#!/bin/sh
# Athas install script
# Usage: curl -fsSL https://athas.dev/install.sh | sh
#
# Environment variables:
#   ATHAS_VERSION    - Install a specific version (e.g., "0.4.4")
#   ATHAS_BIN_DIR    - Custom Linux binary directory (default: ~/.local/bin)
#   ATHAS_APP_DIR    - Custom Linux app directory
#   ATHAS_SKIP_DEPS_CHECK - Set to 1 to skip the Linux WebKitGTK 4.1 check

set -eu

REPO="athasdev/athas"
GITHUB="https://github.com"
GITHUB_API="https://api.github.com"
VERSION_OVERRIDE=""

# --- Helpers ---

info() {
  printf '  \033[1;34m>\033[0m %s\n' "$@"
}

success() {
  printf '  \033[1;32m>\033[0m %s\n' "$@"
}

error() {
  printf '  \033[1;31merror:\033[0m %s\n' "$@" >&2
  exit 1
}

warn() {
  printf '  \033[1;33mwarn:\033[0m %s\n' "$@" >&2
}

usage() {
  cat <<EOF
Athas installer

Usage:
  curl -fsSL https://athas.dev/install.sh | sh

Options:
  --version <version>  Install a specific version, e.g. 0.15.1
  -h, --help           Show this help
EOF
}

need() {
  if ! command -v "$1" > /dev/null 2>&1; then
    error "need '$1' (command not found)"
  fi
}

parse_args() {
  while [ "$#" -gt 0 ]; do
    case "$1" in
      --stable)
        ;;
      --preview)
        error "preview builds are no longer published; run the installer without --preview"
        ;;
      --version)
        shift
        if [ -z "${1:-}" ]; then
          error "--version requires a version"
        fi
        VERSION_OVERRIDE="$1"
        ;;
      --version=*)
        VERSION_OVERRIDE="${1#*=}"
        ;;
      -h | --help)
        usage
        exit 0
        ;;
      *)
        error "unknown option: $1"
        ;;
    esac
    shift
  done
}

# --- Cleanup ---

cleanup() {
  if [ -n "${TMPDIR_INSTALL:-}" ] && [ -d "$TMPDIR_INSTALL" ]; then
    rm -rf "$TMPDIR_INSTALL"
  fi
}

trap cleanup EXIT INT TERM

# --- Download helper ---

download() {
  url="$1"
  output="$2"
  show_progress="${3:-0}"

  if command -v curl > /dev/null 2>&1; then
    if [ "$show_progress" = "1" ]; then
      curl -fL --retry 3 -o "$output" "$url"
    else
      curl -fsSL --retry 3 -o "$output" "$url"
    fi
  elif command -v wget > /dev/null 2>&1; then
    if [ "$show_progress" = "1" ]; then
      if wget --help 2>&1 | grep -q -- '--show-progress'; then
        wget --show-progress --progress=bar:force:noscroll -O "$output" "$url"
      else
        wget -O "$output" "$url"
      fi
    else
      wget -qO "$output" "$url"
    fi
  else
    error "need 'curl' or 'wget' to download files"
  fi
}

fetch() {
  url="$1"

  if command -v curl > /dev/null 2>&1; then
    curl -fsSL --retry 3 "$url"
  elif command -v wget > /dev/null 2>&1; then
    wget -qO- "$url"
  else
    error "need 'curl' or 'wget' to download files"
  fi
}

# --- Detect platform ---

detect_platform() {
  OS="$(uname -s)"
  ARCH="$(uname -m)"

  case "$OS" in
    Darwin) PLATFORM="macos" ;;
    Linux)  PLATFORM="linux" ;;
    MINGW* | MSYS* | CYGWIN*)
      error "Windows is not supported by this script. Download from: $GITHUB/$REPO/releases"
      ;;
    *)
      error "unsupported operating system: $OS"
      ;;
  esac

  case "$ARCH" in
    x86_64 | amd64)  ARCH="x64" ;;
    aarch64 | arm64)  ARCH="aarch64" ;;
    *)
      error "unsupported architecture: $ARCH"
      ;;
  esac
}

# --- Get version ---

normalize_version() {
  printf '%s' "$1" | sed 's/^v//' | tr -d '\r\n'
}

get_latest_stable_version() {
  info "Fetching latest stable version..."

