#!/bin/bash

TRUE=1
FALSE=0
KCL_MAVEN_DIR=~/.m2/repository/software/amazon/kinesis/amazon-kinesis-client

REMOVED_METHODS_FLAG=$FALSE
LATEST_VERSION=""
LATEST_JAR=""
CURRENT_VERSION=""
CURRENT_JAR=""

# Get the JAR from the latest version release on Maven.
get_latest_jar() {
  #  clear the directory so that the latest release will be the only version in the Maven directory after running mvn dependency:get
  rm -rf "$KCL_MAVEN_DIR"
  mvn -B dependency:get -Dartifact=software.amazon.kinesis:amazon-kinesis-client:LATEST
  LATEST_VERSION=$(ls "$KCL_MAVEN_DIR" | grep '[0-9].[0-9].[0-9]')
  LATEST_JAR=$KCL_MAVEN_DIR/$LATEST_VERSION/amazon-kinesis-client-$LATEST_VERSION.jar
}

# Get the JAR with the changes that need to be verified.
get_current_jar() {
  mvn -B install -DskipTests
  CURRENT_VERSION=$(mvn -q  -Dexec.executable=echo -Dexec.args='${project.version}' --non-recursive exec:exec)
  CURRENT_JAR=$KCL_MAVEN_DIR/$CURRENT_VERSION/amazon-kinesis-client-$CURRENT_VERSION.jar
}

# Skip classes with the KinesisClientInternalApi annotation. These classes are subject to breaking backwards compatibility.
ignore_kinesis_client_internal_api() {
  local current_class="$1"
  local grep_internal_api_result=$(javap -v -classpath "$LATEST_JAR" "$current_class" | grep KinesisClientInternalApi)
  if [[ "$grep_internal_api_result" != "" ]]
  then
    continue
  fi
}

# Skip classes which are not public (e.g. package level). These classes will not break backwards compatibility.
ignore_non_public_classes() {
  local current_class="$1"
  local class_definition=$(javap -classpath "$LATEST_JAR" "$current_class" | head -2 | tail -1)
  if [[ "$class_definition" != *"public"* ]]
  then
    continue
  fi
}

# Ignore methods that change from abstract to non-abstract (and vice versa) if the class is an interface.
ignore_abstract_changes_in_interfaces(){
  local current_class="$1"
  local class_definition=$(javap -classpath "$LATEST_JAR" "$current_class" | head -2 | tail -1)
  if [[ $class_definition == *"interface"* ]]
  then
    LATEST_METHODS=${latest_methods// abstract / }
    CURRENT_METHODS=${current_methods// abstract / }
  fi
}

# Checks if there are any methods in the latest version that were removed in the current version.
find_removed_methods() {
  echo "Checking if methods in current version (v$CURRENT_VERSION) were removed from latest version (v$LATEST_VERSION)"
  local latest_classes=$(jar tf $LATEST_JAR | grep .class | tr / . |  sed 's/\.class$//' | sort)
  for class in $latest_classes
  do
    ignore_kinesis_client_internal_api "$class"
    ignore_non_public_classes "$class"

    LATEST_METHODS=$(javap -classpath "$LATEST_JAR" "$class")
    CURRENT_METHODS=$(javap -classpath "$CURRENT_JAR" "$class")

    ignore_abstract_changes_in_interfaces "$class"

    local removed_methods=$(diff <(echo "$latest_methods") <(echo "$current_methods") | grep '^<')

    if [[ "$removed_methods" != "" ]]
    then
      REMOVED_METHODS_FLAG=$TRUE
      echo "$class does not have method(s):"
      echo "$removed_methods"
    fi
  done
}

get_backwards_compatible_result() {
  if [[ $REMOVED_METHODS_FLAG == $TRUE ]]
  then
    echo "Current KCL version is not backwards compatible with version $LATEST_VERSION. See output above for removed packages/methods."
    exit 1
  else
    echo "Current KCL version is backwards compatible with version $LATEST_VERSION."
    exit 0
  fi
}

main() {
  get_latest_jar
  get_current_jar
  find_removed_methods
  get_backwards_compatible_result
}

main