import { useEffect, useState } from 'react'
import { AnimatePresence, motion } from 'framer-motion'
import { cn, getBackgroundImage } from '@/lib/utils'

export type HintPositionOffset = {
  /** 相对窗口中心点的水平偏移（px） */
  x?: number
  /** 相对窗口中心点的垂直偏移（px） */
  y?: number
}

export interface ShowHintOptions {
  /** 自动消失时间（ms）。默认 2000 */
  durationMs?: number
  /** 是否常驻（常驻时不会自动消失） */
  persistent?: boolean
  /** 相对中心点微调位置 */
  offset?: HintPositionOffset
  /** 自定义层级（默认 9999） */
  zIndex?: number
}

type HintState = {
  visible: boolean
  text: string
  options: Required<Pick<ShowHintOptions, 'durationMs' | 'persistent' | 'offset' | 'zIndex'>>
}

const DEFAULT_OPTIONS: HintState['options'] = {
  durationMs: 2000,
  persistent: false,
  offset: { x: 0, y: 0 },
  zIndex: 9999,
}

let current: HintState = {
  visible: false,
  text: '',
  options: DEFAULT_OPTIONS,
}

let hideTimer: number | null = null
const listeners = new Set<(s: HintState) => void>()

function emit(next: HintState) {
  current = next
  listeners.forEach((l) => l(current))
}

function clearHideTimer() {
  if (hideTimer) {
    window.clearTimeout(hideTimer)
    hideTimer = null
  }
}

export function showHint(text: string, options?: ShowHintOptions) {
  if (typeof window === 'undefined') return

  clearHideTimer()

  const mergedOptions: HintState['options'] = {
    ...DEFAULT_OPTIONS,
    ...(options ?? {}),
    offset: {
      ...DEFAULT_OPTIONS.offset,
      ...(options?.offset ?? {}),
    },
  }

  emit({
    visible: true,
    text,
    options: mergedOptions,
  })

  if (!mergedOptions.persistent) {
    hideTimer = window.setTimeout(() => {
      hideHint()
    }, mergedOptions.durationMs)
  }
}

export function hideHint() {
  if (typeof window === 'undefined') return
  clearHideTimer()
  emit({ ...current, visible: false })
}

export function HintHost() {
  const [state, setState] = useState<HintState>(current)

  useEffect(() => {
    listeners.add(setState)
    return () => {
      listeners.delete(setState)
    }
  }, [])

  const offsetX = state.options.offset.x ?? 0
  const offsetY = state.options.offset.y ?? 0

  return (
    <div className="fixed inset-0 pointer-events-none" style={{ zIndex: state.options.zIndex }}>
      <AnimatePresence>
        {state.visible && state.text && (
          <motion.div
            key="hint"
            className="absolute left-1/2"
            style={{
              top: `calc(50% + ${offsetY}px)`,
              x: `calc(-50% + ${offsetX}px)`,
              zIndex: state.options.zIndex,
            }}
            initial={{ opacity: 0, y: 8, filter: 'blur(2px)' }}
            animate={{ opacity: 1, y: 0, filter: 'blur(0px)' }}
            exit={{ opacity: 0, y: 8, filter: 'blur(2px)' }}
            transition={{ duration: 0.22, ease: 'easeOut' }}
          >
            <div
              className={cn(
                'inline-flex items-center justify-center',
                'px-30 py-2',
                // 'bg-linear-to-r from-transparent from-1% via-[#C0945A] via-50% to-transparent to-99% text-white',
                'whitespace-nowrap text-white',
                'text-3xl font-semibold tracking-wide',
                'select-none'
              )}
              style={{
                backgroundImage: getBackgroundImage('components/提示条'),
                backgroundSize: '100% 100%',
                backgroundPosition: 'center',
                backgroundRepeat: 'no-repeat',
              }}
            >
              {state.text}
            </div>
          </motion.div>
        )}
      </AnimatePresence>
    </div>
  )
}