#!/usr/bin/env bash
# ECN A/B Throughput Comparison  (a manual tool, NOT a test)
#
# Runs two identical chaos scenarios — one with ECN enabled, one disabled —
# and prints a side-by-side of iperf3 throughput and congestion counters.
#
# Renamed from ecn-ab-test.sh on 2026-07-23. The old name claimed a verdict
# this has never produced: it asserts nothing, applies no threshold, and no
# runner invokes it. Naming it a test made it look like coverage.
#
# It also could not have worked. It read sim-results/ecn-ab-on/... while the
# runner has written sim-results/<timestamp>-<scenario>/ since 2026-03-20, so
# it has found neither input for at least four months, and there is not one
# archived ecn-ab result directory on disk. That path bug is fixed below.
#
# WHAT IS STILL MISSING, and why it was not added: turning this into a real
# test needs a threshold — how much throughput ECN should buy, or how much
# lower the congestion counters should run — and there is no corpus to derive
# one from, precisely because the tool has never produced a kept result. A
# number invented here would assert the author's guess. The prerequisite is a
# calibration run set, and that is a protocol question about what ECN is
# expected to deliver, not a harness one.
#
# Usage: ./ecn-ab-compare.sh [--seed N] [--duration N]

set -euo pipefail
cd "$(dirname "$0")"

EXTRA_ARGS=()
while [[ $# -gt 0 ]]; do
    case "$1" in
        --seed|--duration)
            EXTRA_ARGS+=("$1" "$2"); shift 2 ;;
        *)
            echo "Unknown arg: $1"; exit 1 ;;
    esac
done

echo "=== ECN A/B Throughput Test ==="
echo ""

# --- Run A: ECN ON ---
echo "--- Phase A: ECN ENABLED ---"
sudo python3 -m sim scenarios/ecn-ab-on.yaml "${EXTRA_ARGS[@]}"
echo ""

# --- Run B: ECN OFF ---
echo "--- Phase B: ECN DISABLED ---"
sudo python3 -m sim scenarios/ecn-ab-off.yaml "${EXTRA_ARGS[@]}"
echo ""

# --- Compare results ---
echo "=== Results ==="
echo ""

python3 - <<'PYEOF'
import glob
import json


def latest(scenario, filename):
    """Newest run directory for a scenario, or None.

    The runner writes sim-results/<timestamp>-<scenario>/, so a fixed path
    such as sim-results/ecn-ab-on/ has never matched anything. Sorting the
    glob works because the timestamp is the leading, fixed-width component.
    """
    dirs = sorted(glob.glob(f"sim-results/*-{scenario}"))
    if not dirs:
        print(f"  no run directory found for {scenario}")
        return None
    path = f"{dirs[-1]}/{filename}"
    if not glob.glob(path):
        print(f"  {scenario}: {filename} missing from {dirs[-1]}")
        return None
    return path

import os
import sys

def load_results(path):
    if not os.path.exists(path):
        return []
    with open(path) as f:
        return json.load(f)

def extract_throughput(results):
    """Extract per-session throughput in Mbps from iperf3 JSON."""
    sessions = []
    for r in results:
        meta = r.get("_meta", {})
        end = r.get("end", {})
        # sum_sent / sum_received contain aggregate stats
        sent = end.get("sum_sent", {})
        recv = end.get("sum_received", {})
        sent_mbps = sent.get("bits_per_second", 0) / 1e6
        recv_mbps = recv.get("bits_per_second", 0) / 1e6
        sessions.append({
            "client": meta.get("client", "?"),
            "server": meta.get("server", "?"),
            "sent_mbps": sent_mbps,
            "recv_mbps": recv_mbps,
        })
    return sessions

def load_congestion(path):
    if not os.path.exists(path):
        return {}
    with open(path) as f:
        return json.load(f)

def print_sessions(label, sessions):
    # Filter out incomplete sessions (killed at teardown, no valid data)
    valid = [s for s in sessions if s["recv_mbps"] > 0]
    incomplete = len(sessions) - len(valid)
    if not valid:
        print(f"  {label}: no completed iperf3 sessions ({incomplete} incomplete)")
        return 0
    print(f"  {label}:")
    total_sent = 0
    total_recv = 0
    for s in valid:
        print(f"    {s['client']:>4} -> {s['server']:<4}  "
              f"sent={s['sent_mbps']:7.2f} Mbps  recv={s['recv_mbps']:7.2f} Mbps")
        total_sent += s["sent_mbps"]
        total_recv += s["recv_mbps"]
    n = len(valid)
    print(f"    {'':>14}  avg sent={total_sent/n:7.2f} Mbps  avg recv={total_recv/n:7.2f} Mbps")
    print(f"    {'':>14}  completed={n}  incomplete={incomplete}")
    return total_recv / n

on_path = latest("ecn-ab-on", "iperf3-results.json")
off_path = latest("ecn-ab-off", "iperf3-results.json")
on_results = load_results(on_path) if on_path else []
off_results = load_results(off_path) if off_path else []

on_sessions = extract_throughput(on_results)
off_sessions = extract_throughput(off_results)

print("Throughput:")
avg_on = print_sessions("ECN ON", on_sessions) or 0
print()
avg_off = print_sessions("ECN OFF", off_sessions) or 0
print()

if avg_on and avg_off:
    delta_pct = ((avg_on - avg_off) / avg_off) * 100
    print(f"  Delta: ECN ON vs OFF = {delta_pct:+.1f}% avg recv throughput")
    print()

# Congestion counters
print("Congestion Counters (final snapshot):")
for label, scenario in [("ECN ON", "ecn-ab-on"), ("ECN OFF", "ecn-ab-off")]:
    path = latest(scenario, "congestion-snapshot-final.json")
    if path is None:
        continue
    snap = load_congestion(path)
    if not snap:
        print(f"  {label}: no snapshot")
        continue
    totals = {"ce_forwarded": 0, "ce_received": 0, "congestion_detected": 0, "kernel_drop_events": 0}
    for node_id, data in sorted(snap.items()):
        cong = data.get("congestion", {})
        for k in totals:
            totals[k] += cong.get(k, 0)
    print(f"  {label}: ce_fwd={totals['ce_forwarded']}  ce_recv={totals['ce_received']}  "
          f"cong_detect={totals['congestion_detected']}  kern_drops={totals['kernel_drop_events']}")
PYEOF