import { CHROMATIC, NATURAL, getNoteAt, getAnswerChoices } from './music.js';
import { FRET_COUNT } from './fretboard.js';

export function genMode1Question(numStrings, naturalOnly) {
  let stringIdx, fret, note;
  let attempts = 0;
  do {
    stringIdx = Math.floor(Math.random() * numStrings);
    fret = Math.floor(Math.random() * (FRET_COUNT + 1));
    note = getNoteAt(stringIdx, fret, numStrings);
    attempts++;
  } while (naturalOnly && !NATURAL.includes(note) && attempts < 100);

  const choices = getAnswerChoices(note, naturalOnly);
  return { stringIdx, fret, note, choices };
}

export function genMode2Question(numStrings, naturalOnly) {
  const pool = naturalOnly ? NATURAL : CHROMATIC;
  const targetNote = pool[Math.floor(Math.random() * pool.length)];

  const rangeLen = Math.random() < 0.5 ? 4 : 5;
  const fretStart = Math.floor(Math.random() * (FRET_COUNT - rangeLen + 1));
  const fretEnd = fretStart + rangeLen;

  const correctSet = new Set();
  for (let s = 0; s < numStrings; s++) {
    for (let f = fretStart; f <= fretEnd; f++) {
      if (getNoteAt(s, f, numStrings) === targetNote) {
        correctSet.add(`${s},${f}`);
      }
    }
  }

  return { targetNote, fretStart, fretEnd, correctSet };
}

export function evaluateMode2(selection, correctSet) {
  const allCorrect = [...correctSet].every(k => selection.has(k)) &&
                     [...selection].every(k => correctSet.has(k));
  const missed = [...correctSet].filter(k => !selection.has(k)).length;
  const extra  = [...selection].filter(k => !correctSet.has(k)).length;
  return { allCorrect, missed, extra };
}