#!/usr/bin/env python3
"""Seed a .torrent with libtorrent on 127.0.0.1 and print the listen port.
Usage: seeder.py <file.torrent> <save_path>
Runs until killed. Prints 'PORT <n>' once it is seeding."""
import libtorrent as lt, os, sys, time

enc_policy = 0 if os.environ.get("NAUT_FORCE_MSE") == "1" else 1

torrent, save_path = sys.argv[1], sys.argv[2]
ses = lt.session({
    "listen_interfaces": "127.0.0.1:0",
    "unchoke_slots_limit": 64,    # unchoke leechers fast
    "in_enc_policy": enc_policy,
    "out_enc_policy": enc_policy,
    "alert_mask": lt.alert_category.all,
})

atp = lt.add_torrent_params()
atp.ti = lt.torrent_info(torrent)
atp.save_path = save_path
atp.flags |= lt.torrent_flags.seed_mode       # data already present; skip recheck
atp.flags &= ~lt.torrent_flags.paused         # must be active to accept peers
atp.flags &= ~lt.torrent_flags.auto_managed   # don't let the queue re-pause it
h = ses.add_torrent(atp)
h.resume()

deadline = time.time() + 30
while not h.status().is_seeding and time.time() < deadline:
    time.sleep(0.05)
if not h.status().is_seeding:
    print("ERROR: not seeding", flush=True); sys.exit(1)

print("PORT %d" % ses.listen_port(), flush=True)
while True:
    for a in ses.pop_alerts():
        print("ALERT %s: %s" % (type(a).__name__, a.message()), flush=True)
    time.sleep(0.2)