export interface BlfEntry {
  id: string;
  blfNo: number;
  blfType: string;
  blfTypeId: string;
  value: string;
}

const BLF_TAG =
  /<BLF\b([^>/]*)(?:\s*\/>|>([\s\S]*?)<\/BLF>)/gi;

function attr(attrs: string, name: string): string {
  const match = attrs.match(new RegExp(`\\b${name}="([^"]*)"`, "i"));
  return match?.[1] ?? "";
}

export function parseBlfs(xml: string | undefined | null): BlfEntry[] {
  if (!xml) {
    return [];
  }
  const entries: BlfEntry[] = [];
  for (const match of xml.matchAll(BLF_TAG)) {
    const attrs = match[1] ?? "";
    const blfNo = Number.parseInt(attr(attrs, "BLFNo"), 10);
    if (!Number.isFinite(blfNo)) {
      continue;
    }
    entries.push({
      id: attr(attrs, "ID") || "-1",
      blfNo,
      blfType: attr(attrs, "BLFType") || "BLF",
      blfTypeId: attr(attrs, "BLFTypeID") || "0",
      value: (match[2] ?? "").trim(),
    });
  }
  return entries;
}

function escapeXml(value: string): string {
  return value
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;");
}

export function serializeBlfs(entries: BlfEntry[]): string {
  const sorted = [...entries].sort((a, b) => a.blfNo - b.blfNo);
  const inner = sorted
    .map((entry) => {
      const attrs = `ID="${escapeXml(entry.id)}" BLFNo="${entry.blfNo}" BLFType="${escapeXml(entry.blfType)}" BLFTypeID="${escapeXml(entry.blfTypeId)}"`;
      if (entry.value === "") {
        return `<BLF ${attrs} />`;
      }
      return `<BLF ${attrs}>${escapeXml(entry.value)}</BLF>`;
    })
    .join("");
  return `<PhoneDevice><BLFS>${inner}</BLFS></PhoneDevice>`;
}

export function blfsEqual(a: string | undefined | null, b: string): boolean {
  return serializeBlfs(parseBlfs(a)) === serializeBlfs(parseBlfs(b));
}