#!/bin/bash

# Copyright Security Onion Solutions LLC and/or licensed to Security Onion Solutions LLC under one
# or more contributor license agreements. Licensed under the Elastic License 2.0 as shown at 
# https://securityonion.net/license; you may not use this file except in compliance with the
# Elastic License 2.0.

if [[ -f /usr/sbin/so-common ]]; then
  source /usr/sbin/so-common
else
  source $(dirname $0)/../../../common/tools/sbin/so-common
fi

function usage() {
  cat <<USAGE_EOF
  Usage: $0 <operation> [supporting parameters]
  
  where <operation> is one of the following:
  
      list: Lists all client IDs and permissions currently defined in the oauth2 system
  
       add: Adds a new client to the oauth2 system and outputs the generated secret
            Required parameters: 
              --name <name>
            Optional parameters: 
              --note <note>             (defaults to blank)
              --json                    output as JSON

    delete: Deletes a client from the oauth2 system
            Required parameters: 
              --id <id>
  
   addperm: Grants a permission to an existing client
            Required parameters: 
              --id <id>
              --permission <permission>
  
   delperm: Removes a permission from an existing client
            Required parameters: 
              --id <id>
              --permission <permission>

    update: Updates a client name and note.
            Required parameters:
              --id <id>
              --name <name>
              --note <note>
              --searchusername <run-as username>
  
  generate-secret: Regenerates a client's secret and outputs the new secret. 
            Required parameters: 
              --id <id>
            Optional parameters: 
              --json                     output as JSON

USAGE_EOF
  exit 1
}

if [[ $# -lt 1 || $1 == --help || $1 == -h || $1 == -? || $1 == --h ]]; then
  usage
fi

operation=$1
shift

searchUsername=__MISSING__
note=__MISSING__

while [[ $# -gt 0 ]]; do
  param=$1
  shift
  case "$param" in
    --id)
      id=$(echo $1 | sed 's/"/\\"/g')
      [[ ${#id} -gt 55 ]] && fail "id cannot be longer than 55 characters"
      shift
      ;;
    --permission)
      perm=$(echo $1 | sed 's/"/\\"/g')
      [[ ${#perm} -gt 50 ]] && fail "permission cannot be longer than 50 characters"
      shift
      ;;
    --name)
      name=$(echo $1 | sed 's/"/\\"/g')
      [[ ${#name} -gt 50 ]] && fail "name cannot be longer than 50 characters"
      shift
      ;;
    --note) 
      note=$(echo $1 | sed 's/"/\\"/g')
      [[ ${#note} -gt 100 ]] && fail "note cannot be longer than 100 characters"
      shift
      ;;
    --searchusername) 
      searchUsername=$(echo $1 | sed 's/"/\\"/g')
      [[ ${#searchUsername} -gt 50 ]] && fail "search username cannot be longer than 50 characters"
      shift
      ;;
    --json) 
      json=1
      ;;
    *) 
      echo "Encountered unexpected parameter: $param"
      usage
      ;;
  esac
done

hydraUrl=${HYDRA_URL:-http://127.0.0.1:4445}
socRolesFile=${SOC_ROLES_FILE:-/opt/so/conf/soc/soc_clients_roles}
soUID=${SOCORE_UID:-939}
soGID=${SOCORE_GID:-939}

function lock() {
  # Obtain file descriptor lock
  exec 99>/var/tmp/so-client.lock || fail "Unable to create lock descriptor; if the system was not shutdown gracefully you may need to remove /var/tmp/so-client.lock manually."
  flock -w 10 99 || fail "Another process is using so-client; if the system was not shutdown gracefully you may need to remove /var/tmp/so-client.lock manually."
  trap 'rm -f /var/tmp/so-client.lock' EXIT
}

function fail() {
  msg=$1
  echo "$1"
  exit 1
}

function require() {
  cmd=$1
  which "$1" 2>&1 > /dev/null
  [[ $? != 0 ]] && fail "This script requires the following command be installed: ${cmd}"
}

