import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import type { Decision } from "./parse";
import { parseDecision } from "./parse";
import { formatDetail, formatLine } from "./format";

/**
 * Pi extension entry point. After each routed provider response it updates a
 * footer status line with the Wayfinder routing decision, and registers a
 * `/wf` command that prints the full last decision.
 *
 * @param pi - The Pi extension API.
 */
export default function (pi: ExtensionAPI): void {
  let last: Decision | null = null;

  pi.on("after_provider_response", (event, ctx) => {
    const decision = parseDecision(event.headers);
    // A non-Wayfinder response yields null; leave the prior line untouched.
    if (!decision) return;
    last = decision;
    if (ctx.hasUI) ctx.ui.setStatus("wayfinder", formatLine(decision));
  });

  pi.on("session_start", (_event, ctx) => {
    last = null;
    if (ctx.hasUI) ctx.ui.setStatus("wayfinder", undefined);
  });

  pi.registerCommand("wf", {
    description: "Show the last Wayfinder routing decision",
    handler: async (_args, ctx) => {
      const lines = last ? formatDetail(last) : ["wayfinder - no routed response yet"];
      ctx.ui.notify(lines.join("\n"), "info");
    },
  });
}