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

/**
 * Applications de dialplan permitidas (agente.md secao 180: nunca deixar
 * input de tenant virar comando arbitrário no FreeSWITCH — "system",
 * "exec", "socket" etc. ficam de fora de propósito, mesmo que existam
 * módulos capazes de rodá-las).
 */
export const ALLOWED_DIALPLAN_APPLICATIONS = [
  "answer",
  "pre_answer",
  "bridge",
  "hangup",
  "park",
  "playback",
  "ring_ready",
  "respond",
  "set",
  "export",
  "transfer",
  "sleep",
  "record_session",
] as const;

export type AllowedDialplanApplication = (typeof ALLOWED_DIALPLAN_APPLICATIONS)[number];

export const ALLOWED_CONDITION_FIELDS = [
  "destination_number",
  "caller_id_number",
  "caller_id_name",
  "context",
  "network_addr",
  "source",
] as const;

export type AllowedConditionField = (typeof ALLOWED_CONDITION_FIELDS)[number];

export interface DialplanAction {
  application: AllowedDialplanApplication;
  data?: string;
}

export interface DialplanExtensionInput {
  name: string;
  conditionField: AllowedConditionField;
  conditionExpr: string;
  actions: DialplanAction[];
  antiActions?: DialplanAction[];
  continueOnFalse: boolean;
  order: number;
}

function actionsXml(tag: "action" | "anti-action", actions: DialplanAction[] | undefined): string {
  if (!actions || actions.length === 0) return "";
  return actions
    .map(
      (a) =>
        `      <${tag} application="${xmlEscape(a.application)}"${
          a.data !== undefined ? ` data="${xmlEscape(a.data)}"` : ""
        }/>`,
    )
    .join("\n");
}

/**
 * XML de dialplan (agente.md secao 43-44). Uma condição por extension —
 * simplificação deliberada em relação ao FreeSWITCH puro (que permite
 * múltiplas <condition> por extension); cobre o editor estruturado descrito
 * na especificação sem a complexidade de encadeamento arbitrário.
 */
export function buildDialplanXml(context: string, extensions: DialplanExtensionInput[]): string {
  const sorted = [...extensions].sort((a, b) => a.order - b.order);

  const extensionsXml = sorted
    .map((ext) => {
      const actionsBlock = actionsXml("action", ext.actions);
      const antiActionsBlock = actionsXml("anti-action", ext.antiActions);
      return `    <extension name="${xmlEscape(ext.name)}" continue="${ext.continueOnFalse ? "true" : "false"}">
      <condition field="${xmlEscape(ext.conditionField)}" expression="${xmlEscape(ext.conditionExpr)}">
${actionsBlock}${antiActionsBlock ? `\n${antiActionsBlock}` : ""}
      </condition>
    </extension>`;
    })
    .join("\n");

  return `<?xml version="1.0" encoding="UTF-8"?>
<document type="freeswitch/xml">
  <section name="dialplan">
    <context name="${xmlEscape(context)}">
${extensionsXml}
    </context>
  </section>
</document>`;
}