// Licensed to the Apache Software Foundation (ASF) under one or more contributor
// license agreements; and to You under the Apache License, Version 2.0.

const messages = require('./messages')

const defaultNamespace = () => {
  return process.env['__OW_NAMESPACE'] || '_'
}

// valid resource identifiers
// - resourceName
// - package/resourceName
// - /namespace/resourceName
// - /namespace/package/resourceName
// - namespace/package/resourceName
const parseIdAndNs = resource => {
  const parts = (resource.match(/\//g) || []).length
  const names = resource.split('/')

  // checking for `resource_name` and `package/resource_name`
  if (parts === 0 ||
     (parts === 1 && !resource.startsWith('/'))) {
    return { namespace: defaultNamespace(), id: resource }
  }

  // checking for `/namespace/resource_name` and `namespace/package/resource_name`
  if (parts === 2) {
    if (resource.startsWith('/')) {
      return { namespace: names[1], id: names[2] }
    } else {
      return { namespace: names[0], id: `${names[1]}/${names[2]}` }
    }
  }

  // checking for `/namespace/package/resource_name`
  if (parts === 3 && resource.startsWith('/')) {
    return { namespace: names[1], id: `${names[2]}/${names[3]}` }
  }

  throw new Error(messages.INVALID_RESOURCE_ERROR)
}

const parseNamespace = id => parseIdAndNs(id).namespace
const parseId = id => parseIdAndNs(id).id

module.exports = {
  defaultNamespace: defaultNamespace,
  parseNamespace: parseNamespace,
  parseId: parseId
}