'use strict';

/**
 * Slot ↔ Planning Center position matching for the Band Lineup module.
 *
 * A "slot" is a mic/pack label the operator wrote for a spot on stage, e.g.
 * "[LEADER, VOX 1, ACOUSTIC] MIX 1". A scheduled person carries their PCO
 * team-position name, e.g. "Vox 1" or "Acoustic / Worship Leader". We assign
 * people to slots by loose token overlap — the same logic the backstage
 * Electron app used, lifted here unchanged so the board matches what the booth
 * is used to. Pure functions only: no I/O, so this file is unit-testable.
 */

function normalizeTeamName(value) {
  return String(value || '').trim().toLowerCase();
}

/** Does a person's PCO team count as a band/stage team we display? `keywords` comes from admin config. */
function isAllowedTeamName(value, keywords) {
  const normalized = normalizeTeamName(value);
  if (!normalized) return false;
  return (keywords || []).some((kw) => {
    const k = normalizeTeamName(kw);
    return k && (normalized === k || normalized.includes(k));
  });
}

function normalizeLabel(value) {
  return String(value || '')
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, ' ')
    .replace(/\s+/g, ' ')
    .trim();
}

/** Fold a single token to a canonical instrument/role word (drops mic/pack noise, pluralises down). */
function normalizeToken(token) {
  const normalized = String(token || '').trim().toLowerCase();
  if (!normalized) return '';
  if (/^\d+$/.test(normalized)) return '';
  if (['mix', 'mic', 'slot', 'channel', 'ch', 'pack', 'wireless', 'input', 'headset'].includes(normalized)) return '';
  if (['vox', 'vocal', 'vocalist', 'vocalists', 'vocals', 'singer', 'singers'].includes(normalized)) return 'vocals';
  if (['keys', 'keyboard', 'keyboards'].includes(normalized)) return 'keys';
  if (['drum', 'drums', 'drummer', 'drummers'].includes(normalized)) return 'drums';
  if (['perc', 'percussionist', 'percussionists'].includes(normalized)) return 'percussion';
  if (['gtr', 'guitar', 'guitars'].includes(normalized)) return 'guitar';
  if (['electric', 'electricguitar'].includes(normalized)) return 'electric';
  if (['acoustic', 'acousticguitar'].includes(normalized)) return 'acoustic';
  if (['b', 'bandleader', 'leader', 'lead'].includes(normalized)) return normalized === 'b' ? '' : 'leader';
  if (['worship', 'calltoworship'].includes(normalized)) return normalized === 'calltoworship' ? 'call' : normalized;
  if (normalized.endsWith('s') && normalized.length > 4) return normalized.slice(0, -1);
  return normalized;
}

function labelTokens(value) {
  const normalized = normalizeLabel(value);
  if (!normalized) return [];
  const tokens = normalized.split(' ').map((t) => normalizeToken(t)).filter(Boolean);
  if (!tokens.length && normalized) return [normalized];
  return [...new Set(tokens)];
}

/**
 * The role part of a slot label to match on: the bracketed content when present
 * ("[VOX 2] MIX 2" → "VOX 2, "), else the whole label ("STAGE MANAGER"). This
 * drops the "MIX n / MC n / HEADSET" mic-assignment noise so a mic number can't
 * be mistaken for a position number.
 */
function slotRoleText(label) {
  const brackets = String(label || '').match(/\[([^\]]*)\]/g);
  if (brackets && brackets.length) return brackets.map((b) => b.slice(1, -1)).join(', ');
  return String(label || '');
}

/** The set of standalone numbers in a label ("vox 2" → {"2"}). */
function numbersIn(value) {
  return new Set(normalizeLabel(value).split(' ').filter((t) => /^\d+$/.test(t)));
}

/** 0–~140 similarity between a slot label and a PCO position name; higher is a better fit. */
function scoreMatch(slotLabel, positionLabel) {
  const slotNormalized = normalizeLabel(slotLabel);
  const positionNormalized = normalizeLabel(positionLabel);
  if (!slotNormalized || !positionNormalized) return 0;
  // A numbered role only matches the same number: "Vox 3" must not take "Vox 2".
  const slotNums = numbersIn(slotLabel);
  const posNums = numbersIn(positionLabel);
  if (slotNums.size && posNums.size && ![...posNums].some((n) => slotNums.has(n))) return 0;
  if (slotNormalized === positionNormalized) return 120;
  if (slotNormalized.includes(positionNormalized) || positionNormalized.includes(slotNormalized)) return 95;

