/*
 * Wiki page references.
 *
 * This module owns the syntax used to identify root and namespaced pages.
 * It has no application or DOM state.
 */

/** Split a wiki reference into its namespace and page slug. */
function splitPageReference(reference) {
  const value = String(reference || "");
  const separator = value.indexOf(":");
  if (separator < 0) return { namespace: "", slug: value };
  return { namespace: value.slice(0, separator), slug: value.slice(separator + 1) };
}

/** Build the compact external reference for a root or namespaced page. */
function pageReference(namespace, slug) {
  const cleanNamespace = String(namespace || "").trim();
  return cleanNamespace ? `${cleanNamespace}:${slug}` : slug;
}

/** Convert one freely entered reference part to a bounded wiki identifier. */
function slugifyReferencePart(value, maximum) {
  return String(value || "")
    .normalize("NFKD")
    .toLocaleLowerCase()
    .replace(/[\u0300-\u036f]/g, "")
    .replace(/[^\p{L}\p{N}]+/gu, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, maximum)
    .replace(/-+$/g, "");
}

/**
 * goal   : Convert a freely entered page title/address to a wiki reference.
 * pre    : input may contain a namespace separated by a colon.
 * post   : No page is created and no application state is changed.
 * result : A normalized reference, or null when the input is empty or invalid.
 */
function newPageReference(input) {
  const parts = splitPageReference(String(input || "").trim());
  const namespace = parts.namespace ? slugifyReferencePart(parts.namespace, 80) : "";
  const slug = slugifyReferencePart(parts.slug, 120);
  if (!slug || (parts.namespace && !namespace)) return null;
  return pageReference(namespace, slug);
}

/** Normalize human-readable text for ambiguity-aware WikiWord matching. */
function normalizeMentionText(text) {
  return String(text || "")
    .normalize("NFKD")
    .replace(/[\u0300-\u036f]/g, "")
    .toLocaleLowerCase()
    .replace(/[^\p{L}\p{N}]+/gu, "");
}

/** Return the separate capitalized words when text is a classic WikiWord. */
function wikiWordParts(text) {
  const value = String(text || "");
  if (!/^(?:\p{Lu}\p{Ll}+){2,}$/u.test(value)) return [];
  return value.match(/\p{Lu}\p{Ll}+/gu) || [];
}

/**
 * goal   : Resolve a classic WikiWord to an existing page or new page target.
 * pre    : aliases is an ambiguity-aware map built by wiki-markdown.js.
 * post   : No page is created and aliases is not changed.
 * result : A slug/title pair, or null when text is not a WikiWord.
 */
function wikiWordTarget(text, aliases, namespace = "") {
  const parts = wikiWordParts(text);
  if (parts.length === 0) return null;

  const aliasKey = `${String(namespace || "").toLocaleLowerCase()}:${normalizeMentionText(text)}`;
  const existing = aliases.get(aliasKey);
  if (existing) return { slug: existing.slug, title: existing.title };

  const slug = parts.map((part) => part.toLocaleLowerCase()).join("-");
  return {
    slug: pageReference(namespace, slug),
    title: parts.join(" ")
  };
}

/** Derive a readable title from the page part of a wiki reference. */
function slugTitle(reference) {
  const slug = splitPageReference(reference || "").slug;
  return slug
    .split("-")
    .filter(Boolean)
    .map((part) => part.charAt(0).toUpperCase() + part.slice(1))
    .join(" ");
}

export {
  newPageReference,
  normalizeMentionText,
  pageReference,
  slugTitle,
  splitPageReference,
  wikiWordTarget
};