#!/usr/bin/env bash
# Why a confidential Spring OAuth2 client does not send PKCE, straight from the bytecode
# of DefaultOAuth2AuthorizationRequestResolver rather than from documentation.
set -u
cd "$(dirname "$0")/.."
OUT=../docs/output/as-pkce-applier.txt
mkdir -p ../docs/output
mvn -B -q -pl oidc-client dependency:build-classpath \
    -Dmdep.outputFile=/tmp/cl-cp.txt -DincludeScope=compile >/dev/null 2>&1
JAR=$(tr ':' '\n' < /tmp/cl-cp.txt | grep 'spring-security-oauth2-client-' | head -1)
WORK=$(mktemp -d); trap 'rm -rf "$WORK"' EXIT
(cd "$WORK" && unzip -o -q "$JAR" 'org/springframework/security/oauth2/client/web/DefaultOAuth2AuthorizationRequestResolver*')
{
  echo "# From $(basename "$JAR")"
  echo "#"
  echo "# The resolver applies its default PKCE customizer only when the registration's"
  echo "# client authentication method is NONE - that is, only for public clients."
  echo "# A registration that has a client secret gets no code_challenge."
  echo
  javap -p -c -cp "$WORK" \
        org.springframework.security.oauth2.client.web.DefaultOAuth2AuthorizationRequestResolver \
    2>/dev/null \
    | grep -E 'ClientAuthenticationMethod.NONE|DEFAULT_PKCE_APPLIER|withPkce' \
    | sed 's/^ *//' | head -8
  echo
  echo "# The fields and the opt-in setter:"
  javap -p -cp "$WORK" \
        org.springframework.security.oauth2.client.web.DefaultOAuth2AuthorizationRequestResolver \
    2>/dev/null \
    | grep -E 'DEFAULT_PKCE_APPLIER|setAuthorizationRequestCustomizer' | sed 's/^ *//'
} > "$OUT" 2>&1
cat "$OUT"