// Paid posts (klonkt-demo-aki) slice 1: the site owner's own Patreon campaign.
// Stores client id/secret + the creator access/refresh token (encrypted) and a
// default price. Separate from PatreonService, which is Klonkt Premium's
// instance-level license flow and stays untouched.
import db from '../config/database.js';
import { encrypt, decrypt, cryptoBoxReady } from './CryptoBox.js';

const TOKEN_URL = 'https://www.patreon.com/api/oauth2/token';

// The owner's config, secrets decrypted. Returns null when unconfigured.
export function getOwnerConfig(siteId) {
  const row = db.prepare('SELECT * FROM paid_patreon WHERE site_id = ?').get(siteId);
  if (!row) return null;
  return {
    siteId: row.site_id,
    clientId: row.client_id || null,
    clientSecret: row.client_secret_enc ? safeDecrypt(row.client_secret_enc) : null,
    campaignId: row.campaign_id || null,
    accessToken: row.access_token_enc ? safeDecrypt(row.access_token_enc) : null,
    refreshToken: row.refresh_token_enc ? safeDecrypt(row.refresh_token_enc) : null,
    tokenExp: row.token_exp || 0,
    defaultMinCents: row.default_min_cents || 0,
    patreonUrl: row.patreon_url || null,
  };
}

// Non-secret status for the admin screen (never returns tokens/secret).
export function ownerStatus(siteId) {
  const c = getOwnerConfig(siteId);
  if (!c) return { configured: false, connected: false, defaultMinCents: 0 };
  return {
    configured: !!(c.clientId && c.clientSecret),
    connected: !!(c.accessToken && c.campaignId),
    clientId: c.clientId || null,
    campaignId: c.campaignId || null,
    defaultMinCents: c.defaultMinCents || 0,
    tokenExp: c.tokenExp || 0,
    hasSecret: !!c.clientSecret,
    patreonUrl: c.patreonUrl || null,
  };
}

// The owner's public Patreon page, for the "Word supporter" link. Null when unset.
export function patreonUrl(siteId) {
  const c = getOwnerConfig(siteId);
  return c && c.patreonUrl ? c.patreonUrl : null;
}

// Upsert. Only overwrites secret/token fields when a new value is provided, so
// the admin form can be re-saved without re-pasting the secret.
export function saveOwnerConfig(siteId, patch) {
  if (!cryptoBoxReady()) throw new Error('encryption key unavailable: cannot store Patreon secrets');
  const cur = getOwnerConfig(siteId) || {};
  const merged = {
    clientId: patch.clientId ?? cur.clientId ?? null,
    clientSecret: patch.clientSecret ?? cur.clientSecret ?? null,
    campaignId: patch.campaignId ?? cur.campaignId ?? null,
    accessToken: patch.accessToken ?? cur.accessToken ?? null,
    refreshToken: patch.refreshToken ?? cur.refreshToken ?? null,
    tokenExp: patch.tokenExp ?? cur.tokenExp ?? 0,
    defaultMinCents: patch.defaultMinCents ?? cur.defaultMinCents ?? 0,
    // undefined = keep (e.g. token refresh doesn't touch it); null/'' = clear.
    patreonUrl: patch.patreonUrl !== undefined ? (patch.patreonUrl || null) : (cur.patreonUrl ?? null),
  };
  db.prepare(`INSERT INTO paid_patreon
      (site_id, client_id, client_secret_enc, campaign_id, access_token_enc, refresh_token_enc, token_exp, default_min_cents, patreon_url, updated_at)
      VALUES (?,?,?,?,?,?,?,?,?,CURRENT_TIMESTAMP)
    ON CONFLICT(site_id) DO UPDATE SET
      client_id=excluded.client_id, client_secret_enc=excluded.client_secret_enc,
      campaign_id=excluded.campaign_id, access_token_enc=excluded.access_token_enc,
      refresh_token_enc=excluded.refresh_token_enc, token_exp=excluded.token_exp,
      default_min_cents=excluded.default_min_cents, patreon_url=excluded.patreon_url, updated_at=CURRENT_TIMESTAMP`)
    .run(
      siteId,
      merged.clientId,
      merged.clientSecret != null ? encrypt(merged.clientSecret) : null,
      merged.campaignId,
      merged.accessToken != null ? encrypt(merged.accessToken) : null,
      merged.refreshToken != null ? encrypt(merged.refreshToken) : null,
      merged.tokenExp || 0,
      Math.max(0, parseInt(merged.defaultMinCents, 10) || 0),
      merged.patreonUrl || null,
    );
}

