#!/usr/bin/env bash
# Installs the latest JayJay for Linux into ~/.local: the AppImage, a jayjay command, a desktop entry, and icons.
# Usage: curl -fsSL https://jayjay.hewig.dev/install.sh | bash
#        JAYJAY_VERSION=0.3.17-beta.4 bash install.sh   # a specific release instead of the latest stable
set -euo pipefail

repo="hewigovens/jayjay"
# The default install follows the XDG data directory the desktop searches; a custom prefix keeps everything under itself.
if [ -n "${JAYJAY_PREFIX:-}" ]; then
  prefix="$JAYJAY_PREFIX"
  case "$prefix" in /*) ;; *) prefix="$PWD/$prefix" ;; esac
  data_dir="$prefix/share"
  bin_dir="$prefix/bin"
else
  data_dir="${XDG_DATA_HOME:-$HOME/.local/share}"
  bin_dir="$HOME/.local/bin"
fi
app_dir="$data_dir/jayjay"

case "$(uname -m)" in
  x86_64 | amd64) arch="x86_64" ;;
  aarch64 | arm64) arch="aarch64" ;;
  *) echo "JayJay ships Linux builds for x86_64 and aarch64 only; this machine is $(uname -m)." >&2; exit 1 ;;
esac

if command -v pacman >/dev/null && pacman -Q jayjay-appimage >/dev/null 2>&1; then
  echo "JayJay is installed as the jayjay-appimage package; upgrade it with sudo pacman -Syu (stable repo) or pacman -U from the release page (betas)." >&2
  exit 1
fi
for tool in curl sha256sum; do
  command -v "$tool" >/dev/null || { echo "$tool is required." >&2; exit 1; }
done
if ! command -v fusermount3 >/dev/null && ! command -v fusermount >/dev/null; then
  echo "AppImages need FUSE. Install the fuse3 package (Arch: fuse3, Debian/Ubuntu: fuse3, Fedora: fuse) and run this again." >&2
  exit 1
fi

# Mirrors the app's Settings > CLI rule: only a symlink to a JayJay AppImage may be replaced; anything else is the user's.
for launcher in "$bin_dir/jayjay" "$bin_dir/jayjay-gpui"; do
  if [ -e "$launcher" ] || [ -L "$launcher" ]; then
    target="$(readlink "$launcher" || true)"
    case "$(basename "$target" | tr '[:upper:]' '[:lower:]')" in
      *jayjay*.appimage) ;;
      *) echo "$launcher already exists and is not a JayJay launcher; move it aside and run this again." >&2; exit 1 ;;
    esac
  fi
done

asset="jayjay-gpui-$arch-linux.AppImage"
if [ -n "${JAYJAY_VERSION:-}" ]; then
  tag="v${JAYJAY_VERSION#v}"
else
  tag="$(curl -fsSLI -o /dev/null -w '%{url_effective}' "https://github.com/$repo/releases/latest")"
  tag="${tag##*/}"
  case "$tag" in v[0-9]*) ;; *) echo "Could not determine the latest release." >&2; exit 1 ;; esac
fi
base="https://github.com/$repo/releases/download/$tag"

version_file="$app_dir/VERSION"
if [ -z "${JAYJAY_FORCE:-}" ] && [ -x "$app_dir/JayJay.AppImage" ] && [ -L "$bin_dir/jayjay" ] && [ "$(cat "$version_file" 2>/dev/null)" = "$tag" ]; then
  echo "JayJay $tag is already installed at $app_dir/JayJay.AppImage. Set JAYJAY_FORCE=1 to reinstall."
  exit 0
fi

tmp="$(mktemp -d)"
trap 'rm -rf "$tmp"' EXIT
echo "Installing JayJay $tag for $arch..."
curl -fsSL --retry 3 -o "$tmp/$asset" "$base/$asset"
curl -fsSL --retry 3 -o "$tmp/$asset.sha256" "$base/$asset.sha256"
(cd "$tmp" && sha256sum -c --quiet "$asset.sha256")
chmod +x "$tmp/$asset"

# The runtime extracts named files without FUSE, so the desktop entry and icons come from the image itself. Older images keep both at the root.
(cd "$tmp" && for pattern in 'usr/share/applications/*' 'usr/share/icons/*' '*.desktop' '*.svg'; do "./$asset" --appimage-extract "$pattern" >/dev/null 2>&1 || true; done)
desktop_entry="$(find "$tmp/squashfs-root" -type f -name 'dev.hewig.JayJay.desktop' | head -1)"
[ -n "$desktop_entry" ] || { echo "The image has no desktop entry." >&2; exit 1; }

mkdir -p "$app_dir" "$bin_dir" "$data_dir/applications" "$data_dir/icons/hicolor/scalable/apps"
install -m755 "$tmp/$asset" "$app_dir/JayJay.AppImage"
ln -sfn "$app_dir/JayJay.AppImage" "$bin_dir/jayjay"
ln -sfn "$app_dir/JayJay.AppImage" "$bin_dir/jayjay-gpui"
# The menu entry must not depend on the session PATH, so it launches the image by its absolute path, quoted per the desktop-entry rules.
exec_path="$(printf '%s' "$app_dir/JayJay.AppImage" | sed 's/[\\"$`]/\\&/g')"
while IFS= read -r line || [ -n "$line" ]; do
  case "$line" in
    Exec=*) printf 'Exec="%s" %%F\n' "$exec_path" ;;
    *) printf '%s\n' "$line" ;;
  esac
done < "$desktop_entry" > "$data_dir/applications/dev.hewig.JayJay.desktop"
if [ -d "$tmp/squashfs-root/usr/share/icons" ]; then
  cp -R "$tmp/squashfs-root/usr/share/icons/." "$data_dir/icons/"
else
  install -m644 "$tmp/squashfs-root/dev.hewig.JayJay.svg" "$data_dir/icons/hicolor/scalable/apps/dev.hewig.JayJay.svg"
fi
command -v update-desktop-database >/dev/null && update-desktop-database "$data_dir/applications" 2>/dev/null || true
printf '%s\n' "$tag" > "$version_file"

echo "Installed JayJay $tag to $app_dir/JayJay.AppImage"
echo "Run: jayjay /path/to/repo"
echo "Upgrade: run this script again when a new release is out."
case ":$PATH:" in
  *":$bin_dir:"*) ;;
  *) echo "Note: add $bin_dir to your PATH to run jayjay by name." ;;
esac