#!/usr/bin/env sh
# Safe, self-contained local Dosh benchmark harness.
#
# Spins up a THROWAWAY dosh-server bound to 127.0.0.1 on a random free port in a
# temp HOME, runs the full path matrix (native cold auth, cached attach-ticket,
# UDP resume, and local-auth), prints raw samples + summary stats, then tears
# everything down.
#
# It NEVER touches the production server: it never uses UDP port 50000, never
# restarts any systemd unit, and never reads or writes the real ~/.config/dosh
# or ~/.local. Everything lives under a mktemp HOME that is removed on exit.
#
# Usage:
#   scripts/bench-local.sh [ITERATIONS]
# Environment:
#   DOSH_BENCH_ITERS   iteration count (default 20; overridden by $1)
#   DOSH_BENCH_JSON=1  emit machine-readable JSON instead of the table
#   DOSH_BENCH_PROFILE release|debug build profile (default release)
set -eu

iters="${1:-${DOSH_BENCH_ITERS:-20}}"
profile="${DOSH_BENCH_PROFILE:-release}"

repo_root="$(cd "$(dirname "$0")/.." && pwd)"
cd "$repo_root"

# Make sure cargo is reachable in non-login shells.
if ! command -v cargo >/dev/null 2>&1; then
  # shellcheck disable=SC1090
  [ -f "$HOME/.cargo/env" ] && . "$HOME/.cargo/env"
fi

if [ "$profile" = "release" ]; then
  cargo build --release >&2
  bindir="$repo_root/target/release"
else
  cargo build >&2
  bindir="$repo_root/target/debug"
fi
server_bin="$bindir/dosh-server"
client_bin="$bindir/dosh-client"
bench_bin="$bindir/dosh-bench"

# Pick a free UDP port that is NOT the production port (50000).
free_udp_port() {
  python3 - <<'PY'
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(("127.0.0.1", 0))
print(s.getsockname()[1])
s.close()
PY
}
dosh_port="$(free_udp_port)"
if [ "$dosh_port" = "50000" ]; then
  dosh_port="$(free_udp_port)"
fi
if [ "$dosh_port" = "50000" ]; then
  echo "refusing to bind production port 50000" >&2
  exit 1
fi

home="$(mktemp -d)"
server_pid=""
cleanup() {
  if [ -n "$server_pid" ]; then
    kill "$server_pid" 2>/dev/null || true
    wait "$server_pid" 2>/dev/null || true
  fi
  rm -rf "$home"
}
trap cleanup EXIT INT TERM

mkdir -p "$home/.config/dosh" "$home/.ssh" "$home/.local/share/dosh"

# Client identity used by the native cold-auth path.
ssh-keygen -t ed25519 -N "" -q -f "$home/.ssh/id_ed25519"
client_pub="$(cat "$home/.ssh/id_ed25519.pub")"
printf '%s\n' "$client_pub" > "$home/authorized_keys"

# Throwaway server config: localhost only, throwaway port, attach tickets on.
cat > "$home/.config/dosh/server.toml" <<EOF
port = $dosh_port
bind = "127.0.0.1"
scrollback = 5000
auth_ttl_secs = 30
attach_ticket_ttl_secs = 3600
allow_attach_tickets = true
client_timeout_secs = 60
retransmit_window = 256
default_input_mode = "read-write"
prewarm_sessions = ["default"]
create_on_attach = true
shell = "/bin/sh"
sessions_dir = "$home/sessions"
secret_path = "$home/secret"
host_key = "$home/host_key"
authorized_keys = ["$home/authorized_keys"]
EOF

# Client config: native auth, trust-on-first-use (no SSH needed), localhost UDP.
write_client_config() {
  # $1 = cache_attach_tickets (true|false)
  cat > "$home/.config/dosh/client.toml" <<EOF
server = "local"
dosh_host = "127.0.0.1"
dosh_port = $dosh_port
default_session = "default"
reconnect_timeout_secs = 5
view_only = false
predict = false
cache_attach_tickets = $1
credential_cache = "$home/.local/share/dosh/credentials"
known_hosts = "$home/.config/dosh/known_hosts"
auth_preference = "native"
trust_on_first_use = true
EOF
}

start_server() {
  HOME="$home" "$server_bin" serve --config "$home/.config/dosh/server.toml" \
    >"$home/server.log" 2>&1 &
  server_pid="$!"
  # Wait for the UDP socket to come up.
  i=0
  while [ "$i" -lt 50 ]; do
    if grep -q "listening on" "$home/server.log" 2>/dev/null; then
      return 0
    fi
    if ! kill -0 "$server_pid" 2>/dev/null; then
      echo "dosh-server exited early:" >&2
      cat "$home/server.log" >&2 || true
      exit 1
    fi
    i=$((i + 1))
    sleep 0.1
  done
}

run_bench() {
  # $@ extra args forwarded to dosh-bench
  json_flag=""
  [ "${DOSH_BENCH_JSON:-0}" = "1" ] && json_flag="--json"
  label="$(uname -s) $(uname -m), profile=$profile"
  HOME="$home" "$bench_bin" \
    --client "$client_bin" \
    --server local \
    --dosh-host 127.0.0.1 \
    --dosh-port "$dosh_port" \
    --session default \
    --skip-ssh-baseline \
    --iterations "$iters" \
    --label "$label" \
    $json_flag \
    "$@"
}

echo "dosh local benchmark: port=$dosh_port iters=$iters profile=$profile home=$home" >&2

# 1) Native cold auth + cached attach-ticket in one run (ticket cache on).
write_client_config true
start_server
echo "== native cold auth + cached attach-ticket ==" >&2
run_bench --cold-native --cached-ticket
# Sanity: native cold auth must have trusted the host (proves the generated
# client config loaded and the native handshake ran instead of silently
# falling back to a different path).
if [ ! -s "$home/.config/dosh/known_hosts" ]; then
  echo "native cold auth did not record a trusted host; check server.log:" >&2
  cat "$home/server.log" >&2 || true
  exit 1
fi
kill "$server_pid" 2>/dev/null || true
wait "$server_pid" 2>/dev/null || true
server_pid=""

# 2) Self-contained local-auth path (no SSH, no native handshake).
#
# Note on UDP resume: resume is the roaming path for a client that is STILL
# attached when its network endpoint changes. The `--attach-only` benchmark
# model detaches after each iteration, which tears the client down on the
# server, so a fresh-process resume has nothing live to resume and is not
# meaningful here. The cold fresh-process reconnect fast path is the attach
# ticket (measured above). Roaming resume is validated by the integration test
# `resume_updates_udp_endpoint_for_roaming`. `dosh-bench --resume` exists for
# scenarios that keep a live session out-of-band (e.g. remote soak tests).
rm -rf "$home/.local/share/dosh/credentials"
write_client_config true
start_server
echo "== local-auth (no SSH) ==" >&2
run_bench --local-auth --no-cache