#!/bin/bash

REPODIR=/repo/x86_64
BUILDDIR=/repo/build
REPONAME=
UPDATE=N
CLEAN=N
SIGN=N
KEY=""
NUM_OLD=5
export PACKAGER="John Doe <jd@change.me>"
EMAIL=""

ERRORS=""

#Helper for finding newest and oldest files
#Sourced from stack overflow
function newold_matching_file
{
    # Use ${1-} instead of $1 in case 'nounset' is set
    local -r glob_pattern=${2-}

    # To avoid printing garbage if no files match the pattern, set
    # 'nullglob' if necessary
    local -i need_to_unset_nullglob=0
    if [[ ":$BASHOPTS:" != *:nullglob:* ]] ; then
        shopt -s nullglob
        need_to_unset_nullglob=1
    fi

    file=
    for f in $glob_pattern ; do
		if [ $1 == "n" ]; then
			[[ -z $f || $f -nt $_file ]] && file=$f
		elif [ $1 == "o" ]; then
			[[ -z $f || $f -ot $_file ]] && file=$f
		fi
    done

    # To avoid unexpected behaviour elsewhere, unset nullglob if it was
    # set by this function
    (( need_to_unset_nullglob )) && shopt -u nullglob

    # Use printf instead of echo in case the file name begins with '-'
    [[ -n $file ]] && printf '%s\n' "$file"

    return 0
}

#Build latest version of a package
function build_pkg {
	#check if PKGBUILD has updated, don't rebuild if hasn't changed
	#rebuild if git is in filename (git tree may change without PKGBUILD)
	#rebuild if forced
	if [[ ! -z $(git pull | grep "Already up to date.") && -z $(echo $1 | grep git) && -z $2 ]]; then
		return 2
	fi
	makepkg -s --noconfirm $([ $CLEAN == "Y" ] && echo "-c") $([ $SIGN == "Y" ] && echo "--sign --key $KEY") $([ "$2" == "-f" ] && echo -f)
	if [ $? != 0 ]; then
		#Register error
		ERRORS=$(printf '%s %s' "$ERRORS" "$1")
		return 1
	fi

	#copy package to repo directory
	latest="$(newold_matching_file n '*.pkg.tar.xz')"
	cp $latest $REPODIR/$latest
	repo-add $([ "$SIGN" == "Y" ] && echo "--sign --key $KEY") $REPODIR/$REPONAME.db.tar.xz $REPODIR/$latest

	#Remove old versions of packages
	while [ $NUM_OLD \< $(find . -name '*.pkg.tar.xz' | wc -l) ]
	do
		old=$(newold_matching_file o '*.pkg.tar.xz')
		rm $REPODIR/$old $old
	done
	return 0
}

#Update packages in BUILDDIR
function build_all {
	#system update
	if [ $UPDATE == "Y" ]; then
		sudo pacman -Syu --noconfirm
	fi
	#update every package currently stored
	for d in $(find $BUILDDIR -maxdepth 1 -mindepth 1 -not -path '*/\.*' -type d)
	do
		cd $d
		build_pkg $(echo $d | rev | cut -d'/' -f1 | rev) $1
	done

	return 0
}

#Add a new package to be built
function add {
	cd $BUILDDIR
	git clone https://aur.archlinux.org/$1.git
	cd $1
	build_pkg $1 new
	return 0
}

#Check config and create build folders
function init {
	#check for configuration here
	[ -z $REPODIR ] && echo "Enter REPODIR" && return 1
	[ -z $BUILDDIR ] && echo "Enter BUILDDIR" && return 2
	[ -z $REPONAME ] && echo "Enter REPONAME" && return 3

	#make build directories
	[ ! -d $REPODIR ] && mkdir -p $REPODIR
	[ ! -d $BUILDDIR ] && mkdir -p $BUILDDIR

	#packages required to build others
	sudo pacman -S --noconfirm base-devel git

	#add repo to pacman.conf so can install own packages
	if [ -z $(grep "$REPONAME" /etc/pacman.conf) ]; then
		printf "[$REPONAME]\nSigLevel = Optional TrustAll\nServer = file://$REPODIR\n" >> /etc/pacman.conf
	fi

	#create GPG key for package signing
	if [ "$SIGN" == "Y" && "$KEY" == "" ]; then
		(
			echo "Key-Type: RSA"
			echo "Key-Length: 2048"
			echo "Subkey-Type: RSA"
			echo "Subkey-Length: 2048"
			echo "Passphrase: \"\""
			echo "Expire-Date: 0"
			echo "Name-Real: John Doe"
			echo "Name-Comment: Arch buildbot"
			echo "Name-Email: $(whoami)@localhost"
			echo "%commit"
		) | gpg --batch --generate-key
		gpg --export --output $REPONAME.key --armor "John Doe"
		gpg --export-secret-keys --output $REPONAME.secret.key --armor "John Doe"
		echo "Please change the key information in this file"
	fi

	return 0
}

case $1 in
	"init")
		init;;
	"add")
		add $2;;
	"build-all")
		build_all $([ "$2" == "-f" ] && echo "-f")
		if [ "$ERRORS" != "" ]; then
			echo "Errors in packages $ERRORS"
			if [ "$EMAIL" != "" ]; then
				printf "Build for $(date)\nErrors found in $ERRORS\nPlease address these soon" | sendmail $EMAIL
			fi
		else
			echo "All packages built successfully"
		fi
		;;
	*)
		printf "Invalid usage\nUsage: $0 init|add|build_all\n";;
esac