#!/bin/sh
# doctor — report skills-library drift on this host.
#
# Written because every failure this fleet actually hit was SILENT: 243
# dangling symlinks hidden from git by the **/.claude/skills/ ignore rule, a
# checkout that still resolved but was 20 skills behind, a loose .md that
# loaded in no harness, and two machines where the library was simply absent.
# None of it errored. Exit status here is the signal that was missing.
#
#   doctor            human report, non-zero exit on drift
#   doctor --quiet    print only when something is wrong (SessionStart hook)
#   doctor --json     machine-readable findings
#
# POSIX sh on purpose: it runs on macOS and Linux, before any toolchain is
# guaranteed present, and inside a session-start hook where latency shows.
# It does no network I/O and never shells out to git for a fetch.
#
# Test seams: $HOME drives harness paths, $DOCTOR_CHECKOUT names the checkout.

set -u

QUIET=0
JSON=0
for arg in "$@"; do
  case "$arg" in
    --quiet) QUIET=1 ;;
    --json)  JSON=1 ;;
    -h|--help)
      sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'
      exit 0 ;;
    *) printf 'doctor: unknown option %s\n' "$arg" >&2; exit 2 ;;
  esac
done

SELF_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
SELF_CHECKOUT=$(CDPATH= cd -- "$SELF_DIR/.." && pwd)

# The canonical checkout is whatever ~/.agents/skills resolves to — NOT the
# copy doctor happens to be running from. When invoked as a plugin hook, $0
# lives in the plugin cache, which is legitimately a second copy: judging the
# harness links against it would flag every one of them as "outside".
if [ -n "${DOCTOR_CHECKOUT:-}" ]; then
  CHECKOUT="$DOCTOR_CHECKOUT"
elif [ -d "$HOME/.agents/skills" ]; then
  # Resolve the link FIRST, then take the parent. "cd X/.." resolves ".."
  # lexically against the link path, which lands back in ~/.agents.
  _resolved=$(CDPATH= cd -- "$HOME/.agents/skills" 2>/dev/null && pwd -P)
  CHECKOUT=$(dirname -- "$_resolved")
else
  CHECKOUT="$SELF_CHECKOUT"
fi
SKILLS_DIR="$CHECKOUT/skills"

findings=0
report=""

# add <severity> <check> <detail>
add() {
  findings=$((findings + 1))
  if [ "$JSON" -eq 1 ]; then
    report="${report}{\"severity\":\"$1\",\"check\":\"$2\",\"detail\":\"$(printf '%s' "$3" | sed 's/"/\\"/g')\"},"
  else
    report="${report}$1 $2: $3
"
  fi
}

# count_skills <dir> — directories containing a SKILL.md, one level down.
count_skills() {
  [ -d "$1" ] || { printf '0'; return; }
  find "$1"/ -mindepth 2 -maxdepth 2 -name SKILL.md 2>/dev/null | wc -l | tr -d ' '
}

# --- the checkout itself ----------------------------------------------------
if [ ! -d "$SKILLS_DIR" ]; then
  add FAIL checkout "no skills/ directory at $CHECKOUT"
  # Nothing downstream can be judged without it.
  printf 'FAIL checkout: no skills/ directory at %s\n' "$CHECKOUT" >&2
  exit 1
fi

EXPECTED=$(count_skills "$SKILLS_DIR")
[ "$EXPECTED" -gt 0 ] || add FAIL checkout "skills/ holds no SKILL.md at all"

# --- stray entries in the checkout -----------------------------------------
# A loose foo.md where foo/SKILL.md was meant loads in NO harness and errors
# in none either. That is exactly how secret-hygiene.md sat dead for months.
for entry in "$SKILLS_DIR"/*; do
  [ -e "$entry" ] || continue
  name=$(basename "$entry")
  if [ ! -d "$entry" ]; then
    add FAIL stray "$SKILLS_DIR/$name is not a directory — it loads nowhere"
  elif [ ! -f "$entry/SKILL.md" ]; then
    add FAIL stray "$SKILLS_DIR/$name has no SKILL.md"
  fi
done

# --- harness wiring ---------------------------------------------------------
# Canonical location first; Pi reads it directly and the others link to it.
for dir in \
  "$HOME/.agents/skills" \
  "$HOME/.config/crush/skills" \
  "$HOME/.config/opencode/skills"
do
  [ -L "$dir" ] || [ -d "$dir" ] || continue

  if [ -L "$dir" ] && [ ! -e "$dir" ]; then
    add FAIL dangling "$dir -> $(readlink "$dir") (target does not exist)"
    continue
  fi

