#!/bin/sh
#
# xrdp: A Remote Desktop Protocol server.
#
# Copyright (C) 2021 Matt Burt, all xrdp contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

# Wrapper to call install_pulseaudio_sources.sh and tidy up afterwards

# The command line switches --mirror= and --keyring= can be specified if
# these switches are needed for a system based on Debian (e.g. a Raspberry
# Pi)

# ---------------------------------------------------------------------------
# G L O B A L S
# ---------------------------------------------------------------------------
# Where the output files are going. Must be under $HOME as schroot
# assumes this.
PULSE_DIR=$HOME/pulseaudio.src

# Absolute path to the script we're wrapping. This picks it up from
# the same directory this file is in
WRAPPED_SCRIPT=$(cd $(dirname $0) && pwd)/install_pulseaudio_sources_apt.sh

# The buildroot directory. Choose fast, temporary storage if available
BUILDROOT=/var/lib/pa-build/$USER

# Extra packages to install in the build root which the wrapped script
# may be using. These are packages available by default when using
# GitHub actions
WRAPPED_SCRIPT_DEPS="sudo lsb-release"

# -----------------------------------------------------------------------------
# I N S T A L L   R E Q U I R E D   P A C K A G E S
#
# Installs packages required for the build on the host machine
# -----------------------------------------------------------------------------
InstallRequiredPackages()
{
    set -- \
        /usr/sbin/debootstrap   debootstrap \
        /usr/bin/schroot        schroot \
        /usr/bin/lsb_release    lsb-release

    pkgs=
    while [ $# -ge 2 ]; do
        if [ ! -x $1 ]; then
            pkgs="$pkgs $2"
        fi
        shift 2
    done

    if [ -n "$pkgs" ]; then
        echo "- Need to install packages :$pkgs"
        echo
        echo "  These can be removed when this script completes with:-"
        echo "  sudo apt-get purge$pkgs && apt-get autoremove"
        echo
        sudo apt-get install -y $pkgs
    fi
}

# -----------------------------------------------------------------------------
# R U N   W R A P P E D   S C R I P T
#
# Runs the wrapped build script using schroot
#
# This function definition uses () rather than {} to create an extra
# sub-process where we can run 'set -e' without affecting the parent
# -----------------------------------------------------------------------------
RunWrappedScript()
(
    # In this sub-process, fail on error
    set -e

    # Install extra dependencies
    schroot -c pa-build-$USER -u root -- \
        apt-get install -y $WRAPPED_SCRIPT_DEPS

    # Allow normal user to sudo without a password
    schroot -c pa-build-$USER -u root -- \
        /bin/sh -c "echo '$USER ALL=(ALL) NOPASSWD:ALL'>/etc/sudoers.d/nopasswd-$USER"
    schroot -c pa-build-$USER -u root -- chmod 400 /etc/sudoers.d/nopasswd-$USER

    # Call the wrapped script
    schroot -c pa-build-$USER -- /wrapped_script -d $PULSE_DIR
)

# -----------------------------------------------------------------------------
# M A I N
# -----------------------------------------------------------------------------

debootstrap_mirror=""
debootstrap_switches=""

# Parse command line switches
while [ -n "$1" ]; do
    case "$1" in
        --mirror=*)
            debootstrap_mirror="${1#--mirror=}"
            ;;
        --keyring=*)
            file="${1#--keyring=}"
            if [ -f "$file" ]; then
                debootstrap_switches="$debootstrap_switches $1"
            else
                echo "** Ignoring missing keyring $1" >&2
            fi
            ;;
        *)  echo "** Unrecognised parameter '$1'" >&2
            exit 1
    esac
    shift
done

# Start with a few sanity checks
if [ -d $PULSE_DIR ]; then
    echo "** Target directory $PULSE_DIR already exists" >&2
    exit 0
fi

if [ ! -x $WRAPPED_SCRIPT ]; then
    echo "** Can't find wrapped script $WRAPPED_SCRIPT" >&2
    exit 1
fi

if [ -e $BUILDROOT ]; then
    echo "** Remove old build root $BUILDROOT before running this script"
    exit 1
fi

# Do we need extra packages?
InstallRequiredPackages || exit $?

# We should be able to determine the distro now
distro=$(lsb_release -cs) ; # e.g. 'bullseye'
if [ -z "$distro" ]; then
    echo "** Can't determine current distro" >&2
    exit 1
fi

# Create the build root
log=/var/tmp/pa-build-$USER-debootstrap.log
echo "- Creating $distro build root. Log file in $log"
sudo debootstrap \
    $debootstrap_switches \
    $distro $BUILDROOT "$debootstrap_mirror" >$log 2>&1 || {
    echo "** debootstrap failed. Check log file $log" >&2
    exit 1
}

# Create the config file for schroot
schroot_conf=/etc/schroot/chroot.d/pa-build-$USER.conf
echo "- Creating schroot config file $schroot_conf"
{
    echo "[pa-build-$USER]"
    echo "description=Build PA on current system for $USER"
    echo "directory=$BUILDROOT"
    echo "root-users=$USER"
    echo "users=$USER"
    echo "type=directory"
} | sudo tee $schroot_conf >/dev/null || exit $?

# Copy some files to the build root
for file in /etc/apt/sources.list; do
    echo "- Copying $file to the root"
    sudo cp $file $BUILDROOT/$file || exit $?
done

# Copy the wrapped script to the buildroot root
echo "- Copying the wrapped script to the root"
sudo cp $WRAPPED_SCRIPT $BUILDROOT/wrapped_script || exit $?
sudo chmod +x $BUILDROOT/wrapped_script || exit $?

# Run the wrapped script
log=/var/tmp/pa-build-$USER-schroot.log
echo "- Building PA sources. Log file in $log"
RunWrappedScript >$log 2>&1 || {
    echo "** schroot failed. Check log file $log" >&2
    exit 1
}

# Done! Remove the schroot config file as its no longer needed
echo "- Removing schroot config file and build root"
sudo rm -rf $schroot_conf $BUILDROOT

echo "- All done. Configure PA xrdp module with PULSE_DIR=$PULSE_DIR"
exit 0