/*

value.mjs - <short description TODO>

Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/core/value.mjs>

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/

import { curry } from './util.mjs';

import { logger } from './logger.mjs';

export function unionWithObj(a, b, func) {

  if (b?.value !== undefined && Object.keys(b).length === 1) {

    // https://codeberg.org/uzu/strudel/issues/1026

    logger(`[warn]: Can't do arithmetic on control pattern.`);

    return a;

  }

  const common = Object.keys(a).filter((k) => Object.keys(b).includes(k));

  return Object.assign({}, a, b, Object.fromEntries(common.map((k) => [k, func(a[k], b[k])])));

}

export const mul = curry((a, b) => a * b);

export const valued = (value) => {

  if (value?.constructor?.name === 'Value') {

    return value;

  }

  return Value.of(value);

};

export class Value {

  constructor(value) {

    this.value = value;

  }

  static of(x) {

    return new Value(x);

  }

  get isNothing() {

    return this.value === null || this.value === undefined;

  }

  map(f) {

    if (this.isNothing) {

      return this;

    }

    return Value.of(f(this.value));

  }

  mul(n) {

    return this.map(mul).ap(n);

  }

  ap(other) {

    return valued(other).map(this.value);

  }

  unionWith(other, func) {

    const type = typeof this.value;

    other = valued(other);

    if (type !== typeof other.value) {

      throw new Error('unionWith: both Values must have same type!');

    }

    if (Array.isArray(type) || type !== 'object') {

      throw new Error('unionWith: expected objects');

    }

    return this.map((v) => unionWithObj(v, other.value, func));

  }

}

export const map = curry((f, anyFunctor) => anyFunctor.map(f));