const WhatsAppTemplate = require('../models/WhatsAppTemplate');
const { getOrgWhatsAppCredentials, listMessageTemplates } = require('../utils/metaWhatsApp');

function normLang(s) {
  return String(s || '')
    .trim()
    .replace(/-/g, '_')
    .toLowerCase();
}

function rejectionFromMeta(m) {
  if (!m || typeof m !== 'object') return '';
  return String(m.rejected_reason || m.reason || '').trim();
}

function normalizeCategory(raw) {
  const c = String(raw || '')
    .trim()
    .toUpperCase();
  if (c === 'MARKETING' || c === 'UTILITY' || c === 'AUTHENTICATION') return c;
  return 'UTILITY';
}

async function resolveCreatedBy(organizationId, locals) {
  for (const loc of locals || []) {
    if (loc.createdBy) return loc.createdBy;
  }
  try {
    const User = require('../models/User');
    const u = await User.findOne({ organization: organizationId }).select('_id').lean();
    if (u?._id) return u._id;
  } catch {
    /* ignore */
  }
  return undefined;
}

/**
 * Pull template rows from Meta and upsert local docs (by metaTemplateId or name+language).
 * Creates local rows for Meta templates that are not yet in the dashboard.
 * @param {import('mongoose').Types.ObjectId|string} organizationId
 * @param {{ onlyNames?: string[] }} [opts] — when set, only upsert these Meta template names
 */
async function syncOrganizationTemplates(organizationId, opts = {}) {
  const creds = await getOrgWhatsAppCredentials(organizationId);
  if (!creds) {
    return { ok: false, error: 'WhatsApp Cloud is not configured for this organisation (WABA + access token).' };
  }

  const data = await listMessageTemplates(creds.wabaId, creds.accessToken);
  let list = Array.isArray(data.data) ? data.data : [];
  const onlyNames = Array.isArray(opts.onlyNames)
    ? opts.onlyNames.map((n) => String(n || '').trim().toLowerCase()).filter(Boolean)
    : null;
  if (onlyNames && onlyNames.length) {
    list = list.filter((m) => onlyNames.includes(String(m.name || '').trim().toLowerCase()));
  }

  const locals = await WhatsAppTemplate.find({ organization: organizationId }).lean();
  const now = new Date();
  let updated = 0;
  let created = 0;

  for (const loc of locals) {
    let m = null;
    if (loc.metaTemplateId) {
      m = list.find((x) => String(x.id) === String(loc.metaTemplateId));
    }
    if (!m) {
      m = list.find((x) => x.name === loc.name && normLang(x.language) === normLang(loc.language));
    }
    if (m) {
      const st = m.status != null ? String(m.status).toUpperCase() : loc.status;
      const $set = {
        metaTemplateId: String(m.id),
        status: st,
        rejectionReason: rejectionFromMeta(m),
        lastSyncedAt: now,
        lastError: '',
      };
      if (m.category) $set.category = normalizeCategory(m.category);
      if (Array.isArray(m.components) && m.components.length) $set.components = m.components;
      await WhatsAppTemplate.updateOne({ _id: loc._id }, { $set });
      updated += 1;
    }
  }

  const createdBy = await resolveCreatedBy(organizationId, locals);

  for (const m of list) {
    const name = String(m.name || '').trim();
    const language = String(m.language || '').trim().replace(/-/g, '_');
    if (!name || !language) continue;
    const exists = locals.some(
      (loc) =>
        (loc.metaTemplateId && String(loc.metaTemplateId) === String(m.id)) ||
        (loc.name === name && normLang(loc.language) === normLang(language)),
    );
    if (exists) continue;

    try {
      await WhatsAppTemplate.create({
        organization: organizationId,
        name,
        language,
        category: normalizeCategory(m.category),
        components: Array.isArray(m.components) ? m.components : [],
        metaTemplateId: m.id != null ? String(m.id) : '',
        status: m.status != null ? String(m.status).toUpperCase() : 'PENDING',
        rejectionReason: rejectionFromMeta(m),
        lastSyncedAt: now,
        lastError: '',
        variableBindings: { header: [], body: [], url: [] },
        ...(createdBy ? { createdBy } : {}),
      });
      created += 1;
    } catch (e) {
      if (e && e.code === 11000) {
        await WhatsAppTemplate.updateOne(
          { organization: organizationId, name, language },
          {
            $set: {
              metaTemplateId: m.id != null ? String(m.id) : '',
              status: m.status != null ? String(m.status).toUpperCase() : 'PENDING',
              rejectionReason: rejectionFromMeta(m),
              lastSyncedAt: now,
              lastError: '',
              ...(m.category ? { category: normalizeCategory(m.category) } : {}),
              ...(Array.isArray(m.components) && m.components.length ? { components: m.components } : {}),
            },
          },
        );
        updated += 1;
        continue;
      }
      throw e;
    }
  }

  return { ok: true, metaCount: list.length, updated, created };
}

module.exports = { syncOrganizationTemplates };