#!/bin/sh
# maturita.c installer for Linux.
#
# Carries no application of its own: it downloads whatever the newest release
# is at the moment you run it, so this file never goes stale. GitHub resolves
# the /releases/latest/download/ path to the current tag on every request.
#
# Run it with:  sh maturita-installer-linux.sh
# The app updates itself from then on.

set -eu

REPO="pepaskopec-blip/maturita.c"
ASSET="maturita-linux-x86_64.AppImage"
URL="https://github.com/$REPO/releases/latest/download/$ASSET"

# ~/Applications is where desktop environments look for AppImages, and the app
# keeps its progress/ directory next to its own file.
DEST_DIR="$HOME/Applications"
DEST="$DEST_DIR/maturita.AppImage"
DESKTOP_DIR="$HOME/.local/share/applications"
ICON_DIR="$HOME/.local/share/icons/hicolor/512x512/apps"

say() { printf '%s\n' "$*"; }
die() { printf '\nError: %s\n' "$*" >&2; exit 1; }

say "Installing maturita.C"
say "---------------------"

arch=$(uname -m)
if [ "$arch" != "x86_64" ]; then
    die "only x86_64 builds are published, but this machine reports '$arch'.
Build from source instead: https://github.com/$REPO"
fi

command -v curl >/dev/null 2>&1 || die "curl was not found. Install it first."

mkdir -p "$DEST_DIR"

tmp=$(mktemp -d)
trap 'rm -rf "$tmp"' EXIT INT TERM

say "Downloading the latest release..."
curl -fL --progress-bar -o "$tmp/$ASSET" "$URL" ||
    die "the download failed. Check your internet connection."

say "Installing to $DEST"
chmod +x "$tmp/$ASSET"
mv -f "$tmp/$ASSET" "$DEST" || die "could not write to $DEST_DIR."

# A menu entry needs the icon as a separate file, which the AppImage can
# unpack without FUSE. Losing the icon is not worth failing the install over.
if (cd "$tmp" && "$DEST" --appimage-extract \
        'usr/share/icons/hicolor/512x512/apps/maturita.png' >/dev/null 2>&1); then
    icon="$tmp/squashfs-root/usr/share/icons/hicolor/512x512/apps/maturita.png"
    if [ -f "$icon" ]; then
        mkdir -p "$ICON_DIR"
        cp -f "$icon" "$ICON_DIR/maturita.png"
    fi
fi

mkdir -p "$DESKTOP_DIR"
cat > "$DESKTOP_DIR/maturita.desktop" <<EOF
[Desktop Entry]
Type=Application
Name=maturita.C
Comment=Practice app for the Czech maturita exam
Exec=$DEST
Icon=maturita
Terminal=false
Categories=Education;
EOF

command -v update-desktop-database >/dev/null 2>&1 &&
    update-desktop-database "$DESKTOP_DIR" >/dev/null 2>&1 || true

say ""
say "Done. Starting the app..."
"$DEST" >/dev/null 2>&1 &