#!/bin/bash
#
# SPDX-License-Identifier: GPL-3.0-or-later

shopt -s extglob

m4_include(lib/common.sh)

usage() {
    cat <<- _EOF_
		Usage: ${BASH_SOURCE[0]##*/} [OPTIONS]

		Searches for a locally built package corresponding to the PKGBUILD, and
		downloads the last version of that package from the Pacman repositories.
		It then compares them with diffoscope.

		OPTIONS
		    -M, --makepkg-config Set an alternate makepkg configuration file
		    -h, --help           Show this help text
_EOF_
}

MAKEPKG_CONF=/etc/makepkg.conf

# option checking
while (( $# )); do
	case $1 in
		-h|--help)
			usage
			exit 0
			;;
		-M|--makepkg-config)
			MAKEPKG_CONF="$2"
			shift 2
			;;
		--)
			shift
			break
			;;
		-*,--*)
			die "invalid argument: %s" "$1"
			;;
		*)
			break
			;;
	esac
done

# Source makepkg.conf; fail if it is not found
if [[ -r "${MAKEPKG_CONF}" ]]; then
	# shellcheck source=makepkg-x86_64.conf
	source "${MAKEPKG_CONF}"
else
	die "${MAKEPKG_CONF} not found!"
fi

# Source user-specific makepkg.conf overrides
if [[ -r "${XDG_CONFIG_HOME:-$HOME/.config}/pacman/makepkg.conf" ]]; then
	# shellcheck source=/dev/null
	source "${XDG_CONFIG_HOME:-$HOME/.config}/pacman/makepkg.conf"
elif [[ -r "$HOME/.makepkg.conf" ]]; then
	# shellcheck source=/dev/null
	source "$HOME/.makepkg.conf"
fi

if [[ ! -f PKGBUILD ]]; then
	die 'This must be run in the directory of a built package.'
fi

# shellcheck source=PKGBUILD.proto
. ./PKGBUILD
if [[ ${arch[0]} == 'any' ]]; then
	CARCH='any'
fi

STARTDIR=$(pwd)
trap 'rm -rf $TEMPDIR' EXIT INT TERM QUIT
TEMPDIR=$(mktemp -d --tmpdir diffpkg-script.XXXX)

for _pkgname in "${pkgname[@]}"; do
	comparepkg=$_pkgname
	pkgurl=
	target_pkgver=$(get_full_version "$_pkgname")
	if ! pkgfile=$(find_cached_package "$_pkgname" "$target_pkgver" "$CARCH"); then
		die 'tarball not found for package: %s' "${_pkgname}-$target_pkgver"
	fi

	ln -s "$pkgfile" "$TEMPDIR"

	if (( $# )); then
		case $1 in
			*://*)
				pkgurl=$1 ;;
			/*|*/*)
				pkgurl=$(readlink -m "$1") ;;
			*.pkg.tar*)
				pkgurl=$1 ;;
			'')
				;;
			*)
				comparepkg=$1 ;;
		esac
		shift
	fi
	[[ -n $pkgurl ]] || pkgurl=$(pacman -Spdd --print-format '%l' --noconfirm "$comparepkg") ||
		die "Couldn't download previous package for %s." "$comparepkg"

	oldpkg=${pkgurl##*/}

	if [[ ${oldpkg} = "${pkgfile##*/}" ]]; then
		die "The built package (%s) is the one in the repo right now!" "$_pkgname"
	fi

	if [[ $pkgurl = file://* || ( $pkgurl = /* && -f $pkgurl ) ]]; then
		ln -s "${pkgurl#file://}" "$TEMPDIR/$oldpkg"
	elif [[ -f "$PKGDEST/$oldpkg" ]]; then
		ln -s "$PKGDEST/$oldpkg" "$TEMPDIR/$oldpkg"
	elif [[ -f "$STARTDIR/$oldpkg" ]]; then
		ln -s "$STARTDIR/$oldpkg" "$TEMPDIR/$oldpkg"
	else
		curl -fsLC - --retry 3 --retry-delay 3 -o "$TEMPDIR/$oldpkg" "$pkgurl"
	fi

        diffoscope $TEMPDIR/$oldpkg $pkgfile
done