  const slotTokens = labelTokens(slotLabel);
  const positionTokens = labelTokens(positionLabel);
  if (!slotTokens.length || !positionTokens.length) return 0;

  const positionSet = new Set(positionTokens);
  const slotSet = new Set(slotTokens);
  const overlap = slotTokens.filter((t) => positionSet.has(t));
  if (!overlap.length) return 0;

  const overlapCount = overlap.length;
  const slotCoverage = overlapCount / slotSet.size;
  const positionCoverage = overlapCount / positionSet.size;
  const sharedPhrase = overlap.join(' ');

  let score = Math.round(slotCoverage * 70 + positionCoverage * 20 + overlapCount * 4);
  if (slotCoverage === 1) score += 18;
  if (positionCoverage === 1) score += 10;
  if (sharedPhrase && slotNormalized.includes(sharedPhrase) && positionNormalized.includes(sharedPhrase)) score += 8;
  return score;
}

/**
 * Assign scheduled members to the ordered slot list. Greedy by best score, each
 * member used once. Returns an array aligned to `slots`, each entry the chosen
 * member or null. `MIN_SCORE` keeps a weak coincidence from claiming a slot.
 */
const MIN_SCORE = 60;
function assignMembersToSlots(slots, members) {
  const pool = members.slice();
  return slots.map((slotLabel) => {
    const role = slotRoleText(slotLabel);
    let bestIndex = -1;
    let bestScore = MIN_SCORE - 1;
    for (let i = 0; i < pool.length; i += 1) {
      const score = scoreMatch(role, pool[i].label);
      if (score > bestScore) { bestScore = score; bestIndex = i; }
    }
    if (bestIndex < 0) return null;
    return pool.splice(bestIndex, 1)[0];
  });
}

/**
 * Best library photo for a Planning Center person, matched by name so Sync can use the folder
 * photo instead of the PCO headshot. Handles full names, "First L" and first-name-only files,
 * preferring the most specific. Returns the entry, or null when there's no confident, UNAMBIGUOUS
 * match (e.g. two people share a first name and the photo is first-name-only) — then PCO's photo is used.
 * `entries` is [{ ...whatever, name }].
 */
function bestLibraryMatch(pcoName, entries) {
  const target = normalizeLabel(pcoName);
  if (!target) return null;
  const T = target.split(' ').filter(Boolean);
  const scoreOf = (name) => {
    const ln = normalizeLabel(name);
    if (!ln) return 0;
    if (ln === target) return 100; // exact full name
    const L = ln.split(' ').filter(Boolean);
    if (!L.length || !T.length) return 0;
    // Align the library name against a leading run of the person's name, token by token.
    // Every library token must equal the person's token in that position — except the LAST
    // library token, which may be an initial/prefix ("m" of "Moniz"). This makes "Brian M"
    // match "Brian Moniz" and "Alex" match "Alex Gaitan", but NOT "Alex" → "Alexander Zinni".
    let ok = true; let exact = 0; let usedPrefix = false;
    for (let k = 0; k < L.length; k += 1) {
      const lt = L[k]; const tt = T[k];
      if (!tt) { ok = false; break; }
      if (lt === tt) { exact += 1; continue; }
      if (k === L.length - 1 && tt.startsWith(lt)) { usedPrefix = true; continue; }
      ok = false; break;
    }
    if (ok) {
      if (L.length >= 2) return usedPrefix ? 86 : 92;   // "brian m" / "alex gaitan"
      if (exact === 1) return 90;                        // first name matches exactly ("alex")
      if (usedPrefix) return 45;                         // "alex" vs "alexander" — too ambiguous
    }
    // Otherwise: a library surname that appears anywhere in the person's name.
    const last = L[L.length - 1];
    if (last && last.length >= 3 && T.includes(last)) return 78;
    return 0;
  };
  let best = null;
  let bestScore = 0;
  let tie = false;
  for (const e of entries) {
    const s = scoreOf(e.name);
    if (s > bestScore) { bestScore = s; best = e; tie = false; }
    else if (s === bestScore && s > 0) tie = true;
  }
  if (bestScore < 60 || tie) return null; // no confident / unambiguous winner → PCO photo
  return best;
}

module.exports = {
  normalizeTeamName,
  isAllowedTeamName,
  bestLibraryMatch,
  normalizeLabel,
  normalizeToken,
  labelTokens,
  slotRoleText,
  numbersIn,
  scoreMatch,
  assignMembersToSlots,
  MIN_SCORE,
};