const addressArrayKeys = [
  "from",
  "to",
  "cc",
  "bcc",
  "reply_to",
  "bounce_to",
  "disposition_notification_to"
];

export function campaignJsonForAttachmentPreview(draft: Record<string, unknown>): Record<string, unknown> {
  const next = cloneJson(draft);
  const entries = asRecord(next.entries);
  if (Array.isArray(entries.inline)) {
    entries.inline = entries.inline.map((entry) => normalizePreviewEntry(entry));
  }
  if (isRecord(entries.defaults)) {
    entries.defaults = normalizePreviewEntry(entries.defaults);
  }
  next.entries = entries;
  if (isRecord(next.recipients)) {
    next.recipients = normalizeAddressContainer(next.recipients);
  }
  return next;
}

function normalizePreviewEntry(value: unknown): Record<string, unknown> {
  const entry = { ...asRecord(value) };
  if (typeof entry.email === "string" && !entry.email.trim()) delete entry.email;
  if (typeof entry.name === "string" && !entry.name.trim()) delete entry.name;

  for (const key of addressArrayKeys) {
    const current = entry[key];
    if (Array.isArray(current)) {
      const filtered = current.map(normalizeRecipient).filter((item): item is Record<string, unknown> => Boolean(item));
      entry[key] = filtered;
      continue;
    }
    if (isRecord(current)) {
      const normalized = normalizeRecipient(current);
      if (normalized) entry[key] = normalized;
      else delete entry[key];
    }
  }

  return entry;
}

function normalizeAddressContainer(value: Record<string, unknown>): Record<string, unknown> {
  const container = { ...value };
  for (const key of addressArrayKeys) {
    const current = container[key];
    if (Array.isArray(current)) {
      container[key] = current.map(normalizeRecipient).filter((item): item is Record<string, unknown> => Boolean(item));
      continue;
    }
    if (isRecord(current)) {
      const normalized = normalizeRecipient(current);
      if (normalized) container[key] = normalized;
      else delete container[key];
    }
  }
  return container;
}

function normalizeRecipient(value: unknown): Record<string, unknown> | null {
  const recipient = { ...asRecord(value) };
  const email = typeof recipient.email === "string" ? recipient.email.trim() : "";
  if (!email) return null;
  recipient.email = email;
  if (typeof recipient.name === "string" && !recipient.name.trim()) delete recipient.name;
  return recipient;
}

function cloneJson<T>(value: T): T {
  return JSON.parse(JSON.stringify(value ?? {})) as T;
}

function asRecord(value: unknown): Record<string, unknown> {
  return value && typeof value === "object" && !Array.isArray(value) ? value as Record<string, unknown> : {};
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return value !== null && typeof value === "object" && !Array.isArray(value);
}