#!/usr/bin/env bash
# Applies this app's local patches on top of the shared Zephyr checkout, so
# that checkout stays a clean, reusable resource for other projects while
# still carrying the changes this app needs. Run once after a fresh
# `west update`, or after pulling upstream changes into the shared tree.
#
# Patches are tracked in zephyr-patches/ as plain `git format-patch`
# output; applied with `git am` so they land as real commits (reviewable,
# revertable) rather than a silent working-tree diff.
set -euo pipefail

ZEPHYR_BASE="${ZEPHYR_BASE:-./zephyrproject/zephyr}"
PATCH_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/zephyr-patches"

if [ ! -d "$ZEPHYR_BASE/.git" ]; then
	echo "error: $ZEPHYR_BASE is not a git checkout" >&2
	exit 1
fi

cd "$ZEPHYR_BASE"

if [ -n "$(git status --porcelain)" ]; then
	echo "error: $ZEPHYR_BASE has uncommitted changes - commit, stash, or" >&2
	echo "       reset it before applying patches, so it's clear which" >&2
	echo "       commits came from these patches vs. local hacking." >&2
	exit 1
fi

for patch in "$PATCH_DIR"/*.patch; do
	# git mailinfo is the same header parser `git am` itself uses, so it
	# correctly strips "[PATCH]"/"[PATCH 1/2]" prefixes and un-wraps a
	# subject line that spans multiple header lines - a plain sed/grep
	# on "Subject:" got this wrong for a >1-patch series and silently
	# skipped every patch without applying them (grep -qF against an
	# empty extracted subject matches any line).
	msgfile=$(mktemp)
	bodyfile=$(mktemp)
	subject=$(git mailinfo "$msgfile" "$bodyfile" < "$patch" | sed -n 's/^Subject: //p')
	rm -f "$msgfile" "$bodyfile"

	if [ -z "$subject" ]; then
		echo "error: could not extract a Subject from $(basename "$patch")" >&2
		exit 1
	fi

	history=$(git log --oneline)
	if grep -qF "$subject" <<< "$history"; then
		echo "skip (already applied): $subject"
		continue
	fi
	echo "applying: $(basename "$patch")"
	git am "$patch"
done

echo "done - $ZEPHYR_BASE now carries $(ls "$PATCH_DIR"/*.patch | wc -l | tr -d ' ') local patch(es)."