#!/usr/bin/env bash
# check-mcp-client-sync.sh — drift guard for the vendored streamable-HTTP MCP client.
#
# The RemoteMcpClient in extensions/pi/mempalace.ts is a VENDORED copy of the
# canonical implementation in pi-extensions/extensions/mcp-loader.ts (the two
# repos ship independently, so a shared import isn't practical for one small,
# protocol-frozen class — see the annotated header in mempalace.ts).
#
# Both blocks carry a matching sync token:
#     MCP-STREAMABLE-HTTP-CLIENT-SYNC: vN
# Bump it in BOTH files whenever the streamable-HTTP protocol handling changes.
# This guard fails when the tokens diverge, so a protocol fix in one file can't
# silently skip the other.
#
# It is a LOCAL developer guard: it needs the sibling pi-extensions checkout to
# compare against. If that isn't found it SKIPS (exit 0) rather than failing —
# so it's safe to wire into CI that only checks out this repo.
#
# Point it at a specific checkout with:  PI_EXTENSIONS_DIR=/path/to/pi-extensions
set -euo pipefail

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
VENDORED="$REPO_ROOT/extensions/pi/mempalace.ts"

TOKEN_RE='MCP-STREAMABLE-HTTP-CLIENT-SYNC: v[0-9]+'
extract_token() { grep -oE "$TOKEN_RE" "$1" 2>/dev/null | head -1 | grep -oE 'v[0-9]+' || true; }

if [[ ! -f "$VENDORED" ]]; then
  echo "ERROR: vendored file not found: $VENDORED" >&2
  exit 1
fi

VENDORED_TOKEN="$(extract_token "$VENDORED")"
if [[ -z "$VENDORED_TOKEN" ]]; then
  echo "FAIL: no '$TOKEN_RE' token in $VENDORED" >&2
  echo "      The vendored RemoteMcpClient must carry a sync token." >&2
  exit 1
fi

# Locate the canonical mcp-loader.ts across common dev layouts.
CANDIDATES=(
  "${PI_EXTENSIONS_DIR:-}/extensions/mcp-loader.ts"
  "$REPO_ROOT/../pi-extensions/extensions/mcp-loader.ts"
  "/workspace/pi-extensions/extensions/mcp-loader.ts"
  "$HOME/src/pi-extensions/extensions/mcp-loader.ts"
  "$HOME/src/src_local/pi-extensions/extensions/mcp-loader.ts"
  "/opt/pi-extensions/extensions/mcp-loader.ts"
)
CANONICAL=""
for c in "${CANDIDATES[@]}"; do
  [[ -n "$c" && -f "$c" ]] && { CANONICAL="$c"; break; }
done

if [[ -z "$CANONICAL" ]]; then
  echo "SKIP: canonical pi-extensions/extensions/mcp-loader.ts not found — cannot compare."
  echo "      (vendored token: $VENDORED_TOKEN). Set PI_EXTENSIONS_DIR to enable the check."
  exit 0
fi

CANONICAL_TOKEN="$(extract_token "$CANONICAL")"
if [[ -z "$CANONICAL_TOKEN" ]]; then
  echo "FAIL: no '$TOKEN_RE' token in canonical $CANONICAL" >&2
  exit 1
fi

if [[ "$VENDORED_TOKEN" != "$CANONICAL_TOKEN" ]]; then
  echo "FAIL: MCP client sync token drift." >&2
  echo "      vendored  ($VENDORED): $VENDORED_TOKEN" >&2
  echo "      canonical ($CANONICAL): $CANONICAL_TOKEN" >&2
  echo "      A streamable-HTTP protocol change landed in one file but not the other." >&2
  echo "      Reconcile RemoteMcpClient in both, then bump the token in BOTH to match." >&2
  exit 1
fi

echo "OK: MCP client sync token matches ($VENDORED_TOKEN)."
echo "    vendored:  $VENDORED"
echo "    canonical: $CANONICAL"