#!/bin/sh
#/
#/ NAME:
#/ delete-empty-repos - For a GitHub Enterprise Instance, lists every empty repository
#/ in format <organization>:<repository> and deletes them if option is passed.
#/
#/ AUTHOR: @IAmHughes
#/
#/ SYNOPSIS:
#/ delete-empty-repos.sh [--org=MyOrganization] [--execute=TRUE]
#/
#/ DESCRIPTION:
#/ For a GitHub Enterprise Instance, lists every empty repository in format
#/ <organization>:<repository> separated by new lines. Deleting them if passed
#/ the option [--execute=true]. "Empty" meaning any repository with a zero size
#/ attribute, i.e. initialized only or those with no content at all.
#/   - Example Output: List all empty repositories
#/     <organization>:<repository1>
#/     <organization>:<repository2>
#/     <organization>:<repository3>
#/
#/ PRE-REQUISITES:
#/ Before running this script, you must create a Personal Access Token (PAT)
#/ at https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/
#/ with the permissions <repo> and <admin:org> scopes and <delete_repo>. Read more
#/ about scopes here: https://developer.github.com/apps/building-oauth-apps/scopes-for-oauth-apps/
#/
#/ Once created, you must export your PAT as an environment variable
#/ named <GITHUB_TOKEN>.
#/   - Exporting PAT as GITHUB_TOKEN
#/   $ export GITHUB_TOKEN=abcd1234efg567
#/
#/ Additionally you will need to set the $API_ROOT at the top of the script to
#/ your instance of GitHub Enterprise.
#/  - _i.e._: https://MyGitHubEnterprise.com/api/v3
#/
#/ Finally, you will need to ensure you have installed jq: https://stedolan.github.io/jq/
#/
#/ OPTIONS:
#/ --org
#/ -o
#/ When running the tool, this flag sets which organization's repositories you
#/ want to inspect and delete (if they're empty).
#/
#/ --execute
#/ -e
#/ When running the tool, this flag will delete every repo listed.
#/   * _NOTE:_ You should run the script without this option first, verifying
#/      that you want to delete every repository listed.
#/
#/ EXAMPLES:
#/
#/   - Lists all empty repositories for the given organization.
#/   $ bash delete-empty-repos.sh --org=MyOrganization
#/
#/   - Deletes all empty repositories for the given organization.
#/   $ bash delete-empty-repos.sh --org=MyOrganization --execute=TRUE
#/
#/ API DOCUMENTATION:
#/ All documentation can be found at https://developer.github.com/v3/

##########
# HEADER #
##########

echo ""
echo "############################################"
echo "############################################"
echo "###                                      ###"
echo "### Delete Empty Repos from Organization ###"
echo "###                                      ###"
echo "############################################"
echo "############################################"
echo ""

########
# VARS #
########
API_ROOT="https://<your-domain>/api/v3"
EXECUTE="FALSE"
EMPTY_REPO_COUNTER=0
ERROR_COUNT=0 # Total errors found

##################################
# Parse options/flags passed in. #
##################################

for param in "$@"
do
  case $param in
    -e=*|--execute=*)
    EXECUTE="${param#*=}"
    shift
    ;;
    -o=*|--org=*)
    ORG_NAME="${param#*=}"
    shift
    ;;
    *)
    # unknown option, do nothing
    ;;
  esac
done

#################
# Verify Inputs #
#################

# If GITHUB_TOKEN wasn't set in Environment
if [[ -z ${GITHUB_TOKEN} ]]; then
  echo "ERROR: GITHUB_TOKEN was not found in your environment. You must export "
  echo "this token prior to running the script."
  echo "  Ex: export GITHUB_TOKEN=abc123def456"
  echo ""
  echo "Exiting script with no changes."
  echo ""
  exit 1
fi

# If ORG_NAME wasn't passed
if [[ -z ${ORG_NAME} ]]; then
  echo "ERROR: ORG_NAME was not provided."
  echo "  Ex: bash delete-empty-repos.sh --org=MyOrganization --execute=TRUE"
  echo ""
  echo "Exiting script with no changes."
  echo ""
  exit 1
fi

# If EXECUTE exists, it needs to equal TRUE or FALSE
if [[ ${EXECUTE} != "TRUE" ]] && [[ ${EXECUTE} != "FALSE" ]]; then
    echo "ERROR: EXECUTE was not set to a proper value."
    echo "  Ex: bash delete-empty-repos.sh --org=MyOrganization --execute=TRUE"
    echo ""
    echo "Exiting script with no changes."
    echo ""
    exit 1
fi

if [[ ${EXECUTE} = "TRUE" ]]; then
  echo "Searching for empty repositories within the Organization: "${ORG_NAME}
  echo "EXECUTE was set to TRUE!!! Empty repositories will be deleted!!!"
  echo "You have 5 seconds to cancel this script."
  sleep 5
else
  echo "Searching for empty repositories within the Organization: "${ORG_NAME}
  echo "EXECUTE was set to FALSE, no repositories will be deleted."
fi

