import { get } from './store'
import type { EventTarget, HandlerObject } from './store'
import { EventObject } from './object'

export const returnTrue = () => true
export const returnFalse = () => false
export function stopPropagationCallback(e: Event) {
  e.stopPropagation()
}

export function addEventListener<TElement extends Element>(
  elem: TElement,
  type: string,
  handler: EventListener,
) {
  if (elem.addEventListener != null) {
    elem.addEventListener(type, handler as any)
  }
}

export function removeEventListener<TElement extends Element>(
  elem: TElement,
  type: string,
  handler: EventListener,
) {
  if (elem.removeEventListener != null) {
    elem.removeEventListener(type, handler as any)
  }
}

const rNotHTMLWhite = /[^\x20\t\r\n\f]+/g
const rNamespace = /^([^.]*)(?:\.(.+)|)/

export function splitType(types: string) {
  return (types || '').match(rNotHTMLWhite) || ['']
}

export function normalizeType(type: string) {
  const parts = rNamespace.exec(type) || []
  return {
    originType: parts[1] ? parts[1].trim() : parts[1],
    namespaces: parts[2]
      ? parts[2]
          .split('.')
          .map((ns) => ns.trim())
          .sort()
      : [],
  }
}

export function isValidTarget(target: Element | Record<string, any>) {
  // Accepts only:
  //  - Node
  //    - Node.ELEMENT_NODE
  //    - Node.DOCUMENT_NODE
  //  - Object
  //    - Any
  return target.nodeType === 1 || target.nodeType === 9 || !+target.nodeType
}

export function isValidSelector(elem: EventTarget, selector?: string) {
  if (selector) {
    const node = elem as Element
    return node.querySelector != null && node.querySelector(selector) != null
  }
  return true
}

type Handler = (...args: any[]) => void

let seed = 0
const cache: WeakMap<Handler, number> = new WeakMap()

export function ensureHandlerId(handler: Handler) {
  if (!cache.has(handler)) {
    cache.set(handler, seed)
    seed += 1
  }

  return cache.get(handler)!
}

export function getHandlerId(handler: Handler) {
  return cache.get(handler)
}

export function removeHandlerId(handler: Handler) {
  return cache.delete(handler)
}

export function setHandlerId(handler: Handler, id: number) {
  return cache.set(handler, id)
}

export function getHandlerQueue(elem: EventTarget, event: EventObject) {
  const queue = []
  const store = get(elem)
  const bag = store && store.events && store.events[event.type]
  const handlers = (bag && bag.handlers) || []
  const delegateCount = bag ? bag.delegateCount : 0

  if (
    delegateCount > 0 &&
    // Support: Firefox <=42 - 66+
    // Suppress spec-violating clicks indicating a non-primary pointer button (trac-3861)
    // https://www.w3.org/TR/DOM-Level-3-Events/#event-type-click
    // Support: IE 11+
    // ...but not arrow key "clicks" of radio inputs, which can have `button` -1 (gh-2343)
    !(
      event.type === 'click' &&
      typeof event.button === 'number' &&
      event.button >= 1
    )
  ) {
    for (
      let curr = event.target as Node;
      curr !== elem;
      curr = curr.parentNode || (elem as Node)
    ) {
      // Don't check non-elements
      // Don't process clicks on disabled elements
      if (
        curr.nodeType === 1 &&
        !(event.type === 'click' && (curr as any).disabled === true)
      ) {
        const matchedHandlers: HandlerObject[] = []
        const matchedSelectors: { [selector: string]: boolean } = {}

        for (let i = 0; i < delegateCount; i += 1) {
          const handleObj = handlers[i]
          const selector = handleObj.selector!

          if (selector != null && matchedSelectors[selector] == null) {
            const node = elem as Element
            const nodes: Element[] = []

            node.querySelectorAll(selector).forEach((child) => {
              nodes.push(child)
            })

            matchedSelectors[selector] = nodes.includes(curr as Element)
          }

          if (matchedSelectors[selector]) {
            matchedHandlers.push(handleObj)
          }
        }

        if (matchedHandlers.length) {
          queue.push({ elem: curr, handlers: matchedHandlers })
        }
      }
    }
  }

  // Add the remaining (directly-bound) handlers
  if (delegateCount < handlers.length) {
    queue.push({ elem, handlers: handlers.slice(delegateCount) })
  }

  return queue
}

export function isWindow(obj: any): obj is Window {
  return obj != null && obj === obj.window
}

export function contains(a: any, b: any) {
  const adown = a.nodeType === 9 ? a.documentElement : a
  const bup = b && b.parentNode

  return (
    a === bup ||
    !!(
      bup &&
      bup.nodeType === 1 &&
      // Support: IE 9 - 11+
      // IE doesn't have `contains` on SVG.
      (adown.contains
        ? adown.contains(bup)
        : a.compareDocumentPosition && a.compareDocumentPosition(bup) & 16)
    )
  )
}