import { DISCOVER_BASE_URL } from "./env";

// Maps Minnect's public discovery payload (GET /api/v1/individual/home) to
// PUBLIC FIELDS ONLY. The mappers build each object from an explicit
// allow-list, so phone, DOB, zip, email, gender, KYC/Stripe fields,
// is_blocking, scores and rates can never leak through. No token is sent or logged.

export interface DiscoverExpert {
  id: string | number;
  slug: string | null;
  displayName: string;
  byline: string | null;
  pictureUrl: string | null;
  rating: number | null;
  reviewsCount: number | null;
  available: boolean | null;
  location: { city: string | null; country: string | null };
}

export interface DiscoverMinnect {
  id: string | number;
  question: string | null;
  views: number | null;
  thumbnailUrl: string | null;
  audio: {
    url: string | null;
    duration: number | null;
    waveform: number[] | string | null;
  };
  expert: {
    slug: string | null;
    displayName: string;
    pictureUrl: string | null;
    byline: string | null;
    rating: number | null;
  };
}

export interface DiscoverCategory {
  id: string | number;
  name: string;
  icon: string | null;
  sortOrder: number;
}

export interface DiscoverData {
  featuredExperts: DiscoverExpert[];
  trendingMinnects: DiscoverMinnect[];
  categories: DiscoverCategory[];
}

export type DiscoverResult =
  | { ok: true; data: DiscoverData }
  | { ok: false; status: 502; error: "discover_unavailable" };

type Rec = Record<string, unknown>;

const rec = (v: unknown): Rec =>
  v && typeof v === "object" && !Array.isArray(v) ? (v as Rec) : {};
const arr = (v: unknown): unknown[] => (Array.isArray(v) ? v : []);
const str = (v: unknown): string | null =>
  typeof v === "string" && v.trim() ? v : null;
const num = (v: unknown): number | null =>
  typeof v === "number" && Number.isFinite(v) ? v : null;
const bool = (v: unknown): boolean | null => (typeof v === "boolean" ? v : null);
const id = (v: unknown): string | number | null =>
  typeof v === "string" && v ? v : typeof v === "number" ? v : null;

function displayName(r: Rec): string {
  return [str(r.first_name), str(r.last_name)].filter(Boolean).join(" ");
}

export function mapExpert(raw: unknown): DiscoverExpert | null {
  const r = rec(raw);
  const eid = id(r.id);
  if (eid === null) return null;
  return {
    id: eid,
    slug: str(r.slug),
    displayName: displayName(r),
    byline: str(r.byline),
    pictureUrl: str(r.url_picture),
    rating: num(r.rating),
    reviewsCount: num(r.reviews_count),
    available: bool(r.available),
    location: { city: str(r.city), country: str(r.country) },
  };
}

function waveform(v: unknown): number[] | string | null {
  if (Array.isArray(v)) return v.filter((n): n is number => typeof n === "number");
  return str(v);
}

export function mapMinnect(raw: unknown): DiscoverMinnect | null {
  const r = rec(raw);
  const mid = id(r.id);
  if (mid === null) return null;
  const answer = rec(r.answer);
  const expert = rec(r.expert);
  return {
    id: mid,
    question: str(r.question_text),
    views: num(r.views),
    thumbnailUrl: str(rec(r.thumbnail).url),
    audio: {
      url: str(answer.url),
      duration: num(answer.duration),
      waveform: waveform(answer.waveform_data),
    },
    expert: {
      slug: str(expert.slug),
      displayName: displayName(expert),
      pictureUrl: str(expert.url_picture),
      byline: str(expert.byline),
      rating: num(expert.rating),
    },
  };
}

export function mapCategory(raw: unknown): DiscoverCategory | null {
  const r = rec(raw);
  const cid = id(r.id);
  const name = str(r.name);
  if (cid === null || !name || r.active === false) return null;
  return { id: cid, name, icon: str(r.icon), sortOrder: num(r.sort_order) ?? 0 };
}

export function mapDiscover(body: unknown): DiscoverData {
  const data = rec(rec(body).data);
  const keep = <T>(x: T | null): x is T => x !== null;
  return {
    featuredExperts: arr(data.featured_experts).map(mapExpert).filter(keep),
    trendingMinnects: arr(data.trending_conversations).map(mapMinnect).filter(keep),
    categories: arr(data.trending_categories)
      .map(mapCategory)
      .filter(keep)
      .sort((a, b) => a.sortOrder - b.sortOrder),
  };
}

const UNAVAILABLE: DiscoverResult = {
  ok: false,
  status: 502,
  error: "discover_unavailable",
};

/** Fetch and map the public discovery data. Never throws; upstream failure -> 502. */
export async function getDiscover(
  fetchImpl: typeof fetch = fetch,
): Promise<DiscoverResult> {
  try {
    const res = await fetchImpl(`${DISCOVER_BASE_URL}/api/v1/individual/home`, {
      headers: { Accept: "application/json" },
      cache: "no-store",
    });
    if (!res.ok) return UNAVAILABLE;
    const body: unknown = await res.json();
    return { ok: true, data: mapDiscover(body) };
  } catch {
    return UNAVAILABLE;
  }
}