/* PCO Plan — the Teams tile.

   Who is scheduled on the current plan, by team and position, from the same
   server state the Plan tile draws (state.teams). Everything shown is this
   tile's own choice (gear menu): which teams and positions, what each row
   carries, and the colours. Photos come from ProdDash's own avatar route —
   the browser never talks to Planning Center. */

const REFRESH_SVG = '<svg viewBox="0 0 24 24" width="14" height="14" fill="none" stroke="currentColor" stroke-width="2.2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 12a9 9 0 1 1-2.64-6.36"/><path d="M21 3v6h-6"/></svg>';

const DEFAULT_TEMPLATE = '{serviceType} • {date} | {people} on {teams}';

/** Colours for "Tint teams", walked in order so neighbouring teams differ. */
const TEAM_HUES = [152, 205, 32, 275, 12, 180, 320, 95, 240, 50];

export default function createTeams({ root, moduleApi }) {
  let state = null;
  let feedOffline = false;
  let stream = null;
  let lastKey = '';

  root.innerHTML = `
    <div class="tm-wrap">
      <header class="tm-head">
        <div class="tm-title"></div>
        <div class="tm-sub"></div>
      </header>
      <div class="tm-body"></div>
    </div>`;

  const wrap = root.querySelector('.tm-wrap');
  const headEl = root.querySelector('.tm-head');
  const titleEl = root.querySelector('.tm-title');
  const subEl = root.querySelector('.tm-sub');
  const bodyEl = root.querySelector('.tm-body');

  const cfg = () => moduleApi.instanceSettings || {};
  const on = (key) => cfg()[key] !== false; // unset = shown

  /* ── title-bar controls ─────────────────────────────────────────── */

  const refreshBtn = moduleApi.header.addButton({
    icon: REFRESH_SVG,
    title: 'Re-read from Planning Center',
    onClick() {
      refreshBtn.classList.add('active');
      moduleApi.fetch('/refresh', { method: 'POST' })
        .catch(() => { /* the stream reports the outcome */ })
        .finally(() => refreshBtn.classList.remove('active'));
    },
  });

  /* ── helpers ────────────────────────────────────────────────────── */

  function colorOf(value, fallback) {
    const s = String(value || '').trim();
    return /^#[0-9a-fA-F]{3,8}$/.test(s) ? s : fallback;
  }

  /**
   * A team's colour when "Tint teams" is on. Taken from the team's position
   * in the plan, not a hash of its name: neighbouring teams then always look
   * different, which is the whole point of tinting them.
   */
  function teamColor(index) {
    if (!cfg().tintTeams) return colorOf(cfg().teamColor, '#2ee59a');
    return `hsl(${TEAM_HUES[index % TEAM_HUES.length]} 70% 55%)`;
  }

  function statusColor(status) {
    if (status === 'confirmed') return colorOf(cfg().confirmedColor, '#2ee59a');
    if (status === 'declined') return colorOf(cfg().declinedColor, '#f4433c');
    return colorOf(cfg().unconfirmedColor, '#f0b429');
  }

  const STATUS_LABEL = { confirmed: 'Confirmed', unconfirmed: 'Unconfirmed', declined: 'Declined' };

  /** "Sarah Miles" → "SM"; one word → its first two letters. */
  function initialsOf(name) {
    const words = String(name || '').trim().split(/\s+/).filter(Boolean);
    if (!words.length) return '?';
    if (words.length === 1) return words[0].slice(0, 2).toUpperCase();
    return (words[0][0] + words[words.length - 1][0]).toUpperCase();
  }

  /** A saved multiselect list, or null when the tile has never chosen (= all). */
  function chosen(key) {
    const v = cfg()[key];
    return Array.isArray(v) ? v : null;
  }

