/**
 * Snapshots interesting ids/phones/customer keys that arrive on `globalEvent`
 * payloads so the Methods tab can pre-fill them as `{{placeholders}}` (mirrors
 * the debuggerOmni `extractAndSaveContext` / `applySavedContextToSample`
 * pattern). Lossy by design — only the fields we know how to use elsewhere.
 */

export type AafEventContext = {
  /** Voice / chat call id (sometimes `crtObjectId`). */
  crtObjectId?: string;
  /** Customer id from `voiceCustomerLinked`, `customerCallMemberCreated`, etc. */
  customerId?: string;
  /** Active campaign id from `campaignSelectionChange` / agent session. */
  campaignId?: string;
  /** Latest dialled / connected phone. */
  phone?: string;
  /** Display variant of the phone if the host normalised it. */
  displayPhone?: string;
  /** Chat or voice user object id (when the host shares it). */
  userCrtObjectId?: string;
  /** Chat or voice customer object id. */
  customerCrtObjectId?: string;
  /** Ticket id from attachment / disposition events. */
  ticketId?: string;
};

const STRING_FIELDS = new Set<keyof AafEventContext>([
  "crtObjectId",
  "customerId",
  "campaignId",
  "phone",
  "displayPhone",
  "userCrtObjectId",
  "customerCrtObjectId",
  "ticketId"
]);

function asString(v: unknown): string | undefined {
  if (v === null || v === undefined) return undefined;
  if (typeof v === "string") return v.trim() === "" ? undefined : v;
  if (typeof v === "number" || typeof v === "bigint") return String(v);
  return undefined;
}

function pickStringFromAny(value: unknown, key: string, depth: number, seen: WeakSet<object>): string | undefined {
  if (value === null || value === undefined) return undefined;
  if (typeof value !== "object") return undefined;
  if (depth > 4) return undefined;
  if (seen.has(value as object)) return undefined;
  seen.add(value as object);
  // `campaignSelectionChange` (and others) deliver arrays at the top level —
  // walk every entry as if it were a sibling object.
  if (Array.isArray(value)) {
    for (const item of value) {
      const nested = pickStringFromAny(item, key, depth + 1, seen);
      if (nested) return nested;
    }
    return undefined;
  }
  const obj = value as Record<string, unknown>;
  if (key in obj) {
    const direct = asString(obj[key]);
    if (direct) return direct;
  }
  for (const v of Object.values(obj)) {
    if (v && typeof v === "object") {
      const nested = pickStringFromAny(v, key, depth + 1, seen);
      if (nested) return nested;
    }
  }
  return undefined;
}

/** Merge anything we can recognise from `payload` into `current`. Returns a NEW object only when something changed. */
export function extractContextUpdates(
  current: AafEventContext,
  payload: unknown
): AafEventContext | null {
  if (!payload || typeof payload !== "object") return null;
  const next: AafEventContext = { ...current };
  let changed = false;

  for (const field of STRING_FIELDS) {
    const found = pickStringFromAny(payload, field as string, 0, new WeakSet());
    if (found && found !== next[field]) {
      next[field] = found;
      changed = true;
    }
  }

  // Some Ameyo payloads expose `phone1` (column name) — fall back when no `phone` key exists.
  if (!next.phone) {
    const alt = pickStringFromAny(payload, "phone1", 0, new WeakSet());
    if (alt) {
      next.phone = alt;
      changed = true;
    }
  }

  // ECC `ContextEventService` and ticket payloads use `interactionId` for the
  // ticket / call id; treat that as ticketId for placeholder fill-in.
  if (!next.ticketId) {
    const alt =
      pickStringFromAny(payload, "interactionId", 0, new WeakSet()) ??
      pickStringFromAny(payload, "ticketId", 0, new WeakSet());
    if (alt) {
      next.ticketId = alt;
      changed = true;
    }
  }

  return changed ? next : null;
}

/**
 * Replaces `{{customerId}}`, `{{campaignId}}`, `{{phone}}`, `{{userCrtObjectId}}`,
 * `{{customerCrtObjectId}}`, `{{crtObjectId}}`, `{{ticketId}}`, `{{displayPhone}}`
 * tokens with the latest captured value, or sensible literal fallbacks so the
 * sample is still valid JSON.
 */
export function applyContextToSample(template: string, ctx: AafEventContext): string {
  if (!template) return template;
  const fallbacks: Record<keyof AafEventContext, string> = {
    crtObjectId: "crt-object-id-from-event",
    customerId: "1",
    campaignId: "1",
    phone: "9999999999",
    displayPhone: "9999999999",
    userCrtObjectId: "user-crt-from-event",
    customerCrtObjectId: "customer-crt-from-event",
    ticketId: "ticket-id-from-event"
  };
  return template.replace(/\{\{(\w+)\}\}/g, (_match, key: string) => {
    const k = key as keyof AafEventContext;
    return ctx[k] ?? fallbacks[k] ?? `{{${key}}}`;
  });
}