// Team settings: the rota, who is in the team, where its alerts come from,
// what it escalates through, and which of its alerts are heartbeats.
//
// Everything here was API-only until now, which meant a team owner had to use
// curl to set up escalation — the feature this whole line of work exists for.
//
// The server decides what a role may do: an owner's edits succeed, a member's
// are refused with 403, and a non-member gets 404 for the lot. This view hides
// the controls a member cannot use, because a form that always fails is worse
// than no form, but it is not the thing enforcing anything.

import * as api from './api.js';
import { h, clear, spinner, confirm, icon, openSheet, closeSheet } from './ui.js';
import { state, currentTeam, users as allUsers, myID } from './state.js';
import { isoDate, addDays, mondayOf, initial } from './format.js';

const view = () => document.getElementById('view-team');

let teamID = null;
let data = null; // { team, members, integrations, escalation, deadman, schedule, users }
let error = null;
let freshKey = null; // an integration key, shown once, until the view is left

export function show() {
  if (!data) clear(view(), spinner());
  refresh();
}

function selectedTeam() {
  const teams = state.teams || [];
  return teams.find((t) => t.id === teamID) || currentTeam();
}

export async function refresh() {
  const team = selectedTeam();
  if (!team) {
    data = null;
    render();
    return;
  }
  teamID = team.id;
  const grid = gridDays();
  try {
    // A member may read all of this; only the writes are owner-only.
    const [members, integrations, escalation, deadman, schedule, users] = await Promise.all([
      api.teamMembers(team.id),
      api.integrations(team.id),
      api.escalation(team.id),
      api.deadman(team.id),
      api.schedule(team.id, isoDate(grid.start), isoDate(addDays(grid.start, grid.count - 1))),
      allUsers(),
    ]);
    data = { team, members, integrations, escalation, deadman, schedule, users };
    error = null;
  } catch (err) {
    error = err.message;
  }
  render();
}

function isOwner() {
  return data?.team?.role === 'owner' || state.me?.user?.is_admin;
}

function render() {
  if (!data) {
    clear(view(), error
      ? h('div', { class: 'load-error', text: error })
      : h('div', { class: 'card' }, h('p', { class: 'muted', text: 'You are not in a team yet.' })));
    return;
  }
  clear(view(),
    error && h('div', { class: 'load-error', text: `Showing older data: ${error}` }),
    teamPicker(),
    !isOwner() && h('div', { class: 'card' },
      h('p', { class: 'muted small', text: 'You are a member of this team. Only an owner can change its settings.' })),
    scheduleCard(),
    escalationCard(),
    integrationsCard(),
    deadmanCard(),
    membersCard(),
  );
}

// Only shown to somebody in more than one team, like the queue's filter chips.
function teamPicker() {
  if ((state.teams || []).length < 2) {
    return h('div', { class: 'card' }, h('h2', { text: data.team.name }));
  }
  const select = h('select', { class: 'team-picker' },
    ...state.teams.map((t) => h('option', {
      value: String(t.id), text: t.name, selected: t.id === teamID,
    })));
  select.addEventListener('change', () => {
    teamID = Number(select.value);
    data = null;
    freshKey = null;
    show();
  });
  return h('div', { class: 'card' }, h('h2', { text: 'Team' }), select);
}

// --- schedule --------------------------------------------------------------

// The rota is one person per UTC day. The on-call page shows it; this is where
// it is set, which until now was the TUI's job and the TUI cannot do it any
// more.
//
// A month of it, as a grid. It used to be thirty rows of "date — username",
// which is a rota spelled out one day at a time: the question asked of it is
// "who has which stretch", and thirty names down a column is the one shape
// that answer cannot be read in. So each day carries a coloured initial
// instead, the legend says whose, and a shift becomes a run of one colour.
//
// The same month laid out the same way as the on-call page's week, because it
// is the same rota — heading and arrows outside the card, days inside it.

