#!/usr/bin/env bash
# PreToolUse hook for mcp__mem0__add_memory.
# Injects default metadata fields (confidence, files, source, type) when the
# agent omits them. Uses the hookSpecificOutput.updatedInput contract to
# actually modify the tool call parameters.
#
# Hook contract:
#   exit 0 = allow. If stdout contains {"hookSpecificOutput": {"updatedInput": ...}},
#            the updatedInput replaces the tool's input parameters.
#   exit 2 = block (stderr shown as rejection reason).

set -euo pipefail

INPUT=$(cat)

TOOL_NAME=$(echo "$INPUT" | jq -r '.tool_name // ""' 2>/dev/null)
case "$TOOL_NAME" in
  mcp__mem0__add_memory|mcp__plugin_mem0_mem0__add_memory) ;;
  *) exit 0 ;;
esac

TOOL_INPUT=$(echo "$INPUT" | jq -r '.tool_input // "{}"' 2>/dev/null)

_PATCH_OUT="/tmp/mem0_enforce_$$"
_MEM0_TOOL_INPUT="$TOOL_INPUT" python3 <<'PYEOF' > "$_PATCH_OUT" 2>/dev/null || true
import json, os, sys

raw = os.environ.get("_MEM0_TOOL_INPUT", "{}")
try:
    inp = json.loads(raw)
except Exception:
    sys.exit(0)

meta = inp.get("metadata") or {}
changed = False

if "confidence" not in meta:
    meta["confidence"] = 0.7
    changed = True
if "files" not in meta:
    meta["files"] = ["*"]
    changed = True
if "source" not in meta:
    meta["source"] = "auto_capture"
    changed = True
if "type" not in meta:
    meta["type"] = "task_learning"
    changed = True

if meta.get("confidence", 0) >= 1.0 and "infer" not in inp:
    inp["infer"] = False
    changed = True

if "run_id" not in inp:
    session_file = "/tmp/mem0_session_id_" + os.environ.get("USER", "default")
    if os.path.isfile(session_file):
        try:
            with open(session_file) as f:
                sid = f.read().strip()
            if sid:
                inp["run_id"] = sid
                changed = True
        except OSError:
            pass

if changed:
    inp["metadata"] = meta
    print(json.dumps(inp))
PYEOF
PATCHED=$(cat "$_PATCH_OUT" 2>/dev/null)
rm -f "$_PATCH_OUT"

if [ -n "$PATCHED" ] && echo "$PATCHED" | jq empty 2>/dev/null; then
  jq -n --argjson updated "$PATCHED" '{
    "hookSpecificOutput": {
      "hookEventName": "PreToolUse",
      "permissionDecision": "allow",
      "updatedInput": $updated
    }
  }'
fi

exit 0