Update buf installer script

scripts/buf-installer.sh

@@ -1,53 +1,127 @@
 #!/bin/bash
 
-BIN="/usr/local/bin"
-GITHUB_API_URL="https://api.github.com/repos/bufbuild/buf/releases/latest"
-GITHUB_RELEASES_URL="https://api.github.com/repos/bufbuild/buf/releases"
+# Functions
+show_help() {
+  echo "This script downloads and installs the buf CLI utility."
+  echo "Usage: $0 [OPTION]"
+  echo ""
+  echo "Options:"
+  echo "  --version=VERSION    Install a specific version of buf, Ex: v1.28.1"
+  echo "  --do-not-validate    Do not validate version from releases"
+  echo "  --list               List available versions without installing"
+  echo "  --help               Display this help message"
+}
+
+validate_dependencies() {
+  for dep in curl jq; do
+    command -v $dep >/dev/null 2>&1 || { echo >&2 "This script requires $dep but it's not installed. Aborting."; exit 1; }
+  done
+}
+
+get_available_versions() {
+  curl -s "${GITHUB_API_URL_RELEASES}" | jq -r '.[].tag_name'
+}
 
-# Function to fetch latest version
-fetch_latest_version() {
-    curl -sSL $GITHUB_API_URL | grep '"tag_name":' | sed -E 's/.*"([^"]+)".*/\1/' | sed 's/v//'
+validate_version() {
+  local available_versions=$1
+  local version_regex="^$VERSION$"
+  if ! grep -qx "$version_regex" <<< "$available_versions"; then
+    echo -e "Error: Version '$VERSION' not found. \nAvailable versions: \n$available_versions" >&2
+    exit 1
+  fi
 }
 
-# Function to list all versions
 list_versions() {
-    curl -sSL $GITHUB_RELEASES_URL | grep '"tag_name":' | sed -E 's/.*"([^"]+)".*/\1/'
+  local available_versions=$1
+  echo "Available buf versions:"
+  echo "$available_versions"
+  exit 0
+}
+
+download_and_install() {
+  local version=$1
+  local temp_file=$(mktemp)
+
+  # Download the file
+  local download_url="https://github.com/bufbuild/buf/releases/download/${version}/buf-$(uname -s)-$(uname -m)"
+  echo "Downloading: $download_url"
+  if ! curl -sSL "$download_url" -o "$temp_file"; then
+    echo "Error: Failed to download buf version ${version}."
+    rm -f "$temp_file"
+    exit 1
+  fi
+
+  # Move the file to the bin directory
+  if ! mv "$temp_file" "${BIN}/buf"; then
+    echo "Error: Failed to move buf to ${BIN}."
+    rm -f "$temp_file"
+    exit 1
+  fi
+
+  # Set executable permissions
+  if ! chmod +x "${BIN}/buf"; then
+    echo "Error: Failed to set executable permissions on buf."
+    exit 1
+  fi
+
+  echo "buf version ${version} installed successfully."
 }
 
-# Argument parsing
 VERSION=""
-LIST_VERSIONS=false
-for i in "$@"
-do
-case $i in
+LIST_ONLY=false
+SHOW_HELP=false
+DO_NOT_VALIDATE=false
+
+# Bin directory for installation
+BIN="/usr/local/bin"
+
+# Github URLs
+GITHUB_API_URL_RELEASES="https://api.github.com/repos/bufbuild/buf/releases"
+GITHUB_API_URL_LATEST="${GITHUB_API_URL_RELEASES}/latest"
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+  case $1 in
     --version=*)
-    VERSION="${i#*=}"
-    shift
-    ;;
+      VERSION="${1#*=}"
+      ;;
+    --do-not-validate)
+      DO_NOT_VALIDATE=true
+      ;;
     --list)
-    LIST_VERSIONS=true
-    shift
-    ;;
+      LIST_ONLY=true
+      ;;
+    --help)
+      SHOW_HELP=true
+      ;;
     *)
-    # unknown option
-    ;;
-esac
+      echo "Unknown option: $1" >&2
+      exit 1
+      ;;
+  esac
+  shift
 done
 
-# Logic for listing versions
-if [ "$LIST_VERSIONS" = true ]; then
-    list_versions
-    exit 0
+if [[ "$SHOW_HELP" == true ]]; then
+  show_help
+  exit 0
 fi
 
-# Set the default version to the latest if not specified
-if [ -z "$VERSION" ]; then
-    VERSION=$(fetch_latest_version)
+validate_dependencies
+
+if [[ "$LIST_ONLY" == true ]] || { [[ -n "$VERSION" ]] && [[ "$DO_NOT_VALIDATE" != true ]]; }; then
+  AVAILABLE_VERSIONS=$(get_available_versions)
 fi
 
-# Installation
-echo "Installing buf version $VERSION..."
-curl -sSL "https://github.com/bufbuild/buf/releases/download/v${VERSION}/buf-$(uname -s)-$(uname -m)" \
--o "${BIN}/buf" && \
-chmod +x "${BIN}/buf"
+if [[ "$LIST_ONLY" == true ]]; then
+  list_versions "$AVAILABLE_VERSIONS"
+  exit 0
+fi
+
+if [[ -z "$VERSION" ]]; then
+  VERSION=$(curl -sSL "${GITHUB_API_URL_LATEST}" | jq -r '.tag_name')
+elif [[ "$DO_NOT_VALIDATE" != true ]]; then
+  validate_version "$AVAILABLE_VERSIONS"
+fi
 
+download_and_install "$VERSION"