#!/bin/bash
# To run this, you need to first install cargo-lock.
#
# TODO: this script has a known bug in: if the Debian patches being applied,
# changes the set of dependencies, then "cargo vendor" is not re-run in order
# to pick up this new set of dependencies. This is manifested by an error
# message like: "perhaps a crate was updated and forgotten to be re-vendored?"
#
set -e

SCRIPTDIR="$(dirname "$(readlink -f "$0")")"

not_needed() {
	diff -ur packages-before packages-after | grep "^-- " | cut -d' ' -f2-3
}

ghetto_parse_cargo() {
	cat "$1" \
	 | tr '\n' '\t' \
	 | sed -e 's/\t\[/\n[/g' \
	 | perl -ne 'print if s/^\[(?:package|project)\].*\tname\s*=\s*"(.*?)".*\tversion\s*=\s*"(.*?)".*/\1 \2/g'
}

pruned_paths() {
	for i in vendor/*/Cargo.toml; do
		pkgnamever=
		pkgnamever=$(ghetto_parse_cargo "$i")
		if [ -z "$pkgnamever" ]; then
			echo >&2 "failed to parse: $i"
			exit 1
		fi
		echo "$pkgnamever $i"
	done | grep -F -f <(not_needed) | cut '-d ' -f3 | while read x; do
		echo " $(dirname $x)"
	done
}

crate_to_debcargo_conf() {
    echo "$1" | sed -e 's/_/-/g'
}

rm -rf vendor/
if [ -e "$CARGO_PRE_VENDOR" ]; then
	"$CARGO_PRE_VENDOR"
fi
cargo vendor --verbose vendor/
mkdir -p .cargo
cat >.cargo/config <<eof
[source.crates-io]
replace-with = "vendored-sources"

[source.vendored-sources]
directory = "$PWD/vendor"
eof
cargo lock list > packages-before
cp Cargo.lock Cargo.lock.orig

if [ -d debcargo-conf ]; then ( cd debcargo-conf && git pull );
else git clone "${DEBCARGO_CONF:-https://salsa.debian.org/rust-team/debcargo-conf}"; fi

# keep applying patches, and drop to a subshell for manual fixing, until it succeeds
while ! ( cd vendor
x=true
for i in *; do
	debname=$(crate_to_debcargo_conf "$i")
	cd $i
	# if there is a d/rules then don't mess with it, it's too custom for this
	# script to deal with - just use the upstream version. example: backtrace-sys
	# TODO: deal with those better, especially backtrace-sys
	if [ -e ../../debcargo-conf/src/$debname/debian/rules ]; then
		echo >&2 "$0: the debcargo-conf for crate $i has a custom rules file, but applying patches anyway"
		echo >&2 "$0: you may want to examine this situation more closely"
	fi
	if [ -d ../../debcargo-conf/src/$debname/debian/patches ]; then
		echo >&2 "$0: patching $i"
		mkdir -p debian
		if [ ! -d debian/patches ]; then
			cp -a -n "../../debcargo-conf/src/$debname/debian/patches" debian/
		fi
		# first unapply any patches applied in the previous iteration
		QUILT_PATCHES=debian/patches quilt pop -af
		QUILT_PATCHES=debian/patches quilt push -a
		case $? in
		0|2) true;;
		*)  echo >&2 "$0: patching $i failed <<<<<<<<<<<<<<<<<<<<<<<<"
			QUILT_PATCHES=debian/patches quilt pop -af
			x=false;;
		esac
	fi
	if [ -f ../../debcargo-conf/src/$debname/debian/build.rs ]; then
		echo >&2 "$0: overwriting build.rs with our custom one"
		if [ ! -f build.rs.orig ]; then
			cp -f build.rs build.rs.orig
		fi
		cp -f ../../debcargo-conf/src/$i/debian/build.rs build.rs
	fi
	cd ..
done; $x ); do
	echo >&2 "================================================================================"
	echo >&2 "$0: You are now in a sub-shell!"
	echo >&2 "$0: Fix the failed patches in debcargo-conf/, then exit the sub-shell by pressing ctrl-D ONCE."
	echo >&2 "$0: If you need to abort this process, press ctrl-D then quickly ctrl-C."
	if [ -f "${SRCDIR:-$PWD}/debian/debcargo-conf.patch" ]; then
		echo >&2 "$0: Previous patch changes exist, to apply them run:"
		echo >&2 "  $ patch -d vendor -p2 < '${SRCDIR:-$PWD}/debian/debcargo-conf.patch'"
	fi
	echo >&2 "================================================================================"
	bash || true
	echo >&2 "$0: trying patches again..."
done
rm -rf vendor/*/.pc
find vendor/*/debian/patches -name '*~' -delete || true
cargo update
cargo lock list > packages-after
pruned_paths | while read x; do echo >&2 "$0: removing, because debcargo-conf patches makes it obsolete: $x"; rm -rf "$x"; done

# remove excluded files
( cd vendor
for i in *; do (
	debname=$(crate_to_debcargo_conf "$i")
	shopt -s globstar # needed for double-glob to work in excludes
	cd $i
	if [ -e ../../debcargo-conf/src/$debname/debian/rules ]; then
		echo >&2 "$0: the debcargo-conf for crate $i has a custom rules file, but applying excludes anyway"
		echo >&2 "$0: you may want to examine this situation more closely"
	fi
	if grep -q excludes ../../debcargo-conf/src/$debname/debian/debcargo.toml 2>/dev/null; then
		sed -nre 's/.*excludes\s*=\s*(\[[^]]*\]).*/\1/p' \
		  ../../debcargo-conf/src/$i/debian/debcargo.toml \
		  | python3 -c "import ast, sys; x=ast.literal_eval(sys.stdin.read()); print('\n'.join((i[:-3] if i.endswith('/**') else i) for i in x));" \
		  | while read x; do echo >&2 "$0: removing, since it's excluded by debcargo-conf: vendor/$i/$x"; rm -rf $x; done
	fi
); done; )

# TODO: rm special logic from debcargo and put into debcargo-conf instead
echo >&2 "$0: removing winapi archives"
rm -rf vendor/winapi-*-pc-windows-gnu/lib/*.a

echo >&2 "$0: pruning all checksums.."
for i in vendor/*; do ${SCRIPTDIR}/prune-checksums "$i"; done

( cd vendor
for i in *; do (
	cd $i
	debname=$(crate_to_debcargo_conf "$i")
	if [ -d debian/patches ]; then
		rm -rf "../../debcargo-conf/src/$debname/debian/patches"
		cp -a debian/patches "../../debcargo-conf/src/$debname/debian/"
	fi
); done; )
( cd debcargo-conf
git add .
if ! git diff --cached --quiet; then
	git commit -m "Manual changes from debian-cargo-vendor"
	git diff @~ > ../../debcargo-conf.patch || true
	(cd ../.. ; echo >&2 "$0: backed up patch changes to $PWD/debcargo-conf.patch")
	echo >&2 "$0: you should backport/merge them back into debcargo-conf.git"
fi
)

echo >&2 "$0: cleaning up..."
rm -rf .cargo Cargo.lock debcargo-conf packages-before packages-after

echo >&2 "$0: restoring original Cargo.lock"
mv Cargo.lock.orig Cargo.lock