/**
 * ============LICENSE_START========================================================================
 * ONAP : ccsdk feature sdnr wt odlux
 * =================================================================================================
 * Copyright (C) 2019 highstreet technologies GmbH Intellectual Property. All rights reserved.
 * =================================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 * ============LICENSE_END==========================================================================
 */

export type ViewElementBase = {
  "id": string;
  "label": string;
  "module": string;
  "path": string;
  "config": boolean;
  "ifFeature"?: string;
  "when"?: string;
  "mandatory"?: boolean;
  "description"?: string;
  "isList"?: boolean;
  "default"?: string;
  "status"?: "current" | "deprecated" | "obsolete",
  "reference"?: string, // https://tools.ietf.org/html/rfc7950#section-7.21.4
}

// https://tools.ietf.org/html/rfc7950#section-9.8
export type ViewElementBinary = ViewElementBase & {
  "uiType": "binary";
  "length"?: Expression<YangRange>;  // number of octets
}

// https://tools.ietf.org/html/rfc7950#section-9.7.4
export type ViewElementBits = ViewElementBase & {
  "uiType": "bits";
  "flags": {
    [name: string]: number | undefined;    // 0 - 4294967295
  }
}

// https://tools.ietf.org/html/rfc7950#section-9
export type ViewElementString = ViewElementBase & {
  "uiType": "string";
  "pattern"?: Expression<RegExp>;
  "length"?: Expression<YangRange>;
  "invertMatch"?: true;
}

// special case derived from 
export type ViewElementDate = ViewElementBase & {
  "uiType": "date";
  "pattern"?: Expression<RegExp>;
  "length"?: Expression<YangRange>;
  "invertMatch"?: true;
}

// https://tools.ietf.org/html/rfc7950#section-9.3
export type ViewElementNumber = ViewElementBase & {
  "uiType": "number";
  "min": number;
  "max": number;
  "range"?: Expression<YangRange>;
  "units"?: string;
  "format"?: string;
  "fDigits"?: number;
}

// https://tools.ietf.org/html/rfc7950#section-9.5
export type ViewElementBoolean = ViewElementBase & {
  "uiType": "boolean";
  "trueValue"?: string;
  "falseValue"?: string;
}

// https://tools.ietf.org/html/rfc7950#section-9.6.4
export type ViewElementSelection = ViewElementBase & {
  "uiType": "selection";
  "multiSelect"?: boolean
  "options": {
    "key": string;
    "value": string;
    "description"?: string,
    "status"?: "current" | "deprecated" | "obsolete",
    "reference"?: string,
  }[];
}

// is a list if isList is true ;-)
export type ViewElementObject = ViewElementBase & {
  "uiType": "object";
  "isList"?: false;
  "viewId": string;
}

// Hint: read only lists do not need a key
export type ViewElementList = (ViewElementBase & {
  "uiType": "object";
  "isList": true;
  "viewId": string;
  "key"?: string;
});

export type ViewElementReference = ViewElementBase & {
  "uiType": "reference";
  "referencePath": string;
  "ref": (currentPath: string) => [ViewElement , string] | undefined;
}

export type ViewElementUnion = ViewElementBase & {
  "uiType": "union";
  "elements": ViewElement[];
}

export type ViewElementChoiseCase = { id: string, label: string, description?: string, elements: { [name: string]: ViewElement }  };

export type ViewElementChoise = ViewElementBase & {
  "uiType": "choise";
  "cases": {
    [name: string]: ViewElementChoiseCase;
  }
}

// https://tools.ietf.org/html/rfc7950#section-7.14.1
export type ViewElementRpc = ViewElementBase & {
  "uiType": "rpc";
  "inputViewId"?: string;
  "outputViewId"?: string;
}

export type ViewElementEmpty = ViewElementBase & {
  "uiType": "empty";
}

export type ViewElement =
  | ViewElementEmpty
  | ViewElementBits
  | ViewElementBinary
  | ViewElementString
  | ViewElementDate
  | ViewElementNumber
  | ViewElementBoolean
  | ViewElementObject
  | ViewElementList
  | ViewElementSelection
  | ViewElementReference
  | ViewElementUnion
  | ViewElementChoise
  | ViewElementRpc;

export const isViewElementString = (viewElement: ViewElement): viewElement is ViewElementString => {
  return viewElement && (viewElement.uiType === "string" || viewElement.uiType === "date");
}

export const isViewElementDate = (viewElement: ViewElement): viewElement is ViewElementDate => {
  return viewElement && (viewElement.uiType === "date");
}

export const isViewElementNumber = (viewElement: ViewElement): viewElement is ViewElementNumber => {
  return viewElement && viewElement.uiType === "number";
}

export const isViewElementBoolean = (viewElement: ViewElement): viewElement is ViewElementBoolean => {
  return viewElement && viewElement.uiType === "boolean";
}

export const isViewElementObject = (viewElement: ViewElement): viewElement is ViewElementObject => {
  return viewElement && viewElement.uiType === "object" && viewElement.isList === false;
}

export const isViewElementList = (viewElement: ViewElement): viewElement is ViewElementList => {
  return viewElement && viewElement.uiType === "object" && viewElement.isList === true;
}

export const isViewElementObjectOrList = (viewElement: ViewElement): viewElement is ViewElementObject | ViewElementList => {
  return viewElement && viewElement.uiType === "object";
}

export const isViewElementSelection = (viewElement: ViewElement): viewElement is ViewElementSelection => {
  return viewElement && viewElement.uiType === "selection";
}

export const isViewElementReference = (viewElement: ViewElement): viewElement is ViewElementReference => {
  return viewElement && viewElement.uiType === "reference";
}

export const isViewElementUnion = (viewElement: ViewElement): viewElement is ViewElementUnion => {
  return viewElement && viewElement.uiType === "union";
}

export const isViewElementChoise = (viewElement: ViewElement): viewElement is ViewElementChoise => {
  return viewElement && viewElement.uiType === "choise";
}

export const isViewElementRpc = (viewElement: ViewElement): viewElement is ViewElementRpc => {
  return viewElement && viewElement.uiType === "rpc";
}

export const isViewElementEmpty = (viewElement: ViewElement): viewElement is ViewElementRpc => {
  return viewElement && viewElement.uiType === "empty";
}

export const ResolveFunction = Symbol("IsResolved");

export type ViewSpecification = {
  "id": string;
  "ns"?: string;
  "name"?: string;
  "title"?: string;
  "parentView"?: string;
  "language": string;
  "ifFeature"?: string;
  "when"?: string;
  "uses"?: (string[]) & { [ResolveFunction]?: (parent: string) => void };
  "elements": { [name: string]: ViewElement };
  "config": boolean;
  readonly "canEdit": boolean;
}

export type YangRange = {
  min: number,
  max: number,
}

export type Expression<T> =
  | T
  | Operator<T>;

export type Operator<T> = {
  operation: "AND" | "OR";
  arguments: Expression<T>[];
}