foliate-js/reader.js

import "./view.js";
import { createTOCView } from "./ui/tree.js";
import { createMenu } from "./ui/menu.js";
import { Overlayer } from "./overlayer.js";

const getCSS = ({ spacing, justify, hyphenate }) => `
    @namespace epub "http://www.idpf.org/2007/ops";
    html {
        color-scheme: light dark;
    }
    /* https://github.com/whatwg/html/issues/5426 */
    @media (prefers-color-scheme: dark) {
        a:link {
            color: lightblue;
        }
    }
    p, li, blockquote, dd {
        line-height: ${spacing};
        text-align: ${justify ? "justify" : "start"};
        -webkit-hyphens: ${hyphenate ? "auto" : "manual"};
        hyphens: ${hyphenate ? "auto" : "manual"};
        -webkit-hyphenate-limit-before: 3;
        -webkit-hyphenate-limit-after: 2;
        -webkit-hyphenate-limit-lines: 2;
        hanging-punctuation: allow-end last;
        widows: 2;
    }
    /* prevent the above from overriding the align attribute */
    [align="left"] { text-align: left; }
    [align="right"] { text-align: right; }
    [align="center"] { text-align: center; }
    [align="justify"] { text-align: justify; }

    pre {
        white-space: pre-wrap !important;
    }
    aside[epub|type~="endnote"],
    aside[epub|type~="footnote"],
    aside[epub|type~="note"],
    aside[epub|type~="rearnote"] {
        display: none;
    }
`;

const $ = document.querySelector.bind(document);

const locales = "en";
const percentFormat = new Intl.NumberFormat(locales, { style: "percent" });
const listFormat = new Intl.ListFormat(locales, {
  style: "short",
  type: "conjunction",
});

const formatLanguageMap = (x) => {
  if (!x) return "";
  if (typeof x === "string") return x;
  const keys = Object.keys(x);
  return x[keys[0]];
};

const formatOneContributor = (contributor) =>
  typeof contributor === "string"
    ? contributor
    : formatLanguageMap(contributor?.name);

const formatContributor = (contributor) =>
  Array.isArray(contributor)
    ? listFormat.format(contributor.map(formatOneContributor))
    : formatOneContributor(contributor);

class Reader {
  #tocView;
  style = {
    spacing: 1.4,
    justify: true,
    hyphenate: true,
  };
  annotations = new Map();
  annotationsByValue = new Map();
  closeSideBar() {
    $("#dimming-overlay").classList.remove("show");
    $("#side-bar").classList.remove("show");
  }
  constructor() {
    $("#side-bar-button").addEventListener("click", () => {
      $("#dimming-overlay").classList.add("show");
      $("#side-bar").classList.add("show");
    });
    $("#dimming-overlay").addEventListener("click", () => this.closeSideBar());

    const menu = createMenu([
      {
        name: "layout",
        label: "Layout",
        type: "radio",
        items: [
          ["Paginated", "paginated"],
          ["Scrolled", "scrolled"],
        ],
        onclick: (value) => {
          this.view?.renderer.setAttribute("flow", value);
        },
      },
      {
        name: "panel-mode",
        label: "Panel Mode",
        type: "checkbox",
        checked: false,
        onclick: () => {
          // ← No 'value' parameter for checkbox
          const renderer = this.view?.renderer;
          if (!renderer?.togglePanelMode) return;

          const isActive = renderer.hasAttribute("panel-mode");
          if (isActive) {
            renderer.removeAttribute("panel-mode");
          } else {
            renderer.togglePanelMode();
          }
        },
      },
    ]);
    menu.element.classList.add("menu");

    $("#menu-button").append(menu.element);
    $("#menu-button > button").addEventListener("click", () =>
      menu.element.classList.toggle("show"),
    );
    menu.groups.layout.select("paginated");
  }
  async open(file) {
    this.view = document.createElement("foliate-view");
    document.body.append(this.view);
    await this.view.open(file);
    this.view.addEventListener("load", this.#onLoad.bind(this));
    this.view.addEventListener("relocate", this.#onRelocate.bind(this));

    const { book } = this.view;
    book.transformTarget?.addEventListener("data", ({ detail }) => {
      detail.data = Promise.resolve(detail.data).catch((e) => {
        console.error(new Error(`Failed to load ${detail.name}`, { cause: e }));
        return "";
      });
    });
    this.view.renderer.setStyles?.(getCSS(this.style));
    this.view.renderer.next();

