export interface ToolOk {
  ok: true
  message: string
  data?: Record<string, unknown>
  legal_next?: string[]
}

export interface ToolErr {
  ok: false
  error: string
  legal_next?: string[]
  data?: Record<string, unknown>
}

export type ToolResult = ToolOk | ToolErr

export function ok(
  message: string,
  data?: Record<string, unknown>,
  legal_next?: string[],
): ToolResult {
  const r: ToolOk = { ok: true, message }
  if (data) r.data = data
  if (legal_next?.length) r.legal_next = legal_next
  return r
}

export function err(
  error: string,
  opts?: { legal_next?: string[]; data?: Record<string, unknown> },
): ToolErr {
  return {
    ok: false,
    error,
    legal_next: opts?.legal_next,
    data: opts?.data,
  }
}

export function formatResult(r: ToolResult): string {
  const legal = r.legal_next?.length
    ? `\nlegal_next: ${r.legal_next.join(", ")}`
    : ""
  const extra = r.data ? `\n${JSON.stringify(r.data, null, 2)}` : ""
  return r.ok
    ? `OK: ${r.message}${legal}${extra}`
    : `ERROR: ${r.error}${legal}${extra}`
}

export function toolContent(r: ToolResult) {
  return {
    content: [{ type: "text" as const, text: formatResult(r) }],
    details: r,
  }
}