const prisma = require('../config/db');
const { safeErrorMessage } = require('../utils/errorUtils');
const { logAdminAction } = require('../utils/adminAudit');
const { getClientIp } = require('../utils/requestUtils');
const { describeUserAgent } = require('../utils/userAgent');
const {
  isMinor, consentStatusFor, validateConsentAnswer, sealJson, openJson, latestRequestsFor,
  findRequestByToken, resendConsentRequest, createConsentRequest,
} = require('../utils/consent');

const STAFF = ['admin', 'supervisor', 'staff'];
const fail = (res, error) => res.status(error.statusCode || (res.statusCode === 200 ? 400 : res.statusCode)).json({ message: safeErrorMessage(error) });

// What the parent sees — never the registrant's contact details or other attendees.
function publicView(request) {
  const ev = request.event;
  const latestForAttendee = request._isLatest !== false;
  return {
    status: request.status,
    superseded: !latestForAttendee,
    expired: new Date(request.expiresAt) < new Date(),
    respondedAt: request.respondedAt,
    attendeeName: request.attendee.name,
    parentName: request.parentName,
    consentText: request.consentText,
    textVersion: request.textVersion,
    event: { title: ev.title, startDate: ev.startDate, endDate: ev.endDate, location: ev.location },
    collect: { medical: ev.consentCollectMedical, emergency: ev.consentCollectEmergency, photo: ev.consentCollectPhoto },
  };
}

// @desc    Consent page data for a parent/guardian
// @route   GET /api/consent/:token
// @access  Public (the token is the credential)
const getConsent = async (req, res) => {
  try {
    const request = await findRequestByToken(req.params.token);
    if (!request) { res.status(404); throw new Error('This consent link is not valid. It may have been replaced by a newer one — check your latest message.'); }
    const latest = (await latestRequestsFor([request.attendeeId])).get(request.attendeeId);
    res.json(publicView({ ...request, _isLatest: latest?.id === request.id }));
  } catch (error) {
    fail(res, error);
  }
};

// @desc    Give or decline consent
// @route   POST /api/consent/:token
// @access  Public (the token is the credential)
const answerConsent = async (req, res) => {
  try {
    const request = await findRequestByToken(req.params.token);
    if (!request) { res.status(404); throw new Error('This consent link is not valid.'); }
    if (request.status !== 'pending') { res.status(409); throw new Error(`Consent has already been ${request.status}.`); }
    if (new Date(request.expiresAt) < new Date()) { res.status(410); throw new Error('This consent link has expired because the event has ended.'); }
    const latest = (await latestRequestsFor([request.attendeeId])).get(request.attendeeId);
    if (latest?.id !== request.id) { res.status(409); throw new Error('A newer consent request replaced this one — please use the link in your latest message.'); }

    let answer;
    try { answer = validateConsentAnswer(req.body || {}, request.event); } catch (e) { res.status(400); throw e; }

    // Only flips pending → answered once, even if the form is submitted twice at once.
    const updated = await prisma.consentRequest.updateMany({
      where: { id: request.id, status: 'pending' },
      data: {
        status: answer.decision === 'give' ? 'given' : 'declined',
        signedName: answer.signedName,
        ip: getClientIp(req),
        device: describeUserAgent(req.headers['user-agent']),
        medical: sealJson(answer.medical),
        emergency: sealJson(answer.emergency),
        photoConsent: answer.photoConsent,
        respondedAt: new Date(),
      },
    });
    if (updated.count !== 1) { res.status(409); throw new Error('Consent has already been answered.'); }

    notifyConsentAnswered(request.id).catch(e => console.error('[consent] notify failed:', e?.message || e));
    res.json({ message: answer.decision === 'give' ? 'Thank you — consent has been given.' : 'Thank you — consent has been declined.', status: answer.decision === 'give' ? 'given' : 'declined' });
  } catch (error) {
    fail(res, error);
  }
};