    $("#header-bar").style.visibility = "visible";
    $("#nav-bar").style.visibility = "visible";
    $("#left-button").addEventListener("click", () => this.view.goLeft());
    $("#right-button").addEventListener("click", () => this.view.goRight());

    const slider = $("#progress-slider");
    slider.dir = book.dir;
    slider.addEventListener("input", (e) =>
      this.view.goToFraction(parseFloat(e.target.value)),
    );
    for (const fraction of this.view.getSectionFractions()) {
      const option = document.createElement("option");
      option.value = fraction;
      $("#tick-marks").append(option);
    }

    document.addEventListener("keydown", this.#handleKeydown.bind(this));

    const title = formatLanguageMap(book.metadata?.title) || "Untitled Book";
    document.title = title;
    $("#side-bar-title").innerText = title;
    $("#side-bar-author").innerText = formatContributor(book.metadata?.author);
    Promise.resolve(book.getCover?.())?.then((blob) =>
      blob ? ($("#side-bar-cover").src = URL.createObjectURL(blob)) : null,
    );

    const toc = book.toc;
    if (toc) {
      this.#tocView = createTOCView(toc, (href) => {
        this.view.goTo(href).catch((e) => console.error(e));
        this.closeSideBar();
      });
      $("#toc-view").append(this.#tocView.element);
    }

    // load and show highlights embedded in the file by Calibre
    const bookmarks = await book.getCalibreBookmarks?.();
    if (bookmarks) {
      const { fromCalibreHighlight } = await import("./epubcfi.js");
      for (const obj of bookmarks) {
        if (obj.type === "highlight") {
          const value = fromCalibreHighlight(obj);
          const color = obj.style.which;
          const note = obj.notes;
          const annotation = { value, color, note };
          const list = this.annotations.get(obj.spine_index);
          if (list) list.push(annotation);
          else this.annotations.set(obj.spine_index, [annotation]);
          this.annotationsByValue.set(value, annotation);
        }
      }
      this.view.addEventListener("create-overlay", (e) => {
        const { index } = e.detail;
        const list = this.annotations.get(index);
        if (list)
          for (const annotation of list) this.view.addAnnotation(annotation);
      });
      this.view.addEventListener("draw-annotation", (e) => {
        const { draw, annotation } = e.detail;
        const { color } = annotation;
        draw(Overlayer.highlight, { color });
      });
      this.view.addEventListener("show-annotation", (e) => {
        const annotation = this.annotationsByValue.get(e.detail.value);
        if (annotation.note) alert(annotation.note);
      });
    }
  }
  #handleKeydown(event) {
    const k = event.key;
    const renderer = this.view?.renderer;

    // Check if in panel mode
    if (renderer?.hasAttribute?.("panel-mode")) {
      if (k === "ArrowRight" || k === "l") {
        event.preventDefault();
        renderer.nextPanel();
      } else if (k === "ArrowLeft" || k === "h") {
        event.preventDefault();
        renderer.prevPanel();
      } else if (k === "Escape" || k === "p") {
        event.preventDefault();
        renderer.togglePanelMode();
      }
      return;
    }
    if (k === "ArrowLeft" || k === "h") this.view.goLeft();
    else if (k === "ArrowRight" || k === "l") this.view.goRight();
    else if (k === "p") {
      event.preventDefault();
      renderer?.togglePanelMode?.();
    }
  }
  #onLoad({ detail: { doc } }) {
    doc.addEventListener("keydown", this.#handleKeydown.bind(this));
  }
  #onRelocate({ detail }) {
    const { fraction, location, tocItem, pageItem } = detail;
    const percent = percentFormat.format(fraction);
    const loc = pageItem ? `Page ${pageItem.label}` : `Loc ${location.current}`;
    const slider = $("#progress-slider");
    slider.style.visibility = "visible";
    slider.value = fraction;
    slider.title = `${percent} · ${loc}`;
    if (tocItem?.href) this.#tocView?.setCurrentHref?.(tocItem.href);
  }
}

const open = async (file) => {
  document.body.removeChild($("#drop-target"));
  const reader = new Reader();
  globalThis.reader = reader;
  await reader.open(file);
};

const dragOverHandler = (e) => e.preventDefault();
const dropHandler = (e) => {
  e.preventDefault();
  const item = Array.from(e.dataTransfer.items).find(
    (item) => item.kind === "file",
  );
  if (item) {
    const entry = item.webkitGetAsEntry();
    open(entry.isFile ? item.getAsFile() : entry).catch((e) =>
      console.error(e),
    );
  }
};
const dropTarget = $("#drop-target");
dropTarget.addEventListener("drop", dropHandler);
dropTarget.addEventListener("dragover", dragOverHandler);

$("#file-input").addEventListener("change", (e) =>
  open(e.target.files[0]).catch((e) => console.error(e)),
);
$("#file-button").addEventListener("click", () => $("#file-input").click());

const params = new URLSearchParams(location.search);
const url = params.get("url");
if (url) open(url).catch((e) => console.error(e));
else dropTarget.style.visibility = "visible";