onenote-tools/src/onenote/export/zip.ts

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
// SPDX-License-Identifier: MPL-2.0

import { strToU8, zipSync, type Zippable } from 'fflate';
import { forceFilenameExtension, sanitizeExportFilename } from './naming.js';
import {
  createOneNoteExportPlan,
  enforceOutputByteLength,
  utf8ByteLength,
  type OneNoteExportPlan,
} from './plan.js';
import {
  serializeHtmlWithPlan,
  serializeMarkdownWithPlan,
  serializePlainTextWithPlan,
  serializeStructuredJsonWithPlan,
} from './serializers.js';
import {
  OneNoteExportError,
  type OneNoteExportOptions,
  type OneNoteExportSnapshot,
} from './types.js';

export interface OneNoteStaticNotebookManifest {
  schemaVersion: number;
  exportKind: 'onenote-tools-static-notebook';
  app: OneNoteExportSnapshot['app'];
  parser: OneNoteExportSnapshot['parser'];
  supportLevel: OneNoteExportSnapshot['supportLevel'];
  supportNotes: string[];
  source: OneNoteExportSnapshot['source'];
  notebookName: string;
  files: {
    viewer: 'index.html';
    structuredData: 'notebook.json';
    plainText: 'notebook.txt';
    markdown: 'notebook.md';
    warnings: 'warnings.json';
  };
  counts: {
    sections: number;
    pages: number;
    blocks: number;
    resources: number;
    diagnostics: number;
    exportWarnings: number;
    unsupportedContent: number;
  };
  sections: Array<{
    id: string;
    name: string;
    sourcePath?: string;
    pageCount: number;
  }>;
  resources: Array<{
    sectionId: string;
    id: string;
    kind: 'image' | 'attachment';
    path: string;
    filename: string;
    mediaType: string;
    size: number;
  }>;
}

export interface OneNoteExportWarningsManifest {
  schemaVersion: number;
  app: OneNoteExportSnapshot['app'];
  parser: OneNoteExportSnapshot['parser'];
  supportLevel: OneNoteExportSnapshot['supportLevel'];
  source: OneNoteExportSnapshot['source'];
  diagnostics: OneNoteExportPlan['diagnostics'];
  exportWarnings: OneNoteExportPlan['warnings'];
  unsupportedContent: OneNoteExportPlan['unsupportedContent'];
}

export interface OneNoteStaticNotebookZipArtifact {
  filename: string;
  mediaType: 'application/zip';
  bytes: Uint8Array;
  manifest: OneNoteStaticNotebookManifest;
}

/**
 * Create an application-owned static export. This never writes or claims to
 * write a .one/.onepkg file, and it never interprets source HTML or SVG.
 */
export function createOneNoteStaticNotebookZip(
  snapshot: OneNoteExportSnapshot,
  options: OneNoteExportOptions = {}
): OneNoteStaticNotebookZipArtifact {
  const plan = createOneNoteExportPlan(snapshot, options);
  enforceProjectedStaticNotebookSize(plan);
  const manifest = createStaticManifest(snapshot, plan);
  const warnings: OneNoteExportWarningsManifest = {
    schemaVersion: snapshot.schemaVersion,
    app: snapshot.app,
    parser: snapshot.parser,
    supportLevel: snapshot.supportLevel,
    source: snapshot.source,
    diagnostics: plan.diagnostics,
    exportWarnings: plan.warnings,
    unsupportedContent: plan.unsupportedContent,
  };

  const files: Zippable = Object.create(null) as Zippable;
  const members: Array<{ path: string; byteLength: number }> = [];
  let memberBytes = 0;
  addTextMember('index.html', serializeHtmlWithPlan(snapshot, plan, true));
  addTextMember(
    'notebook.json',
    serializeStructuredJsonWithPlan(snapshot, plan)
  );
  addTextMember('notebook.txt', serializePlainTextWithPlan(snapshot, plan));
  addTextMember('notebook.md', serializeMarkdownWithPlan(snapshot, plan, true));
  addTextMember('manifest.json', jsonText(manifest));
  addTextMember('warnings.json', jsonText(warnings));
  for (const resource of plan.resources) {
    addBinaryMember(resource.path, resource.bytes);
  }

  enforceOutputByteLength(
    plan,
    projectedZipByteLength(members),
    'Projected static notebook ZIP'
  );