const monthFmt = new Intl.DateTimeFormat(undefined, { month: 'long', year: 'numeric' });
const weekdayFmt = new Intl.DateTimeFormat(undefined, { weekday: 'short' });
const longDayFmt = new Intl.DateTimeFormat(undefined, {
  weekday: 'long', day: 'numeric', month: 'long',
});

let monthStart = firstOfMonth(new Date());

function firstOfMonth(d) {
  return new Date(d.getFullYear(), d.getMonth(), 1);
}

// The grid runs Monday to Sunday, so it starts before the 1st and ends after
// the last. Both overhangs are fetched and drawn: a shift that begins on the
// 30th is a fact about this month even though the days it runs into are not.
function gridDays() {
  const start = mondayOf(monthStart);
  const last = new Date(monthStart.getFullYear(), monthStart.getMonth() + 1, 0);
  const span = Math.round((last - start) / 86400000) + 1;
  return { start, count: Math.ceil(span / 7) * 7 };
}

function shiftMonth(n) {
  monthStart = new Date(monthStart.getFullYear(), monthStart.getMonth() + n, 1);
  refresh();
}

function scheduleCard() {
  const { start, count } = gridDays();
  const byDate = new Map((data.schedule || []).map((e) => [e.date, e]));
  const today = isoDate(new Date());
  const month = monthStart.getMonth();

  // Whose colours to explain, in the order the month meets them. Only the days
  // of this month count: a name that appears solely in the overhang belongs to
  // the month next door and would be explaining a chip nobody asked about.
  const seen = new Map();
  const cells = [];
  for (let i = 0; i < count; i++) {
    const d = addDays(start, i);
    const key = isoDate(d);
    const e = byDate.get(key);
    const inMonth = d.getMonth() === month;
    if (inMonth && e && !seen.has(e.user_id)) seen.set(e.user_id, e.username);
    cells.push(dayCell(d, key, e, inMonth, today));
  }

  const heads = [];
  for (let i = 0; i < 7; i++) {
    // Any Monday will do; this one is a Monday.
    heads.push(h('span', { class: 'rota-wd', text: weekdayFmt.format(new Date(2024, 0, 1 + i)) }));
  }

  return [
    h('div', { class: 'page-head' },
      h('h2', { text: 'On-call rota' }),
      h('div', { class: 'week-nav' },
        h('button', {
          class: 'btn btn-ghost btn-icon', type: 'button',
          'aria-label': 'Previous month', onclick: () => shiftMonth(-1),
        }, icon('chevronLeft')),
        h('button', {
          class: 'btn btn-ghost label', type: 'button',
          title: 'Back to this month',
          onclick: () => { monthStart = firstOfMonth(new Date()); refresh(); },
          text: monthFmt.format(monthStart),
        }),
        h('button', {
          class: 'btn btn-ghost btn-icon', type: 'button',
          'aria-label': 'Next month', onclick: () => shiftMonth(1),
        }, icon('chevronRight')),
      ),
    ),
    h('div', { class: 'card' },
      h('div', { class: 'rota-grid' }, heads, cells),
      h('div', { class: 'rota-foot' }, legend(seen), coverNote(byDate)),
      // The range form is the way to fill a whole shift at once, but it is not
      // what the page is for, so it stays folded away under the month it edits.
      isOwner() && h('details', { class: 'rota-bulk' },
        h('summary', { text: 'Assign a range of days' }),
        assignForm()),
    ),
  ];
}

function dayCell(d, key, e, inMonth, today) {
  const cls = ['rota-day', !inMonth && 'outside', key === today && 'today', key < today && 'past']
    .filter(Boolean).join(' ');
  const label = `${key} · ${e ? e.username : 'nobody'}`;
  const body = [
    h('span', { class: 'rota-num', text: String(d.getDate()) }),
    e
      ? h('span', { class: `rota-chip ${colorClass(e.user_id)}`, text: initial(e.username) })
      : h('span', { class: 'rota-chip none' }),
  ];
  // A member sees the same grid without the affordance, the way every other
  // control on this page is hidden rather than shown and refused.
  return isOwner()
    ? h('button', {
      class: cls, type: 'button', title: label, 'aria-label': label,
      onclick: () => daySheet(key, e),
    }, body)
    : h('div', { class: cls, title: label }, body);
}

