#!/usr/bin/env bash

set -euo pipefail

VERSION="${RALPH_SKILLS_VERSION:-}"
SENTINEL_PREFIX="__RALPH"
SENTINEL_SUFFIX="_SKILLS_GITHUB_REPO__"
REPO_SENTINEL="${SENTINEL_PREFIX}${SENTINEL_SUFFIX}"
DEFAULT_GITHUB_REPO="1450Digital/ralph-skills"
GITHUB_REPO="${RALPH_SKILLS_GITHUB_REPO:-$DEFAULT_GITHUB_REPO}"
INSTALL_DIR="${RALPH_SKILLS_INSTALL_DIR:-}"
BINARY_NAME="ralph-skills"

say() {
  printf '%s\n' "$*"
}

fail() {
  say "ralph-skills install failed: $*" >&2
  exit 1
}

need_cmd() {
  command -v "$1" >/dev/null 2>&1 || fail "missing required command: $1"
}

download_file() {
  local url output
  url="$1"
  output="$2"

  say "Downloading ${url}"

  if [ -t 2 ]; then
    curl -fL# "$url" -o "$output"
  else
    curl -fsSL "$url" -o "$output"
  fi
}

resolve_version() {
  if [ -n "$VERSION" ]; then
    return
  fi
}

detect_platform() {
  local os arch
  os="$(uname -s)"
  arch="$(uname -m)"

  case "$os" in
    Darwin) os="macos" ;;
    Linux) os="linux" ;;
    MINGW*|MSYS*|CYGWIN*|Windows_NT) os="windows" ;;
    *) fail "unsupported operating system: $os" ;;
  esac

  case "$arch" in
    arm64|aarch64) arch="arm64" ;;
    x86_64|amd64) arch="x64" ;;
    *) fail "unsupported architecture: $arch" ;;
  esac

  PLATFORM="${os}"
  ARCH="${arch}"
}

select_artifact() {
  case "${PLATFORM}-${ARCH}" in
    macos-arm64) ARTIFACT="ralph-skills-macos-arm64" ;;
    macos-x64) ARTIFACT="ralph-skills-macos-x64" ;;
    linux-x64) ARTIFACT="ralph-skills-linux-x64" ;;
    linux-arm64) ARTIFACT="ralph-skills-linux-arm64" ;;
    windows-x64) ARTIFACT="ralph-skills-windows-x64.exe" ;;
    *) fail "no release artifact for ${PLATFORM}-${ARCH}" ;;
  esac
}

choose_install_dir() {
  if [ -n "$INSTALL_DIR" ]; then
    return
  fi

  if [ -w "/usr/local/bin" ]; then
    INSTALL_DIR="/usr/local/bin"
  else
    INSTALL_DIR="${HOME}/.local/bin"
  fi
}

install_binary() {
  local url tmp_file target_file
  if [ -z "$GITHUB_REPO" ] || [ "$GITHUB_REPO" = "$REPO_SENTINEL" ]; then
    fail "RALPH_SKILLS_GITHUB_REPO is not set. Use the hosted installer or set it to owner/repo before running the installer."
  fi

  if [ -n "$VERSION" ]; then
    url="https://github.com/${GITHUB_REPO}/releases/download/v${VERSION}/${ARTIFACT}"
  else
    url="https://github.com/${GITHUB_REPO}/releases/latest/download/${ARTIFACT}"
  fi
  tmp_file="$(mktemp "${TMPDIR:-/tmp}/ralph-skills.XXXXXX")"
  target_file="${INSTALL_DIR}/${BINARY_NAME}"

  mkdir -p "$INSTALL_DIR"
  download_file "$url" "$tmp_file"
  chmod +x "$tmp_file"
  mv "$tmp_file" "$target_file"

  say "Installed ${BINARY_NAME} to ${target_file}"

  case ":$PATH:" in
    *":${INSTALL_DIR}:"*) ;;
    *)
      say ""
      say "Add ${INSTALL_DIR} to your PATH to run ${BINARY_NAME}:"
      say "  export PATH=\"${INSTALL_DIR}:\$PATH\""
      ;;
  esac
}

main() {
  need_cmd curl
  resolve_version
  detect_platform
  select_artifact
  choose_install_dir
  install_binary
}

main "$@"