quartz-research-note/quartz/plugins/transformers/ofm.ts

import { PluggableList } from "unified"
import { QuartzTransformerPlugin } from "../types"
import { Root, HTML, BlockContent, DefinitionContent, Code } from 'mdast'
import { findAndReplace } from "mdast-util-find-and-replace"
import { slugify } from "../../path"
import rehypeRaw from "rehype-raw"
import { visit } from "unist-util-visit"
import path from "path"

export interface Options {
  highlight: boolean
  wikilinks: boolean
  callouts: boolean
  mermaid: boolean
}

const defaultOptions: Options = {
  highlight: true,
  wikilinks: true,
  callouts: true,
  mermaid: false,
}

const icons = {
  infoIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"></circle><line x1="12" y1="16" x2="12" y2="12"></line><line x1="12" y1="8" x2="12.01" y2="8"></line></svg>`,
  pencilIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="2" x2="22" y2="6"></line><path d="M7.5 20.5 19 9l-4-4L3.5 16.5 2 22z"></path></svg>`,
  clipboardListIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="8" y="2" width="8" height="4" rx="1" ry="1"></rect><path d="M16 4h2a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h2"></path><path d="M12 11h4"></path><path d="M12 16h4"></path><path d="M8 11h.01"></path><path d="M8 16h.01"></path></svg>`,
  checkCircleIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z"></path><path d="m9 12 2 2 4-4"></path></svg>`,
  flameIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M8.5 14.5A2.5 2.5 0 0 0 11 12c0-1.38-.5-2-1-3-1.072-2.143-.224-4.054 2-6 .5 2.5 2 4.9 4 6.5 2 1.6 3 3.5 3 5.5a7 7 0 1 1-14 0c0-1.153.433-2.294 1-3a2.5 2.5 0 0 0 2.5 2.5z"></path></svg>`,
  checkIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="20 6 9 17 4 12"></polyline></svg>`,
  helpCircleIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"></circle><path d="M9.09 9a3 3 0 0 1 5.83 1c0 2-3 3-3 3"></path><line x1="12" y1="17" x2="12.01" y2="17"></line></svg>`,
  alertTriangleIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="m21.73 18-8-14a2 2 0 0 0-3.48 0l-8 14A2 2 0 0 0 4 21h16a2 2 0 0 0 1.73-3Z"></path><line x1="12" y1="9" x2="12" y2="13"></line><line x1="12" y1="17" x2="12.01" y2="17"></line></svg>`,
  xIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>`,
  zapIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polygon points="13 2 3 14 12 14 11 22 21 10 12 10 13 2"></polygon></svg>`,
  bugIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect width="8" height="14" x="8" y="6" rx="4"></rect><path d="m19 7-3 2"></path><path d="m5 7 3 2"></path><path d="m19 19-3-2"></path><path d="m5 19 3-2"></path><path d="M20 13h-4"></path><path d="M4 13h4"></path><path d="m10 4 1 2"></path><path d="m14 4-1 2"></path></svg>`,
  listIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="8" y1="6" x2="21" y2="6"></line><line x1="8" y1="12" x2="21" y2="12"></line><line x1="8" y1="18" x2="21" y2="18"></line><line x1="3" y1="6" x2="3.01" y2="6"></line><line x1="3" y1="12" x2="3.01" y2="12"></line><line x1="3" y1="18" x2="3.01" y2="18"></line></svg>`,
  quoteIcon: `<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M3 21c3 0 7-1 7-8V5c0-1.25-.756-2.017-2-2H4c-1.25 0-2 .75-2 1.972V11c0 1.25.75 2 2 2 1 0 1 0 1 1v1c0 1-1 2-2 2s-1 .008-1 1.031V20c0 1 0 1 1 1z"></path><path d="M15 21c3 0 7-1 7-8V5c0-1.25-.757-2.017-2-2h-4c-1.25 0-2 .75-2 1.972V11c0 1.25.75 2 2 2h.75c0 2.25.25 4-2.75 4v3c0 1 0 1 1 1z"></path></svg>`,
}

function canonicalizeCallout(calloutName: string): keyof typeof callouts {
  let callout = calloutName.toLowerCase() as keyof typeof calloutMapping

  const calloutMapping: Record<string, keyof typeof callouts> = {
    note: "note",
    abstract: "abstract",
    info: "info",
    todo: "todo",
    tip: "tip",
    hint: "tip",
    important: "tip",
    success: "success",
    check: "success",
    done: "success",
    question: "question",
    help: "question",
    faq: "question",
    warning: "warning",
    attention: "warning",
    caution: "warning",
    failure: "failure",
    missing: "failure",
    fail: "failure",
    danger: "danger",
    error: "danger",
    bug: "bug",
    example: "example",
    quote: "quote",
    cite: "quote"
  }

  return calloutMapping[callout]
}

const callouts = {
  note: icons.pencilIcon,
  abstract: icons.clipboardListIcon,
  info: icons.infoIcon,
  todo: icons.checkCircleIcon,
  tip: icons.flameIcon,
  success: icons.checkIcon,
  question: icons.helpCircleIcon,
  warning: icons.alertTriangleIcon,
  failure: icons.xIcon,
  danger: icons.zapIcon,
  bug: icons.bugIcon,
  example: icons.listIcon,
  quote: icons.quoteIcon,
}

const capitalize = (s: string): string => {
  return s.substring(0, 1).toUpperCase() + s.substring(1);
}

