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

# Fails the push when root apm.yml's executables.allow key stops naming
# kyberforge's actual version. The grant itself is version-blind — apm matches
# the version-less name alongside '<package>#<version>' (exec_gate.py builds
# the candidate list, _map_grants matches it) — so a stale key keeps granting
# kyberforge's hooks/ and bin/ and deployment does not break. What this gate
# buys is repo-level, not apm-level: a version bump without the matching key
# edit fails this repo's own pre-push, so the key stays an accurate record of
# what was approved. See ADR-0019's 2026-09-19 correction and docs/spec/gates.md,
# "check-executables-allow-sync"; nothing else in the pre-push gate compares
# these two files.
#
# Run from repo root or pass REPO_ROOT as arg.

REPO_ROOT="${1:-$(git rev-parse --show-toplevel 2>/dev/null || pwd)}"
# A nonexistent REPO_ROOT fails loudly rather than falling through to the
# "no kyberforge plugin here" no-op below: that no-op is for a repo that
# legitimately does not ship the plugin, not for a typo'd or stale path, and
# exit 0 would read as "checked, in sync" when nothing was compared at all.
if [[ ! -d "$REPO_ROOT" ]]; then
  echo "FAIL: executables-allow sync check: REPO_ROOT '$REPO_ROOT' is not a directory." >&2
  echo "  Fix: run this from the repo root, or pass a real repo path as the first argument." >&2
  exit 1
fi
REPO_ROOT="$(cd "$REPO_ROOT" && pwd)"

PLUGIN_DIR="$REPO_ROOT/plugins/kyberforge"
PLUGIN_MANIFEST="$PLUGIN_DIR/apm.yml"
ROOT_MANIFEST="$REPO_ROOT/apm.yml"

# Only a repo with no kyberforge plugin at all is a legitimate no-op — there is
# no version to pin and no hook to deploy.
if [[ ! -d "$PLUGIN_DIR" ]]; then
  exit 0
fi

if [[ ! -f "$PLUGIN_MANIFEST" ]]; then
  echo "FAIL: plugins/kyberforge/ exists but has no apm.yml, so its version cannot be read." >&2
  echo "  Why: this gate compares that version against root apm.yml's executables.allow key;" >&2
  echo "       without the manifest it would exit 0 having compared nothing." >&2
  echo "  Fix: restore plugins/kyberforge/apm.yml, or remove plugins/kyberforge/ entirely." >&2
  exit 1
fi

if [[ ! -f "$ROOT_MANIFEST" ]]; then
  echo "FAIL: root apm.yml is missing, so kyberforge's executables allow key cannot be verified." >&2
  echo "  Why: apm reads executables.allow from the consuming package's manifest; with no root" >&2
  echo "       manifest nothing grants kyberforge's hooks/ and bin/ permission to deploy." >&2
  echo "  Fix: restore apm.yml at the repo root." >&2
  exit 1
fi

# ---------------------------------------------------------------------------
# Manifest facts
# ---------------------------------------------------------------------------
# Both readers emit the same line protocol, so the rest of the script does not
# care which ran:
#
#   v<TAB><kyberforge version>        exactly once
#   a<TAB>present|absent              exactly once — is executables.allow a mapping?
#   k<TAB><allow key>                 zero or more
#
# python3 + PyYAML is preferred where importable; the fallback below is not a
# YAML parser, it recognises only the two shapes these manifests use. PyYAML
# stays optional so a missing pip package can't block every push (ADR-0019).

read_facts_python() {
  python3 - "$ROOT_MANIFEST" "$PLUGIN_MANIFEST" << 'PY'
import sys
import yaml


def load(path):
    with open(path) as fh:
        data = yaml.safe_load(fh)
    return data if isinstance(data, dict) else {}


root, plugin = load(sys.argv[1]), load(sys.argv[2])

version = plugin.get("version")
# A 2-component version parses as a YAML float and would render back as e.g.
# "1.5" from 1.50 — a mismatch invented by the reader rather than found in the
# files. Refuse instead of guessing; semver keys here are always strings.
if version is not None and not isinstance(version, str):
    sys.stderr.write(
        "kyberforge's version: is not a string (%r) — quote it so the "
        "executables.allow key can be compared verbatim.\n" % (version,)
    )
    raise SystemExit(2)
print("v\t%s" % ("" if version is None else version))

executables = root.get("executables")
allow = executables.get("allow") if isinstance(executables, dict) else None
if isinstance(allow, dict):
    print("a\tpresent")
    for key in allow:
        print("k\t%s" % key)
else:
    print("a\tabsent")
PY
}

