <PopoverContent
        anchor={activeLink.anchor}
        align="center"
        positionMethod="fixed"
        className="w-80 gap-1.5 p-2"
        finalFocus={() => editor.getRootElement()}
        initialFocus={showEditor ? inputRef : undefined}
        showArrow
      >
        <PopoverTitle className="sr-only">
          {activeLink.kind === "selection" ? insertLinkLabel : linkDetailsLabel}
        </PopoverTitle>
        {showEditor ? (
          <form
            className="min-w-0"
            onSubmit={(event) => {
              event.preventDefault()
              saveLink()
            }}
          >
            <div className="mb-1.5 flex items-center gap-1 ps-1">
              <label
                htmlFor={inputId}
                className="text-xs font-medium text-muted-foreground"
              >
                {linkAddressLabel}
              </label>
              <div className="-my-1 ms-auto flex items-center gap-1">
                <InputGroupButton
                  type="submit"
                  size="icon-xs"
                  aria-label={applyLinkLabel}
                >
                  <Check className="size-3" />
                </InputGroupButton>
                {activeLink.kind === "existing" && (
                  <InputGroupButton
                    size="icon-xs"
                    aria-label={removeLinkLabel}
                    onClick={removeLink}
                  >
                    <Trash2 className="size-3" />
                  </InputGroupButton>
                )}
              </div>
            </div>
            <InputGroup>
              <InputGroupTextarea
                id={inputId}
                ref={inputRef}
                aria-label={linkAddressLabel}
                className="min-h-16 resize-y break-all"
                inputMode="url"
                placeholder="https://example.com"
                rows={2}
                value={draftUrl}
                onChange={(event) => setDraftUrl(event.target.value)}
                onKeyDown={(event) => {
                  if (
                    event.key === "Enter" &&
                    (event.metaKey || event.ctrlKey)
                  ) {
                    event.preventDefault()
                    saveLink()
                    return
                  }

                  if (
                    event.key === "Escape" &&
                    activeLink.kind === "existing"
                  ) {
                    event.preventDefault()
                    setEditing(false)
                  }
                }}
              />
            </InputGroup>
          </form>
        ) : (
          <>
            <div className="flex items-center gap-1 ps-1">
              <span className="text-xs font-medium text-muted-foreground">
                {linkAddressLabel}
              </span>
              <div className="-my-1 ms-auto flex items-center gap-1">
                <Button
                  type="button"
                  variant="ghost"
                  size="icon-xs"
                  aria-label={editLinkLabel}
                  onClick={startEditing}
                >
                  <Pencil />
                </Button>
                <Button
                  type="button"
                  variant="ghost"
                  size="icon-xs"
                  aria-label={removeLinkLabel}
                  onClick={removeLink}
                >
                  <Trash2 />
                </Button>
              </div>
            </div>
            <a
              href={activeLink.url}
              target="_blank"
              rel="noreferrer"
              className="block max-h-24 overflow-y-auto px-1 break-all text-primary underline underline-offset-3"
            >
              {activeLink.url}
            </a>
          </>
        )}
      </PopoverContent>
    </Popover>
  )
}