// A colour per person, taken from their place in the member list so that it
// holds still as you page between months. Somebody who holds days but has
// since left the team is not in that list and falls back to their id.
function colorClass(userID) {
  const i = (data.members || []).findIndex((m) => m.user_id === userID);
  return `rc${((i < 0 ? userID : i) % 6) + 1}`;
}

function legend(seen) {
  if (!seen.size) return null;
  return h('div', { class: 'rota-legend' },
    [...seen].map(([id, name]) => h('span', { class: 'rota-key' },
      h('span', { class: `rota-chip ${colorClass(id)}`, text: initial(name) }),
      h('span', { text: name }),
      id === myID() && h('span', { class: 'you', text: 'you' }),
    )));
}

// The gap count, which is the one thing the grid states only by omission. Days
// already past are not counted: an empty Tuesday last week is history, not a
// hole somebody still has to fill.
function coverNote(byDate) {
  const today = isoDate(new Date());
  const last = new Date(monthStart.getFullYear(), monthStart.getMonth() + 1, 0).getDate();
  let gaps = 0;
  for (let day = 1; day <= last; day++) {
    const key = isoDate(new Date(monthStart.getFullYear(), monthStart.getMonth(), day));
    if (key >= today && !byDate.has(key)) gaps++;
  }
  if (gaps === 0) return h('p', { class: 'rota-note', text: 'Every day left this month has somebody on call.' });
  return h('p', { class: 'rota-note' },
    h('strong', { text: gaps === 1 ? '1 day' : `${gaps} days` }),
    ' left this month with nobody on call.');
}

// One day, in the sheet: who has it, who should, and the way to empty it. This
// is where the per-row Clear button went — the grid has no room for thirty of
// them, and the day you want to change is the one you just tapped.
function daySheet(date, entry) {
  const who = memberSelect(entry ? entry.user_id : undefined);
  openSheet(() => [
    h('h2', { class: 'sheet-title', text: longDayFmt.format(parseISO(date)) }),
    h('p', { class: 'sheet-text', text: entry ? `${entry.username} is on call.` : 'Nobody is on call.' }),
    h('label', { class: 'sheet-pick' }, 'On call ', who),
    h('div', { class: 'sheet-actions' },
      entry && h('button', {
        class: 'btn btn-danger', type: 'button', text: 'Clear',
        onclick: () => { closeSheet(); act(() => api.unassignSchedule(teamID, entry.id)); },
      }),
      h('button', {
        class: 'btn btn-primary', type: 'button', autofocus: true, text: 'Assign',
        // replace, where the range form asks first: the sheet has just named
        // whoever holds the day, so taking it from them is the thing that was
        // asked for rather than something to be warned about.
        onclick: () => {
          closeSheet();
          act(() => api.assignSchedule(teamID, Number(who.value), [date], true));
        },
      }),
    ),
  ]);
}

function parseISO(s) {
  const [y, m, d] = s.split('-').map(Number);
  return new Date(y, m - 1, d);
}

function assignForm() {
  const who = memberSelect();
  // The form opens on the month above it rather than on today: it is folded
  // into that month's card, and paging to March to fill March and being handed
  // today's date would be the card and the form disagreeing about the subject.
  const now = new Date();
  const sameMonth = monthStart.getFullYear() === now.getFullYear()
    && monthStart.getMonth() === now.getMonth();
  const from = h('input', {
    type: 'date', required: true, value: isoDate(sameMonth ? now : monthStart),
  });
  const days = h('input', { type: 'number', min: '1', max: '31', value: '1', class: 'setting-value' });
  const replace = h('input', { type: 'checkbox' });

  const form = h('form', { class: 'stacked-form' },
    h('label', {}, 'Who ', who),
    h('label', {}, 'From ', from),
    h('label', {}, 'Days ', days),
    // Taking a day somebody else holds has to be asked for, the same rule the
    // API enforces: a plain assignment that silently moved a shift would move
    // who gets paged without telling either of them.
    h('label', { class: 'checkbox' }, replace, ' Take days somebody else holds'),
    h('button', { class: 'btn', type: 'submit', text: 'Assign' }));