  /* ── which teams and people to show ─────────────────────────────── */

  function visibleTeams() {
    const teams = Array.isArray(state?.teams) ? state.teams : [];
    const wantTeams = chosen('teams');
    const wantPositions = chosen('positions');
    const out = [];
    for (const team of teams) {
      if (wantTeams && !wantTeams.includes(team.id)) continue;
      const members = team.members.filter((m) => {
        if (wantPositions && !wantPositions.includes(m.position || '(no position)')) return false;
        if (m.status === 'declined' && !on('showDeclined')) return false;
        if (m.status === 'unconfirmed' && !on('showUnconfirmed')) return false;
        return true;
      });
      if (!members.length && !cfg().showEmptyTeams) continue;
      out.push({ ...team, members });
    }
    return out;
  }

  /* ── status dot ─────────────────────────────────────────────────── */

  function renderStatus() {
    if (feedOffline) return moduleApi.setStatus('error', 'ProdDash server unreachable — reconnecting…');
    if (!state) return moduleApi.setStatus('connecting', 'Connecting…');
    if (!state.configured) return moduleApi.setStatus('error', 'No Planning Center credentials — add them in Admin');
    if (!state.serviceTypeSet) return moduleApi.setStatus('error', 'No service type selected — pick one in Admin');
    if (!state.reachable) {
      return moduleApi.setStatus(state.lastFetched ? 'error' : 'connecting', state.lastError || 'Reading the plan…');
    }
    if (state.teamsError) return moduleApi.setStatus('error', `Team list: ${state.teamsError}`);
    const people = (state.teams || []).reduce((n, t) => n + t.members.length, 0);
    moduleApi.setStatus('ok', `${people} scheduled · read ${new Date(state.lastFetched).toLocaleTimeString()}`);
  }

  /* ── top bar ────────────────────────────────────────────────────── */

  /** The counts describe what this tile shows, not what the plan holds. */
  function templateValues() {
    const plan = state?.plan || {};
    const teams = visibleTeams();
    const people = teams.reduce((n, t) => n + t.members.length, 0);
    const confirmed = teams.reduce((n, t) => n + t.counts.confirmed, 0);
    return {
      series: plan.seriesTitle || '',
      part: plan.title || '',
      servicetype: state?.serviceType?.name || '',
      date: plan.dates || '',
      shortdate: plan.shortDates || plan.dates || '',
      time: plan.serviceStartsAt
        ? new Date(plan.serviceStartsAt).toLocaleTimeString([], { hour: 'numeric', minute: '2-digit' })
        : '',
      people: people ? `${people} ${people === 1 ? 'person' : 'people'}` : '',
      teams: teams.length ? `${teams.length} ${teams.length === 1 ? 'team' : 'teams'}` : '',
      confirmed: confirmed ? `${confirmed} confirmed` : '',
    };
  }

  /**
   * "{serviceType} • {date} | {people} on {teams}" → up to two lines. Within
   * a line • separates segments and a segment whose placeholders all came out
   * empty is dropped, so a plan with no series never leaves a stray bullet.
   */
  function renderTemplate(template, values) {
    return String(template || DEFAULT_TEMPLATE).split('|').slice(0, 2).map((line) => {
      const kept = [];
      for (const seg of line.split(/\s*[•·]\s*/)) {
        let sawVar = false;
        let allEmpty = true;
        const text = seg.replace(/\{([a-zA-Z]+)\}/g, (m, name) => {
          sawVar = true;
          const v = values[name.toLowerCase()];
          if (v) allEmpty = false;
          return v || '';
        }).trim();
        if (sawVar && allEmpty) continue;
        if (text) kept.push(text);
      }
      return kept.join(' • ');
    });
  }

  function renderHead() {
    const show = on('showTopBar') && state?.plan;
    headEl.hidden = !show;
    if (!show) return;
    const [line1, line2] = renderTemplate(cfg().headerTemplate, templateValues());
    titleEl.textContent = line1 || line2 || state.serviceType?.name || 'Teams';
    subEl.textContent = line1 ? line2 || '' : '';
    subEl.hidden = !subEl.textContent;
  }

