// Context.js
const Context = React.createContext(
  {} // default value
)
export const Provider = Context.Provider
export const Consumer = Context.Consumer

// App.jsx
import {Provider} from './Context'
import Page from './Page'

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      name: 'zz',
    }
      
      setName = name =>{
          this.setState({name})
      }
  }

  render() {
    const val = {
      ...this.state,
      setName: this.setName
    }
    return (
      <Provider value={val}>
          <Page />
      </Provider>
    );
  }
}

// View.jsx
import React from 'react'
import {Consumer} from './Context'

export default class Page extends React.Component {
  return (
    <Consumer>
      { val => (
        <button onClick={val.setName}>
          {val.name}
        </button>
      )}
      </Consumer>
  );
}

// App.jsx
import React from 'react'
import { Provider } from './Context'

@Provider
export default class App extends React.Component{
    // state 不写在这里，抽取到Context中
}

// Page.jsx
import React from 'react'
import { Consumer } from './Context'

// 方法中传入需要map到props中的属性的key数组，如果不传，所有属性都会map
@Consumer(['list', 'query'])
export default class Page extends React.Component{
    render(){
        const { list, query } = this.props
        return(
            // ...
        )
    }
}

// Context.js
import React from 'react'
import service from './service'

const Context = React.createContext()

class ProviderClass extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      list: [],
      keywords: null,
      pagination: {
        current: 1,
        total: 0,
      },
    }
  }
  componentWillUnmount() {
    this.unmount = true
  }
  update = state =>
    new Promise((resolve, reject) => {
      if (!this.unmount) {
        this.setState(state, resolve)
      }
    })
  query = () => {
    const {
      keywords,
      pagination: { current },
    } = this.state
    service.query(current, keywords).then(({ count, pageNo, list }) => {
      this.update({
        list,
        pagination: {
          current: pageNo,
          total: count,
        },
      })
    })
  }
  search = keywords => this.update({ keywords }).then(this.query)
  pageTo = (pageNo = 1) => {
    this.update({
      pagination: {
        ...this.pagination,
        current: pageNo,
      },
    }).then(this.query)
  }

  render() {
    const val = {
      ...this.state,
      query: this.query,
      pageTo: this.pageTo,
      search: this.search,
    }
    return (
      <Context.Provider value={val}>{this.props.children}</Context.Provider>
    )
  }
}

export const Provider => Comp => props => (
  <ProviderClass>
    <Comp {...props} />
  </ProviderClass>
)

export const Consumer = keys => Comp => props => (
  <Context.Consumer>
    {val => {
      let p = { ...props }
      if (!keys) {
        p = {
          ...p,
          ...val,
        }
      } else if (keys instanceof Array) {
        keys.forEach(k => {
          p[k] = val[k]
        })
      } else if (keys instanceof Function) {
        p = {
          ...p,
          ...keys(val),
        }
      } else if (typeof keys === 'string') {
        p[keys] = val[keys]
      }
      return <Comp {...p} />
    }}
  </Context.Consumer>
)

// Store.js
import axios from 'axios'
class Store {
  userId = 00001
  userName = zz
  addr = {
    province: 'Zhejiang',
    city: 'Hangzhou'
  }

  login() {
    axios.post('/login', {
      // login data
    }).then(({ userId, userName, prov, city }) => {
      this.userId = userId
      this.userName = userName
      this.addr.province = prov
      this.addr.city = city
    })
  }
}
export default new Store()

// App.jsx
import React from 'react'
import {Provider} from 'ctx-react'
import store from './Store'
import Page from './Page'

@Provider(store)
export default class App extends React.Component {
  render(){
    return(
      <Page />
    )
  }
}

// Page.jsx
import React from 'react'
import {Consumer} from 'ctx-react'

@Consumer
export default class Page extends React.Component {
  render(){
    const {userId, userName, addr:{province,city}, login} = this.props
    return(
      <div>
        <div className="user-id">{userId}</div>
        <div className="user-name">{userName}</div>
        <div className="addr-prov">{province}</div>
        <div className="addr-city">{city}</div>
        {/* form */}
        <button onClick={login}>Login</button>
      </div>
    )
  }
}

// Provider中传入多个Store
@Provider(store1, store2, store3)

// Consumer 中只map需要的data和action到props中
@Consumer('name', 'setName')

// 再灵活一点？
@Consumer('userId',data => ({
  prov: data.addr.provvince,
  city: data.addr.city
}),'userName')

// 想要Multi Context ?
import { Provider, Consumer } from 'ctx-react' // 默认导出一个Provider和一个Consumer
import Context as {Context: Context1, Provider: Provider1} from 'ctx-react'
import Context as {Context: Context2, Provider: Provider2} from 'ctx-react'

// Store中有些数据不想要被代理，也不想传到Context中？
import { exclude } from 'ctx-react'

class Store{
    name: 'zz',
  	@exclude temp: '这个字段不会进入到Context中'
}