# Verify this environment is capable of running this script
function verifyEnvironment() {
  require "jq"
  require "curl"
  response=$(curl -Ss -L ${hydraUrl}/)
  [[ "$response" != *"Error 404"* ]] && fail "Unable to communicate with Hydra; specify URL via HYDRA_URL environment variable"
}

function createFile() {
  filename=$1
  uid=$2
  gid=$3

  mkdir -p $(dirname "$filename")
  truncate -s 0 "$filename"
  chmod 600 "$filename"
  chown "${uid}:${gid}" "$filename"
}

function ensureRoleFileExists() {
  if [[ ! -f "$socRolesFile" ]]; then
    # Generate the new roles file
    rolesTmpFile="${socRolesFile}.tmp"
    createFile "$rolesTmpFile" "$soUID" "$soGID"

    if [[ -d "$socRolesFile" ]]; then
      echo "Removing invalid roles directory created by Docker"
      rm -fr "$socRolesFile"
    fi
    mv "${rolesTmpFile}" "${socRolesFile}"
  fi
}

function listClients() {
  response=$(curl -Ss -L -f ${hydraUrl}/admin/clients)
  [[ $? != 0 ]] && fail "Unable to communicate with Hydra"

  clientIds=$(echo "${response}" | jq -r ".[] | .client_id" | sort)
  for clientId in $clientIds; do
    perms=$(grep ":$clientId\$" "$socRolesFile" | cut -d: -f1 | tr '\n' ' ')
    echo "$clientId: $perms"
  done
}

function addClientPermission() {
  id=$1
  perm=$2

  adjustClientPermission "$id" "$perm" "add"
}

function deleteClientPermission() {
  id=$1
  perm=$2

  adjustClientPermission "$id" "$perm" "del"
}

function adjustClientPermission() {
  identityId=$1
  perm=$2
  op=$3

  [[ ${identityId} == "" ]] && fail "Client not found"

  ensureRoleFileExists

  filename="$socRolesFile"
  hasPerm=0
  grep "^$perm:" "$socRolesFile" | grep -q "$identityId" && hasPerm=1
  if [[ "$op" == "add" ]]; then
    if [[ "$hasPerm" == "1" ]]; then
      echo "Client '$identityId' already has the permission: $perm"
      return 1
    else
      echo "$perm:$identityId" >> "$filename"
    fi
  elif [[ "$op" == "del" ]]; then
    if [[ "$hasPerm" -ne 1 ]]; then
      fail "Client '$identityId' does not have the permission: $perm"
    else
      sed -e "\!^$perm:$identityId\$!d" "$filename" > "$filename.tmp"
      cat "$filename".tmp > "$filename"
      rm -f "$filename".tmp
    fi
  else
    fail "Unsupported permission adjustment operation: $op"
  fi
  return 0
}

function convertNameToId() {
    name=$1

    name=${name//[^[:alnum:]]/_}
    echo "socl_$name" | tr '[:upper:]' '[:lower:]'
}

function createClient() {
  name=$1
  note=$2

  id=$(convertNameToId "$name")
  now=$(date -u +%FT%TZ)
  secret=$(get_random_value)
  body=$(cat <<EOF
{
  "access_token_strategy": "opaque",
  "client_id": "$id",
  "client_secret": "$secret",
  "client_name": "$name",
  "grant_types": [ "client_credentials" ],
  "response_types": [ "code" ],
  "metadata": {
    "note": "$note",
    "searchUsername": ""
  }
}
EOF
  )
  
  response=$(curl -Ss -L --fail-with-body -X POST ${hydraUrl}/admin/clients -d "$body")
  if [[ $? != 0 ]]; then
    error=$(echo $response | jq .error)
    fail "Failed to submit request to Hydra: $error"
  fi
}