  /* ── the list ───────────────────────────────────────────────────── */

  function emptyMessage() {
    if (feedOffline && !state) return { title: 'Feed offline', hint: 'Not receiving updates from the ProdDash server.' };
    if (!state) return { title: 'Connecting…', hint: '' };
    if (!state.configured) {
      return {
        title: 'Planning Center not connected',
        hint: 'Enter the Planning Center credentials under PCO Plan in Admin.',
        link: { href: '/admin', text: 'Open Admin' },
      };
    }
    if (!state.serviceTypeSet) {
      return {
        title: 'No service type selected',
        hint: 'Pick the service type to follow under PCO Plan in Admin.',
        link: { href: '/admin', text: 'Open Admin' },
      };
    }
    if (!state.reachable && !state.plan) {
      return { title: state.lastFetched ? 'Planning Center unavailable' : 'Reading the plan…', hint: state.lastError || '' };
    }
    if (!state.plan) {
      return {
        title: 'No plan found',
        hint: `${state.serviceType?.name || 'This service type'} has no upcoming or recent plans.`,
      };
    }
    if (!(state.teams || []).length) {
      return {
        title: 'Nobody scheduled yet',
        hint: state.teamsError || 'This plan has no team members in Planning Center.',
      };
    }
    if (!visibleTeams().length) {
      return { title: 'Nothing to show', hint: 'Every team is hidden by this tile’s settings (gear menu).' };
    }
    return null;
  }

  function buildMember(member) {
    const row = document.createElement('div');
    row.className = `tm-person is-${member.status}`;

    if (on('showAvatars')) {
      const avatar = document.createElement('div');
      avatar.className = 'tm-avatar';
      avatar.textContent = initialsOf(member.name);
      if (member.hasPhoto) {
        const img = document.createElement('img');
        img.loading = 'lazy';
        img.alt = '';
        img.src = `/api/modules/${moduleApi.id}/team-avatar/${encodeURIComponent(member.id)}`;
        // No photo, or the CDN is unreachable: the initials underneath stand.
        img.addEventListener('error', () => img.remove());
        avatar.appendChild(img);
      }
      row.appendChild(avatar);
    }

    const main = document.createElement('div');
    main.className = 'tm-person-main';
    const nameEl = document.createElement('div');
    nameEl.className = 'tm-name';
    nameEl.textContent = member.name;
    main.appendChild(nameEl);

    if (on('showPosition') && member.position && !cfg().groupByPosition) {
      const pos = document.createElement('div');
      pos.className = 'tm-position';
      pos.textContent = member.position;
      main.appendChild(pos);
    }
    if (cfg().showNotes && (member.notes || member.declineReason)) {
      const note = document.createElement('div');
      note.className = 'tm-note';
      note.textContent = member.declineReason ? `Declined: ${member.declineReason}` : member.notes;
      main.appendChild(note);
    }
    row.appendChild(main);

    if (on('showStatus')) {
      const status = document.createElement('div');
      status.className = 'tm-status';
      status.style.setProperty('--tm-status', statusColor(member.status));
      status.title = STATUS_LABEL[member.status] || member.status;
      row.appendChild(status);
    }
    return row;
  }

  /** One team: its header band, then its people (optionally under position sub-headings). */
  function buildTeam(team, index) {
    const section = document.createElement('section');
    section.className = 'tm-team';
    section.style.setProperty('--tm-team', teamColor(index));

    if (on('showTeamHeaders')) {
      const header = document.createElement('div');
      header.className = 'tm-team-head';
      const name = document.createElement('span');
      name.className = 'tm-team-name';
      name.textContent = team.name;
      header.appendChild(name);
      if (on('showTeamCounts')) {
        const counts = document.createElement('span');
        counts.className = 'tm-team-count';
        const pending = team.counts.unconfirmed;
        counts.textContent = pending ? `${team.members.length} · ${pending} pending` : String(team.members.length);
        header.appendChild(counts);
      }
      section.appendChild(header);
    }

