import { approveDevicePairing, listDevicePairing } from "./api.js";
import { formatPendingRequests } from "./notify.js";

type PendingPairingEntry = Awaited<ReturnType<typeof listDevicePairing>>["pending"][number];
type ApprovePairingResult = Awaited<ReturnType<typeof approveDevicePairing>>;
type ApprovedPairingEntry = Exclude<ApprovePairingResult, null | { status: "forbidden" }>;

function buildMultiplePendingApprovalReply(pending: PendingPairingEntry[]): { text: string } {
  return {
    text:
      `${formatPendingRequests(pending)}\n\n` +
      "Multiple pending requests found. Approve one explicitly:\n" +
      "/pair approve <requestId>\n" +
      "Or approve the most recent:\n" +
      "/pair approve latest",
  };
}

export function selectPendingApprovalRequest(params: {
  pending: PendingPairingEntry[];
  requested?: string;
}): { pending?: PendingPairingEntry; reply?: { text: string } } {
  if (params.pending.length === 0) {
    return { reply: { text: "No pending device pairing requests." } };
  }

  if (!params.requested) {
    return params.pending.length === 1
      ? { pending: params.pending[0] }
      : { reply: buildMultiplePendingApprovalReply(params.pending) };
  }

  if (params.requested.toLowerCase() === "latest") {
    return {
      pending: [...params.pending].toSorted((a, b) => (b.ts ?? 0) - (a.ts ?? 0))[0],
    };
  }

  return {
    pending: params.pending.find((entry) => entry.requestId === params.requested),
    reply: undefined,
  };
}

function formatApprovedPairingReply(approved: ApprovedPairingEntry): { text: string } {
  const label = approved.device.displayName?.trim() || approved.device.deviceId;
  const platform = approved.device.platform?.trim();
  const platformLabel = platform ? ` (${platform})` : "";
  return { text: `✅ Paired ${label}${platformLabel}.` };
}

export async function approvePendingPairingRequest(params: {
  requestId: string;
  callerScopes?: readonly string[];
}): Promise<{ text: string }> {
  const approved =
    params.callerScopes === undefined
      ? await approveDevicePairing(params.requestId)
      : await approveDevicePairing(params.requestId, { callerScopes: params.callerScopes });
  if (!approved) {
    return { text: "Pairing request not found." };
  }
  if (approved.status === "forbidden") {
    return {
      text: `⚠️ This command requires ${approved.missingScope} to approve this pairing request.`,
    };
  }
  return formatApprovedPairingReply(approved);
}