#!/bin/bash
# test-harness-parity.sh — W14 section-C pin for K19 (harness honesty).
#
# K19 (review, core.md): the MCP tree server (mcp_tree.ml) carries a
# PARALLEL primitive table, and it drifted from the real runtime
# (sx_primitives.ml) — e.g. (get {:a 1} :a 99) returned nil in the harness
# but 1 in production, (split "a--b" "--") was char-class vs substring.
# CLAUDE.md mandates harness verification, so drift silently produces
# false findings/passes. dc7aa709 aligned 8 entries as a stopgap; the real
# fix (mcp_tree links sx_primitives directly) is hosts-lane work.
#
# This pin runs the finding's exact probe battery through BOTH environments
# — mcp_tree.exe sx_eval (JSON-RPC over stdio) and a fresh sx_server.exe
# (epoch protocol) — and fails on ANY divergence. Errors are compared by
# message, values by serialized form. Both subprocesses are fresh and
# timeout-bounded; no shared process is touched.
#
# Exit: 0 = full parity; 1 = drift (harness lies about the runtime again).
set -uo pipefail
cd "$(dirname "$0")/.."

MCP=hosts/ocaml/_build/default/bin/mcp_tree.exe
SERVER=hosts/ocaml/_build/default/bin/sx_server.exe
for bin in "$MCP" "$SERVER"; do
  if [[ ! -x "$bin" ]]; then
    echo "SKIP: $bin not built (run sx_build target=ocaml first)" >&2
    exit 2
  fi
done

python3 - "$MCP" "$SERVER" <<'PYEOF'
import json, re, subprocess, sys

MCP, SERVER = sys.argv[1], sys.argv[2]

# K19 probe battery — the finding's confirmed drift cases + stopgap entries.
PROBES = [
    '(empty? "")', '(empty? {})',
    '(get {:a 1} :a 99)', '(get {:a 1} :zz 99)', '(get (list 10 20) 1)',
    '(split "a--b" "--")', '(split "abc" "")',
    '(equal? (list 1 2) (list 1 2))',
    '(contains? {:a 1} :a)', '(keyword-name :kw)',
    '(char-code "A")', '(parse-number "42")',
]

def norm_error(msg):
    """Extract the quoted inner error message so harness/server error
    envelopes compare equal when the underlying failure is the same."""
    m = re.search(r'Unhandled exception: \\?"(.*?)\\?"', msg)
    if m:
        return "<ERROR> " + m.group(1)
    return "<ERROR> " + msg.strip()[:80]

# --- harness side: mcp_tree sx_eval over JSON-RPC ---
lines = [
    json.dumps({"jsonrpc": "2.0", "id": 1, "method": "initialize",
                "params": {"protocolVersion": "2024-11-05", "capabilities": {},
                           "clientInfo": {"name": "parity", "version": "0"}}}),
    json.dumps({"jsonrpc": "2.0", "method": "notifications/initialized"}),
]
for i, p in enumerate(PROBES):
    lines.append(json.dumps({"jsonrpc": "2.0", "id": 100 + i, "method": "tools/call",
                             "params": {"name": "sx_eval", "arguments": {"expr": p}}}))
out = subprocess.run(["timeout", "60", MCP], input="\n".join(lines) + "\n",
                     capture_output=True, text=True).stdout
harness = {}
for l in out.splitlines():
    try:
        j = json.loads(l)
    except ValueError:
        continue
    if isinstance(j.get("id"), int) and j["id"] >= 100:
        txt = j.get("result", {}).get("content", [{}])[0].get("text", "<none>").strip()
        if txt.startswith("Error:") or j.get("result", {}).get("isError"):
            txt = norm_error(txt)
        harness[j["id"] - 100] = txt

# --- server side: fresh sx_server over the epoch protocol ---
inp = []
for i, p in enumerate(PROBES):
    inp.append(f"(epoch {i + 1})")
    inp.append(f"(eval {json.dumps(p)})")
sout = subprocess.run(["timeout", "60", SERVER], input="\n".join(inp) + "\n",
                      capture_output=True, text=True).stdout
server, cur = {}, None
for l in sout.splitlines():
    if l.startswith("(ok-len "):
        cur = int(l.split()[1]); server[cur - 1] = None
    elif l.startswith("(error "):
        idx = int(l.split()[1]); server[idx - 1] = norm_error(l); cur = None
    elif cur is not None and server.get(cur - 1) is None:
        server[cur - 1] = l.strip(); cur = None

fails = 0
for i, p in enumerate(PROBES):
    h = harness.get(i, "<missing>")
    s = server.get(i, "<missing>")
    if h == s:
        print(f"PASS: {p:40s} both -> {h!r}")
    else:
        print(f"FAIL: {p:40s} harness={h!r} server={s!r}")
        fails += 1

print()
print(f"harness-parity: {len(PROBES) - fails} passed, {fails} failed")
sys.exit(1 if fails else 0)
PYEOF