#!/usr/bin/env bash
set -euo pipefail

# CASAN H1 context validator.
# Before a sub-agent trusts pipeline-context.yaml, verify every referenced
# artifact / trace file actually exists on disk, and (optionally) is not
# staler than CASAN_CONTEXT_TTL_SECONDS relative to the context file itself.
# Catches renamed/deleted/missing artifacts before they cause a silent bad read.
#
# Usage: context-validate.sh <pipeline-context.yaml>
# Exit: 0 all good, 2 a referenced path is missing, 3 a referenced path is stale.

CTX="${1:-}"
if [[ -z "$CTX" || ! -f "$CTX" ]]; then
  echo "Usage: context-validate.sh <pipeline-context.yaml>" >&2
  exit 64
fi

CTX_DIR="$(cd "$(dirname "$CTX")" && pwd)"
# Resolve paths relative to the repo root (3 levels up from this script).
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/casan-paths.sh"
PROJECT_ROOT="$CASAN_APP_ROOT"

python - "$CTX" "$PROJECT_ROOT" "${CASAN_CONTEXT_TTL_SECONDS:-0}" <<'PY'
import os, re, sys, subprocess

ctx, root, ttl = sys.argv[1], sys.argv[2], int(sys.argv[3])
ctx_mtime = os.path.getmtime(ctx)
missing, stale, checked = [], [], 0

def path_exists(p):
    """Check existence using both Python and bash (handles MSYS2/Windows path mismatch)."""
    if os.path.exists(p):
        return True
    # On Windows+MSYS2, /tmp maps to AppData/Local/Temp but Windows Python resolves it as C:\tmp.
    # Fall back to bash test for absolute paths that Python can't find.
    try:
        r = subprocess.run(["bash", "-c", f"test -e {repr(p)}"], capture_output=True, timeout=3)
        return r.returncode == 0
    except Exception:
        return False

with open(ctx, encoding="utf-8") as fh:
    for line in fh:
        m = re.match(r"\s*(?:artifact|trace_file|path|data-model|spec|plan):\s*(\S+)", line)
        if not m:
            continue
        ref = m.group(1).strip().strip('"').strip("'")
        if ref in ("", "null", "<from", "pipeline-context>"):
            continue
        if "<" in ref or ref.endswith(">"):
            continue  # unresolved template placeholder, not a concrete path
        cand = ref if os.path.isabs(ref) else os.path.join(root, ref)
        checked += 1
        if not path_exists(cand):
            missing.append(ref)
            continue
        if ttl > 0 and (ctx_mtime - os.path.getmtime(cand)) > ttl:
            stale.append(ref)

if missing:
    sys.stderr.write("CONTEXT_INVALID missing=%d: %s\n" % (len(missing), ", ".join(missing)))
    raise SystemExit(2)
if stale:
    sys.stderr.write("CONTEXT_STALE stale=%d: %s\n" % (len(stale), ", ".join(stale)))
    raise SystemExit(3)
print(f"CONTEXT_VALID checked={checked} all referenced artifacts present")
PY