import { addLeadingSlash, CONTEXT_ACTIONS, Current, document, env, eventCenter, requestAnimationFrame, window } from '@tarojs/runtime'
import { hooks } from '@tarojs/shared'

import { ON_HIDE, ON_LOAD, ON_READY, ON_SHOW, ON_UNLOAD } from './constant'
import { incrementId, isArray, isFunction, isUndefined } from './utils'

import type { PageConfig } from '@tarojs/taro'

const instances = new Map<string, any>()
const pageId = incrementId(1)

export function injectPageInstance (inst: any, id: string) {
  hooks.call('mergePageInstance', instances.get(id), inst)
  instances.set(id, inst)
}

export function getPageInstance (id: string): any {
  return instances.get(id)
}

export function removePageInstance (id: string) {
  instances.delete(id)
}

export function safeExecute (path: string, lifecycle: string, ...args: unknown[]) {
  const instance = instances.get(path)

  if (instance == null) {
    return
  }

  lifecycle = lifecycle.replace(/^on(Show|Hide)$/, 'componentDid$1')
  const func = instance[lifecycle]

  if (isArray(func)) {
    const res = func.map(fn => fn.apply(instance, args))
    return res[0]
  }

  if (!isFunction(func)) {
    return
  }

  return func.apply(instance, args)
}

export function stringify (obj?: Record<string, unknown>) {
  if (obj == null) {
    return ''
  }
  const path = Object.keys(obj).map((key) => {
    return key + '=' + obj[key]
  }).join('&')
  return path === '' ? path : '?' + path
}

export function getPath (id: string, options?: Record<string, unknown>): string {
  const idx = id.indexOf('?')

  return `${idx > -1 ? id.substring(0, idx) : id}${stringify(options)}`
}

export function getOnReadyEventKey (path: string) {
  return path + '.' + ON_READY
}

export function getOnShowEventKey (path: string) {
  return path + '.' + ON_SHOW
}

export function getOnHideEventKey (path: string) {
  return path + '.' + ON_HIDE
}

export function createPageConfig (component: any, pageName?: string, pageConfig?: PageConfig) {
  // 小程序 Page 构造器是一个傲娇小公主，不能把复杂的对象挂载到参数上
  const id = pageName ?? `taro_page_${pageId()}`
  const [
    ONLOAD,
    ONUNLOAD,
    ONREADY,
    ONSHOW,
    ONHIDE,
    LIFECYCLES,
    SIDE_EFFECT_LIFECYCLES,
  ] = hooks.call('getMiniLifecycleImpl')!.page

  let pageElement: any = null
  let unmounting = false
  let prepareMountList: (() => void)[] = []

  function setCurrentRouter (page) {
    const router = page.route || page.__route__ || page.$taroPath

    Current.router = {
      params: page.$taroParams!,
      path: addLeadingSlash(router),
      $taroPath: page.$taroPath,
      onReady: getOnReadyEventKey(page.$taroPath),
      onShow: getOnShowEventKey(page.$taroPath),
      onHide: getOnHideEventKey(page.$taroPath),
      getEventName (event: string) {
        return `${page.$taroPath}.${event}`
      },
    }

    if (!isUndefined(page.exitState)) {
      Current.router.exitState = page.exitState
    }
  }

  let loadResolver: (...args: any[]) => void
  let hasLoaded: Promise<void>
  const page = {
    [ONLOAD] (options: Readonly<Record<string, unknown>> = {}, cb?: (...args: any[]) => any) {
      hasLoaded = new Promise(resolve => { loadResolver = resolve })

      Current.page = this as any

      // this.$taroPath 是页面唯一标识
      const uniqueOptions = Object.assign({}, options, { $taroTimestamp: Date.now() })
      const $taroPath = this.$taroPath = getPath(id, uniqueOptions)