// Tells the registrant and the event's notify recipients how a parent answered.
async function notifyConsentAnswered(requestId) {
  const request = await prisma.consentRequest.findUnique({
    where: { id: requestId },
    include: {
      attendee: { include: { registration: { include: { user: { select: { id: true, name: true, email: true, phoneNumber: true, notificationPreference: true } } } } } },
      event: { include: { createdBy: { select: { id: true, name: true, email: true } }, notifyRecipients: { select: { id: true, name: true, email: true } } } },
    },
  });
  if (!request) return;
  const { sendMail, emailWrapper } = require('../utils/email');
  const { shouldEmail, waText } = require('../utils/notify');
  const { buildEventNotifyRecipientList } = require('../utils/notifications');
  const given = request.status === 'given';
  const verb = given ? 'given' : 'declined';
  const who = request.attendee.name;
  const ev = request.event.title;
  const payer = request.attendee.registration.user;
  const line = given
    ? `${request.signedName} gave parental consent for ${who} for ${ev}.`
    : `${request.signedName} declined parental consent for ${who} for ${ev}. ${who} can't be checked in — please contact the organisers about a refund.`;

  const sends = [];
  const payerHasEmail = payer?.email && !payer.email.endsWith('@guest.local') && !payer.email.endsWith('@deleted.invalid');
  if (payerHasEmail && shouldEmail(payer) && payer.email !== request.parentEmail) {
    sends.push(sendMail({ to: payer.email, subject: `Consent ${verb} for ${who}`, html: emailWrapper(`<p>${line}</p>`), text: line }));
  }
  if (payer) sends.push(waText(payer, line));
  const staff = buildEventNotifyRecipientList(request.event);
  if (staff.length) {
    sends.push(sendMail({ to: staff.join(','), subject: `Consent ${verb}: ${who} — ${ev}`, html: emailWrapper(`<p>${line}</p>`), text: line }));
  }
  await Promise.allSettled(sends);
}

/** One row per attendee on the event, with consent state — for the consent tracker. */
async function consentRows(eventId) {
  const event = await prisma.event.findUnique({ where: { id: eventId } });
  if (!event) return { event: null, rows: [] };
  const attendees = await prisma.attendee.findMany({
    where: { registration: { eventId, status: { not: 'cancelled' } } },
    include: { registration: { select: { id: true, status: true, user: { select: { id: true, name: true, email: true } } } } },
    orderBy: [{ registrationId: 'asc' }, { order: 'asc' }],
  });
  const latest = await latestRequestsFor(attendees.map(a => a.id));
  const rows = attendees.map(a => {
    const r = latest.get(a.id) || null;
    return {
      attendeeId: a.id,
      name: a.name,
      dateOfBirth: a.dateOfBirth,
      minor: isMinor(a.dateOfBirth, event.startDate),
      parentName: a.parentName, parentEmail: a.parentEmail, parentPhone: a.parentPhone,
      registrationId: a.registrationId,
      registrationStatus: a.registration.status,
      bookedBy: a.registration.user,
      status: consentStatusFor(a, event, r),
      request: r && {
        id: r.id, status: r.status, textVersion: r.textVersion, signedName: r.signedName, respondedAt: r.respondedAt,
        lastSentAt: r.lastSentAt, remindersSent: r.remindersSent, photoConsent: r.photoConsent,
        outdated: r.status === 'given' && r.textVersion < (event.consentTextVersion || 1),
      },
    };
  });
  return { event, rows };
}

// @desc    Consent status for every attendee on an event
// @route   GET /api/consent/events/:eventId
// @access  Private/Staff
const listEventConsent = async (req, res) => {
  try {
    const { event, rows } = await consentRows(req.params.eventId);
    if (!event) { res.status(404); throw new Error('Event not found'); }
    const counts = rows.reduce((c, r) => { c[r.status] = (c[r.status] || 0) + 1; return c; }, {});
    res.json({
      event: { id: event.id, title: event.title, startDate: event.startDate, requiresParentalConsent: event.requiresParentalConsent, consentTextVersion: event.consentTextVersion },
      counts,
      rows,
    });
  } catch (error) {
    fail(res, error);
  }
};

