const EventEmitter = require("events")
const fetch = require("isomorphic-fetch")
const config = require("../config")
const compressQuery = require("graphql-query-compress")

/**
 * Run a GraphQL query against the rpdata backend
 * 
 * @param {string} query The query to run
 * @param {{[x:string]: any}} variables 
 * @param {{operationName:string, token: string, permissions: string[]}} options 
 */
function query(query, variables = {}, options = {}) {
  return fetch(config.graphqlEndpoint, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": options.token ? `Bearer ${options.token}` : null,
      //"X-Permissions": options.permissions ? options.permissions.join(",") : null,
    },
    body: JSON.stringify({query: query.length > 256 ? compressQuery(query || "") : query, variables, operationName: options.operationName}),
    credentials: "include",
  }).then(res => {
    return res.json()
  }).then(json => {
    if (json.errors != null && json.errors.length > 0) {
      return Promise.reject(json.errors)
    }

    return json.data
  })
}

/**
 * 
 * 
 * @param {string} query GQL Query
 * @param {Object} variables Variables
 * @param {{token?:string,permissions?:string[]}} options 
 */
function queryForm(query, variables = {}, options = {}) {
  const map = {}
  const files = []
  
  function findFiles(prefix, data) {
    for (const key in data) {
      if (!data.hasOwnProperty(key)) {
        continue
      }
      const value = data[key]

      if (value instanceof File) {
        map[files.length] = [`${prefix}.${key}`]
        files.push(value)
      } else if (typeof(value) === 'object') {
        data[key] = findFiles(`${prefix}.${key}`, Object.assign({}, value))
      }
    }

    return data
  }
  const operations = {
    query: query,
    variables: findFiles("variables", Object.assign({}, variables)),
  }

  const form = new FormData()
  form.append("operations", JSON.stringify(operations))
  form.append("map", JSON.stringify(map))
  for (let i = 0; i < files.length; ++i) {
    form.append(i.toString(), files[i])
  }

  console.log(form)

  return fetch(config.graphqlEndpoint, {
    method: "POST",
    headers: {
      "Authorization": options.token ? `Bearer ${options.token}` : null,
      "X-Permissions": options.permissions ? options.permissions.join(",") : null,
    },
    body: form,
    credentials: "include",
  }).then(res => {
    return res.json()
  }).then(json => {
    if (json.errors != null && json.errors.length > 0) {
      return Promise.reject(json.errors)
    }

    return json.data
  })
}

class Subscription extends EventEmitter {
  constructor(query, variables) {
    super()

    this.query = query
    this.variables = Object.assign({}, variables)
    this.websocket = null
    this.verboseLogging = false
  }

  connect() {
    const baseUrl = (window.location.protocol === 'https:' ? 'wss://' : 'ws://') + window.location.host
    let id = 1

    this.websocket = new WebSocket(baseUrl + config.graphqlEndpoint, "graphql-ws")
    
    this.websocket.onopen = () => {
      this.websocket.send(JSON.stringify({type: "connection_init", payload: {}}));
      this.websocket.send(JSON.stringify({id: (id++).toFixed(0), type: "start", payload: {
        query: this.query,
        variables: this.variables,
        extensions: {},
      }}));

      console.log("WS Open")
    }

    this.websocket.onmessage = (ev) => {
      let data = {}
      try {
        data = JSON.parse(ev.data)
      } catch (err) {
        console.warn("Error", err, ev)
        return
      }

      if (this.verboseLogging) {
        console.log("WS Data:", data)
      }

      switch (data.type) {
        case "connection_ack": {
          this.emit("connect")
          
          break;
        }

        case "connection_error": {
          console.warn("WS Connection Error", data.payload.message)
          this.websocket.close()

          this.emit("error", new Error(data.payload.message))

          break;
        }

        case "data": {
          if (data.payload.errors != null && data.payload.errors.length > 0) {
            this.emit("error", data.payload.errors)
          } else {
            this.emit("data", data.payload.data)
          }

          break;
        }
      }
    }

    this.websocket.onerror = (err) => {
      console.warn("WS Error", err)
    }

    this.websocket.onclose = () => {
      this.emit("disconnect")
    }
  }

  disconnect() {
    if (this.websocket != null) {
      this.websocket.close();
    }
  }
}

module.exports = { query, queryForm, Subscription }