// The React state and reducer of a D3Graph component showing an onion graph state.

import {PrimitiveValue} from "onion/types";
import {INodeState, IValueState, GraphStateListener} from "onion/graph_state";
import {D3GraphData, D3NodeData, D3LinkData} from "../d3graph";

export type D3OnionNodeData = D3NodeData<INodeState|IValueState>;
export type D3OnionLinkData = D3LinkData<null>;
export type D3OnionGraphData = D3GraphData<INodeState|IValueState,null>;

interface AddNode {type:'addNode', ns: INodeState, x: number, y: number}
interface RemoveNode {type:'removeNode', id: PrimitiveValue}
interface AddValue {type:'addValue', vs: IValueState, x: number, y: number}
interface RemoveValue {type:'removeValue', value: PrimitiveValue}
interface AddLinkToNode {type:'addLinkToNode', sourceId: PrimitiveValue, label: string, targetId: PrimitiveValue}
interface AddLinkToValue {type:'addLinkToValue', sourceId: PrimitiveValue, label: string, targetValue: PrimitiveValue}
interface RemoveLink {type:'removeLink', sourceId: PrimitiveValue, label: string}

export type D3OnionGraphAction =
    Readonly<AddNode>
  | Readonly<RemoveNode>
  | Readonly<AddValue>
  | Readonly<RemoveValue>
  | Readonly<AddLinkToNode>
  | Readonly<AddLinkToValue>
  | Readonly<RemoveLink>;

export function onionGraphReducer(prevState: D3OnionGraphData, action: D3OnionGraphAction): D3OnionGraphData {
  switch (action.type) {
    case 'addNode': {
      return {
        nodes: [...prevState.nodes, {
          id: nodeNodeId(action.ns.creation.id.value),
          label: JSON.stringify(action.ns.creation.id.value),
          x: action.x,
          y: action.y,
          color: "darkturquoise",
          obj: action.ns,
          bold: false,
        }],
        links: prevState.links,
      };
    }
    case 'removeNode': {
      return {
        nodes: prevState.nodes.filter(n => !n.obj.isNode(action.id)),
        links: prevState.links,
      };
    }
    case 'addValue': {
      return {      
        nodes: [...prevState.nodes, {
          id: valueNodeId(action.vs.value),
          label: JSON.stringify(action.vs.value),
          x: action.x,
          y: action.y,
          color: "darkorange",
          obj: action.vs,
          bold: false,
        }],
        links: prevState.links,
      };
    }
    case 'removeValue': {
      return {
        nodes: prevState.nodes.filter(n => !n.obj.isValue(action.value)),
        links: prevState.links,
      };
    }
    case 'addLinkToNode': {
      return {    
        nodes: prevState.nodes,
        links: [...prevState.links, {
          source: prevState.nodes.find(n => n.obj.isNode(action.sourceId)),   // AR: here is the problem!
          target: prevState.nodes.find(n => n.obj.isNode(action.targetId)),
          label: action.label,
          color: 'black',
          obj: null,
        }],
      };
    }
    case 'addLinkToValue': {
      return {    
        nodes: prevState.nodes,
        links: [...prevState.links, {
          source: prevState.nodes.find(n => n.obj.isNode(action.sourceId)),
          target: prevState.nodes.find(n => n.obj.isValue(action.targetValue)),
          label: action.label,
          color: 'black',
          obj: null,
        }],
      };
    }
    case 'removeLink': {
      return {    
        nodes: prevState.nodes,
        links: prevState.links.filter(l => l.source.obj.creation.id.value !== action.sourceId || l.label !== action.label),
      };
    }
  }
}

function nodeNodeId(nodeId: PrimitiveValue) {
  return "N"+JSON.stringify(nodeId);
}

function valueNodeId(value: PrimitiveValue) {
  return "V"+JSON.stringify(value);
}


// Responds to changes to a GraphState object by updating the React state of a d3Graph component.
export class D3GraphUpdater implements GraphStateListener {
  readonly setGraph: (cb: (prevGraph: D3OnionGraphData) => D3OnionGraphData) => void;

  // SVG coordinates for newly created nodes
  // This information cannot be part of our NodeCreation deltas, but it must come from somewhere...
  x: number;
  y: number;

  constructor(setGraph: (cb: (prevGraph: D3OnionGraphData) => D3OnionGraphData) => void, x, y) {
    this.setGraph = setGraph;
    this.x = x;
    this.y = y;
  }

  createNode(ns: INodeState) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'addNode', ns, x: this.x, y: this.y}));
  }
  createValue(vs: IValueState) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'addValue', vs, x: this.x, y: this.y}));
  }
  deleteNode(id: PrimitiveValue) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'removeNode', id}));
  }
  deleteValue(value: PrimitiveValue) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'removeValue', value}));
  }
  createLinkToNode(sourceId: PrimitiveValue, label: string, targetId: PrimitiveValue) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'addLinkToNode', sourceId, label, targetId}));
  }
  createLinkToValue(sourceId: PrimitiveValue, label: string, targetValue: PrimitiveValue) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'addLinkToValue', sourceId, label, targetValue}));
  }
  deleteLink(sourceId: PrimitiveValue, label: string) {
    this.setGraph(prevGraph => onionGraphReducer(prevGraph, {type: 'removeLink', sourceId, label}));
  }
}