import { pageRoute } from "../routes.js";

/* Orphaned-upload administration view. */

/** Format a byte count for the administrative upload list. */
function formatFileSize(size) {
  const bytes = Number(size || 0);
  if (bytes < 1024) return `${bytes} B`;
  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
}

class OrphanedUploadsAdmin {
  /**
   * goal   : Create the controller for uploads without current references.
   * pre    : api performs authenticated requests and translate resolves UI keys.
   * post   : The controller is connected to the orphaned-upload list.
   * result : A directly usable orphaned-upload administration controller.
   */
  constructor(api, translate) {
    this.api = api;
    this.translate = translate;
    this.list = document.getElementById("orphaned-uploads-list");
  }

  /**
   * goal   : Load orphaned uploads and their last historical uses.
   * pre    : The current session has administrator permission.
   * post   : The upload list represents the current server state.
   * result : A promise that resolves when all upload rows have been rendered.
   */
  async load() {
    const result = await this.api("/api/admin/uploads/orphaned");
    const uploads = result.uploads || [];
    this.list.replaceChildren();

    if (uploads.length === 0) {
      const empty = document.createElement("p");
      empty.className = "muted";
      empty.textContent = this.translate("no-orphaned-uploads", "No orphaned uploads.");
      this.list.append(empty);
      return;
    }

    for (const upload of uploads) this.list.append(this.#renderUpload(upload));
  }

  /** Build one upload row with history, view link and deletion action. */
  #renderUpload(upload) {
    const row = document.createElement("article");
    row.className = "orphaned-upload-row";

    const title = document.createElement("strong");
    title.textContent = upload.originalName;

    const meta = document.createElement("div");
    meta.className = "muted";
    meta.textContent = `${upload.mimeType} · ${formatFileSize(upload.size)} · ` +
      `${this.translate("uploaded-by", "uploaded by")} ${upload.uploadedBy}`;

    const history = this.#uploadHistory(upload);
    const actions = document.createElement("div");
    actions.className = "orphaned-upload-actions";

    const view = document.createElement("a");
    view.href = `/uploads/${encodeURIComponent(upload.ownerSlug)}/` +
      encodeURIComponent(upload.storedName);
    view.target = "_blank";
    view.rel = "noopener";
    view.textContent = this.translate("view", "View");

    const remove = document.createElement("button");
    remove.className = "danger";
    remove.textContent = this.translate("delete", "Delete");
    remove.addEventListener("click", () => {
      this.#deleteUpload(upload).catch((error) => console.error(error));
    });

    actions.append(view, remove);
    row.append(title, meta, history, actions);
    return row;
  }

  /** Build the historical-use portion of one upload row. */
  #uploadHistory(upload) {
    const history = document.createElement("div");
    const lastUses = Array.isArray(upload.lastUses) ? upload.lastUses : [];
    if (lastUses.length === 0) {
      history.textContent = this.translate(
        "never-referenced", "Never referenced by a saved page.");
      return history;
    }

    const label = document.createElement("div");
    label.textContent = `${this.translate("last-used", "Last used")}:`;
    const uses = document.createElement("ul");
    uses.className = "orphaned-upload-uses";
    for (const use of lastUses) {
      const item = document.createElement("li");
      const link = document.createElement("a");
      link.href = pageRoute(use.slug);
      link.textContent = use.title || use.slug;
      item.append(link);
      if (use.version) {
        item.append(document.createTextNode(
          ` · ${this.translate("version", "Version")} ${use.version}`));
      }
      uses.append(item);
    }
    history.append(label, uses);
    return history;
  }

  /** Confirm and remove one still-orphaned upload, then refresh the list. */
  async #deleteUpload(upload) {
    const question = this.translate(
      "delete-orphaned-upload-confirm", "Delete this orphaned upload?");
    if (!window.confirm(question)) return;
    await this.api(`/api/admin/uploads/orphaned/${upload.id}`, { method: "DELETE" });
    await this.load();
  }
}

export { OrphanedUploadsAdmin };