import {useContext, useEffect, useReducer} from "react"

import FetcherContext from "~/components/fetcher.js"
import UserContext from "~/components/user.js"

const reducer = (state, action) => {
  const {type, payload} = action
  switch (type) {
    case "SET_URL":
    case "FETCH_INIT":
      return {
        ...state,
        ...(payload && payload.url && {url: payload.url}),
        data: null,
        loading: true,
        error: null,
      }
    case "FETCH_SUCCESS":
      return {
        ...state,
        data: payload.data,
        loading: false,
        error: null,
      }
    case "FETCH_FAILURE":
      return {
        ...state,
        data: null,
        loading: false,
        error: payload.error,
      }
  }
}

const useFetcher = (url, options) => {
  let initialState = {
    url: url || null,
    loading: false,
    data: null,
    error: null,
  }
  const [state, dispatch] = useReducer(reducer, initialState)
  const {api, options: fetchOptions} = useContext(FetcherContext)
  const userContext = useContext(UserContext)

  const setURL = url => dispatch({type: "SET_URL", payload: {url}})
  const setURLAndFetch = url => {
    dispatch({type: "SET_URL", payload: {url}})
    doFetch()
  }

  const doFetch = async (url, options) => {
    dispatch({type: "FETCH_INIT", ...(url && {payload: {url}})})
    try {
      const finalUrl = url ? url : state.url
      const res = await fetch(`${api}${finalUrl}`, {
        ...fetchOptions,
        ...options,
      })
      for (const [header, value] of res.headers) {
        if (header.toLowerCase() === "x-auth") {
          if (value !== "") {
            const error = "AUTH_REQUIRED"
            dispatch({type: "FETCH_FAILURE", payload: {error}})
            userContext.setAuthFields(value.split(";"), finalUrl)
            return
          }
        }
        if (header.toLowerCase() === "x-authlastresult") {
          if (value === "true") {
            userContext.removeAuthFields()
          }
        }
      }
      const data = await res.json()
      dispatch({type: "FETCH_SUCCESS", payload: {data}})
    } catch (error) {
      dispatch({type: "FETCH_FAILURE", payload: {error}})
    }
  }

  useEffect(() => {
    if (url) {
      doFetch()
    }
  }, [url, options])

  return {...state, setURL, setURLAndFetch, doFetch}
}

export default useFetcher