import { thenMaybe } from '#src/core/results.ts';
import { defineInterceptor } from '../core/interceptors.ts';
import type { UpdateCheckConfig } from '../feature/update-check.ts';
import type { AnyPadroneBuilder, CommandTypesBase } from '../types/index.ts';
import { getVersion } from '../util/utils.ts';

// ── Interceptor ─────────────────────────────────────────────────────────

function createUpdateCheckInterceptor(config: UpdateCheckConfig) {
  return defineInterceptor({ id: 'padrone:update-check', name: 'padrone:update-check', order: 1000 }, () => {
    let checkPromise: Promise<(() => void) | undefined> | undefined;
    let suppressed = false;

    return {
      start(ctx, next) {
        const rootCommand = ctx.command;
        const runtime = ctx.runtime;

        checkPromise = Promise.resolve(getVersion(rootCommand.version)).then((currentVersion) =>
          import('../feature/update-check.ts').then(({ createUpdateChecker }) =>
            createUpdateChecker(rootCommand.name, currentVersion, config, runtime),
          ),
        );

        return next();
      },
      parse(_ctx, next) {
        return thenMaybe(next(), (res) => {
          if ('update-check' in res.rawArgs) {
            if (res.rawArgs['update-check'] === false) suppressed = true;
            delete res.rawArgs['update-check'];
          }
          return res;
        });
      },
      shutdown(_ctx, next) {
        const result = next();
        if (suppressed || !checkPromise) return result;

        // Try to show notification synchronously if the check already resolved
        let resolved: (() => void) | undefined | null = null;
        checkPromise.then(
          (fn) => {
            resolved = fn;
          },
          () => {
            resolved = undefined;
          },
        );

        if (resolved !== null) {
          (resolved as (() => void) | undefined)?.();
        }

        return result;
      },
    };
  });
}

// ── Extension ────────────────────────────────────────────────────────────

/**
 * Extension that adds background update checking:
 * - Checks for newer versions on npm (or custom registry) in the background
 * - Shows an update notification after command execution
 * - Respects `--no-update-check` flag to suppress
 *
 * Usage:
 * ```ts
 * createPadrone('my-cli')
 *   .extend(padroneUpdateCheck({ packageName: 'my-cli' }))
 * ```
 */
export function padroneUpdateCheck(config: UpdateCheckConfig = {}): <T extends CommandTypesBase>(builder: T) => T {
  return ((builder: AnyPadroneBuilder) => builder.intercept(createUpdateCheckInterceptor(config))) as any;
}