#!/bin/bash

set -e
shopt -s extglob

# Set defaults from the running kernel
arch="$(dpkg --print-architecture)"
kernelabi="$(uname -r)"
ff="${kernelabi#+([^-])-@(trunk|?(rc)+([0-9])|+([0-9]).bpo.+([0-9]))-}"
if [ "x$ff" != "x$kernelabi" ]; then
    flavour="${ff#@(openvz|rt|vserver|xen)-}"
    if [ "x$flavour" != "x$ff" ]; then
	featureset="${ff%-$flavour}"
    else
	featureset=none
    fi
else
    flavour=
    featureset=none
fi

fuzz=0
jobs=$(nproc)

eval "set -- $(getopt -n "$0" -o "f:j:s:" -l "fuzz:" -- "$@")"
while true; do
    case "$1" in
	-f) flavour="$2"; shift 2 ;;
	-j) jobs="$2"; shift 2 ;;
	-s) featureset="$2"; shift 2 ;;
	--fuzz) fuzz="$2"; shift 2;;
	--) shift 1; break ;;
    esac
done
	    
if [ $# -lt 1 ]; then
    echo >&2 "Usage: $0 [<options>] <patch>..."
    cat >&2 <<EOF
Options:
     -f <flavour>     specify the 'flavour' of kernel to build, e.g. 686-pae
     -j <jobs>        specify number of compiler jobs to run in parallel
                      (default: number of available processors)
     -s <featureset>  specify an optional featureset to apply, e.g. rt
     --fuzz <num>     set the maximum patch fuzz factor (default: 0)
EOF
    exit 2
fi

if [ -z "$flavour" ]; then
    echo >&2 "You must specify a flavour to build with the -f option"
    exit 2
fi

export DEB_BUILD_PROFILES=pkg.linux.notools
export MAKEFLAGS="$MAKEFLAGS -j$jobs"

dpkg-checkbuilddeps -B

# Append 'a~test' to Debian version; this should be less than any official
# successor and easily recognisable
version="$(dpkg-parsechangelog | sed 's/^Version: //; t; d')"
if [ "${version%a~test}" = "$version" ]; then
    version="$version"a~test
    dch -v "$version" --distribution UNRELEASED "Testing patches $*"
fi

# Ignore user's .quiltrc
alias quilt='quilt --quiltrc -'

# Try to clean up any previous test patches
if [ "$featureset" = none ]; then
    patchdir=debian/patches
    while patch="$(quilt next 2>/dev/null || quilt top 2>/dev/null)" && \
	[ "${patch#test/}" != "$patch" ]; do
        quilt delete -r "$patch"
    done
else
    patchdir=debian/patches-${featureset}
    sed -i '/^test\//d' $patchdir/series
fi

# Prepare a new directory for the patches
rm -rf $patchdir/test/
mkdir $patchdir/test

# Regenerate control and included rules
rm debian/control debian/rules.gen
debian/rules debian/control-real && exit 1 || true
test -f debian/control
test -f debian/rules.gen

# Clean up old build; apply existing patches for featureset
debian/rules clean
debian/rules source

# Apply the additional patches
for patch in "$@"; do
    patch_abs="$(readlink -f "$patch")"
    (cd "debian/build/source_${featureset}" && \
     quilt import -P "test/$(basename "$patch")" "$patch_abs" && \
     quilt push --fuzz="$fuzz")
done

# Build selected binaries
fakeroot make -f debian/rules.gen binary-arch_"$arch"_"$featureset"_"$flavour"