      // this.$taroParams 作为暴露给开发者的页面参数对象，可以被随意修改
      if (this.$taroParams == null) {
        this.$taroParams = uniqueOptions
      }

      setCurrentRouter(this)

      window.trigger(CONTEXT_ACTIONS.INIT, $taroPath)

      const mount = () => {
        Current.app!.mount!(component, $taroPath, null as any, () => {
          pageElement = document.getElementById($taroPath)

          if (!pageElement) {
            throw new Error(`没有找到页面实例。`)
          }

          safeExecute($taroPath, ON_LOAD, this.$taroParams)
          loadResolver()
          cb && cb(pageElement)
          pageElement.ctx = this
        })
      }

      if (unmounting) {
        prepareMountList.push(mount)
      } else {
        mount()
      }
    },
    [ONUNLOAD] () {
      const $taroPath = this.$taroPath
      // 销毁当前页面的上下文信息
      window.trigger(CONTEXT_ACTIONS.DESTROY, $taroPath)

      // 触发onUnload生命周期
      safeExecute($taroPath, ON_UNLOAD)
      unmounting = true
      Current.app!.unmount!($taroPath, () => {
        unmounting = false
        instances.delete($taroPath)
        if (pageElement) {
          pageElement.ctx = null
          pageElement = null
        }
        if (prepareMountList.length) {
          prepareMountList.forEach(fn => fn())
          prepareMountList = []
        }
      })
    },
    [ONREADY] () {
      hasLoaded.then(() => {
        // 触发生命周期
        safeExecute(this.$taroPath, ON_READY)
        // 通过事件触发子组件的生命周期
        requestAnimationFrame(() => eventCenter.trigger(getOnReadyEventKey(this.$taroPath)))
        this.onReady = {}
        this.onReady.called = true
      })
    },
    [ONSHOW] (options = {}) {
      hasLoaded.then(() => {
        // 设置 Current 的 page 和 router
        Current.page = this as any
        setCurrentRouter(this)
        // 恢复上下文信息
        window.trigger(CONTEXT_ACTIONS.RECOVER, this.$taroPath)
        // 触发生命周期
        safeExecute(this.$taroPath, ON_SHOW, options)
        // 通过事件触发子组件的生命周期
        requestAnimationFrame(() => eventCenter.trigger(getOnShowEventKey(this.$taroPath)))
      })
    },
    [ONHIDE] () {
      // 缓存当前页面上下文信息
      window.trigger(CONTEXT_ACTIONS.RESTORE, this.$taroPath)

      // 设置 Current 的 page 和 router
      if (Current.page === this) {
        Current.page = null
        Current.router = null
      }
      // 触发生命周期
      safeExecute(this.$taroPath, ON_HIDE)
      // TODO 通过事件触发子组件的生命周期
      eventCenter.trigger(getOnHideEventKey(this.$taroPath))
    },
  }

  LIFECYCLES.forEach((lifecycle) => {
    let isDefer = false
    lifecycle = lifecycle.replace(/^defer:/, () => {
      isDefer = true
      return ''
    })
    page[lifecycle] = function () {
      const exec = () => {
        eventCenter.trigger(`${this.$taroPath}.${lifecycle}`, ...arguments)
        return safeExecute(this.$taroPath, lifecycle, ...arguments)
      }
      if (isDefer) {
        hasLoaded.then(exec)
      } else {
        return exec()
      }
    }
  })

  // onShareAppMessage 和 onShareTimeline 一样，会影响小程序右上方按钮的选项，因此不能默认注册。
  SIDE_EFFECT_LIFECYCLES.forEach(lifecycle => {
    if (component[lifecycle] ||
      component.prototype?.[lifecycle] ||
      component[lifecycle.replace(/^on/, 'enable')] ||
      pageConfig?.[lifecycle.replace(/^on/, 'enable')]
    ) {
      page[lifecycle] = function (...args) {
        const target = args[0]?.target as any
        if (target?.id) {
          const id = target.id
          const element = (env.document as any).container.getElementById(id)
          if (element) {
            target.dataset = element.dataset
          }
        }
        eventCenter.trigger(`${this.$taroPath}.${lifecycle}`, ...arguments)
        return safeExecute(this.$taroPath, lifecycle, ...args)
      }
    }
  })

  return page
}