/**
 * Match live-lijst zenders → XMLTV channel id over alle geconfigureerde EPG-bronnen.
 * Preferentie: exacte id (odido/<externalId>) → contentId → genormaliseerde display-name.
 */

export type EpgChannelOption = { id: string; name: string };

export function normalizeEpgLabel(raw: string | null | undefined): string {
  let s = String(raw ?? "")
    .toLowerCase()
    .normalize("NFD")
    .replace(/\p{M}/gu, "");
  // "1. NPO 1" / "150. ESPN"
  s = s.replace(/^\d+\.\s*/, "");
  s = s.replace(/\b(hd|fhd|uhd|4k|hevc|hdr|sd)\b/g, " ");
  s = s.replace(/&/g, " and ");
  s = s.replace(/[^a-z0-9+]+/g, "");
  return s;
}

/** Bouw lookup: genormaliseerde naam → voorkeurs-id (stabiele eerste winnaar). */
export function buildEpgNameIndex(
  options: Iterable<EpgChannelOption>,
  preferIdPrefix?: string
): Map<string, string> {
  const byName = new Map<string, string>();
  const prefer = preferIdPrefix?.toLowerCase();
  const preferBetter = (existing: string, next: string) => {
    if (!prefer) return false;
    const e = existing.toLowerCase().startsWith(prefer);
    const n = next.toLowerCase().startsWith(prefer);
    return n && !e;
  };
  for (const { id, name } of options) {
    const keys = new Set<string>();
    const nName = normalizeEpgLabel(name);
    const nId = normalizeEpgLabel(id);
    if (nName) keys.add(nName);
    if (nId) keys.add(nId);
    const bare = id.includes("/") ? id.slice(id.lastIndexOf("/") + 1) : "";
    if (bare) {
      const nBare = normalizeEpgLabel(bare);
      if (nBare) keys.add(nBare);
    }
    for (const key of keys) {
      const prev = byName.get(key);
      if (!prev || preferBetter(prev, id)) byName.set(key, id);
    }
  }
  return byName;
}

export type MatchEpgInput = {
  name: string;
  externalId?: string | null;
  contentId?: string | null;
  /** provider hint: bij "odido" eerst odido/<id> proberen */
  provider?: string | null;
};

/**
 * Zoek beste XMLTV-id. `idSet` bevat alle bekende ids (case-sensitive + lower aliases ok).
 * `byName` uit buildEpgNameIndex.
 */
export function matchEpgChannelId(
  input: MatchEpgInput,
  idSet: Set<string>,
  byName: Map<string, string>
): string | null {
  const candidates: string[] = [];
  const externalId = input.externalId?.trim();
  const contentId = input.contentId?.trim();
  const provider = (input.provider ?? "").trim().toLowerCase();

  if (externalId) {
    if (provider === "odido" || !provider) {
      candidates.push(`odido/${externalId}`);
    }
    candidates.push(externalId);
  }
  if (contentId) {
    if (provider === "odido" || !provider) {
      candidates.push(`odido/${contentId}`);
    }
    candidates.push(contentId);
  }

  for (const c of candidates) {
    if (idSet.has(c)) return c;
    const lower = c.toLowerCase();
    if (lower !== c && idSet.has(lower)) return lower;
    // case-insensitive scan
    for (const id of idSet) {
      if (id.toLowerCase() === lower) return id;
    }
  }

  const nameKey = normalizeEpgLabel(input.name);
  if (nameKey && byName.has(nameKey)) return byName.get(nameKey)!;

  // Lichte fuzzy: name bevat of zit in EPG-label (alleen bij unieke hit)
  if (nameKey && nameKey.length >= 4) {
    const hits: string[] = [];
    for (const [key, id] of byName) {
      if (key === nameKey) return id;
      if (key.includes(nameKey) || nameKey.includes(key)) hits.push(id);
    }
    const unique = [...new Set(hits)];
    if (unique.length === 1) return unique[0];
    // Bij Odido: prefer odido/-ids
    if (provider === "odido") {
      const odidoHits = unique.filter((id) => id.toLowerCase().startsWith("odido/"));
      if (odidoHits.length === 1) return odidoHits[0];
    }
  }

  return null;
}