  # Use the redirect from /releases/latest to extract the tag; this only returns stable releases.
  if command -v curl > /dev/null 2>&1; then
    redirect_url=$(curl -Ls -o /dev/null -w '%{url_effective}' "$GITHUB/$REPO/releases/latest" 2>/dev/null) || true
  elif command -v wget > /dev/null 2>&1; then
    redirect_url=$(wget -q --max-redirect=5 -S -O /dev/null "$GITHUB/$REPO/releases/latest" 2>&1 | grep -i '^\s*Location:' | tail -1 | awk '{print $2}' | tr -d '\r') || true
  fi

  if [ -z "${redirect_url:-}" ]; then
    error "failed to determine latest version. Set ATHAS_VERSION and try again."
  fi

  VERSION=$(normalize_version "$(echo "$redirect_url" | sed 's|.*/v||')")

  if [ -z "$VERSION" ]; then
    error "failed to parse version from redirect URL. Set ATHAS_VERSION and try again."
  fi

  info "Latest stable version: $VERSION"
}

get_version() {
  requested_version="${VERSION_OVERRIDE:-${ATHAS_VERSION:-}}"
  if [ -n "$requested_version" ]; then
    VERSION=$(normalize_version "$requested_version")
    case "$VERSION" in
      *-preview.*) error "preview builds are no longer published; install a stable version" ;;
    esac
    info "Using specified version: $VERSION"
  else
    get_latest_stable_version
  fi
}

# --- Build download URL ---

get_download_url() {
  BASE="$GITHUB/$REPO/releases/download/v${VERSION}"
  PRODUCT_PREFIX="Athas"

  case "$PLATFORM" in
    macos)
      # The .app.tar.gz updater artifacts don't include the version in the filename
      ARTIFACT="${PRODUCT_PREFIX}_${ARCH}.app.tar.gz"
      ;;
    linux)
      case "$ARCH" in
        x64)      ARTIFACT="${PRODUCT_PREFIX}_${VERSION}_linux-x86_64.tar.gz" ;;
        aarch64)  ARTIFACT="${PRODUCT_PREFIX}_${VERSION}_linux-aarch64.tar.gz" ;;
      esac
      ;;
  esac

  DOWNLOAD_URL="${BASE}/${ARTIFACT}"
  CHECKSUMS_URL="${BASE}/SHA256SUMS.txt"
}

# --- Verify checksum ---

verify_checksum() {
  file="$1"
  checksums_file="$2"

  if [ ! -f "$checksums_file" ]; then
    warn "Checksums file not available, skipping verification"
    return 0
  fi

  expected=$(grep "$(basename "$file")" "$checksums_file" | awk '{print $1}')
  if [ -z "$expected" ]; then
    warn "No checksum found for $(basename "$file"), skipping verification"
    return 0
  fi

  if command -v sha256sum > /dev/null 2>&1; then
    actual=$(sha256sum "$file" | awk '{print $1}')
  elif command -v shasum > /dev/null 2>&1; then
    actual=$(shasum -a 256 "$file" | awk '{print $1}')
  else
    warn "No sha256 tool found, skipping checksum verification"
    return 0
  fi

  if [ "$expected" != "$actual" ]; then
    error "Checksum verification failed for $(basename "$file")
  Expected: $expected
  Actual:   $actual"
  fi

  success "Checksum verified"
}

# --- Install macOS ---

install_macos() {
  app_name="Athas.app"

  info "Installing ${app_name%.app} to /Applications..."

  tar -xzf "$TMPDIR_INSTALL/$ARTIFACT" -C "$TMPDIR_INSTALL"

  # Remove quarantine attribute (curl doesn't set it, but just in case)
  xattr -cr "$TMPDIR_INSTALL/$app_name" 2>/dev/null || true

  if [ -d "/Applications/$app_name" ]; then
    rm -rf "/Applications/$app_name"
  fi

  mv "$TMPDIR_INSTALL/$app_name" "/Applications/$app_name"

  success "Installed ${app_name%.app} $VERSION to /Applications/$app_name"
  info "Launch with: open /Applications/$app_name"
}

# --- Linux runtime dependencies ---

# The tarball links against the system WebKitGTK 4.1 and GTK 3. Bundles from
# releases that still shipped CEF carry their own runtime in libexec/.
bundle_uses_system_webview() {
  [ ! -e "$1/libexec/libcef.so" ]
}

has_webkitgtk() {
  for ldconfig_cmd in ldconfig /sbin/ldconfig /usr/sbin/ldconfig; do
    if command -v "$ldconfig_cmd" > /dev/null 2>&1; then
      if "$ldconfig_cmd" -p 2>/dev/null | grep -q 'libwebkit2gtk-4\.1\.so\.0'; then
        return 0
      fi
      break
    fi
  done

  for lib_dir in /usr/lib /usr/lib64 /usr/local/lib /lib /lib64 \
    /usr/lib/x86_64-linux-gnu /usr/lib/aarch64-linux-gnu; do
    if [ -e "$lib_dir/libwebkit2gtk-4.1.so.0" ]; then
      return 0
    fi
  done