// @desc    Re-send one consent request (with a fresh link)
// @route   POST /api/consent/requests/:id/resend
// @access  Private (the registrant, or staff)
const resendRequest = async (req, res) => {
  try {
    const request = await prisma.consentRequest.findUnique({ where: { id: req.params.id }, include: { attendee: { include: { registration: true } } } });
    if (!request) { res.status(404); throw new Error('Consent request not found'); }
    if (request.attendee.registration.userId !== req.user.id && !STAFF.includes(req.user.role)) { res.status(403); throw new Error('Not authorized'); }
    const latest = (await latestRequestsFor([request.attendeeId])).get(request.attendeeId);
    if (latest?.id !== request.id) { res.status(400); throw new Error('A newer consent request has replaced this one.'); }
    const sent = await resendConsentRequest(request.id);
    res.json({ message: sent.length ? `Consent request re-sent by ${sent.join(' and ')}.` : 'The consent request could not be sent — check the parent\'s email and phone.' });
  } catch (error) {
    fail(res, error);
  }
};

// @desc    Re-send every consent request still pending on an event
// @route   POST /api/consent/events/:eventId/resend-pending
// @access  Private/Supervisor
const resendPending = async (req, res) => {
  try {
    const { rows } = await consentRows(req.params.eventId);
    const pending = rows.filter(r => r.status === 'pending' && r.request);
    let sent = 0;
    for (const r of pending) {
      try { if ((await resendConsentRequest(r.request.id)).length) sent += 1; } catch {}
    }
    res.json({ message: `Re-sent ${sent} of ${pending.length} pending request(s).`, sent, pending: pending.length });
  } catch (error) {
    fail(res, error);
  }
};

// @desc    Ask again for consent where it was given on an older version of the text,
//          and for minors who never got a request (e.g. names added later)
// @route   POST /api/consent/events/:eventId/rerequest
// @access  Private/Supervisor
const rerequestConsent = async (req, res) => {
  try {
    const { event, rows } = await consentRows(req.params.eventId);
    if (!event) { res.status(404); throw new Error('Event not found'); }
    if (!event.requiresParentalConsent) { res.status(400); throw new Error('This event does not need parental consent.'); }
    const targets = rows.filter(r => r.minor && r.registrationStatus !== 'cancelled' && (r.status === 'missing' || r.request?.outdated));
    let created = 0;
    for (const r of targets) {
      if (!r.parentEmail && !r.parentPhone) continue;
      const attendee = await prisma.attendee.findUnique({ where: { id: r.attendeeId } });
      await createConsentRequest(attendee, event);
      created += 1;
    }
    logAdminAction({
      actorId: req.user.id, actorRole: req.user.role, action: 'consent_rerequested',
      targetType: 'Event', targetId: event.id, metadata: { requests: created, textVersion: event.consentTextVersion },
      ip: getClientIp(req),
    });
    res.json({ message: `Sent ${created} new consent request(s).`, created });
  } catch (error) {
    fail(res, error);
  }
};

// @desc    Medical & emergency list for an event (decrypted) — every view is audited
// @route   GET /api/consent/events/:eventId/medical
// @access  Private/Supervisor
const medicalList = async (req, res) => {
  try {
    const event = await prisma.event.findUnique({ where: { id: req.params.eventId } });
    if (!event) { res.status(404); throw new Error('Event not found'); }
    const { rows } = await consentRows(event.id);
    const ids = rows.map(r => r.request?.id).filter(Boolean);
    const full = ids.length ? await prisma.consentRequest.findMany({ where: { id: { in: ids } } }) : [];
    const byId = new Map(full.map(r => [r.id, r]));
    const list = rows
      .filter(r => r.request && byId.get(r.request.id)?.status === 'given')
      .map(r => {
        const fr = byId.get(r.request.id);
        return {
          name: r.name, dateOfBirth: r.dateOfBirth,
          parentName: r.parentName, parentPhone: r.parentPhone, parentEmail: r.parentEmail,
          medical: openJson(fr.medical), emergency: openJson(fr.emergency), photoConsent: fr.photoConsent,
          purged: !!fr.medicalPurgedAt,
        };
      });
    logAdminAction({
      actorId: req.user.id, actorRole: req.user.role, action: 'medical_list_viewed',
      targetType: 'Event', targetId: event.id, metadata: { attendees: list.length },
      ip: getClientIp(req),
    });
    res.json({ event: { id: event.id, title: event.title, startDate: event.startDate }, rows: list });
  } catch (error) {
    fail(res, error);
  }
};

module.exports = { getConsent, answerConsent, listEventConsent, resendRequest, resendPending, rerequestConsent, medicalList };