export const ObsidianFlavoredMarkdown: QuartzTransformerPlugin<Partial<Options> | undefined> = (userOpts) => {
  const opts = { ...defaultOptions, ...userOpts }
  return {
    name: "ObsidianFlavoredMarkdown",
    markdownPlugins() {
      const plugins: PluggableList = []
      if (opts.wikilinks) {
        plugins.push(() => {
          // Match wikilinks 
          // !?               -> optional embedding
          // \[\[             -> open brace
          // ([^\[\]\|\#]+)   -> one or more non-special characters ([,],|, or #) (name)
          // (#[^\[\]\|\#]+)? -> # then one or more non-special characters (heading link)
          // (|[^\[\]\|\#]+)? -> | then one or more non-special characters (alias)
          const backlinkRegex = new RegExp(/!?\[\[([^\[\]\|\#]+)(#[^\[\]\|\#]+)?(\|[^\[\]\|\#]+)?\]\]/, "g")
          return (tree: Root, _file) => {
            findAndReplace(tree, backlinkRegex, (value: string, ...capture: string[]) => {
              const [fp, rawHeader, rawAlias] = capture
              const anchor = rawHeader?.trim() ?? ""
              const alias = rawAlias?.slice(1).trim()

              // embed cases
              if (value.startsWith("!")) {
                const ext = path.extname(fp).toLowerCase()
                const url = slugify(fp.trim()) + ext
                if ([".png", ".jpg", ".jpeg", ".gif", ".bmp", ".svg"].includes(ext)) {
                  const dims = alias ?? ""
                  let [width, height] = dims.split("x", 2)
                  width ||= "auto"
                  height ||= "auto"
                  return {
                    type: 'image',
                    url,
                    data: {
                      hProperties: {
                        width, height
                      }
                    }
                  }
                } else if ([".mp4", ".webm", ".ogv", ".mov", ".mkv"].includes(ext)) {
                  return {
                    type: 'html',
                    value: `<video src="${url}" controls></video>`
                  }
                } else if ([".mp3", ".webm", ".wav", ".m4a", ".ogg", ".3gp", ".flac"].includes(ext)) {
                  return {
                    type: 'html',
                    value: `<audio src="${url}" controls></audio>`
                  }
                } else if ([".pdf"].includes(ext)) {
                  return {
                    type: 'html',
                    value: `<iframe src="${url}"></iframe>`
                  }
                }
                // otherwise, fall through to regular link
              }

              // internal link
              const url = slugify(fp.trim() + anchor)
              return {
                type: 'link',
                url,
                children: [{
                  type: 'text',
                  value: alias ?? fp
                }]
              }
            })
          }
        }
        )
      }

      if (opts.highlight) {
        plugins.push(() => {
          // Match highlights 
          const highlightRegex = new RegExp(/==(.+)==/, "g")
          return (tree: Root, _file) => {
            findAndReplace(tree, highlightRegex, (_value: string, ...capture: string[]) => {
              const [inner] = capture
              return {
                type: 'html',
                value: `<span class="text-highlight">${inner}</span>`
              }
            })
          }
        })
      }

      if (opts.callouts) {
        plugins.push(() => {
          // from https://github.com/escwxyz/remark-obsidian-callout/blob/main/src/index.ts
          const calloutRegex = new RegExp(/^\[\!(\w+)\]([+-]?)/)
          return (tree: Root, _file) => {
            visit(tree, "blockquote", (node) => {
              if (node.children.length === 0) {
                return
              }

              // find first line
              const firstChild = node.children[0]
              if (firstChild.type !== "paragraph" || firstChild.children[0]?.type !== "text") {
                return
              }

              const text = firstChild.children[0].value
              const [firstLine, ...remainingLines] = text.split("\n")
              const remainingText = remainingLines.join("\n")

              const match = firstLine.match(calloutRegex)
              if (match && match.input) {
                const [calloutDirective, typeString, collapseChar] = match
                const calloutType = typeString.toLowerCase() as keyof typeof callouts
                const collapse = collapseChar === "+" || collapseChar === "-"
                const defaultState = collapseChar === "-" ? "collapsed" : "expanded"
                const title = match.input.slice(calloutDirective.length).trim() || capitalize(calloutType)

                const titleNode: HTML = {
                  type: "html",
                  value: `<div 
                  class="callout-title"
                >
                  <div class="callout-icon">${callouts[canonicalizeCallout(calloutType)]}</div>
                  <div class="callout-title-inner">${title}</div>
                </div>`
                }

                const blockquoteContent: (BlockContent | DefinitionContent)[] = [titleNode]
                if (remainingText.length > 0) {
                  blockquoteContent.push({
                    type: 'paragraph',
                    children: [{
                      type: 'text',
                      value: remainingText,
                    }]

                  })
                }

                // replace first line of blockquote with title and rest of the paragraph text
                node.children.splice(0, 1, ...blockquoteContent)

                // add properties to base blockquote
                node.data = {
                  hProperties: {
                    ...(node.data?.hProperties ?? {}),
                    className: `callout ${collapse ? "is-collapsible" : ""} ${defaultState === "collapsed" ? "is-collapsed" : ""}`,
                    "data-callout": calloutType,
                    "data-callout-fold": collapse,
                  }
                }
              }
            })
          }
        })
      }

      if (opts.mermaid) {
        plugins.push(() => {
          return (tree: Root, _file) => {
            visit(tree, 'code', (node: Code) => {
              if (node.lang === 'mermaid') {
                node.data = {
                  hProperties: {
                    className: 'mermaid'
                  }
                }
              }
            })
          }
        })
      }

      return plugins
    },
    htmlPlugins() {
      return [rehypeRaw]
    },
    externalResources: {
      js: [{
        script: `
import mermaid from 'https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.esm.min.mjs';
mermaid.initialize({ startOnLoad: true });
        `,
        loadTime: 'afterDOMReady',
        moduleType: 'module',
        contentType: 'inline'
      }]
    }
  }
}