  form.addEventListener('submit', (e) => {
    e.preventDefault();
    const start = new Date(from.value + 'T00:00:00Z');
    const dates = [];
    for (let i = 0; i < Number(days.value || 1); i++) dates.push(isoDate(addDays(start, i)));
    act(() => api.assignSchedule(teamID, Number(who.value), dates, replace.checked));
  });
  return form;
}

function memberSelect(selected) {
  return h('select', {},
    ...(data.members || []).map((m) => h('option', {
      value: String(m.user_id), text: m.username, selected: m.user_id === selected,
    })));
}

// --- escalation ------------------------------------------------------------

// The ladder is edited as a whole and sent as a whole, because the API replaces
// it wholesale: the levels are an order, and patching one rung would leave the
// numbering of the others undecided.
let draft = null;

function escalationCard() {
  const esc = data.escalation;
  if (!draft) {
    draft = {
      repeat_count: esc.repeat_count || 0,
      fallback_topic: esc.fallback_topic || '',
      levels: (esc.levels || []).map((l) => ({
        timeout_seconds: l.timeout_seconds,
        targets: (l.targets || []).map((t) => ({ kind: t.kind, user_id: t.user_id })),
      })),
    };
  }

  const body = [];
  if (!draft.levels.length) {
    body.push(h('p', { class: 'muted' },
      'No ladder. An unacknowledged incident re-pages the same person every ',
      'reminder interval and nobody else is woken.'));
  }

  draft.levels.forEach((level, i) => {
    body.push(h('div', { class: 'ladder-level' },
      h('div', { class: 'ladder-head' },
        h('strong', { text: `Level ${i + 1}` }),
        isOwner() && h('button', {
          class: 'btn-sm danger', type: 'button', text: 'Remove',
          onclick: () => { draft.levels.splice(i, 1); render(); },
        })),
      h('label', {}, 'Wait ', minutesInput(level.timeout_seconds, (secs) => {
        level.timeout_seconds = secs;
      }), ' before the next level'),
      h('div', { class: 'ladder-targets' },
        ...level.targets.map((t, ti) => targetRow(level, t, ti)),
        isOwner() && h('button', {
          class: 'btn-sm', type: 'button', text: '+ target',
          onclick: () => { level.targets.push({ kind: 'oncall' }); render(); },
        })),
    ));
  });

  if (isOwner()) {
    body.push(h('button', {
      class: 'btn-sm', type: 'button', text: '+ level',
      onclick: () => {
        draft.levels.push({ timeout_seconds: 300, targets: [{ kind: 'oncall' }] });
        render();
      },
    }));

    const repeat = h('input', {
      type: 'number', min: '0', max: '10', class: 'setting-value',
      value: String(draft.repeat_count),
      oninput: (e) => { draft.repeat_count = Number(e.target.value); },
    });
    const fallback = h('input', {
      type: 'text', value: draft.fallback_topic, placeholder: 'terdut-oncall-all',
      oninput: (e) => { draft.fallback_topic = e.target.value; },
    });
    body.push(h('label', {}, 'Repeat the whole ladder ', repeat, ' more times'));
    body.push(h('label', {}, 'Then page this ntfy topic once ', fallback));
    body.push(h('button', {
      class: 'btn', type: 'button', text: 'Save ladder',
      onclick: () => act(() => api.setEscalation(teamID, draft), { resetDraft: true }),
    }));
  }

  return h('div', { class: 'card' },
    h('h2', { text: 'Escalation' }),
    h('p', { class: 'muted small' },
      'When a level’s wait passes and nobody has acknowledged, the next level is ',
      'paged. Acknowledging or resolving stops it; snoozing pauses it.'),
    ...body,
  );
}