# Strips one layer of matching quotes plus surrounding whitespace from a scalar.
unquote() {
  local value="$1"
  read -r value <<< "$value"
  case "$value" in
    \"*\") value="${value#\"}"; value="${value%\"}" ;;
    \'*\') value="${value#\'}"; value="${value%\'}" ;;
  esac
  printf '%s\n' "$value"
}

read_facts_bash() {
  local line version="" allow_state="absent" in_executables=0 in_allow=0 key

  while IFS= read -r line || [[ -n "$line" ]]; do
    [[ "$line" == version:* ]] || continue
    version="$(unquote "${line#version:}")"
    break
  done < "$PLUGIN_MANIFEST"

  while IFS= read -r line || [[ -n "$line" ]]; do
    # Blank and full-line comments carry no structure at any depth.
    case "$line" in
      '' | '#'*) continue ;;
    esac
    # A top-level key (column 0) closes whatever block was open. Checked before
    # anything else so `marketplace:` after `executables:` cannot leak keys in.
    if [[ "$line" != [[:space:]]* ]]; then
      if [[ "$line" == executables:* ]]; then
        in_executables=1
      else
        in_executables=0
      fi
      in_allow=0
      continue
    fi
    [[ $in_executables -eq 1 ]] || continue
    # 2-space indent: a key directly under executables:. `allow:` opens the
    # mapping this gate reads; any sibling key closes it.
    if [[ "$line" =~ ^\ \ [^[:space:]#] ]]; then
      if [[ "$line" =~ ^\ \ allow: ]]; then
        in_allow=1
        allow_state="present"
      else
        in_allow=0
      fi
      continue
    fi
    # 4-space indent while inside allow: — an allow key. Keys contain '#' by
    # construction ("kyberforge#1.5.0"), so a trailing-comment strip would eat
    # them; there is none, and inline comments are not used on these lines.
    if [[ $in_allow -eq 1 && "$line" =~ ^\ \ \ \ ([^[:space:]#][^:]*): ]]; then
      key="$(unquote "${BASH_REMATCH[1]}")"
      printf 'k\t%s\n' "$key"
    fi
  done < "$ROOT_MANIFEST"

  printf 'v\t%s\n' "$version"
  printf 'a\t%s\n' "$allow_state"
}

if command -v python3 > /dev/null 2>&1 && python3 -c 'import yaml' > /dev/null 2>&1; then
  READER="python3 + PyYAML"
  if ! FACTS="$(read_facts_python)"; then
    echo "FAIL: could not read apm.yml / plugins/kyberforge/apm.yml (see the parser error above)." >&2
    echo "  Why: this gate compares kyberforge's version against root apm.yml's executables.allow" >&2
    echo "       key; an unreadable manifest means the comparison did not happen." >&2
    echo "  Fix: make both manifests valid YAML, then re-run." >&2
    exit 1
  fi
else
  READER="shape-scan fallback (PyYAML unavailable)"
  FACTS="$(read_facts_bash)"
fi

VERSION="$(printf '%s\n' "$FACTS" | sed -n 's/^v\t//p')"
ALLOW_STATE="$(printf '%s\n' "$FACTS" | sed -n 's/^a\t//p')"
ALLOW_KEYS="$(printf '%s\n' "$FACTS" | sed -n 's/^k\t//p')"

if [[ -z "$VERSION" ]]; then
  echo "FAIL: plugins/kyberforge/apm.yml declares no version:, so no allow key can be checked against it." >&2
  echo "  Why: apm's executables.allow lookup is keyed on '<package>#<version>' exactly; with no" >&2
  echo "       version there is nothing for root apm.yml's key to stay in sync with." >&2
  echo "  Fix: give plugins/kyberforge/apm.yml a top-level version: (read by $READER)." >&2
  exit 1
fi

EXPECTED_KEY="kyberforge#$VERSION"

if [[ "$ALLOW_STATE" != "present" ]]; then
  echo "FAIL: root apm.yml has no executables.allow mapping, but plugins/kyberforge is version $VERSION." >&2
  echo "  Why: without an allow entry apm refuses to deploy kyberforge's hooks/ and bin/, so the" >&2
  echo "       SessionStart hook that keeps this install level with the remote never runs and the" >&2
  echo "       deployed skills go stale silently (ADR-0019)." >&2
  echo "  Fix: add to root apm.yml:" >&2
  echo "         executables:" >&2
  echo "           allow:" >&2
  echo "             $EXPECTED_KEY:" >&2
  echo "               hooks: true" >&2
  echo "               bin: true" >&2
  exit 1
fi

if grep -qxF "$EXPECTED_KEY" <<< "$ALLOW_KEYS"; then
  exit 0
fi

STALE_KEYS="$(printf '%s\n' "$ALLOW_KEYS" | grep '^kyberforge#' || true)"

echo "FAIL: root apm.yml's executables.allow has no '$EXPECTED_KEY' key, but that is kyberforge's version." >&2
if [[ -n "$STALE_KEYS" ]]; then
  echo "  Found instead:" >&2
  printf '%s\n' "$STALE_KEYS" | sed 's/^/    /' >&2
fi
echo "  Why: nothing is broken right now — apm's grant is version-blind, so a key naming another" >&2
echo "       version still grants kyberforge's hooks/ and bin/. This gate is a repo-level record" >&2
echo "       check: a version bump without the matching key edit fails here, which is what keeps" >&2
echo "       the key an accurate record of what was approved (ADR-0019, 2026-09-19 correction)." >&2
echo "  Fix: bump the key in root apm.yml to '$EXPECTED_KEY:' — the version bump in" >&2
echo "       plugins/kyberforge/apm.yml is not complete without it." >&2
exit 1