/**
 * Ask how pending CMap changes should be handled before navigation.
 *
 * Each call to choose resolves once with "save", "discard" or "cancel".
 * Saving and discarding remain workspace responsibilities because they change
 * the active editor and persistence state.
 */
export class CmapUnsavedDialog {
  constructor(dialog) {
    this.dialog = dialog;
    this.resolveChoice = null;

    dialog.querySelector("#cmap-unsaved-save")
      .addEventListener("click", () => this.finish("save"));
    dialog.querySelector("#cmap-unsaved-discard")
      .addEventListener("click", () => this.finish("discard"));
    dialog.querySelector("#cmap-unsaved-cancel")
      .addEventListener("click", () => this.finish("cancel"));
    dialog.addEventListener("cancel", (event) => {
      event.preventDefault();
      this.finish("cancel");
    });
  }

  choose() {
    if (this.resolveChoice) return Promise.resolve("cancel");
    this.dialog.showModal();
    return new Promise((resolve) => {
      this.resolveChoice = resolve;
    });
  }

  chooseSave() {
    this.finish("save");
  }

  finish(choice) {
    const resolve = this.resolveChoice;
    if (!resolve) return;
    this.resolveChoice = null;
    this.dialog.close();
    resolve(choice);
  }
}