import { buildHighlightDataFromEvent } from '@/lib/build-highlight-data'
import { isMobileBrowserProfile } from '@/lib/client-platform'
import { useCreateHighlight } from './CreateHighlightContext'
import { Event } from 'nostr-tools'
import { Highlighter } from 'lucide-react'
import { useCallback, useEffect, useRef, useState } from 'react'
import { useTranslation } from 'react-i18next'
import { Button } from '@/components/ui/button'

function getParagraphContextFromRange(range: Range): string {
  let node: Node | null = range.commonAncestorContainer
  if (node.nodeType !== Node.ELEMENT_NODE) node = node.parentElement
  let el = node as Element | null
  while (el) {
    const tag = el.tagName?.toLowerCase()
    if (tag === 'p' || (tag?.startsWith('h') && /^h[1-6]$/.test(tag))) {
      return el.textContent?.trim() || range.toString().trim()
    }
    el = el.parentElement
  }
  return range.toString().trim()
}

export default function SelectionHighlightTrigger({
  event,
  children
}: {
  event: Event
  children: React.ReactNode
}) {
  const { t } = useTranslation()
  const openHighlight = useCreateHighlight()
  const containerRef = useRef<HTMLDivElement>(null)
  const [toolbar, setToolbar] = useState<{
    selectedText: string
    paragraphContext: string
    top: number
    left: number
  } | null>(null)
  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null)
  // True while a touch is physically in contact with the screen.
  const isTouchActiveRef = useRef(false)

  const evaluateSelection = useCallback(() => {
    if (!openHighlight || !containerRef.current) return
    const sel = window.getSelection()
    if (!sel || sel.rangeCount === 0 || sel.isCollapsed) {
      setToolbar(null)
      return
    }
    const range = sel.getRangeAt(0)
    if (!containerRef.current.contains(range.commonAncestorContainer)) {
      setToolbar(null)
      return
    }
    const selectedText = range.toString().trim()
    if (!selectedText) {
      setToolbar(null)
      return
    }

    const rect = range.getBoundingClientRect()
    const toolbarHeight = 44
    const margin = 8
    // Prefer above the selection; fall back to below if too close to top of viewport.
    const top =
      rect.top - toolbarHeight < margin ? rect.bottom + margin : rect.top - toolbarHeight
    const rawLeft = rect.left + rect.width / 2 - 80
    const left = Math.max(margin, Math.min(rawLeft, window.innerWidth - 176 - margin))

    setToolbar({ selectedText, paragraphContext: getParagraphContextFromRange(range), top, left })
  }, [openHighlight])

  // Desktop: mouseup fires reliably after text selection by mouse.
  const handleMouseUp = useCallback(() => {
    evaluateSelection()
  }, [evaluateSelection])

  useEffect(() => {
    if (!openHighlight) return

    const schedule = (delayMs: number) => {
      if (debounceRef.current) clearTimeout(debounceRef.current)
      debounceRef.current = setTimeout(evaluateSelection, delayMs)
    }

    // Mobile: finger touches screen — mark active so selectionchange is suppressed during
    // the gesture itself (avoids positioning the toolbar mid-drag).
    const onTouchStart = () => {
      isTouchActiveRef.current = true
    }

    // Mobile: finger lifts — wait for the browser to settle the selection, then evaluate.
    // Shorter delay on coarse pointers; contextmenu (below) is the reliable path when the OS shows the callout.
    const onTouchEnd = () => {
      isTouchActiveRef.current = false
      schedule(isMobileBrowserProfile() ? 280 : 600)
    }

    // Both: covers keyboard selection (Shift+Arrow) on desktop and selection-handle
    // dragging on mobile (which may not generate touch events in our DOM).
    const onSelectionChange = () => {
      if (isTouchActiveRef.current) return
      schedule(80)
    }

    // When the system opens the text callout / context menu, selection is still valid here; delayed
    // touchend/selectionchange often misses on iOS/Android because the selection is cleared before we run.
    const onContextMenu = (e: MouseEvent) => {
      if (!containerRef.current) return
      const t = e.target
      if (!(t instanceof Node) || !containerRef.current.contains(t)) return
      queueMicrotask(() => evaluateSelection())
    }

    document.addEventListener('touchstart', onTouchStart, { passive: true })
    document.addEventListener('touchend', onTouchEnd, { passive: true })
    document.addEventListener('selectionchange', onSelectionChange)
    document.addEventListener('contextmenu', onContextMenu)

    return () => {
      document.removeEventListener('touchstart', onTouchStart)
      document.removeEventListener('touchend', onTouchEnd)
      document.removeEventListener('selectionchange', onSelectionChange)
      document.removeEventListener('contextmenu', onContextMenu)
      if (debounceRef.current) clearTimeout(debounceRef.current)
    }
  }, [openHighlight, evaluateSelection])

  const handleCreateHighlight = useCallback(() => {
    if (!toolbar || !openHighlight) return
    const highlightData = buildHighlightDataFromEvent(event, toolbar.paragraphContext)
    openHighlight(highlightData, toolbar.selectedText)
    setToolbar(null)
    window.getSelection()?.removeAllRanges()
  }, [event, toolbar, openHighlight])

  const handleDismiss = useCallback(() => {
    setToolbar(null)
  }, [])

  if (!openHighlight) return <>{children}</>

  return (
    <div ref={containerRef} onMouseUp={handleMouseUp} className="relative">
      {children}
      {toolbar && (
        <>
          <div
            className="fixed z-[150] flex items-center gap-1 rounded-md border bg-background px-2 py-1.5 shadow-lg"
            style={{ top: toolbar.top, left: toolbar.left }}
          >
            <Button
              type="button"
              variant="ghost"
              size="sm"
              className="h-8 gap-1.5"
              onClick={handleCreateHighlight}
            >
              <Highlighter className="h-4 w-4" />
              {t('Create Highlight')}
            </Button>
            <Button type="button" variant="ghost" size="sm" className="h-8 px-2" onClick={handleDismiss}>
              {t('Cancel')}
            </Button>
          </div>
          <div className="fixed inset-0 z-[149]" aria-hidden onClick={handleDismiss} />
        </>
      )}
    </div>
  )
}