function targetRow(level, target, index) {
  const kind = h('select', {},
    h('option', { value: 'oncall', text: 'Whoever is on call', selected: target.kind === 'oncall' }),
    h('option', { value: 'user', text: 'A specific person', selected: target.kind === 'user' }));
  kind.addEventListener('change', () => {
    target.kind = kind.value;
    target.user_id = kind.value === 'user' ? (data.members[0] || {}).user_id : undefined;
    render();
  });

  const who = target.kind === 'user'
    ? memberSelect(target.user_id)
    : null;
  if (who) {
    who.addEventListener('change', () => { target.user_id = Number(who.value); });
  }

  return h('div', { class: 'target-row' }, kind, who,
    isOwner() && h('button', {
      class: 'btn-sm danger', type: 'button', text: '×',
      title: 'Remove this target',
      onclick: () => { level.targets.splice(index, 1); render(); },
    }));
}

function minutesInput(seconds, onChange) {
  const input = h('input', {
    type: 'number', min: '1', class: 'setting-value',
    value: String(Math.max(1, Math.round(seconds / 60))),
    oninput: (e) => onChange(Number(e.target.value) * 60),
  });
  return h('span', {}, input, ' minutes');
}

// --- integrations ----------------------------------------------------------

function integrationsCard() {
  const rows = (data.integrations || []).map((i) =>
    h('tr', {},
      h('td', {}, h('strong', { text: i.name })),
      h('td', { class: 'muted small', text: i.kind }),
      h('td', { class: 'muted small', text: i.last_used_at ? 'in use' : 'never used' }),
      h('td', {}, isOwner() && h('button', {
        class: 'btn-sm danger', type: 'button', text: 'Revoke',
        onclick: async () => {
          if (!(await confirm({
            title: `Revoke ${i.name}?`,
            text: 'Anything posting with this key stops delivering immediately.',
            confirmLabel: 'Revoke',
            danger: true,
          }))) return;
          act(() => api.deleteIntegration(teamID, i.id));
        },
      })),
    ));

  return h('div', { class: 'card' },
    h('h2', { text: 'Alert sources' }),
    h('p', { class: 'muted small' },
      'Alerts arrive on an integration key, which says both that the sender may ',
      'post and which team the alerts belong to.'),
    rows.length
      ? h('table', { class: 'admin-table' }, h('tbody', {}, rows))
      : h('p', { class: 'muted', text: 'No alert source yet, so nothing can reach this team.' }),
    freshKey && newKeyPanel(),
    isOwner() && !freshKey && newIntegrationForm(),
  );
}

// The key is returned exactly once. Say so, show it large, and give the
// Alertmanager snippet with it already in place — the next thing anybody does
// with it is paste it into a config.
function newKeyPanel() {
  const url = freshKey.url || `${location.origin}/api/integrations/${freshKey.key}/alertmanager`;
  const snippet = `receivers:
  - name: terdut
    webhook_configs:
      - url: ${url}
        send_resolved: true`;

  return h('div', { class: 'key-panel' },
    h('strong', { text: 'Copy this now — it is not shown again.' }),
    h('pre', { class: 'key-url' }, h('code', { text: url })),
    h('button', {
      class: 'btn-sm', type: 'button', text: 'Copy URL',
      onclick: () => navigator.clipboard?.writeText(url),
    }),
    h('p', { class: 'muted small', text: 'Alertmanager receiver:' }),
    h('pre', {}, h('code', { text: snippet })),
    h('button', {
      class: 'btn-sm', type: 'button', text: 'Done',
      onclick: () => { freshKey = null; render(); },
    }),
  );
}

function newIntegrationForm() {
  const name = h('input', { type: 'text', placeholder: 'prod alertmanager', required: true });
  const form = h('form', { class: 'inline-form' }, name,
    h('button', { class: 'btn', type: 'submit', text: 'Add' }));
  form.addEventListener('submit', async (e) => {
    e.preventDefault();
    try {
      freshKey = await api.createIntegration(teamID, name.value.trim());
      await refresh();
    } catch (err) {
      error = err.message;
      render();
    }
  });
  return form;
}

