#!/usr/bin/env bash
# Phase 4 tracker gate: discover a real libtorrent seed from a localhost HTTP
# tracker, then complete the download without explicit peer arguments.
set -u
ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
SWARM="${1:-$ROOT/build/naut_swarm}"
MODE="${2:-http}"
SEEDER="$ROOT/tests/integration/seeder.py"
if [ "$MODE" = "udp" ]; then
  TRACKER="$ROOT/tests/integration/udp_tracker.py"
else
  TRACKER="$ROOT/tests/integration/http_tracker.py"
fi
SOURCE_TOR="$ROOT/tests/fixtures/single_v1.torrent"
DATA="$ROOT/tests/fixtures/data"

python3 -c 'import libtorrent' 2>/dev/null || {
  echo "SKIP: python libtorrent not available"
  exit 77
}
[ -x "$SWARM" ] || { echo "FAIL: $SWARM not built"; exit 1; }

out="$(mktemp -d /tmp/naut_tracker_swarm.XXXXXX)"
seed_log="$(mktemp /tmp/naut_tracker_seed.XXXXXX)"
tracker_log="$(mktemp /tmp/naut_http_tracker.XXXXXX)"
swarm_log="$(mktemp /tmp/naut_tracker_client.XXXXXX)"
tor="$(mktemp /tmp/naut_tracker.XXXXXX.torrent)"
seed=""
tracker=""

cleanup() {
  [ -n "$seed" ] && kill "$seed" 2>/dev/null || true
  [ -n "$tracker" ] && kill "$tracker" 2>/dev/null || true
  rm -rf "$out" "$seed_log" "$tracker_log" "$swarm_log" "$tor"
}
trap cleanup EXIT

python3 "$SEEDER" "$SOURCE_TOR" "$DATA" > "$seed_log" 2>&1 &
seed=$!
seed_port=""
for _ in $(seq 1 100); do
  seed_port="$(grep -oP 'PORT \K[0-9]+' "$seed_log" 2>/dev/null || true)"
  [ -n "$seed_port" ] && [ "$seed_port" != 0 ] && break
  sleep 0.1
done
if [ -z "$seed_port" ] || [ "$seed_port" = 0 ]; then
  echo "FAIL: seeder did not start"
  cat "$seed_log"
  exit 1
fi

python3 "$TRACKER" "$seed_port" > "$tracker_log" 2>&1 &
tracker=$!
tracker_port=""
for _ in $(seq 1 100); do
  tracker_port="$(grep -oP 'PORT \K[0-9]+' "$tracker_log" 2>/dev/null || true)"
  [ -n "$tracker_port" ] && break
  sleep 0.05
done
if [ -z "$tracker_port" ]; then
  echo "FAIL: tracker did not start"
  cat "$tracker_log"
  exit 1
fi

# Replace only the top-level dictionary. The raw info dictionary is copied
# byte-for-byte so its SHA-1 info hash remains unchanged.
if [ "$MODE" = "udp" ]; then
  announce="udp://127.0.0.1:$tracker_port/announce"
else
  announce="http://127.0.0.1:$tracker_port/announce"
fi
backup="http://127.0.0.1:1/lower-tier-should-not-be-contacted"
python3 - "$SOURCE_TOR" "$tor" "$announce" "$backup" <<'PY'
import sys


def skip(data, pos):
    token = data[pos]
    if token == ord("i"):
        return data.index(b"e", pos) + 1
    if token in (ord("l"), ord("d")):
        pos += 1
        while data[pos] != ord("e"):
            pos = skip(data, pos)
            if token == ord("d"):
                pos = skip(data, pos)
        return pos + 1
    colon = data.index(b":", pos)
    size = int(data[pos:colon])
    return colon + 1 + size


source, target = sys.argv[1], sys.argv[2]
announce, backup = sys.argv[3].encode(), sys.argv[4].encode()
data = open(source, "rb").read()
pos = 1
raw_info = None
while data[pos] != ord("e"):
    colon = data.index(b":", pos)
    key_len = int(data[pos:colon])
    key_start = colon + 1
    key = data[key_start:key_start + key_len]
    pos = key_start + key_len
    value_start = pos
    pos = skip(data, pos)
    if key == b"info":
        raw_info = data[value_start:pos]
assert raw_info is not None
rewritten = (
    b"d8:announce" + str(len(announce)).encode() + b":" + announce
    + b"13:announce-listll" + str(len(announce)).encode() + b":" + announce
    + b"el" + str(len(backup)).encode() + b":" + backup + b"ee"
    + b"4:info" + raw_info + b"e"
)
open(target, "wb").write(rewritten)
PY

if ! timeout 30 "$SWARM" "$tor" "$out" > "$swarm_log" 2>&1; then
  echo "FAIL: tracker-discovered swarm did not complete"
  cat "$swarm_log" "$tracker_log"
  exit 1
fi
if ! diff -r "$out/single.bin" "$DATA/single.bin" >/dev/null; then
  echo "FAIL: content mismatch"
  exit 1
fi
if ! grep -q "REQUEST" "$tracker_log"; then
  echo "FAIL: tracker received no announce"
  exit 1
fi
if grep -q "$backup" "$swarm_log"; then
  echo "FAIL: lower tracker tier was contacted after primary success"
  cat "$swarm_log"
  exit 1
fi

echo "PASS: $MODE tracker discovery produced byte-identical output"