// Day review: the chronological cross-file section list behind a day's
// Highlights button.
//
// The user is blind and uses a screen reader — there is deliberately no day
// timeline graphic. The panel is linear text and buttons: summary line ->
// key-hint note -> chips toggle -> chips.

import {$, fmtDur, fmtClock, fileStartEpoch, announce, chipToggle} from './util.js';
import {fetchAnalysis} from './analysis.js';
import {armQueue, playFrom, hideClipBar} from './clips.js';
import {analysisParams, hlParams} from './settings.js';

let dayActiveSections = [];
let dayActiveId = null;
// dayId -> section list of an already-built highlights panel, so collapsing
// and re-expanding it re-arms J/K without recomputing
const dayHlSections = new Map();

export function setHlExpanded(dayId, exp) {
  const btn = $('dayhln-' + dayId);
  if (!btn) return;
  btn.setAttribute('aria-expanded', exp);
  const arrow = btn.querySelector('.day-arrow');
  if (arrow) arrow.textContent = exp ? '▾ ' : '▸ ';
}

// The status suffix inside the Highlights button (" · analysed", progress).
// The button has no aria-label, so this text is part of its accessible name.
const setHlStatus = (dayId, text) => {
  const el = $('dayhls-' + dayId);
  if (el) el.textContent = text;
};

// Point the clip queue at a day's cross-file section list, from either the
// fresh-build path or the re-open-a-kept-panel path. Coupled globals set in
// two places is how the stale-_idx and diverging-label bugs happened.
function armDayQueue(dayId, sections) {
  dayActiveSections = sections;
  dayActiveId       = dayId;
  armQueue(sections);
}

function jumpToDaySection(si) {
  if (si < 0 || si >= dayActiveSections.length) return;
  playFrom(dayActiveSections, si);
}

// The day was collapsed: close its panel and drop its queue
export function releaseDay(dayId) {
  const panel = $('dayhl-' + dayId);
  if (panel) panel.hidden = true;
  setHlExpanded(dayId, false);
  if (dayActiveId === dayId) {
    dayActiveSections = [];
    dayActiveId = null;
    hideClipBar();
  }
}

// Highlights button: expand/collapse the panel; only (re)compute when it has
// not been built yet this session or the analysis params changed
export function toggleHighlights(dayId, files) {
  const panel = $('dayhl-' + dayId);
  const btn   = $('dayhln-' + dayId);
  if (btn?.dataset.busy) return;
  if (!panel.hidden) {                         // collapse, keep the panel
    panel.hidden = true;
    setHlExpanded(dayId, false);
    return;
  }
  if (panel.dataset.loaded === hlParams()) {   // re-open and re-arm J/K
    panel.hidden = false;
    setHlExpanded(dayId, true);
    armDayQueue(dayId, dayHlSections.get(dayId) || []);
    return;
  }
  dayHighlights(dayId, files);
}

async function dayHighlights(dayId, files) {
  const panel   = $('dayhl-' + dayId);
  const content = $('dayhlc-' + dayId);
  const btn     = $('dayhln-' + dayId);
  const n       = files.length;

  panel.hidden = false;
  setHlExpanded(dayId, true);
  // Busy, not disabled: disabling the focused button would throw the screen
  // reader's focus to the top of the page
  btn.dataset.busy = '1';
  btn.setAttribute('aria-disabled', 'true');

  const progBar  = document.createElement('div'); progBar.className = 'prog-bar';
  const progFill = document.createElement('div'); progFill.className = 'prog-fill';
  progBar.setAttribute('aria-hidden', 'true');
  progBar.appendChild(progFill);
  const progFile = document.createElement('p'); progFile.className = 'prog-file';
  content.replaceChildren(progBar, progFile);

  const params = analysisParams();
  const results = [];
  let nCached = 0;
  for (let i = 0; i < n; i++) {
    const f = files[i];
    progFile.textContent = `${i + 1} / ${n} — ${f.name}`;
    progFill.style.width = `${(i / n) * 100}%`;
    setHlStatus(dayId, ` · ${i + 1} of ${n}`);
    try {
      const d = await fetchAnalysis(f.name, params);
      if (!d.error) { results.push({f, data: d}); if (d.cached) nCached++; }
    } catch { /* counted as missing below */ }
  }
  delete btn.dataset.busy;
  btn.removeAttribute('aria-disabled');
  // Every file is now cached with the current params
  setHlStatus(dayId, results.length === n ? ' · analysed' : '');