  # A real directory where a link belongs holds content nothing manages: it
  # cannot receive new skills and silently shadows the checkout. Distinguished
  # from the foreign-checkout case below because the fix differs — move it
  # aside and re-run install.sh, rather than re-point a link.
  if [ ! -L "$dir" ] && [ -d "$dir" ]; then
    add FAIL unmanaged "$dir is a real directory, not a link into the checkout — it holds $(count_skills "$dir") unmanaged skill(s); move it aside and re-run install.sh"
    continue
  fi

  # Resolve to a physical path and confirm it lands inside THIS checkout.
  # A link that resolves to a different checkout is the dangerous case: it
  # works, so nothing complains, while serving stale content.
  resolved=$(CDPATH= cd -- "$dir" 2>/dev/null && pwd -P)
  canonical=$(CDPATH= cd -- "$SKILLS_DIR" 2>/dev/null && pwd -P)
  if [ -n "$resolved" ] && [ "$resolved" != "$canonical" ]; then
    add FAIL outside "$dir resolves to $resolved, outside the active checkout $canonical"
    continue
  fi

  got=$(count_skills "$dir")
  if [ "$got" != "$EXPECTED" ]; then
    add FAIL count "$dir sees $got skills, checkout has $EXPECTED"
  fi
done

# --- dangling links anywhere under the harness dirs -------------------------
for dir in "$HOME/.agents/skills" "$HOME/.config/crush/skills" \
           "$HOME/.config/opencode/skills" "$HOME/.claude/skills"
do
  [ -d "$dir" ] || continue
  # Plain glob, not find|while: a while loop on the right of a pipe runs in a
  # subshell, so add() would increment a counter that dies with it and doctor
  # would exit 0 having found faults.
  for link in "$dir"/*; do
    [ -L "$link" ] || continue
    [ -e "$link" ] && continue
    add FAIL dangling "$link -> $(readlink "$link") (target does not exist)"
  done
done

# --- Claude Code: plugin vs leftover per-skill symlinks ---------------------
# Plugin skills do NOT override same-named user skills — both stay visible. So
# leftover links from the pre-plugin era mean every skill appears twice.
CLAUDE_SKILLS="$HOME/.claude/skills"
if [ -d "$CLAUDE_SKILLS" ]; then
  legacy=$(find "$CLAUDE_SKILLS"/ -maxdepth 1 -type l 2>/dev/null | wc -l | tr -d ' ')
  if [ "$legacy" -gt 0 ]; then
    add FAIL legacy "$CLAUDE_SKILLS holds $legacy per-skill symlink(s) from the pre-plugin wiring — remove them or every skill loads twice"
  fi
fi

# Two delivery mechanisms means two copies that can drift apart: the plugin
# (Claude Code) and the checkout the other harnesses link to. Same host,
# different skill sets, no error — compare them.
# Skipped when DOCTOR_CHECKOUT is set: that scopes doctor to an explicit
# target, so comparing it against whatever copy the script lives in is
# meaningless rather than informative.
if [ -z "${DOCTOR_CHECKOUT:-}" ] && [ -f "$SELF_DIR/../.claude-plugin/plugin.json" ] \
   && [ "$SELF_CHECKOUT" != "$CHECKOUT" ]; then
  plugin_count=$(count_skills "$SELF_CHECKOUT/skills")
  if [ "$plugin_count" != "$EXPECTED" ]; then
    add FAIL drift "Claude Code plugin serves $plugin_count skills, the other harnesses see $EXPECTED — the two copies have diverged"
  fi
fi

INSTALLED="$HOME/.claude/plugins/installed_plugins.json"
if [ -f "$INSTALLED" ]; then
  grep -q '"skills@mathias"' "$INSTALLED" 2>/dev/null \
    || add WARN plugin "skills@mathias is not installed for Claude Code — /plugin marketplace add https://git.d-ma.be/mathias/skills.git"
fi

# --- output -----------------------------------------------------------------
if [ "$JSON" -eq 1 ]; then
  printf '{"checkout":"%s","expected":%s,"findings":[%s]}\n' \
    "$CHECKOUT" "$EXPECTED" "${report%,}"
elif [ "$findings" -gt 0 ]; then
  printf 'skills doctor — %s finding(s), checkout %s\n\n%s\n' \
    "$findings" "$CHECKOUT" "$report"
elif [ "$QUIET" -eq 0 ]; then
  printf 'skills doctor: clean — %s skills, checkout %s\n' "$EXPECTED" "$CHECKOUT"
fi

[ "$findings" -eq 0 ]