  return 1
}

webkitgtk_install_hint() {
  if command -v apt-get > /dev/null 2>&1; then
    echo "sudo apt install libwebkit2gtk-4.1-0"
  elif command -v dnf > /dev/null 2>&1; then
    echo "sudo dnf install webkit2gtk4.1"
  elif command -v pacman > /dev/null 2>&1; then
    echo "sudo pacman -S webkit2gtk-4.1"
  elif command -v zypper > /dev/null 2>&1; then
    echo "sudo zypper install libwebkit2gtk-4_1-0"
  fi
}

require_webkitgtk() {
  if [ "${ATHAS_SKIP_DEPS_CHECK:-}" = "1" ] || has_webkitgtk; then
    return 0
  fi

  hint=$(webkitgtk_install_hint)
  if [ -n "$hint" ]; then
    error "Athas needs WebKitGTK 4.1 (libwebkit2gtk-4.1), which is not installed.
  Install it with:
    $hint
  Then run this installer again. The AppImage download at
  https://athas.dev/download needs no system WebKitGTK."
  fi

  error "Athas needs WebKitGTK 4.1 (libwebkit2gtk-4.1), which is not installed.
  Install it with your distribution's package manager, then run this
  installer again. Set ATHAS_SKIP_DEPS_CHECK=1 to install anyway."
}

# --- Install Linux ---

install_linux() {
  bin_dir="${ATHAS_BIN_DIR:-$HOME/.local/bin}"
  app_dir_name="athas.app"
  bin_name="athas"
  desktop_id="com.code.athas"
  product_name="Athas"
  app_dir="${ATHAS_APP_DIR:-$HOME/.local/share/athas/$app_dir_name}"
  app_parent=$(dirname "$app_dir")
  extract_dir="$TMPDIR_INSTALL/linux-extract"

  info "Installing $product_name to $app_dir..."

  need tar

  mkdir -p "$bin_dir" "$app_parent" "$extract_dir"
  tar -xzf "$TMPDIR_INSTALL/$ARTIFACT" -C "$extract_dir"

  extracted_app="$extract_dir/$app_dir_name"
  if [ ! -d "$extracted_app" ]; then
    extracted_app=$(find "$extract_dir" -maxdepth 2 -type d -name "$app_dir_name" | head -n 1)
  fi

  if [ -z "$extracted_app" ] || [ ! -d "$extracted_app" ]; then
    error "downloaded Linux bundle does not contain $app_dir_name"
  fi

  if [ ! -x "$extracted_app/bin/athas" ]; then
    error "downloaded Linux bundle does not contain bin/athas"
  fi

  if bundle_uses_system_webview "$extracted_app"; then
    require_webkitgtk
  fi

  rm -rf "$app_dir"
  mv "$extracted_app" "$app_dir"
  chmod +x "$app_dir/bin/athas"
  ln -sf "$app_dir/bin/athas" "$bin_dir/$bin_name"

  if [ -d "$app_dir/share/icons" ]; then
    mkdir -p "$HOME/.local/share/icons"
    cp -R "$app_dir/share/icons/." "$HOME/.local/share/icons/" 2>/dev/null || true
  fi

  desktop_file="$app_dir/share/applications/$desktop_id.desktop"
  if [ -f "$desktop_file" ]; then
    mkdir -p "$HOME/.local/share/applications"
    sed "s|^Exec=.*|Exec=$bin_dir/$bin_name %U|" "$desktop_file" \
      > "$HOME/.local/share/applications/$desktop_id.desktop"
  fi

  success "Installed $product_name $VERSION to $app_dir"

  case ":$PATH:" in
    *":$bin_dir:"*) ;;
    *)
      warn "$bin_dir is not in your PATH"
      info "Add this to your shell profile:"
      info "  export PATH=\"$bin_dir:\$PATH\""
      ;;
  esac

  info "Launch with: $bin_name"
}

# --- Main ---

main() {
  printf '\n  \033[1mAthas Installer\033[0m\n\n'

  parse_args "$@"
  detect_platform
  get_version
  get_download_url

  TMPDIR_INSTALL=$(mktemp -d)

  info "Downloading $PRODUCT_PREFIX $VERSION for $PLATFORM ($ARCH)..."
  download "$DOWNLOAD_URL" "$TMPDIR_INSTALL/$ARTIFACT" 1

  # Try to download checksums (may not exist for older releases)
  download "$CHECKSUMS_URL" "$TMPDIR_INSTALL/SHA256SUMS.txt" 2>/dev/null || true
  verify_checksum "$TMPDIR_INSTALL/$ARTIFACT" "$TMPDIR_INSTALL/SHA256SUMS.txt"

  case "$PLATFORM" in
    macos) install_macos ;;
    linux) install_linux ;;
  esac

  printf '\n'
}

main "$@"