function update() {
  clientId=$1
  name=$2
  note=$3
  username=$4
  
  body=$(cat <<EOF
[
    {
        "op": "replace",
        "path": "/client_name",
        "value": "$name"
    },
    {
        "op": "replace",
        "path": "/metadata",
        "value": {
          "note": "$note",
          "searchUsername": "$username"
        }
    }
]
EOF
  )
  
  response=$(curl -Ss -L --fail-with-body -X PATCH ${hydraUrl}/admin/clients/$id -d "$body")
  if [[ $? != 0 ]]; then
    error=$(echo $response | jq .error)
    fail "Failed to submit request to Hydra: $error"
  fi
}

function generateSecret() {
  clientId=$1
  
  secret=$(get_random_value)
  body=$(cat <<EOF
[
    {
        "op": "replace",
        "path": "/client_secret",
        "value": "$secret"
    }
]
EOF
  )
  
  response=$(curl -Ss -L --fail-with-body -X PATCH ${hydraUrl}/admin/clients/$id -d "$body")
  if [[ $? != 0 ]]; then
    error=$(echo $response | jq .error)
    fail "Failed to submit request to Hydra: $error"
  fi
}

function deleteClient() {
  identityId=$1

  [[ ${identityId} == "" ]] && fail "Client not found"

  response=$(curl -Ss -XDELETE -L --fail-with-body "${hydraUrl}/admin/clients/$identityId")
  if [[ $? != 0 ]]; then
    error=$(echo $response | jq .error)
    fail "Failed to submit request to Hydra: $error"
  fi

  rolesTmpFile="${socRolesFile}.tmp"
  createFile "$rolesTmpFile" "$soUID" "$soGID"
  grep -v "$identityId" "$socRolesFile" > "$rolesTmpFile"
  cat "$rolesTmpFile" > "$socRolesFile"
}

case "${operation}" in
  "add")
    verifyEnvironment
    [[ "$name" == "" ]] && fail "A short client name must be provided"

    lock
    createClient "$name" "$note"
    if [[ "$json" == "1" ]]; then
      echo "{\"id\":\"$id\",\"secret\":\"$secret\"}"
    else
      echo "Successfully added client ID $id with generated secret: $secret"
    fi
    ;;

  "list")
    verifyEnvironment
    listClients
    ;;

  "addperm")
    verifyEnvironment
    [[ "$id" == "" ]] && fail "Id must be provided"
    [[ "$perm" == "" ]] && fail "Permission must be provided"

    lock
    if addClientPermission "$id" "$perm"; then
      echo "Successfully added permission to client"
    fi
    ;;

  "delperm")
    verifyEnvironment
    [[ "$id" == "" ]] && fail "Id must be provided"
    [[ "$perm" == "" ]] && fail "Permission must be provided"

    lock
    deleteClientPermission "$id" "$perm"
    echo "Successfully removed permission from client"
    ;;

  "update")
    verifyEnvironment
    [[ "$id" == "" ]] && fail "Id must be provided"
    [[ "$name" == "" ]] && fail "Name must be provided"
    [[ "$note" == "__MISSING__" ]] && fail "Note must be provided"
    [[ "$searchUsername" == "__MISSING__" ]] && fail "Search Username must be provided"

    lock
    update "$id" "$name" "$note" "$searchUsername"
    echo "Successfully updated client"
    ;;

  "generate-secret")
    verifyEnvironment
    [[ "$id" == "" ]] && fail "Id must be provided"

    lock
    generateSecret "$id"
    if [[ "$json" == "1" ]]; then
      echo "{\"secret\":\"$secret\"}"
    else
      echo "Successfully generated secret: $secret"
    fi
    ;;

  "delete")
    verifyEnvironment
    [[ "$id" == "" ]] && fail "Id must be provided"

    lock
    deleteClient "$id"
    echo "Successfully deleted client."
    ;;
  *)
    fail "Unsupported operation: $operation"
    usage
    ;;
esac

exit 0