  // Map files onto the day. The filename is the clock: f.date is the
  // recording start parsed server-side; mtime (≈ file end) is only a fallback
  // for non-standard names.
  const sections = [];
  results.forEach(({f, data}) => {
    const fileDur = data.duration || f.duration || 0;
    if (fileDur <= 0) return;
    const startEpoch = fileStartEpoch(f.date);
    const fileStart  = startEpoch != null ? startEpoch : f.mtime - fileDur;
    (data.sections || []).forEach(s => sections.push({
      filename: f.name, start: s.start, end: s.end, score: s.score,
      absStart: fileStart + s.start,
    }));
  });
  sections.sort((a, b) => a.absStart - b.absStart);
  // Arm the clip queue so J/K steps through the day immediately
  armDayQueue(dayId, sections);

  const box = document.createElement('div');
  box.className = 'wbox';
  const nRes = results.length, nSec = sections.length;
  const missing = n - nRes;
  // Totals first, then the key hint, then the chips: linear reading order
  const summary = document.createElement('p');
  summary.className = 'quiet';
  summary.textContent = `${nRes} recording${nRes !== 1 ? 's' : ''} analysed`
    + (nCached ? ` (${nCached} from cache)` : '')
    + (missing ? `, ${missing} failed` : '')
    + ` · ${nSec} loud section${nSec !== 1 ? 's' : ''}`;
  box.appendChild(summary);

  if (nSec) {
    const note = document.createElement('p');
    note.className = 'quiet';
    note.textContent = 'J / K plays through all sections in time order, U / I by loudness (loudest first). Hold Shift to jump to the first / last section (Shift + J / K) or the loudest / quietest (Shift + U / I)';
    box.appendChild(note);

    const MAX_DAY_CHIPS = 50;
    // When there are too many sections to show them all, show the ones most
    // worth reviewing: the top MAX_DAY_CHIPS by score, loudest first.
    let chipList = sections.map((sec, si) => ({sec, si}));
    const truncated = chipList.length > MAX_DAY_CHIPS;
    if (truncated) {
      chipList = chipList
        .sort((a, b) => (b.sec.score || 0) - (a.sec.score || 0))
        .slice(0, MAX_DAY_CHIPS);
    }
    const chips = document.createElement('div');
    chips.className = 'chips';
    chips.setAttribute('role', 'group');
    chips.setAttribute('aria-label', 'Day loud sections');
    chipList.forEach(({sec, si}) => {
      const c = document.createElement('button');
      c.className = 'chip';
      c.title = sec.filename + ' @ ' + fmtDur(sec.start);
      c.textContent = fmtClock(sec.absStart) + (sec.score != null ? ` · +${Math.round(sec.score)} dB` : '');
      c.addEventListener('click', () => jumpToDaySection(si));
      chips.appendChild(c);
    });
    const tog = chipToggle(chips, truncated
      ? `Top ${chipList.length} sections by loudness`
      : `${chipList.length} sections`);
    if (tog) box.appendChild(tog);
    box.appendChild(chips);
  }

  content.replaceChildren(box);
  panel.dataset.loaded = hlParams();
  dayHlSections.set(dayId, sections);
  announce(nSec
    ? `${nSec} loud section${nSec !== 1 ? 's' : ''} across ${nRes} recording${nRes !== 1 ? 's' : ''}. K plays the first, I the loudest.`
    : `No loud sections in ${nRes} recording${nRes !== 1 ? 's' : ''}.`);
}