const newid = require("./newid")

const UNICODE_MAX = "\ufff0"
const SEPARATOR = "_"

const DocumentTypes = {
  MODEL: "mo",
  RECORD: "re",
  USER: "us",
  AUTOMATION: "au",
  LINK: "li",
  APP: "app",
  ACCESS_LEVEL: "ac",
}

exports.DocumentTypes = DocumentTypes
exports.SEPARATOR = SEPARATOR
exports.UNICODE_MAX = UNICODE_MAX

/**
 * If creating DB allDocs/query params with only a single top level ID this can be used, this
 * is usually the case as most of our docs are top level e.g. models, automations, users and so on.
 * More complex cases such as link docs and records which have multiple levels of IDs that their
 * ID consists of need their own functions to build the allDocs parameters.
 * @param {string} docType The type of document which input params are being built for, e.g. user,
 * link, app, model and so on.
 * @param {string|null} docId The ID of the document minus its type - this is only needed if looking
 * for a singular document.
 * @param {object} otherProps Add any other properties onto the request, e.g. include_docs.
 * @returns {object} Parameters which can then be used with an allDocs request.
 */
function getDocParams(docType, docId = null, otherProps = {}) {
  if (docId == null) {
    docId = ""
  }
  return {
    ...otherProps,
    startkey: `${docType}${SEPARATOR}${docId}`,
    endkey: `${docType}${SEPARATOR}${docId}${UNICODE_MAX}`,
  }
}

/**
 * Gets parameters for retrieving models, this is a utility function for the getDocParams function.
 */
exports.getModelParams = (modelId = null, otherProps = {}) => {
  return getDocParams(DocumentTypes.MODEL, modelId, otherProps)
}

/**
 * Generates a new model ID.
 * @returns {string} The new model ID which the model doc can be stored under.
 */
exports.generateModelID = () => {
  return `${DocumentTypes.MODEL}${SEPARATOR}${newid()}`
}

/**
 * Gets the DB allDocs/query params for retrieving a record.
 * @param {string} modelId The model in which the records have been stored.
 * @param {string|null} recordId The ID of the record which is being specifically queried for. This can be
 * left null to get all the records in the model.
 * @param {object} otherProps Any other properties to add to the request.
 * @returns {object} Parameters which can then be used with an allDocs request.
 */
exports.getRecordParams = (modelId, recordId = null, otherProps = {}) => {
  if (modelId == null) {
    throw "Cannot build params for records without a model ID"
  }
  const endOfKey =
    recordId == null
      ? `${modelId}${SEPARATOR}`
      : `${modelId}${SEPARATOR}${recordId}`
  return getDocParams(DocumentTypes.RECORD, endOfKey, otherProps)
}

/**
 * Gets a new record ID for the specified model.
 * @param {string} modelId The model which the record is being created for.
 * @returns {string} The new ID which a record doc can be stored under.
 */
exports.generateRecordID = modelId => {
  return `${DocumentTypes.RECORD}${SEPARATOR}${modelId}${SEPARATOR}${newid()}`
}

/**
 * Gets parameters for retrieving users, this is a utility function for the getDocParams function.
 */
exports.getUserParams = (username = null, otherProps = {}) => {
  return getDocParams(DocumentTypes.USER, username, otherProps)
}

/**
 * Generates a new user ID based on the passed in username.
 * @param {string} username The username which the ID is going to be built up of.
 * @returns {string} The new user ID which the user doc can be stored under.
 */
exports.generateUserID = username => {
  return `${DocumentTypes.USER}${SEPARATOR}${username}`
}

/**
 * Gets parameters for retrieving automations, this is a utility function for the getDocParams function.
 */
exports.getAutomationParams = (automationId = null, otherProps = {}) => {
  return getDocParams(DocumentTypes.AUTOMATION, automationId, otherProps)
}

/**
 * Generates a new automation ID.
 * @returns {string} The new automation ID which the automation doc can be stored under.
 */
exports.generateAutomationID = () => {
  return `${DocumentTypes.AUTOMATION}${SEPARATOR}${newid()}`
}

/**
 * Generates a new link doc ID. This is currently not usable with the alldocs call,
 * instead a view is built to make walking to tree easier.
 * @param {string} modelId1 The ID of the linker model.
 * @param {string} modelId2 The ID of the linked model.
 * @param {string} recordId1 The ID of the linker record.
 * @param {string} recordId2 The ID of the linked record.
 * @returns {string} The new link doc ID which the automation doc can be stored under.
 */
exports.generateLinkID = (modelId1, modelId2, recordId1, recordId2) => {
  return `${DocumentTypes.AUTOMATION}${SEPARATOR}${modelId1}${SEPARATOR}${modelId2}${SEPARATOR}${recordId1}${SEPARATOR}${recordId2}`
}

/**
 * Generates a new app ID.
 * @returns {string} The new app ID which the app doc can be stored under.
 */
exports.generateAppID = () => {
  return `${DocumentTypes.APP}${SEPARATOR}${newid()}`
}

/**
 * Gets parameters for retrieving apps, this is a utility function for the getDocParams function.
 */
exports.getAppParams = (appId = null, otherProps = {}) => {
  return getDocParams(DocumentTypes.APP, appId, otherProps)
}

/**
 * Generates a new access level ID.
 * @returns {string} The new access level ID which the access level doc can be stored under.
 */
exports.generateAccessLevelID = () => {
  return `${DocumentTypes.ACCESS_LEVEL}${SEPARATOR}${newid()}`
}

/**
 * Gets parameters for retrieving an access level, this is a utility function for the getDocParams function.
 */
exports.getAccessLevelParams = (accessLevelId = null, otherProps = {}) => {
  return getDocParams(DocumentTypes.ACCESS_LEVEL, accessLevelId, otherProps)
}