/**
 *  `useLeader()` – React hook that checks whether the current tab is the primary one.
 *  works over `BroadcastChannel` and uses slightly modified "Bully" leader election.
 */

// simple usage
import { useLeader } from "use-leader"
const { isLeader } = useLeader() // true/false

// alias, provides boolean value only
import { useIsLeader } from "use-leader"
const isLeader = useIsLeader() // true/false

// additional state 
const { 
  id,       // id of the current node (tab)
  leaderId, // id of the elected leader
  ref       // reference to election instance, can be used for imperative control
            // over the state of the node e.g. `ref.lead()` - force become a leader
} = useLeader()

// each node has a unique identifier, when the leader is elected, every node holds 
// the leading id. these ids are randomly generated... so why would you want 
// to override it?
const { isLeader } = useLeader({ id: 'my1d' })

// the answer is instance sharing. if your app has two places where `useLeader()` 
// is called, they both have access to the same node instance.

<CompOne />   // useLeader() - true, id = "abc"
<CompTwo />   // useLeader() - true, id = "abc"
<CompThree /> // useLeader({ id: "efg" }) - false, id = "efg"

// when all components that rely on `useLeader()` exit the tree, the node shuts down,
// meaning that the other tabs now can take the advantage and relect the leader

// "totalitarian" mode (`true` by default) means that when a new node enters the quorum, 
// the existing leader won't give up power even if the new node's id is higher.

useLeader({ totalitarian: false })

// see website https://use-leader.surge.sh/ for interactive demos