import type { RunState, NodeInstanceState } from "./types.ts";

export interface LoopWidgetOptions {
  /** Number of columns used for node progress. Defaults to 2. */
  columns?: number;
  /** Animation frame for running-node loaders. Defaults to Date.now-derived frame. */
  frame?: number;
  /** Whether to show attempt count when a node has retried. Defaults to true. */
  showAttempts?: boolean;
}

/**
 * Build the standard extension-level loop progress widget.
 *
 * The renderer is intentionally generic: it uses node labels from the loop
 * definition and never hardcodes workflow-specific step names. Running nodes use
 * a 4-dot loader where 3 highlighted dots move through the 4 positions.
 */
export function renderLoopWidget(run: RunState, options: LoopWidgetOptions = {}): string[] {
  const columns = Math.max(1, options.columns ?? 2);
  const frame = options.frame ?? Math.floor(Date.now() / 350);
  const showAttempts = options.showAttempts ?? true;

  const completed = run.nodes.filter((node) => node.status === "completed").length;
  const header = `Pi Loop: ${run.loopId} · ${run.status} · ${completed}/${run.nodes.length}`;
  const nodeLines = run.nodes.map((node, index) => renderNodeCell(node, index, frame, showAttempts));

  const rows: string[] = [header, ""];
  for (let i = 0; i < nodeLines.length; i += columns) {
    rows.push(nodeLines.slice(i, i + columns).map((line) => line.padEnd(36)).join("  ").trimEnd());
  }
  return rows;
}

function renderNodeCell(node: NodeInstanceState, index: number, frame: number, showAttempts: boolean): string {
  const marker = renderNodeMarker(node, frame);
  const attempts = showAttempts && node.attempts.length > 1 ? ` (${node.attempts.length})` : "";
  return `${String(index + 1).padStart(2, " ")} ${marker} ${node.nodeDef.label}${attempts}`;
}

function renderNodeMarker(node: NodeInstanceState, frame: number): string {
  switch (node.status) {
    case "completed":
      return "✓";
    case "failed":
      return "✗";
    case "skipped":
      return "-";
    case "running":
      return renderFourDotLoader(frame);
    case "pending":
    default:
      return "○";
  }
}

function renderFourDotLoader(frame: number): string {
  const emptyIndex = (3 - (((frame % 4) + 4) % 4) + 4) % 4;
  let out = "";
  for (let i = 0; i < 4; i++) {
    out += i === emptyIndex ? "·" : "●";
  }
  return out;
}