#!/bin/sh
# Nexus fork: enforce [nexus] prefix on all fork commits
# Allows upstream merge commits and rebase-generated commits through
MSG_FILE="$1"
FIRST_LINE=$(head -1 "$MSG_FILE")

# Skip merge commits (git generates these automatically during rebase/merge)
if echo "$FIRST_LINE" | grep -qE "^Merge (branch|pull request|remote-tracking)"; then
  exit 0
fi

# Skip fixup/squash commits (used during interactive rebase)
if echo "$FIRST_LINE" | grep -qE "^(fixup|squash)!"; then
  exit 0
fi

# Enforce [nexus] prefix
if ! echo "$FIRST_LINE" | grep -qE "^\[nexus\]"; then
  echo "ERROR: Commit message must start with [nexus]"
  echo "  Got: $FIRST_LINE"
  echo "  Example: [nexus] feat: add branding package"
  exit 1
fi