WRNexusJS/packages/viewer/src/registry.ts

import { requireConverter } from "./convert/client.ts";
import { mountArchive } from "./renderers/archive.ts";
import { mountConverted } from "./renderers/converted.ts";
import { mountDocx } from "./renderers/docx.ts";
import { mountOpenDocument, mountPresentation } from "./renderers/office.ts";
import { mountRtf } from "./renderers/rtf.ts";
import { mountCode } from "./renderers/code.ts";
import { mountHtml } from "./renderers/html.ts";
import { mountImage } from "./renderers/image.ts";
import { mountMedia } from "./renderers/media.ts";
import { mountJson } from "./renderers/json.ts";
import { mountPdf } from "./renderers/pdf.ts";
import { mountSvg } from "./renderers/svg.ts";
import { mountSheet } from "./renderers/sheet.ts";
import { mountTable } from "./renderers/table.ts";
import { mountXml } from "./renderers/xml.ts";
import { mountZip } from "./renderers/zip.ts";
import { loadOptional } from "./optional/load.ts";
import type { Renderer, ViewerKind } from "./types.ts";

const MB = 1024 * 1024;

/** Terminal rung of the ladder: metadata and a download link, never a preview. */
export const downloadRenderer: Renderer = {
  kind: "binary",
  exts: [],
  tier: 1,
  component: "DownloadCard",
  maxInlineBytes: 0,
};

const builtins: Renderer[] = [
  {
    kind: "markup",
    exts: [".html", ".htm"],
    tier: 2,
    component: "HtmlViewer",
    maxInlineBytes: 2 * MB,
    mount: mountHtml,
  },
  {
    kind: "image",
    exts: [],
    tier: 1,
    component: "ImageViewer",
    maxInlineBytes: 32 * MB,
    streaming: true,
    mount: mountImage,
  },
  {
    kind: "pdf",
    exts: [],
    tier: 1,
    component: "PdfViewer",
    maxInlineBytes: 32 * MB,
    streaming: true,
    mount: mountPdf,
  },
  ...(["audio", "video"] as const).map((kind) => ({
    kind,
    exts: [],
    tier: 1 as const,
    component: "MediaViewer",
    maxInlineBytes: 64 * MB,
    streaming: true,
    mount: mountMedia,
  })),
  // Tier 2: in-package parsers, no runtime dependency. Extension-specific, so a
  // parse failure falls through to the source view below.
  {
    kind: "sheet" as const,
    exts: [".csv", ".tsv"],
    tier: 2 as const,
    component: "TableViewer",
    maxInlineBytes: 8 * MB,
    mount: mountTable,
  },
  {
    kind: "code" as const,
    exts: [".json"],
    tier: 2 as const,
    component: "JsonViewer",
    maxInlineBytes: 8 * MB,
    mount: mountJson,
  },
  {
    kind: "code" as const,
    exts: [".xml"],
    tier: 2 as const,
    component: "XmlViewer",
    maxInlineBytes: 8 * MB,
    mount: mountXml,
  },
  {
    kind: "vector" as const,
    exts: [],
    tier: 2 as const,
    component: "SvgViewer",
    maxInlineBytes: 2 * MB,
    mount: mountSvg,
  },
  {
    kind: "archive" as const,
    exts: [".tar", ".gz", ".tgz"],
    tier: 2 as const,
    component: "ArchiveViewer",
    maxInlineBytes: 64 * MB,
    mount: mountArchive,
  },
  ...(["text", "code", "markup"] as const).map((kind) => ({
    kind,
    exts: [],
    tier: 1 as const,
    component: "CodeViewer",
    maxInlineBytes: 2 * MB,
    mount: mountCode,
  })),
];

/**
 * Tier 2 renderers backed by an optional dependency. `load` imports the runtime
 * asset the plugin only publishes when the package is installed, so a missing
 * dependency is reported the same way a missing converter is: skip and move on.
 */
builtins.push(
  {
    kind: "sheet",
    exts: [".xls", ".xlsx", ".ods"],
    tier: 2,
    component: "SheetViewer",
    maxInlineBytes: 32 * MB,
    load: (options) => loadOptional("viewer-sheet", options?.baseURI),
    mount: mountSheet,
  },
  {
    kind: "archive",
    exts: [".zip"],
    tier: 2,
    component: "ZipViewer",
    maxInlineBytes: 64 * MB,
    load: (options) => loadOptional("viewer-zip", options?.baseURI),
    mount: mountZip,
  },
);

