onioncollab/src/frontend/correspondence.ts

import * as React from "react";

import {newVersionedModel} from "./versioned_model";
import {TrivialParser} from "../parser/trivial_parser";
import {Version} from "../onion/version";
import {GraphState} from "../onion/graph_state"; 

// Pure function
// Replays all deltas in a version to compute the graph state of that version.
function getGraphState(version: Version): GraphState {
  const graphState = new GraphState();
  for (const d of [...version].reverse()) {
    graphState.exec(d);
  }
  return graphState;
}

export function newCorrespondence({generateUUID, primitiveRegistry, cs, as}) {
  // const cs = newVersionedModel({readonly, generateUUID, primitiveRegistry});
  const {initialState, getReducer: getReducerOrig} = newVersionedModel({readonly: true, generateUUID, primitiveRegistry});

  const parser = new TrivialParser(primitiveRegistry, generateUUID);

  const corrMap: Map<Version,{csVersion:Version,asVersion:Version}> = new Map([
    [initialState.version, {csVersion: cs.initialState.version, asVersion: as.initialState.version}]
  ]);

  function getReducer([state, setState], csReducer, asReducer) {
    const {
      getReactComponents,
      callbacks: {
        gotoVersion: gotoVersionOrig,
        createAndGotoNewVersion,
        undo,
        redo,
      },
    } = getReducerOrig([state, setState]);

    const parse = (csDeltas, description: string) => {
      const [csGS, corrGS, asGS] = [csReducer.state.version, state.version, asReducer.state.version].map(v => getGraphState(v));

      const {corrDeltas, asDeltas} = parser.parse(csDeltas, csGS, corrGS, asGS);

      const csVersionPromise = new Promise<Version>(resolve => {
        csReducer.callbacks.createAndGotoNewVersion(csDeltas, description, resolve);
      });
      const corrVersionPromise = new Promise<Version>(resolve => {
        createAndGotoNewVersion(corrDeltas, description, resolve);
      });
      const asVersionPromise = new Promise<Version>(resolve => {
        if (asDeltas.length > 0) {
          asReducer.callbacks.createAndGotoNewVersion(asDeltas, "parse:"+description, resolve);
        } else {
          resolve(asReducer.state.version);
        }
      });

      // Remember which Corr version embeds which CS/AS versions:
      Promise.all([csVersionPromise, corrVersionPromise, asVersionPromise]).then(([csVersion, corrVersion, asVersion]) => {
        corrMap.set(corrVersion, {csVersion, asVersion});        
      });
    };
    const render = (asDeltas, description: string) => {
      const [csGS, corrGS, asGS] = [csReducer.state.version, state.version, asReducer.state.version].map(v => getGraphState(v));
      
      const {corrDeltas, csDeltas} = parser.render(asDeltas, csGS, corrGS, asGS);

      const csVersionPromise = new Promise<Version>(resolve => {
        if (asDeltas.length > 0) {
          csReducer.callbacks.createAndGotoNewVersion(csDeltas, "render:"+description, resolve);
        } else {
          resolve(csReducer.state.version);
        }
      });
      const corrVersionPromise = new Promise<Version>(resolve => {
        createAndGotoNewVersion(corrDeltas, description, resolve);
      });
      const asVersionPromise = new Promise<Version>(resolve => {
        asReducer.callbacks.createAndGotoNewVersion(asDeltas, description, resolve);
      });

      // Remember which Corr version embeds which CS/AS versions:
      Promise.all([csVersionPromise, corrVersionPromise, asVersionPromise]).then(([csVersion, corrVersion, asVersion]) => {
        corrMap.set(corrVersion, {csVersion, asVersion});        
      });
    };
    const gotoVersion = (corrVersion: Version) => {
      const {csVersion, asVersion} = corrMap.get(corrVersion)!;
      csReducer.callbacks.gotoVersion(csVersion);
      gotoVersionOrig(corrVersion);
      asReducer.callbacks.gotoVersion(asVersion);
    };

    return {
      state,
      getReactComponents,
      callbacks: {
        parse,
        render,
        gotoVersion,
        undo,
        redo,
      },
    };
  }

  return {
    initialState,
    getReducer,
  };
}