#!/bin/bash

#
# Script to run ESLint against all the files that have changed in this revision
#
ESLINT="$(git rev-parse --show-toplevel)/node_modules/.bin/eslint"
RUN_LINT=true
PASS_LINT=true

#
# There are two cases for what changes we should be looking for to lint:
# 1. When it's a merge onto master, we want the last commit (the merge), which will contain
#    all changes.
# 2. When it's a PR we want all files in the whole branch, as the last commit may only
#    be part of the full change. I.e. we want the difference between HEAD and master.
#
BRANCH_NAME=$(git rev-parse --abbrev-ref HEAD)
if [[ "$BRANCH_NAME" = "master" ]]; then
  #
  # Master branch, so just the last commit
  #
  echo "ESLint: master branch, so checking last commit."
  JS_FILES_TO_LINT=$(git diff --name-only --diff-filter=ACM HEAD~1...HEAD | grep ".js$")
else
  #
  # Dev branch so we want all the commits in the branch
  # There's a slight wrinkle in that bitbucket pipelines only clone this specific branch, so we
  # have to fetch master first before we can tell where this branch starts
  #
  echo "ESLint: dev branch, so checking whole branch."
  git fetch origin master:master
  JS_FILES_TO_LINT=$(git diff --name-only --diff-filter=ACM master...HEAD | grep ".js$")
fi

#
# Check if we have any JS files to lint
#
if [[ "$JS_FILES_TO_LINT" = "" ]]; then
  echo "ESLint: nothing to test"
  RUN_LINT=false
  PASS_LINT=true
else
  echo "ESLint:"

  # Check for eslint
  if [[ ! -x "$ESLINT" ]]; then
    echo "  - Failed to find " "$ESLINT"
    echo "  - Please install node modules (npm install)"
  fi

  #
  # Iterate throught the files and run them against ESLint
  #
  for FILE in $JS_FILES_TO_LINT
  do
    "$ESLINT" "$FILE"

    if [[ "$?" == 0 ]]; then
      echo "  - Passed: $FILE"
    else
      echo "  - Failed: $FILE"
      PASS_LINT=false
    fi
  done
fi

#
# Check the results
#
if ! $RUN_LINT; then
  echo "* ESLint: not run"
elif ! $PASS_LINT; then
  echo "* ESLint: FAIL!"
  exit 1
else
  echo "* ESLint: pass"
fi

exit 0