package main

import (
	"encoding/json"
	"errors"
	"log"
	"net/http"
	"net/url"
)

func getUsers(token string, channel string) ([]string, error) {
	u, _ := url.Parse("https://slack.com/api/channels.info")
	u.Query().Set("token", token)
	u.Query().Set("channel", channel)
	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	resp, err := getClient().Do(req)
	if err != nil {
		log.Println(err)
		return nil, err
	}
	r := struct {
		OK      bool   `json:"ok"`
		Error   string `json:"error"`
		Channel struct {
			Members []string `json:"members"`
		} `json:"channel"`
	}{}
	if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
		return nil, err
	}
	if !r.OK {
		return nil, errors.New(r.Error)
	}
	return r.Channel.Members, nil
}