#!/bin/sh
# install-actionlint.sh — idempotent installer for rhysd/actionlint.
# Detects OS+arch, downloads the pinned release tarball to ~/.local/bin/actionlint.
# No-op if the binary is already on PATH. On macOS with Homebrew available and
# no local binary, suggests `brew install actionlint` as a faster alternative.
#
# Version pinned after WebFetch verification 2026-04-22.
# [VERIFIED: https://github.com/rhysd/actionlint/releases/tag/v1.7.12]
# Checksums from upstream checksums.txt (same release page).

set -eu

ACTIONLINT_VERSION="1.7.12"
INSTALL_DIR="${HOME}/.local/bin"
BIN="${INSTALL_DIR}/actionlint"

if command -v actionlint >/dev/null 2>&1; then
  printf 'actionlint already on PATH: %s\n' "$(command -v actionlint)"
  exit 0
fi

OS=$(uname -s | tr '[:upper:]' '[:lower:]')
ARCH_RAW=$(uname -m)
case "${ARCH_RAW}" in
  x86_64|amd64) ARCH="amd64" ;;
  arm64|aarch64) ARCH="arm64" ;;
  *) printf 'unsupported arch: %s\n' "${ARCH_RAW}" >&2; exit 2 ;;
esac

case "${OS}" in
  darwin|linux) : ;;
  *) printf 'unsupported os: %s\n' "${OS}" >&2; exit 2 ;;
esac

# Homebrew fast-path on macOS.
if [ "${OS}" = "darwin" ] && command -v brew >/dev/null 2>&1; then
  printf 'Homebrew detected. Fast path:\n  brew install actionlint\n'
  printf 'Falling through to tarball install (~/.local/bin) anyway.\n'
fi

ASSET="actionlint_${ACTIONLINT_VERSION}_${OS}_${ARCH}.tar.gz"
URL="https://github.com/rhysd/actionlint/releases/download/v${ACTIONLINT_VERSION}/${ASSET}"

mkdir -p "${INSTALL_DIR}"
TMP=$(mktemp -d)
trap 'rm -rf "${TMP}"' EXIT INT TERM

printf 'downloading %s\n' "${URL}"
if command -v curl >/dev/null 2>&1; then
  curl -fsSL -o "${TMP}/${ASSET}" "${URL}"
elif command -v wget >/dev/null 2>&1; then
  wget -qO "${TMP}/${ASSET}" "${URL}"
else
  printf 'neither curl nor wget is installed\n' >&2
  exit 2
fi

tar -xzf "${TMP}/${ASSET}" -C "${TMP}" actionlint
install -m 0755 "${TMP}/actionlint" "${BIN}"

printf 'installed: %s\n' "${BIN}"
case ":${PATH}:" in
  *:"${INSTALL_DIR}":*) : ;;
  *) printf 'note: %s is not on PATH — add it to your shell profile.\n' "${INSTALL_DIR}" ;;
esac