import type { MountedVisualizationHandle } from '@astrato-io/visualizations';

/** Orders mounting against visibility changes; readiness must never block that ordering. */
export function createPanelLifecycle(options: {
  mount: () => Promise<MountedVisualizationHandle>;
  onState: (state: string, message: string) => void;
}) {
  let visible = true;
  let destroyed = false;
  let empty = false;
  let state = '';
  const setState = (value: string, message: string) => {
    state = value;
    options.onState(value, message);
  };
  let handle: MountedVisualizationHandle | undefined;
  let lifecycle: Promise<void> = Promise.resolve();
  function reconcile(force = false) {
    lifecycle = lifecycle
      .catch(() => undefined)
      .then(async () => {
        if (force || !visible || destroyed) {
          handle?.unmount();
          handle = undefined;
        }
        if (!visible || destroyed) {
          setState('hidden', 'Chart is hidden and unmounted.');
          return;
        }
        if (handle) return;
        setState('loading', 'Loading live data…');
        try {
          const mounted = await options.mount();
          if (!visible || destroyed) {
            mounted.unmount();
            return;
          }
          handle = mounted;
          void mounted.ready
            .then((result) => {
              if (handle !== mounted || destroyed || !visible) return;
              if (result.status === 'rendered')
                setState(empty ? 'empty' : 'ready', empty ? 'No data for the applied filters.' : '');
              else if (result.status === 'timeout') setState('timeout', 'Rendering is taking longer than expected.');
              else if (result.status === 'error') setState('error', 'This chart could not render.');
            })
            .catch(() => {
              if (handle === mounted && visible && !destroyed) setState('error', 'This chart could not render.');
            });
        } catch (error) {
          if (visible && !destroyed) setState('error', error instanceof Error ? error.message : 'Mount failed.');
        }
      });
    return lifecycle;
  }
  return {
    start: () => reconcile(),
    show() {
      if (destroyed) return lifecycle;
      visible = true;
      return reconcile();
    },
    hide() {
      visible = false;
      return reconcile();
    },
    retry: () => reconcile(true),
    setEmpty(value: boolean) {
      empty = value;
      if (handle && visible && !destroyed && ['ready', 'empty'].includes(state))
        setState(empty ? 'empty' : 'ready', empty ? 'No data for the applied filters.' : '');
    },
    destroy() {
      destroyed = true;
      return reconcile();
    },
  };
}