import {
  isValidTarget,
  removeHandlerId,
  addEventListener,
  ensureHandlerId,
  splitType,
  normalizeType,
  removeEventListener,
  getHandlerId,
  isWindow,
  setHandlerId,
  getHandlerQueue,
  stopPropagationCallback,
} from './util'
import { ensure, remove } from './store'
import { get } from './hook'
import { get as getStore } from './store'
import type { EventTarget, HandlerObject } from './store'
import { EventObject, type EventObjectEvent } from './object'
import { EventHandler } from './types'
import './special'

let triggered: string | undefined

export function on(
  elem: EventTarget,
  types: string,
  handler:
    | EventHandler<any, any>
    | ({
        handler: EventHandler<any, any>
        selector?: string
      } & Partial<HandlerObject>),
  data?: any,
  selector?: string,
) {
  if (!isValidTarget(elem)) {
    return
  }

  // Caller can pass in an object of custom data in lieu of the handler
  let handlerData: any
  if (typeof handler !== 'function') {
    const { handler: h, selector: s, ...others } = handler
    handler = h // eslint-disable-line
    selector = s // eslint-disable-line
    handlerData = others
  }

  // Ensure that invalid selectors throw exceptions at attach time
  // if (!isValidSelector(elem, selector)) {
  //   throw new Error('Delegate event with invalid selector.')
  // }

  const store = ensure(elem)

  // Ensure the main handle
  let mainHandler = store.handler
  if (mainHandler == null) {
    mainHandler = store.handler = function (e, ...args: any[]) {
      return triggered !== e.type ? dispatch(elem, e, ...args) : undefined
    }
  }

  // Make sure that the handler has a unique ID, used to find/remove it later
  const guid = ensureHandlerId(handler)

  // Handle multiple events separated by a space
  splitType(types).forEach((item) => {
    const { originType, namespaces } = normalizeType(item)

    // There *must* be a type, no attaching namespace-only handlers
    if (!originType) {
      return
    }

    let type = originType
    let hook = get(type)

    // If selector defined, determine special event type, otherwise given type
    type = (selector ? hook.delegateType : hook.bindType) || type

    // Update hook based on newly reset type
    hook = get(type)

    // handleObj is passed to all event handlers
    const handleObj: HandlerObject = {
      type,
      originType,
      data,
      selector,
      guid,
      handler: handler as EventHandler<any, any>,
      namespace: namespaces.join('.'),
      ...handlerData,
    }

    // Init the event handler queue if we're the first
    const events = store.events
    let bag = events[type]
    if (!bag) {
      bag = events[type] = { handlers: [], delegateCount: 0 }

      // Only use addEventListener if the `hook.steup` returns false
      if (
        !hook.setup ||
        hook.setup(elem, data, namespaces, mainHandler!) === false
      ) {
        addEventListener(
          elem as Element,
          type,
          mainHandler as any as EventListener,
        )
      }
    }

    if (hook.add) {
      removeHandlerId(handleObj.handler)
      hook.add(elem, handleObj)
      setHandlerId(handleObj.handler, guid)
    }

    // Add to the element's handler list, delegates in front
    if (selector) {
      bag.handlers.splice(bag.delegateCount, 0, handleObj)
      bag.delegateCount += 1
    } else {
      bag.handlers.push(handleObj)
    }
  })
}

export function off(
  elem: EventTarget,
  types: string,
  handler?: EventHandler<any, any>,
  selector?: string,
  mappedTypes?: boolean,
) {
  const store = getStore(elem)
  if (!store) {
    return
  }

  const events = store.events
  if (!events) {
    return
  }

  // Once for each type.namespace in types; type may be omitted
  splitType(types).forEach((item) => {
    const { originType, namespaces } = normalizeType(item)