// --- dead man's switches ---------------------------------------------------

function deadmanCard() {
  const d = data.deadman || {};
  const matchers = h('input', {
    type: 'text', value: d.matchers || '', placeholder: 'alertname=Watchdog',
    class: 'wide',
  });
  const timeout = h('input', {
    type: 'number', min: '0', class: 'setting-value',
    value: String(Math.round((d.timeout_seconds || 0) / 60)),
  });
  const severity = h('select', {},
    ...['critical', 'error', 'warning', 'info'].map((s) =>
      h('option', { value: s, text: s, selected: (d.severity || 'critical') === s })));

  const form = h('form', { class: 'stacked-form' },
    h('label', {}, 'Heartbeat alerts ', matchers),
    h('label', {}, 'Declare dead after ', timeout, ' minutes of silence'),
    h('label', {}, 'Open the incident at severity ', severity),
    h('button', { class: 'btn', type: 'submit', text: 'Save switches' }));

  form.addEventListener('submit', (e) => {
    e.preventDefault();
    act(() => api.setDeadman(teamID, {
      matchers: matchers.value.trim(),
      timeout_seconds: Number(timeout.value) * 60,
      severity: severity.value,
    }));
  });

  return h('div', { class: 'card' },
    h('h2', { text: 'Dead man’s switches' }),
    h('p', { class: 'muted small' },
      'Alerts whose ABSENCE is the signal. Receiving one opens nothing; going ',
      'quiet for longer than the timeout opens an incident. ',
      h('code', { text: 'alertname=Watchdog,cluster=prod; alertname=EdgeHeartbeat' }),
      ' — semicolons separate switches, commas separate conditions, and every ',
      'switch must name an alertname. Leave empty to watch nothing.'),
    isOwner() ? form : h('p', { class: 'muted', text: d.matchers || 'Nothing watched.' }),
  );
}

// --- members ---------------------------------------------------------------

function membersCard() {
  const rows = (data.members || []).map((m) =>
    h('tr', {},
      h('td', {}, h('strong', { text: m.username })),
      h('td', { class: 'muted small', text: m.role }),
      h('td', {}, isOwner() && h('button', {
        class: 'btn-sm', type: 'button',
        text: m.role === 'owner' ? 'Make member' : 'Make owner',
        onclick: () => act(() =>
          api.addTeamMember(teamID, m.user_id, m.role === 'owner' ? 'member' : 'owner')),
      }), isOwner() && h('button', {
        class: 'btn-sm danger', type: 'button', text: 'Remove',
        onclick: () => act(() => api.removeTeamMember(teamID, m.user_id)),
      })),
    ));

  const inTeam = new Set((data.members || []).map((m) => m.user_id));
  const candidates = (data.users || []).filter((u) => !inTeam.has(u.id) && !u.disabled_at);
  const pick = h('select', {},
    ...candidates.map((u) => h('option', { value: String(u.id), text: u.username })));
  const role = h('select', {},
    h('option', { value: 'member', text: 'member' }),
    h('option', { value: 'owner', text: 'owner' }));
  const form = h('form', { class: 'inline-form' }, pick, role,
    h('button', { class: 'btn', type: 'submit', text: 'Add' }));
  form.addEventListener('submit', (e) => {
    e.preventDefault();
    act(() => api.addTeamMember(teamID, Number(pick.value), role.value));
  });

  return h('div', { class: 'card' },
    h('h2', { text: 'Members' }),
    h('table', { class: 'admin-table' }, h('tbody', {}, rows)),
    isOwner() && candidates.length > 0 && form,
  );
}

// --- plumbing --------------------------------------------------------------

// act runs a write and reloads. Errors are shown rather than thrown away: a
// 409 from the last-owner guard or the schedule's conflict rule is the server
// explaining itself, and the reader needs to see it.
async function act(fn, { resetDraft = false } = {}) {
  try {
    await fn();
    error = null;
    if (resetDraft) draft = null;
  } catch (err) {
    error = err.message;
  }
  if (!resetDraft) draft = null;
  await refresh();
}