/**
 * Edit CMap metadata without knowing how the active CMap is persisted.
 *
 * The controller owns field population and validation. Its save handler
 * receives normalized metadata and reports success with a boolean result.
 */
export class CmapMetadataDialog {
  constructor(dialog, tr, normalizePageReference) {
    this.dialog = dialog;
    this.tr = tr;
    this.normalizePageReference = normalizePageReference;
    this.form = dialog.querySelector("form");
    this.summary = dialog.querySelector("#cmap-metadata-summary");
    this.namespace = dialog.querySelector("#cmap-metadata-namespace");
    this.tags = dialog.querySelector("#cmap-metadata-tags");
    this.explanationPage = dialog.querySelector("#cmap-metadata-explanation-page");
    this.saveHandler = null;

    dialog.querySelector("#cmap-metadata-cancel")
      .addEventListener("click", () => dialog.close());
    this.explanationPage.addEventListener("input", () =>
      this.explanationPage.setCustomValidity(""));
    this.form.addEventListener("submit", (event) => {
      event.preventDefault();
      this.save().catch((error) => window.alert(error.message));
    });
  }

  onSave(handler) {
    this.saveHandler = handler;
    return this;
  }

  open(metadata) {
    this.namespace.value = metadata.namespace || "";
    this.summary.value = metadata.summary || "";
    this.tags.value = (metadata.tags || []).join(", ");
    this.explanationPage.value = metadata.explanationPageSlug || "";
    this.explanationPage.setCustomValidity("");
    this.dialog.showModal();
    this.summary.focus();
  }

  metadata() {
    const namespace = this.namespace.value.trim().toLocaleLowerCase();
    if (namespace && !/^[\p{L}\p{N}][\p{L}\p{N}-]*$/u.test(namespace)) {
      this.namespace.setCustomValidity(
        this.tr("invalid-concept-map-namespace", "Use letters, numbers and hyphens for the namespace."));
      this.namespace.reportValidity();
      return null;
    }
    this.namespace.setCustomValidity("");
    const explanationInput = this.explanationPage.value.trim();
    const explanationPageSlug = explanationInput ?
      this.normalizePageReference(explanationInput) : "";
    if (explanationInput && !explanationPageSlug) {
      this.explanationPage.setCustomValidity(
        this.tr("invalid-description-page", "Enter a valid description page address."));
      this.explanationPage.reportValidity();
      return null;
    }
    return {
      namespace,
      tags: this.tags.value.split(",").map((tag) => tag.trim()).filter(Boolean),
      summary: this.summary.value.trim(),
      explanationPageSlug
    };
  }

  async save() {
    const metadata = this.metadata();
    if (!metadata || !this.saveHandler) return false;
    const saved = await this.saveHandler(metadata);
    if (saved) this.dialog.close();
    return saved;
  }
}