    // Unbind all events (on this namespace, if provided) for the element
    if (!originType) {
      Object.keys(events).forEach((key) => {
        off(elem, key + item, handler, selector, true)
      })
      return
    }

    let type = originType
    const hook = get(type)
    type = (selector ? hook.delegateType : hook.bindType) || type
    const bag = events[type]
    if (!bag) {
      return
    }
    const rns =
      namespaces.length > 0
        ? new RegExp(`(^|\\.)${namespaces.join('\\.(?:.*\\.|)')}(\\.|$)`)
        : null

    // Remove matching events
    const originHandlerCount = bag.handlers.length
    for (let i = bag.handlers.length - 1; i >= 0; i -= 1) {
      const handleObj = bag.handlers[i]
      if (
        (mappedTypes || originType === handleObj.originType) &&
        (!handler || getHandlerId(handler) === handleObj.guid) &&
        (rns == null ||
          (handleObj.namespace && rns.test(handleObj.namespace))) &&
        (selector == null ||
          selector === handleObj.selector ||
          (selector === '**' && handleObj.selector))
      ) {
        bag.handlers.splice(i, 1)

        if (handleObj.selector) {
          bag.delegateCount -= 1
        }

        if (hook.remove) {
          hook.remove(elem, handleObj)
        }
      }
    }

    if (originHandlerCount && bag.handlers.length === 0) {
      if (
        !hook.teardown ||
        hook.teardown(elem, namespaces, store.handler!) === false
      ) {
        removeEventListener(
          elem as Element,
          type,
          store.handler as any as EventListener,
        )
      }

      delete events[type]
    }
  })

  // Remove data and the expando if it's no longer used
  if (Object.keys(events).length === 0) {
    remove(elem)
  }
}

export function dispatch(
  elem: EventTarget,
  evt: Event | EventObject | string,
  ...args: any[]
) {
  const event = EventObject.create(evt)
  event.delegateTarget = elem as Element

  const hook = get(event.type)
  if (hook.preDispatch && hook.preDispatch(elem, event) === false) {
    return
  }

  const handlerQueue = getHandlerQueue(elem, event)

  // Run delegates first; they may want to stop propagation beneath us
  for (
    let i = 0, l = handlerQueue.length;
    i < l && !event.isPropagationStopped();
    i += 1
  ) {
    const matched = handlerQueue[i]
    event.currentTarget = matched.elem

    for (
      let j = 0, k = matched.handlers.length;
      j < k && !event.isImmediatePropagationStopped();
      j += 1
    ) {
      const handleObj = matched.handlers[j]
      // If event is namespaced, then each handler is only invoked if it is
      // specially universal or its namespaces are a superset of the event's.
      if (
        event.rnamespace == null ||
        (handleObj.namespace && event.rnamespace.test(handleObj.namespace))
      ) {
        event.handleObj = handleObj
        event.data = handleObj.data

        const hookHandle = get(handleObj.originType).handle

        const result = hookHandle
          ? hookHandle(matched.elem as EventTarget, event, ...args)
          : handleObj.handler.call(matched.elem, event, ...args)
        if (result !== undefined) {
          event.result = result
          if (result === false) {
            event.preventDefault()
            event.stopPropagation()
          }
        }
      }
    }
  }

  // Call the postDispatch hook for the mapped type
  if (hook.postDispatch) {
    hook.postDispatch(elem, event)
  }

  return event.result
}

export function trigger(
  event: (Partial<EventObjectEvent> & { type: string }) | EventObject | string,
  eventArgs: any,
  elem: EventTarget,
  onlyHandlers?: boolean,
) {
  let eventObj = event as EventObject
  let type = typeof event === 'string' ? event : event.type
  let namespaces =
    typeof event === 'string' || eventObj.namespace == null
      ? []
      : eventObj.namespace.split('.')

