import { getInst, getType } from "../primitives/dynamic.js";
import { SymbolBool, SymbolChar, SymbolDouble, SymbolInt, SymbolType, SymbolUnit } from "../primitives/types.js";
import { symbolList, symbolProduct, symbolSet, symbolSum } from "../structures/types.js";
import { compareBools, compareNumbers, compareStrings, compareUnits } from "./primitives.js";
import { compareLists, compareProducts, compareSets, compareSums } from "./structures.js";
import { compareTypes } from "./type.js";

const typeSymbolToCmp = new Map([
  [SymbolInt   , compareNumbers],
  [SymbolChar  , compareStrings],
  [SymbolDouble, compareNumbers],
  [SymbolBool  , compareBools],
  [SymbolUnit  , compareUnits],
  [SymbolType  , compareTypes],

  // these functions take extra comparison callbacks:
  [symbolList   , compareLists],
  [symbolProduct, compareProducts],
  [symbolSum    , compareSums],
  [symbolSet    , compareSets],
]);

export const makeCompareFn = type => {
  return type.params.reduce(
    (acc, cur) => acc(makeCompareFn(cur)),
    typeSymbolToCmp.get(type.symbol)
  );
};

export const compareDynamic = x => y =>
  compareTypes(getType(x))(getType(y))
    || makeCompareFn(getType(x))(getInst(x))(getInst(y));