  const bytes = zipSync(files, {
    level: 6,
    mtime: new Date(1980, 0, 1, 0, 0, 0),
    os: 3,
    attrs: 0o644 << 16,
  });
  enforceOutputByteLength(plan, bytes.byteLength, 'Static notebook ZIP');
  const safeName = sanitizeExportFilename(
    snapshot.notebookName,
    'onenote-export'
  );
  return {
    filename: forceFilenameExtension(safeName, 'zip'),
    mediaType: 'application/zip',
    bytes,
    manifest,
  };

  function addTextMember(path: string, value: string): void {
    ensureMemberCapacity(utf8ByteLength(value));
    const bytes = strToU8(value);
    addMember(path, bytes, bytes.byteLength);
  }

  function addBinaryMember(path: string, value: Uint8Array): void {
    ensureMemberCapacity(value.byteLength);
    addMember(path, value, value.byteLength);
  }

  function addMember(
    path: string,
    value: Uint8Array,
    byteLength: number
  ): void {
    ensureMemberCapacity(byteLength);
    memberBytes += byteLength;
    members.push({ path, byteLength });
    files[path] = value;
  }

  function ensureMemberCapacity(byteLength: number): void {
    if (byteLength > plan.limits.maxOutputBytes - memberBytes) {
      throw new OneNoteExportError(
        'limit-exceeded',
        `Static notebook members exceed ${plan.limits.maxOutputBytes} bytes`
      );
    }
  }
}

function createStaticManifest(
  snapshot: OneNoteExportSnapshot,
  plan: OneNoteExportPlan
): OneNoteStaticNotebookManifest {
  return {
    schemaVersion: snapshot.schemaVersion,
    exportKind: 'onenote-tools-static-notebook',
    app: snapshot.app,
    parser: snapshot.parser,
    supportLevel: snapshot.supportLevel,
    supportNotes: snapshot.supportNotes,
    source: snapshot.source,
    notebookName: snapshot.notebookName,
    files: {
      viewer: 'index.html',
      structuredData: 'notebook.json',
      plainText: 'notebook.txt',
      markdown: 'notebook.md',
      warnings: 'warnings.json',
    },
    counts: {
      sections: snapshot.sections.length,
      pages: plan.pageCount,
      blocks: plan.blockCount,
      resources: plan.resources.length,
      diagnostics: plan.diagnostics.length,
      exportWarnings: plan.warnings.length,
      unsupportedContent: plan.unsupportedContent.length,
    },
    sections: snapshot.sections.map((section) => ({
      id: section.id,
      name: section.name,
      ...(section.sourcePath ? { sourcePath: section.sourcePath } : {}),
      pageCount: section.pages.length,
    })),
    resources: plan.resources.map((resource) => ({
      sectionId: resource.sectionId,
      id: resource.id,
      kind: resource.kind,
      path: resource.path,
      filename: resource.filename,
      mediaType: resource.mediaType,
      size: resource.size,
    })),
  };
}

function jsonText(value: unknown): string {
  return `${JSON.stringify(value, null, 2)}\n`;
}

function enforceProjectedStaticNotebookSize(plan: OneNoteExportPlan): void {
  const available = plan.limits.maxOutputBytes - plan.totalResourceBytes;
  if (available < 0 || plan.projectedOutputBytes > Math.floor(available / 6)) {
    throw new OneNoteExportError(
      'limit-exceeded',
      `Projected static notebook members exceed ${plan.limits.maxOutputBytes} bytes`
    );
  }
}

function projectedZipByteLength(
  members: readonly { path: string; byteLength: number }[]
): number {
  let result = 22;
  for (const member of members) {
    const pathBytes = utf8ByteLength(member.path);
    const deflateOverhead = Math.ceil(member.byteLength / 16_384) * 16 + 128;
    result = safeByteSum(
      result,
      member.byteLength,
      deflateOverhead,
      76,
      pathBytes * 2
    );
  }
  return result;
}

function safeByteSum(...values: number[]): number {
  let total = 0;
  for (const value of values) {
    if (!Number.isSafeInteger(value) || value < 0) {
      return Number.POSITIVE_INFINITY;
    }
    if (total > Number.MAX_SAFE_INTEGER - value) {
      return Number.POSITIVE_INFINITY;
    }
    total += value;
  }
  return total;
}