#!/usr/bin/env sh
set -eu

# Install Codex skills from this Playbook snapshot into CODEX_HOME.
# - Source: <snapshot>/codex/skills/<skill-name>/
# - Dest:   $CODEX_HOME/skills/<skill-name>/  (default CODEX_HOME=~/.codex)
#
# Usage:
#   sh scripts/install_codex_skills.sh -all
#   sh scripts/install_codex_skills.sh -skills style-cleanup,commit-message
#   sh scripts/install_codex_skills.sh -local -all   # install to <cwd>/.codex
#
# Notes:
# - Codex loads skills at startup; restart `codex` after installation.
# - Existing destination skill dirs are backed up with a timestamp suffix.

SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd -P)"
SRC="$(CDPATH= cd -- "$SCRIPT_DIR/.." && pwd -P)"
SKILLS_SRC_ROOT="$SRC/codex/skills"

usage() {
  cat <<'EOF' >&2
Usage:
  sh scripts/install_codex_skills.sh [options]
  sh scripts/install_codex_skills.sh -skills style-cleanup,commit-message
  sh scripts/install_codex_skills.sh -all

Options:
  -local, -l    Install to ./.codex (or CODEX_HOME if set).
  -skills LIST  Comma/space-separated skill names.
  -all          Install all skills.
  -h, -help     Show this help.

Env:
  CODEX_HOME    Target Codex home (default: ~/.codex).
EOF
}

LOCAL_MODE=0
INSTALL_ALL=0
SKILLS=""
while [ $# -gt 0 ]; do
  case "$1" in
    -local|-l)
      LOCAL_MODE=1
      shift
      ;;
    -skills)
      if [ $# -lt 2 ] || [ -z "${2:-}" ]; then
        echo "ERROR: -skills requires a value." >&2
        usage
        exit 1
      fi
      SKILLS="$2"
      shift 2
      ;;
    -all)
      INSTALL_ALL=1
      shift
      ;;
    -h|-help)
      usage
      exit 0
      ;;
    -*)
      echo "ERROR: Unknown option: $1" >&2
      usage
      exit 1
      ;;
    *)
      echo "ERROR: positional args are not supported; use -skills/-all." >&2
      usage
      exit 1
      ;;
  esac
done

if [ "$INSTALL_ALL" -eq 1 ] && [ -n "$SKILLS" ]; then
  echo "ERROR: use either -all or -skills, not both." >&2
  usage
  exit 1
fi
if [ "$INSTALL_ALL" -eq 0 ] && [ -z "$SKILLS" ]; then
  echo "ERROR: -all or -skills is required." >&2
  usage
  exit 1
fi

if [ "$LOCAL_MODE" -eq 1 ]; then
  LOCAL_CODEX_HOME="$(pwd -P)/.codex"
  CODEX_HOME="${CODEX_HOME:-$LOCAL_CODEX_HOME}"
fi

CODEX_HOME="${CODEX_HOME:-$HOME/.codex}"
SKILLS_DST_ROOT="$CODEX_HOME/skills"

if [ ! -d "$SKILLS_SRC_ROOT" ]; then
  echo "ERROR: skills source dir not found: $SKILLS_SRC_ROOT" >&2
  exit 1
fi

mkdir -p "$SKILLS_DST_ROOT"
timestamp="$(date +%Y%m%d%H%M%S 2>/dev/null || echo bak)"

install_one() {
  name="$1"
  src_dir="$SKILLS_SRC_ROOT/$name"
  dst_dir="$SKILLS_DST_ROOT/$name"

  if [ ! -d "$src_dir" ]; then
    echo "ERROR: skill not found: $name ($src_dir)" >&2
    exit 1
  fi
  if [ -e "$dst_dir" ]; then
    mv "$dst_dir" "$SKILLS_DST_ROOT/$name.bak.$timestamp"
    echo "Backed up existing skill: $name -> $name.bak.$timestamp"
  fi
  cp -R "$src_dir" "$dst_dir"
  echo "Installed: $name"
}

if [ "$INSTALL_ALL" -eq 1 ]; then
  for dir in "$SKILLS_SRC_ROOT"/*; do
    [ -d "$dir" ] || continue
    name="$(basename -- "$dir")"
    case "$name" in
      ""|.*) continue ;;
    esac
    install_one "$name"
  done
else
  old_ifs="${IFS}"
  IFS=', '
  set -- $SKILLS
  IFS="${old_ifs}"
  for name in "$@"; do
    [ -n "$name" ] || continue
    install_one "$name"
  done
fi

echo "Done. Skills installed to: $SKILLS_DST_ROOT"