##################################################
# Grab JSON of all repositories for organization #
##################################################

###########################################################
# Get the rel="last" link and harvest the page number     #
# Use this value to build a list of URLs to batch-request #
###########################################################

LAST_PAGE_ID=$(curl -snI "${API_ROOT}/orgs/${ORG_NAME}/repos" | awk '/Link:/ { gsub(/=/, " "); gsub(/>/, " "); print $3 }')

for PAGE in $(seq 1 $LAST_PAGE_ID)
do
        URLS=$URLS"--url ${API_ROOT}/orgs/${ORG_NAME}/repos?page=$PAGE "
done

echo "Getting a list of the repositories within "${ORG_NAME}

REPO_RESPONSE="$(curl --request GET \
$URLS \
-s \
--header "authorization: Bearer ${GITHUB_TOKEN}" \
--header "content-type: application/json")"

#############################################################
# REPO_RESPONSE_CODE collected seperately to not confuse jq #
#############################################################

REPO_RESPONSE_CODE="$(curl --request GET \
${API_ROOT}/orgs/${ORG_NAME}/repos \
-s \
-o /dev/null \
--write-out %{http_code} \
--header "authorization: Bearer ${GITHUB_TOKEN}" \
--header "content-type: application/json"
)"

echo "Getting a list of the repositories within "${ORG_NAME}

########################
# Check for any errors #
########################
if [ $REPO_RESPONSE_CODE != 200 ]; then
  echo ""
  echo "ERROR: Failed to get the list of repositories within ${ORG_NAME}"
  echo "${REPO_RESPONSE}"
  echo ""
  ((ERROR_COUNT++))
else
  ##########################################################################
  # Loop through every organization's repo to get repository name and size #
  ##########################################################################
  echo "Generating list of empty repositories."
  echo ""
  echo "-------------------"
  echo "| Empty Repo List |"
  echo "| Org : Repo Name |"
  echo "-------------------"

  for repo in $(echo "${REPO_RESPONSE}" | jq -r '.[] | @base64');
  do
    #####################################
    # Get the info from the json object #
    #####################################
    get_repo_info()
    {
      echo ${repo} | base64 --decode | jq -r ${1}
    }

    # Get the info from the JSON object
    REPO_NAME=$(get_repo_info '.name')
    REPO_SIZE=$(get_repo_info '.size')

    # If repository has data, size will not be zero, therefore skip.
    if [[ ${REPO_SIZE} -ne 0 ]]; then
      continue;
    fi

    ################################################
    # If we are NOT deleting repository, list them #
    ################################################
    if [[ ${EXECUTE} = "FALSE" ]]; then
      echo "${ORG_NAME}:${REPO_NAME}"

      # Increment counter
      EMPTY_REPO_COUNTER=$((EMPTY_REPO_COUNTER+1))

    #################################################
    # EXECUTE is TRUE, we are deleting repositories #
    #################################################
    elif [[ ${EXECUTE} = "TRUE" ]]; then
        echo "${REPO_NAME} will be deleted from ${ORG_NAME}!"

        ############################
        # Call API to delete repos #
        ############################
        DELETE_RESPONSE="$(curl --request DELETE \
          -s \
          --write-out response=%{http_code} \
          --url ${API_ROOT}/repos/${ORG_NAME}/${REPO_NAME} \
          --header "authorization: Bearer ${GITHUB_TOKEN}")"

        DELETE_RESPONSE_CODE=$(echo "${DELETE_RESPONSE}" | grep 'response=' | sed 's/response=\(.*\)/\1/')

        ########################
        # Check for any errors #
        ########################
        if [ $DELETE_RESPONSE_CODE != 204 ]; then
          echo ""
          echo "ERROR: Failed to delete ${REPO_NAME} from ${ORG_NAME}!"
          echo "${DELETE_RESPONSE}"
          echo ""
          ((ERROR_COUNT++))
        else
          echo "${REPO_NAME} was deleted from ${ORG_NAME} successfully."
        fi

        # Increment counter
        EMPTY_REPO_COUNTER=$((EMPTY_REPO_COUNTER+1))
    fi

  done
fi

##################
# Exit Messaging #
##################
if [[ $ERROR_COUNT -gt 0 ]]; then
  echo "-----------------------------------------------------"
  echo "the script has completed, there were errors"
  exit $ERROR_COUNT
fi

if [[ ${EXECUTE} = "TRUE" ]]; then
  echo ""
  echo "Successfully deleted ${EMPTY_REPO_COUNTER} empty repos from ${ORG_NAME}."
else
  echo ""
  echo "Successfully discovered ${EMPTY_REPO_COUNTER} empty repos within ${ORG_NAME}."
fi
exit 0