export type ResponseMessageShell = {
  result: string;
  why: string[];
  next_action: string[];
};

function asTrimmedString(value: unknown): string {
  return typeof value === "string" ? value.trim() : "";
}

function asTrimmedStringList(value: unknown): string[] {
  if (!Array.isArray(value)) return [];
  return value.map((v) => asTrimmedString(v)).filter(Boolean);
}

export function parseMessageShell(value: unknown): ResponseMessageShell | null {
  if (!value || typeof value !== "object" || Array.isArray(value)) return null;
  const obj = value as Record<string, unknown>;
  const result = asTrimmedString(obj.result);
  const why = asTrimmedStringList(obj.why);
  const nextAction = asTrimmedStringList(obj.next_action ?? obj.next_actions);
  if (!result && why.length === 0 && nextAction.length === 0) return null;
  return {
    result: result || "Request complete.",
    why,
    next_action: nextAction,
  };
}

export function resolveMessageShell(data: unknown, detail?: unknown): ResponseMessageShell | null {
  const detailObj =
    detail && typeof detail === "object" && !Array.isArray(detail) ? (detail as Record<string, unknown>) : null;
  const dataObj = data && typeof data === "object" && !Array.isArray(data) ? (data as Record<string, unknown>) : null;
  const fromDetail = parseMessageShell(detailObj?.message_shell);
  if (fromDetail) return fromDetail;
  return parseMessageShell(dataObj?.message_shell);
}

export function normalizeResultShell(result: string, why: string[] = [], nextAction: string[] = []): ResponseMessageShell {
  return {
    result: asTrimmedString(result) || "Request complete.",
    why: asTrimmedStringList(why),
    next_action: asTrimmedStringList(nextAction),
  };
}

export function resolveApiErrorInfo(data: unknown, fallback: string): { shell: ResponseMessageShell | null; text: string } {
  const dataObj = data && typeof data === "object" && !Array.isArray(data) ? (data as Record<string, unknown>) : null;
  const detail = dataObj?.detail;
  const shell = resolveMessageShell(data, detail);
  if (shell) return { shell, text: shell.result };

  const detailText = asTrimmedString(detail);
  if (detailText) return { shell: null, text: detailText };

  const detailObj = detail && typeof detail === "object" && !Array.isArray(detail) ? (detail as Record<string, unknown>) : null;
  const detailObjMessage = asTrimmedString(detailObj?.message) || asTrimmedString(detailObj?.error);
  if (detailObjMessage) return { shell: null, text: detailObjMessage };

  const message = asTrimmedString(dataObj?.message) || asTrimmedString(dataObj?.error);
  if (message) return { shell: null, text: message };

  return { shell: null, text: fallback };
}

export async function parseResponseBody(response: Response): Promise<unknown> {
  try {
    return await response.json();
  } catch {
    try {
      return await response.text();
    } catch {
      return null;
    }
  }
}