#! /usr/bin/env bash

# Init variables
APTPKG_VERSION="1.1.0"

# Show help
show_help(){
	cat > /dev/stdout <<EOF

aptpkg v$APTPKG_VERSION

Easily create debian packages.

For more documentation, run man aptpkg

Usage:
	aptpkg [directory]
	aptpkg --all [directory]   Build all folders under directory
	aptpkg --auto (commit id)  Autobuild modified packages from commit
	aptpkg -h, --help          Show help
	aptpkg -v, --version       Show version
EOF
}

# Incorrect aptpkg usage: explain, show help, and exit
error_usage_die(){
	echo "ERROR: " "$1"
	show_help
	exit 1
}

# Verify sha512sums
verify(){
	if [ ! "${sha512sums:?}" = "SKIP" ]; then
		echo "${sha512sums:?}" | sha512sum -c
	fi
}

# Copy/ install wrapper for files
cin-bin(){
	install -Dm755 "$@"
}
cin-file(){
	install -Dm644 "$@"
}

# Check that "build" file exists in directory
check(){
	if ! [ -f "$1/build" ]; then
		echo "No package of that name exists."
		exit 1
	fi
}

# Generate the debian control file
gen_control_file(){
	mkdir -p "$builddir"/DEBIAN
	echo "Package: ${name:?}
Version: ${version:?}-${rev:?}
Architecture: amd64
Maintainer: $(grep -am 1 -hr "Maintainer: " build | sed 's/# Maintainer: //')
Section:
Priority:
Homepage: ${url:?}
Description: ${description:?}
${customcontrol:=}
" > "$builddir"/DEBIAN/control
}

# Download a debian package
build_deb(){
	echo "Getting ${source:?}"
	wget "$source" -qP dist/

	( cd dist || error_usage_die "Problem with the dist/ directory" && verify )
}

# Download and build using files
build_file(){
	builddir=${name}_${version}-${rev}_amd64

	cd "$1" || error_usage_die "Problem with changing directory"
	mkdir -p "$builddir"

	for urls in $source; do
		echo "Getting $source"
		wget -q "$urls"
	done

	verify

	# Run
	steps "$@"

	gen_control_file "$@"

	for maintfile in preinst postinst prerm postrm; do
		[ -f $maintfile ] && cin-bin $maintfile "$builddir"/DEBIAN/$maintfile
	done

	cd - || error_usage_die "Problem with changing directory"

	dpkg-deb --build --root-owner-group "$1"/"$builddir" dist/
}

# Determine which function to run
load_build(){
	mkdir -p dist

	# shellcheck disable=SC1090
	# shellcheck disable=SC1091
	source "${1:?}/build"

	case "${type:?}" in
		deb)
			build_deb ;;
		file)
			build_file "$@" ;;
	esac
}

# Autobuild packages based on git list files changed in commit
# latest (HEAD) assumed if commit hash not provided
change_autobuild_pkgs(){
	[ -d .git ] || error_usage_die "Current directory is not a git repository!"

	commitid=$1
	[ -n "$commitid" ] || commitid=HEAD

	if [[ "$commitid" = HEAD ]]; then
		before_run=$(git log HEAD^..HEAD | grep aptpkg-auto-run | sed 's#aptpkg-auto-run: ##' | sed 's#    ##')

		if [ -n "$before_run" ]; then
			for m in $before_run; do
				build_chg_pre=$(git diff-tree --no-commit-id --name-only -r "$m" | grep "build" | sed 's#/build##')
				echo "Using $m with files $build_chg_pre"

				for a in $build_chg_pre; do
					aptpkg "$a"
				done
			done
		fi
	fi

	build_chg=$(git diff-tree --no-commit-id --name-only -r $commitid | grep "build" | sed 's#/build##')
	echo "Using $commitid with files $build_chg"

	for f in $build_chg; do
		aptpkg "$f"
	done
}

# Build all in directory
build_all_in_dir(){
	[ -d "$1" ] || error_usage_die "Provide a directory"
	buildfile_folders=$(ls -d "$1"/*)

	for ww in $buildfile_folders; do
		printf "\nBuilding %s\n\n" "$ww"
		aptpkg "$ww"
	done
}

# Run!
case $1 in
	-h|--help)
		show_help ;;
	--all)
		shift
		build_all_in_dir "$1" ;;
	--auto)
		shift
		change_autobuild_pkgs "$1" ;;
	-v|--version)
		echo "aptpkg $APTPKG_VERSION" ;;
	*)
		if [ $# -ne 1 ]; then
			error_usage_die "You must provide one directory"
		fi

		check "$1"
		load_build "$1" ;;
esac