export function disconnect(siteId) {
  db.prepare('DELETE FROM paid_patreon WHERE site_id = ?').run(siteId);
}

export function defaultMinCents(siteId) {
  const row = db.prepare('SELECT default_min_cents FROM paid_patreon WHERE site_id = ?').get(siteId);
  return row ? (row.default_min_cents || 0) : 0;
}

// True when the stored creator token is missing or within `skewSeconds` of exp.
export function needsRefresh(siteId, skewSeconds = 3600) {
  const c = getOwnerConfig(siteId);
  if (!c || !c.refreshToken) return false;
  return !c.accessToken || (c.tokenExp || 0) <= (Math.floor(Date.now() / 1000) + skewSeconds);
}

// Refresh the creator token via Patreon. Returns true on success. `fetchImpl`
// is injectable for tests; defaults to global fetch.
export async function refreshCreatorToken(siteId, fetchImpl = fetch) {
  const c = getOwnerConfig(siteId);
  if (!c || !c.clientId || !c.clientSecret || !c.refreshToken) return false;
  const body = new URLSearchParams({
    grant_type: 'refresh_token',
    refresh_token: c.refreshToken,
    client_id: c.clientId,
    client_secret: c.clientSecret,
  });
  const res = await fetchImpl(TOKEN_URL, {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: body.toString(),
  });
  if (!res.ok) return false;
  const j = await res.json();
  if (!j || !j.access_token) return false;
  saveOwnerConfig(siteId, {
    accessToken: j.access_token,
    refreshToken: j.refresh_token || c.refreshToken,
    tokenExp: Math.floor(Date.now() / 1000) + (parseInt(j.expires_in, 10) || 0),
  });
  return true;
}

// A valid creator access token, refreshing first if it is stale. Null when the
// owner has not connected. Used by the patron verify path (slice 3).
export async function creatorAccessToken(siteId, fetchImpl = fetch) {
  if (needsRefresh(siteId)) { try { await refreshCreatorToken(siteId, fetchImpl); } catch { /* fall through */ } }
  const c = getOwnerConfig(siteId);
  return c && c.accessToken ? c.accessToken : null;
}

// Pure: pick the owner's-campaign membership out of a Patreon
// identity?include=memberships.campaign response (JSON:API). Returns
// { status, cents } or null.
//
// STRICT match on campaignId only. Patreon's /identity returns ALL of the
// visitor's memberships across every creator they back (verified: a tester had
// 12), NOT just this creator's, so any fallback would grant access to someone
// who backs a DIFFERENT creator. The campaignId must therefore be the owner's
// real campaign; verifyPatron auto-derives it from the creator token so a
// mistyped admin value can't lock real patrons out.
export function pickCampaignMembership(identity, campaignId) {
  if (!campaignId) return null;
  const inc = (identity && identity.included) || [];
  for (const it of inc) {
    if (it.type !== 'member') continue;
    const camp = it.relationships && it.relationships.campaign && it.relationships.campaign.data;
    if (!camp || String(camp.id) !== String(campaignId)) continue;
    const a = it.attributes || {};
    return { status: a.patron_status || null, cents: a.currently_entitled_amount_cents || 0 };
  }
  return null;
}

