import FuzzySearch from 'https://unpkg.com/[email protected]/src/FuzzySearch.js'

const entries = data();
const fzf = new FuzzySearch(Object.keys(entries), [], {
  caseSensitive: false,
  sort: true
});

const search = create_search(entries, true);
const search_name = create_search(entries, false);
const update_input = val => (window.search_form[0].value = val);

const suggest_word = value => () =>
  suggest(value)
    .filter(confirm_word)
    .tap(update_input)
    .map(search);

const search_word = word =>
  search(word)
    .or_else(() => search_name(word))
    .or_else(suggest_word(word))
    .map(format)
    .unwrap_or('word not found');

window.search_form.addEventListener('submit', function(ev) {
  ev.preventDefault();
  window.result.innerHTML = search_word(ev.target[0].value);
});

// Utilities
function create_search(data, exact) {
  return input => {
    const word = exact ? input : capitalize(input);
    return Maybe(data[word]);
  };
}

function suggest(word) {
  const matches = fzf.search(word);
  return Maybe(matches[0]);
}

function confirm_word(value) {
  return confirm(`Did you mean ${value}`);
}

function capitalize(str) {
  return str.charAt(0).toUpperCase() + str.slice(1);
}

function format(results) {
  return results.join('<br>');
}

function Maybe(the_thing) {
  if (the_thing === null || the_thing === undefined || the_thing.is_nothing) {
    return Nothing();
  }

  if (the_thing.is_just) {
    return the_thing;
  }

  return Just(the_thing);
}

function Just(thing) {
  return {
    map: fun => Maybe(fun(thing)),
    and_then: fun => fun(thing),
    or_else: () => Just(thing),
    tap: fun => (fun(thing), Just(thing)),
    unwrap_or: () => thing,

    filter: predicate_fun => (predicate_fun(thing) ? Maybe(thing) : Nothing()),

    is_just: true,
    is_nothing: false,
    inspect: () => `Just(${thing})`
  };
}

function Nothing() {
  return {
    map: Nothing,
    and_then: Nothing,
    or_else: fun => fun(),
    tap: Nothing,
    unwrap_or: arg => arg,

    filter: Nothing,

    is_just: false,
    is_nothing: true,
    inspect: () => `Nothing`
  };
}


// what are you doing here? Get out!!
function data() {
  return {
    "abandoned industrial site": ["Site that cannot be used for any purpose, being contaminated by pollutants."], 
    "abandoned vehicle": ["A vehicle that has been discarded in the environment, urban or otherwise, often found wrecked, destroyed, damaged or with a major component part stolen or missing."],
    "abiotic factor": ["Physical, chemical and other non-living environmental factor."],
    "access road": ["Any street or narrow stretch of paved surface that leads to a specific destination, such as a main highway."],
    "access to the sea": ["The ability to bring goods to and from a port that is able to harbor sea faring vessels."],
    "accident": ["An unexpected, unfortunate mishap, failure or loss with the potential for harming human life, property or the environment.", "An event that happens suddenly or by chance without an apparent cause."], 
    "accumulator": ["A rechargeable device for storing electrical energy in the form of chemical energy, consisting of one or more separate secondary cells.\\n(Source: CED)"], 
    "acidification": ["Addition of an acid to a solution until the pH falls below 7."], 
    "acidity": ["The state of being acid that is of being capable of transferring a hydrogen ion in solution."], 
    "acidity degree": ["The amount of acid present in a solution, often expressed in terms of pH."], 
    "acid rain": ["Rain having a pH less than 5.6."], 
    "acid": ["A compound capable of transferring a hydrogen ion in solution.", "Being harsh or corrosive in tone.", "Having an acid, sharp or tangy taste.", "A powerful hallucinogenic drug manufactured from lysergic acid.", "Having a pH less than 7, or being sour, or having the strength to neutralize  alkalis, or turning a litmus paper red."],
    "acoustic filter": ["A device employed to reject sound in a particular range of frequencies while passing sound in another range of frequencies."],
    "acoustic insulation": ["The process of preventing the transmission of sound by surrounding with a nonconducting material."],
    "acoustic level": ["Physical quantity of sound measured, usually expressed in decibels.\\n(Source: KORENa)"],
    "Paris": ["The capital and largest city of France."]
  };
}