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

EXPECTED_ROOT="${EXPECTED_ROOT:-/Users/apple/github-projects/microdao-daarion}"
REQUIRE_SESSION_STARTER=1

usage() {
  cat <<'USAGE'
Usage:
  bash scripts/session/preflight.sh [--expected-root /path/to/repo] [--no-session-starter]

Checks:
  - current working directory
  - git repository root
  - current branch
  - latest commit
  - docs/SESSION_STARTER.md presence (default required)
  - docs directory presence

Exit codes:
  0  all checks passed
  10 wrong repo root
  11 missing SESSION_STARTER.md
  12 missing docs directory
  13 git not initialized / not a repo
USAGE
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --expected-root)
      EXPECTED_ROOT="$2"
      shift 2
      ;;
    --no-session-starter)
      REQUIRE_SESSION_STARTER=0
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "Unknown arg: $1" >&2
      usage
      exit 2
      ;;
  esac
done

if ! git_root="$(git rev-parse --show-toplevel 2>/dev/null)"; then
  echo "[FAIL] not a git repository" >&2
  exit 13
fi

pwd_now="$(pwd)"
branch="$(git branch --show-current || true)"
head_line="$(git log --oneline -n 1 2>/dev/null || echo 'NO_COMMITS')"

printf "[INFO] pwd: %s\n" "$pwd_now"
printf "[INFO] git_root: %s\n" "$git_root"
printf "[INFO] branch: %s\n" "${branch:-DETACHED_OR_NONE}"
printf "[INFO] head: %s\n" "$head_line"
printf "[INFO] expected_root: %s\n" "$EXPECTED_ROOT"

if [[ "$git_root" != "$EXPECTED_ROOT" ]]; then
  echo "[FAIL] unexpected repository root" >&2
  exit 10
fi

if [[ ! -d "$git_root/docs" ]]; then
  echo "[FAIL] missing docs directory: $git_root/docs" >&2
  exit 12
fi

if [[ "$REQUIRE_SESSION_STARTER" -eq 1 && ! -f "$git_root/docs/SESSION_STARTER.md" ]]; then
  echo "[FAIL] missing SESSION_STARTER: $git_root/docs/SESSION_STARTER.md" >&2
  exit 11
fi

echo "[PASS] preflight OK"