#!/bin/bash
################################################################################
# kiosk-offline-apt - point apt at the offline install bundle, or back.
#
#   sudo kiosk-offline-apt on       apt uses ONLY /opt/kiosk-offline/apt
#   sudo kiosk-offline-apt off      back to the normal Ubuntu archive
#   kiosk-offline-apt status
#
# Installed by the custom ISO (iso/build-iso.sh); the bundle itself is
# only there on ISOs built with --offline. kiosk-firstboot turns this on
# by itself when first boot finds no internet, and back off afterwards.
# By hand it's for installing things later with no internet - e.g. the
# CUPS addon: `sudo kiosk-offline-apt on`, ./install.sh -> Addons -> CUPS,
# then `sudo kiosk-offline-apt off`. While it's on, install.sh also
# unpacks the bundle's prebuilt node_modules instead of running npm
# (lib/config.sh's offline_mode_active checks for the file this writes).
#
# "Only" matters: with the normal archive still listed, apt would pick
# newer versions from it that it then can't download.
################################################################################

set -euo pipefail

BUNDLE_DIR=/opt/kiosk-offline
APT_CONF=/etc/apt/apt.conf.d/90-kiosk-offline

case "${1:-status}" in
    on)
        [[ $EUID -eq 0 ]] || { echo "Run with sudo" >&2; exit 1; }
        if [[ ! -f "$BUNDLE_DIR/apt/Packages" ]]; then
            echo "No offline bundle at $BUNDLE_DIR (ISO not built with --offline)" >&2
            exit 1
        fi
        mkdir -p "$BUNDLE_DIR/sources.d"
        echo "deb [trusted=yes] file:$BUNDLE_DIR/apt ./" > "$BUNDLE_DIR/offline.list"
        cat > "$APT_CONF" <<EOF
// Written by kiosk-offline-apt - remove with: sudo kiosk-offline-apt off
Dir::Etc::SourceList "$BUNDLE_DIR/offline.list";
Dir::Etc::SourceParts "$BUNDLE_DIR/sources.d";
Acquire::Languages "none";
EOF
        apt-get update -q >/dev/null
        echo "apt now installs from the offline bundle only ($BUNDLE_DIR)."
        ;;
    off)
        [[ $EUID -eq 0 ]] || { echo "Run with sudo" >&2; exit 1; }
        rm -f "$APT_CONF"
        echo "apt is back on the normal Ubuntu sources."
        echo "Run 'sudo apt update' once there's internet."
        ;;
    status)
        if [[ -f "$APT_CONF" ]]; then
            echo "on (apt uses $BUNDLE_DIR/apt only)"
        else
            echo "off"
        fi
        [[ -f "$BUNDLE_DIR/bundle-info.txt" ]] && sed -n '1,3p;5,6p' "$BUNDLE_DIR/bundle-info.txt"
        ;;
    *)
        echo "Usage: kiosk-offline-apt on|off|status" >&2
        exit 2
        ;;
esac