  const node = elem as HTMLElement

  // Don't do events on text and comment nodes
  if (node.nodeType === 3 || node.nodeType === 8) {
    return
  }

  if (type.indexOf('.') > -1) {
    // Namespaced trigger; create a regexp to match event type in handle()
    namespaces = type.split('.')
    type = namespaces.shift()!
    namespaces.sort()
  }
  const ontype = type.indexOf(':') < 0 && (`on${type}` as 'onclick')

  // Caller can pass in a EventObject, Object, or just an event type string
  eventObj =
    event instanceof EventObject
      ? event
      : new EventObject(type, typeof event === 'object' ? event : null)

  eventObj.namespace = namespaces.join('.')
  eventObj.rnamespace = eventObj.namespace
    ? new RegExp(`(^|\\.)${namespaces.join('\\.(?:.*\\.|)')}(\\.|$)`)
    : null

  // Clean up the event in case it is being reused
  eventObj.result = undefined
  if (!eventObj.target) {
    eventObj.target = node
  }

  const args: [EventObject, ...any[]] = [eventObj]
  if (Array.isArray(eventArgs)) {
    args.push(...eventArgs)
  } else {
    args.push(eventArgs)
  }

  const hook = get(type)
  if (
    !onlyHandlers &&
    hook.trigger &&
    hook.trigger(node, eventObj, eventArgs) === false
  ) {
    return
  }

  let bubbleType

  // Determine event propagation path in advance, per W3C events spec.
  // Bubble up to document, then to window; watch for a global ownerDocument
  const eventPath = [node]
  if (!onlyHandlers && !hook.noBubble && !isWindow(node)) {
    bubbleType = hook.delegateType || type

    let last: Document | HTMLElement = node
    let curr = node.parentNode as HTMLElement

    while (curr != null) {
      eventPath.push(curr)
      last = curr
      curr = curr.parentNode as HTMLElement
    }

    // Only add window if we got to document
    const doc = node.ownerDocument || document
    if ((last as any) === doc) {
      const win =
        (last as any).defaultView || (last as any).parentWindow || window
      eventPath.push(win)
    }
  }

  let lastElement = node
  // Fire handlers on the event path
  for (
    let i = 0, l = eventPath.length;
    i < l && !eventObj.isPropagationStopped();
    i += 1
  ) {
    const currElement = eventPath[i]
    lastElement = currElement

    eventObj.type = i > 1 ? (bubbleType as string) : hook.bindType || type

    // Custom handler
    const store = getStore(currElement as Element)
    if (store) {
      if (store.events[eventObj.type] && store.handler) {
        store.handler.call(currElement, ...args)
      }
    }

    // Native handler
    const handle = (ontype && currElement[ontype]) || null
    if (handle && isValidTarget(currElement)) {
      eventObj.result = handle.call(currElement, ...args)
      if (eventObj.result === false) {
        eventObj.preventDefault()
      }
    }
  }

  eventObj.type = type

  // If nobody prevented the default action, do it now
  if (!onlyHandlers && !eventObj.isDefaultPrevented()) {
    const preventDefault = hook.preventDefault
    if (
      (preventDefault == null ||
        preventDefault(eventPath.pop()!, eventObj, eventArgs) === false) &&
      isValidTarget(node)
    ) {
      // Call a native DOM method on the target with the same name as the
      // event. Don't do default actions on window.
      if (
        ontype &&
        typeof node[type as 'click'] === 'function' &&
        !isWindow(node)
      ) {
        // Don't re-trigger an onFOO event when we call its FOO() method
        const tmp = node[ontype]
        if (tmp) {
          node[ontype] = null
        }

        // Prevent re-triggering of the same event, since we already bubbled it above
        triggered = type

        if (eventObj.isPropagationStopped()) {
          lastElement.addEventListener(type, stopPropagationCallback)
        }

        node[type as 'click']()

        if (eventObj.isPropagationStopped()) {
          lastElement.removeEventListener(type, stopPropagationCallback)
        }

        triggered = undefined

        if (tmp) {
          node[ontype] = tmp
        }
      }
    }
  }

  return eventObj.result
}