#!/bin/sh
set -euo pipefail

# Determine OS type and architecture
OS=$(uname -s | tr '[:upper:]' '[:lower:]')
ARCH=$(uname -m)

# Map architecture naming
if [ "$ARCH" = "x86_64" ]; then
  ARCH="x64"
elif [ "$ARCH" = "aarch64" ] || [ "$ARCH" = "arm64" ]; then
  ARCH="arm64"
fi

VERSION="${DOCS_BUILDER_VERSION:-latest}"

# Determine binary to download based on OS
if [ "$OS" = "darwin" ]; then
  BINARY="docs-builder-mac-$ARCH.zip"
  DEFAULT_INSTALL_DIR="/usr/local/bin"
elif [ "$OS" = "linux" ]; then
  BINARY="docs-builder-linux-$ARCH.zip"
  DEFAULT_INSTALL_DIR="/usr/local/bin"
else
  echo "Unsupported operating system: $OS"
  exit 1
fi

# Determine if we need sudo for the install directory
INSTALL_DIR="$DEFAULT_INSTALL_DIR"
if [ ! -w "$INSTALL_DIR" ]; then
  USE_SUDO=true
  echo "Note: Installing to $INSTALL_DIR requires administrator privileges."
else
  USE_SUDO=false
fi

# Check if docs-builder already exists, but handle non-interactive shells
if [ -f "$INSTALL_DIR/docs-builder" ]; then
  echo "docs-builder is already installed."
  
  # Check if script is running interactively (has a TTY)
  if [ -t 0 ]; then
    # Running interactively, can prompt for input
    printf "Do you want to update/overwrite it? (y/n): "
    read choice
    case "$choice" in
      y|Y ) echo "Updating docs-builder..." ;;
      n|N ) echo "Installation aborted."; exit 0 ;;
      * ) echo "Invalid choice. Installation aborted."; exit 1 ;;
    esac
  else
    # Non-interactive mode (e.g., piped from curl), default to yes
    echo "Running in non-interactive mode. Proceeding with installation..."
  fi
fi

echo "Downloading docs-builder for $OS/$ARCH..."

if [ "$VERSION" = "latest" ]; then
  DOWNLOAD_URL="https://github.com/elastic/docs-builder/releases/latest/download/$BINARY"
else
  DOWNLOAD_URL="https://github.com/elastic/docs-builder/releases/download/$VERSION/$BINARY"
fi

# Download the appropriate binary
if ! curl -LO "$DOWNLOAD_URL"; then
  echo "Error: Failed to download $BINARY. Please check your internet connection."
  exit 1
fi

# Validate the downloaded file
if [ ! -s "$BINARY" ]; then
  echo "Error: Downloaded file $BINARY is missing or empty."
  exit 1
fi

# Extract only the docs-builder file to /tmp directory
if ! unzip -j -o "$BINARY" docs-builder -d /tmp; then
  echo "Error: Failed to extract docs-builder from $BINARY."
  exit 1
fi

# Ensure the binary is executable
chmod +x /tmp/docs-builder

# Move the binary to the install directory
echo "Installing docs-builder to $INSTALL_DIR..."
if [ "$USE_SUDO" = true ]; then
  sudo mv -f /tmp/docs-builder "$INSTALL_DIR/docs-builder"
else
  mv -f /tmp/docs-builder "$INSTALL_DIR/docs-builder"
fi

# Clean up the downloaded zip file
rm -f "$BINARY"

echo "docs-builder ($VERSION) has been installed successfully and is available in your PATH."
echo "You can run 'docs-builder --help' to see available commands."