import {
  VERSION,
  type ExtensionAPI,
} from "@earendil-works/pi-coding-agent";
import { satisfies, valid } from "semver";
import { AutoCompactController } from "./src/auto-compact-controller.ts";
import { loadAutoCompactConfig, type ConfigLoadResult } from "./src/config.ts";

export const REQUIRED_PI_RANGE = ">=0.84.1";

interface AutoCompactExtensionOptions {
  readonly piVersion?: string;
  readonly loadConfig?: () => ConfigLoadResult;
}

export function supportsPiVersion(version: string): boolean {
  return valid(version) !== null && satisfies(version, REQUIRED_PI_RANGE);
}

export function createWjPiAutoCompactExtension(
  options: AutoCompactExtensionOptions = {},
): (pi: ExtensionAPI) => void {
  const piVersion = options.piVersion ?? VERSION;
  return (pi: ExtensionAPI): void => {
    if (!supportsPiVersion(piVersion)) {
      let warningShown = false;
      pi.on("session_start", (_event, ctx) => {
        if (warningShown || !ctx.hasUI) return;
        warningShown = true;
        ctx.ui.notify(
          `wj-pi-auto-compact is disabled: requires Pi ${REQUIRED_PI_RANGE}; current version: ${piVersion}`,
          "warning",
        );
      });
      return;
    }

    const controller = new AutoCompactController(
      pi,
      (options.loadConfig ?? loadAutoCompactConfig)(),
    );

    pi.on("session_start", (_event, ctx) => controller.startSession(ctx));
    pi.on("turn_end", (event, ctx) => controller.onTurnEnd(event, ctx));
    pi.on("turn_start", (event, ctx) => controller.onTurnStart(event, ctx));
    pi.on("agent_end", (event, ctx) => controller.onAgentEnd(event, ctx));
    pi.on("message_start", (event) => controller.onMessageStart(event));
    pi.on("session_before_compact", (event, ctx) => controller.onSessionBeforeCompact(event, ctx));
    pi.on("session_compact", (event, ctx) => controller.onSessionCompact(event, ctx));
    pi.on("agent_settled", (_event, ctx) => controller.onAgentSettled(ctx));
    pi.on("session_shutdown", () => controller.shutdown());
  };
}

export default createWjPiAutoCompactExtension();