package com.peachpasswords.sync

/**
 * Who speaks first in a relay room.
 *
 * The relay is a two-party splice with no buffering and no "peer joined"
 * signal, so exactly one side must open with `PEACH_RECONNECT` and the other
 * must wait for it. Both sides derive the same room id from the shared pair
 * secret, so the role has to be derivable from state both already hold —
 * there is nothing on the wire to negotiate it with.
 *
 * Two rules, in order:
 *
 *  1. A browser extension can never hold a room open, so it always dials.
 *     Toward an extension peer we therefore always wait.
 *  2. Otherwise — phone to phone, phone to tablet — the lower long-term public
 *     key dials. Comparing the keys is symmetric by construction: each side
 *     compares the same two values and reaches the opposite conclusion, so the
 *     roles can never collide (both dialling, or both waiting, which is what
 *     left phone-to-phone with nobody dialling).
 *
 * The keys are hex of the same length, so an ordinary lexicographic compare is
 * a total order over them. Ties are impossible: two devices sharing a static
 * key are the same device.
 */
internal fun weDialPeer(ourLongTermPublicKeyHex: String, peer: PairedDevice): Boolean {
    if (peer.deviceType == "extension") return false
    val theirs = peer.longTermPublicKeyHex ?: return false
    return ourLongTermPublicKeyHex.compareTo(theirs) < 0
}