#!/bin/bash

set -e
shopt -s extglob

# Set defaults from the running kernel
arch="$(dpkg --print-architecture)"
kernelabi="$(uname -r)"
ff="${kernelabi#+([^-])-@(trunk|?(rc)+([0-9])|0.@(bpo|deb+([0-9])).+([0-9]))-}"
if [ "x$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

dbginfo=
fuzz=0
jobs=$(nproc)

eval "set -- $(getopt -n "$0" -o "f:gj:s:" -l "fuzz:" -- "$@")"
while true; do
    case "$1" in
	-f) flavour="$2"; shift 2 ;;
	-g) dbginfo=y; shift 1 ;;
	-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
     -g               enable debug info
     -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

profiles=nodoc,noudeb,pkg.linux.nosource,pkg.linux.mintools
if [ -z "$dbginfo" ]; then
    profiles="$profiles,pkg.linux.nokerneldbg,pkg.linux.nokerneldbginfo"
fi

# Check build-dependencies early if possible
if [ -f debian/control ]; then
    dpkg-checkbuilddeps -P"$profiles"
fi

# 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 top 2>/dev/null)" && \
	[ "${patch#test/}" != "$patch" ]; do
        quilt pop -f
    done
    while patch="$(quilt next 2>/dev/null)" && \
	[ "${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

# Prepare a new directory for the config; override ABI name, featuresets, flavours
rm -rf debian/config.local
mkdir debian/config.local debian/config.local/"$arch" debian/config.local/"$arch"/"$featureset"
cat >debian/config.local/defines <<EOF
[abi]
abiname: 0.a.test
EOF
cat >debian/config.local/"$arch"/defines <<EOF
[base]
featuresets: $featureset
EOF
cat >debian/config.local/"$arch"/"$featureset"/defines <<EOF
[base]
flavours: $flavour
EOF
if [ "$featureset" = none ]; then
    # default-flavour must refer to a flavour that's enabled
    cat >>debian/config.local/"$arch"/"$featureset"/defines <<EOF
default-flavour: $flavour
EOF
fi

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

# Check build-dependencies now that we know debian/control exists
dpkg-checkbuilddeps -P"$profiles"

# 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
dpkg-buildpackage -b -P"$profiles" -j"$jobs" -nc -uc