// The campaign id owned by the creator token (i.e. the site owner's OWN
// campaign). This is authoritative: it removes the "typed the wrong campaign_id"
// failure mode. Null if there's no valid creator token or the call fails.
export async function fetchOwnerCampaignId(siteId, fetchImpl = fetch) {
  const token = await creatorAccessToken(siteId, fetchImpl).catch(() => null);
  if (!token) return null;
  const res = await fetchImpl('https://www.patreon.com/api/oauth2/v2/campaigns', {
    headers: { Authorization: `Bearer ${token}` },
  }).catch(() => null);
  if (!res || !res.ok) return null;
  const j = await res.json().catch(() => null);
  const id = j && j.data && j.data[0] && j.data[0].id;
  return id ? String(id) : null;
}

// Exchange a patron's auth code and read their membership of the owner's
// campaign. Returns { status, cents, diag } (status null = not a patron); the
// `diag` string is a NON-identifying breadcrumb (campaign ids + status + cents)
// so a stuck owner can see why. Returns null only on hard misconfig. The patron
// token is used once and discarded here: nothing identifying is stored.
export async function verifyPatron(siteId, code, redirectUri, fetchImpl = fetch) {
  const c = getOwnerConfig(siteId);
  if (!c || !c.clientId || !c.clientSecret) return null;
  const none = (diag) => ({ status: null, cents: 0, diag });
  let tokenRes;
  try {
    tokenRes = await fetchImpl(TOKEN_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
      body: new URLSearchParams({
        grant_type: 'authorization_code', code,
        client_id: c.clientId, client_secret: c.clientSecret, redirect_uri: redirectUri,
      }).toString(),
    });
  } catch { return none('token_fetch_error'); }
  if (!tokenRes.ok) return none(`token_http_${tokenRes.status}`);
  const tok = await tokenRes.json();
  if (!tok || !tok.access_token) return none('no_access_token');
  const url = 'https://www.patreon.com/api/oauth2/v2/identity'
    + '?include=memberships.campaign'
    + '&fields%5Bmember%5D=patron_status,currently_entitled_amount_cents';
  const idRes = await fetchImpl(url, { headers: { Authorization: `Bearer ${tok.access_token}` } });
  if (!idRes.ok) return none(`identity_http_${idRes.status}`);
  const identity = await idRes.json();
  // Authoritative campaign id: the one owned by the creator token. Beats a
  // mistyped admin value. Self-heal the stored config when they differ.
  const ownerCampaign = await fetchOwnerCampaignId(siteId, fetchImpl).catch(() => null);
  const campaignId = ownerCampaign || c.campaignId;
  if (ownerCampaign && String(ownerCampaign) !== String(c.campaignId)) {
    try { saveOwnerConfig(siteId, { campaignId: ownerCampaign }); } catch { /* non-fatal */ }
  }
  const membership = pickCampaignMembership(identity, campaignId);   // token goes out of scope, discarded
  const seen = ((identity && identity.included) || [])
    .filter((it) => it.type === 'member')
    .map((it) => {
      const camp = it.relationships && it.relationships.campaign && it.relationships.campaign.data;
      const a = it.attributes || {};
      return `${camp ? camp.id : '?'}:${a.patron_status || 'null'}:${a.currently_entitled_amount_cents || 0}c`;
    });
  const diag = `owner=${ownerCampaign || 'unknown'} config=${c.campaignId || 'none'} seen=[${seen.join(', ') || 'none'}] picked=${membership ? membership.status + '/' + membership.cents + 'c' : 'null'}`;
  if (!membership || membership.status !== 'active_patron') console.warn(`[paid] verifyPatron: ${diag}`);
  return { status: membership ? membership.status : null, cents: membership ? membership.cents : 0, diag };
}

function safeDecrypt(blob) {
  try { return decrypt(blob); } catch { return null; }
}

export default {
  getOwnerConfig, ownerStatus, saveOwnerConfig, disconnect,
  defaultMinCents, patreonUrl, needsRefresh, refreshCreatorToken, creatorAccessToken,
  pickCampaignMembership, fetchOwnerCampaignId, verifyPatron,
};