/**
 * Tier 3: the browser cannot render these at all, so they are handed to a
 * server-side converter. Each carries a `load` that asks the server once
 * whether that format is actually convertible here; when conversion is not
 * enabled the load fails and the ladder moves on to the download card.
 */
const CONVERTIBLE: [ViewerKind, string[]][] = [
  ["doc", [".doc", ".docx", ".dotx", ".odt", ".rtf", ".ppt", ".pptx", ".ppsx", ".potx", ".odp"]],
  ["sheet", [".xls", ".xlsx", ".ods"]],
  ["binary", [".psd", ".ai", ".tif", ".tiff"]],
  ["video", [".avi", ".mkv"]],
  ["archive", [".zip", ".rar", ".7z"]],
];

for (const [kind, exts] of CONVERTIBLE)
  for (const ext of exts)
    builtins.push({
      kind,
      exts: [ext],
      tier: 3,
      component: "ConvertedViewer",
      // The preview comes from the conversion endpoint, so the original bytes
      // are never needed here: streaming keeps the runtime from downloading a
      // whole design file or video into memory only to discard it.
      streaming: true,
      maxInlineBytes: Number.POSITIVE_INFINITY,
      load: (options) => requireConverter([ext], options),
      mount: mountConverted,
    });

/**
 * In-package office readers. Each recovers content and structure, not a page
 * layout, so all of them sit *behind* the converter's PDF and render only when
 * no converter is reachable — the same trade the DOCX path already makes.
 *
 * `.ods` is the exception in spirit rather than order: a spreadsheet is data,
 * and the table view is the better reading of it, so it is registered ahead of
 * the converter alongside `.xlsx`.
 */
builtins.push(
  {
    kind: "doc",
    exts: [".docx"],
    tier: 2,
    component: "DocxViewer",
    maxInlineBytes: 32 * MB,
    load: (options) => loadOptional("viewer-docx", options?.baseURI),
    mount: mountDocx,
  },
  {
    kind: "doc",
    exts: [".pptx", ".ppsx", ".potx"],
    tier: 2,
    component: "SlidesViewer",
    maxInlineBytes: 64 * MB,
    load: (options) => loadOptional("viewer-office", options?.baseURI),
    mount: mountPresentation,
  },
  {
    kind: "doc",
    // `.ods` is here as well as on the spreadsheet reader: SheetJS handles most
    // OpenDocument workbooks, and this is the ladder's next rung when it cannot.
    exts: [".odt", ".odp", ".ods"],
    tier: 2,
    component: "OpenDocumentViewer",
    maxInlineBytes: 64 * MB,
    load: (options) => loadOptional("viewer-office", options?.baseURI),
    mount: mountOpenDocument,
  },
  {
    // No dependency and no converter: RTF is text once the control words go.
    kind: "doc",
    exts: [".rtf"],
    tier: 2,
    component: "RtfViewer",
    maxInlineBytes: 16 * MB,
    mount: mountRtf,
  },
);

export class RendererRegistry {
  private renderers: Renderer[] = [...builtins];

  fork(): RendererRegistry {
    const registry = new RendererRegistry();
    registry.renderers = [...this.renderers];
    return registry;
  }

  register(renderer: Renderer): () => void {
    const entry = {
      ...renderer,
      exts: renderer.exts.map((ext) => "." + ext.replace(/^\./, "").toLowerCase()),
    };
    this.renderers.unshift(entry);
    return () => {
      this.renderers = this.renderers.filter((item) => item !== entry);
    };
  }

  /** Extension-specific renderers outrank kind-wide ones. */
  candidates(kind: ViewerKind, ext: string): Renderer[] {
    return [
      ...this.renderers.filter((item) => item.exts.includes(ext)),
      ...this.renderers.filter((item) => item.kind === kind && item.exts.length === 0),
    ];
  }
}

export const defaultRegistry = new RendererRegistry();

export function registerRenderer(renderer: Renderer): () => void {
  return defaultRegistry.register(renderer);
}