import {
  GramGraphData,
  GramLinkDatum,
  GramNodeDatum,
  GramPathDatum,
  makeGramLinkDatum,
  makeGramNodeDatum,
  MISSING_ID,
  PathDatumRecord,
} from './d3-gram-types';

import { GramEdge, GramNode, GramPath, isGramNode } from '@gram-data/gram-ast';
import { edges, nodes } from '@gram-data/gram-ops';

import unified from 'unified';
import { gramParserPlugin } from '@gram-data/gram-parse';
import * as gramPresetBasic from '@gram-data/gram-preset-basic';

const gramProcessor = unified()
  .use(gramParserPlugin)
  .use(gramPresetBasic);

/**
 * Parses text as [gram](https://github.com/gram-data/gram-js),
 * returning a graph representated nodes, links and paths.
 *
 * @param src
 */
export const parse = (src: string): GramGraphData => {
  const parsed: GramPath = gramProcessor.runSync(
    gramProcessor.parse(src)
  ) as GramPath;
  const gramGraph = {
    nodes: (nodes(parsed) as GramNode[]).map(nodeToD3),
    links: (edges(parsed) as GramEdge[]).map(edgeToD3),
    paths: [] as GramPathDatum[],
  };

  return gramGraph;
};

export const dataFromPath = (p: GramPath): PathDatumRecord => {
  return p.data && p.data.value
    ? (p.data.value as PathDatumRecord)
    : p.record
    ? p.record
    : {};
};

export const nodeToD3 = (node: GramNode): GramNodeDatum => {
  return isGramNode(node)
    ? makeGramNodeDatum(node.id, node.labels, dataFromPath(node))
    : makeGramNodeDatum('random');
};

const source = (edge: GramEdge): string => {
  if (edge.kind === 'left') return edge.children[1].id || MISSING_ID;
  return edge.children[0].id || MISSING_ID;
};

const target = (edge: GramEdge): string => {
  if (edge.kind === 'left') return edge.children[0].id || MISSING_ID;
  return edge.children[1].id || MISSING_ID;
};

export const edgeToD3 = (edge: GramEdge): GramLinkDatum => {
  return makeGramLinkDatum(
    source(edge),
    target(edge),
    edge.id,
    edge.labels,
    dataFromPath(edge)
  );
};