    const columns = String(cfg().columns || 'auto');
    const grouping = Boolean(cfg().groupByPosition) && on('showPosition');
    // Grouped, the container is a plain block so each position heading spans
    // the width and only its own people form a grid.
    const list = document.createElement('div');
    list.className = grouping ? 'tm-groups' : 'tm-people';
    if (!grouping && columns !== 'auto') {
      list.style.setProperty('--tm-cols', columns);
      list.classList.add('is-fixed-cols');
    }

    if (grouping) {
      // Positions keep the order the members already sort in.
      const groups = new Map();
      for (const m of team.members) {
        const key = m.position || '(no position)';
        if (!groups.has(key)) groups.set(key, []);
        groups.get(key).push(m);
      }
      for (const [position, members] of groups) {
        const label = document.createElement('div');
        label.className = 'tm-position-head';
        label.textContent = position;
        list.appendChild(label);
        const sub = document.createElement('div');
        sub.className = 'tm-people is-sub';
        if (columns !== 'auto') sub.style.setProperty('--tm-cols', columns);
        sub.classList.toggle('is-fixed-cols', columns !== 'auto');
        for (const m of members) sub.appendChild(buildMember(m));
        list.appendChild(sub);
      }
    } else {
      for (const m of team.members) list.appendChild(buildMember(m));
    }

    if (!team.members.length) {
      const none = document.createElement('div');
      none.className = 'tm-team-empty';
      none.textContent = 'Nobody scheduled';
      list.appendChild(none);
    }
    section.appendChild(list);
    return section;
  }

  function renderBody() {
    const empty = emptyMessage();
    if (empty) {
      lastKey = '';
      bodyEl.innerHTML = '';
      const box = document.createElement('div');
      box.className = 'tm-empty';
      const t = document.createElement('div');
      t.className = 'tm-empty-title';
      t.textContent = empty.title;
      box.appendChild(t);
      if (empty.hint) {
        const h = document.createElement('div');
        h.className = 'tm-empty-hint';
        h.textContent = empty.hint;
        box.appendChild(h);
      }
      if (empty.link) {
        const a = document.createElement('a');
        a.className = 'tm-empty-link';
        a.href = empty.link.href;
        a.target = '_blank';
        a.rel = 'noopener';
        a.textContent = empty.link.text;
        box.appendChild(a);
      }
      bodyEl.appendChild(box);
      return;
    }

    // Rebuild only when the roster or the settings actually changed: the
    // avatars are <img>s and a needless rebuild makes them flicker.
    const teams = visibleTeams();
    const key = JSON.stringify([teams, cfg()]);
    if (key === lastKey) return;
    lastKey = key;
    bodyEl.innerHTML = '';
    teams.forEach((team, i) => bodyEl.appendChild(buildTeam(team, i)));
  }

  function render() {
    wrap.classList.toggle('is-offline', feedOffline);
    wrap.classList.toggle('tint-rows', Boolean(cfg().tintTeams && cfg().tintRows));
    wrap.classList.toggle('header-gradient', on('headerGradient'));
    renderStatus();
    renderHead();
    renderBody();
  }

  /* ── live feed ──────────────────────────────────────────────────── */

  function accept(payload) {
    if (!payload || typeof payload !== 'object' || !payload.state) return;
    state = payload.state;
    feedOffline = false;
    render();
  }

  function connect() {
    stream = moduleApi.sse('/stream', {
      open() { feedOffline = false; render(); },
      error() { feedOffline = true; render(); },
      events: {
        state(ev) {
          try {
            accept(JSON.parse(ev.data));
          } catch { /* a bad frame is not fatal */ }
        },
      },
    });
  }

  /* ── lifecycle ──────────────────────────────────────────────────── */

  return {
    start() {
      moduleApi.setStatus('connecting', 'Connecting…');
      moduleApi.fetch('/state')
        .then((res) => (res.ok ? res.json() : null))
        .then((body) => { if (body && !state) accept(body); })
        .catch(() => { /* the stream will cover it */ });
      connect();
      render();
    },
    stop() {
      stream?.close();
      stream = null;
      root.innerHTML = '';
    },
    onConfigChange() {
      // Admin holds the connection only; the server re-inits and re-sends.
    },
  };
}