1 files changed, 213 insertions, 0 deletions
diff --git a/packages/integrations/markdoc/src/runtime.ts b/packages/integrations/markdoc/src/runtime.ts
new file mode 100644
index 000000000..f62bcec1a
--- /dev/null
+++ b/packages/integrations/markdoc/src/runtime.ts
@@ -0,0 +1,213 @@
+import type { MarkdownHeading } from '@astrojs/markdown-remark';
+import Markdoc, {
+	type ConfigType,
+	type Node,
+	type NodeType,
+	type RenderableTreeNode,
+} from '@markdoc/markdoc';
+import type { AstroInstance } from 'astro';
+import { createComponent, renderComponent } from 'astro/runtime/server/index.js';
+import type { AstroMarkdocConfig } from './config.js';
+import { setupHeadingConfig } from './heading-ids.js';
+import { htmlTag } from './html/tagdefs/html.tag.js';
+import type { MarkdocIntegrationOptions } from './options.js';
+/**
+ * Merge user config with default config and set up context (ex. heading ID slugger)
+ * Called on each file's individual transform.
+ * TODO: virtual module to merge configs per-build instead of per-file?
+ */
+export async function setupConfig(
+	userConfig: AstroMarkdocConfig = {},
+	options: MarkdocIntegrationOptions | undefined,
+): Promise<MergedConfig> {
+	let defaultConfig: AstroMarkdocConfig = setupHeadingConfig();
+
+	if (userConfig.extends) {
+		for (let extension of userConfig.extends) {
+			if (extension instanceof Promise) {
+				extension = await extension;
+			}
+
+			defaultConfig = mergeConfig(defaultConfig, extension);
+		}
+	}
+
+	let merged = mergeConfig(defaultConfig, userConfig);
+
+	if (options?.allowHTML) {
+		merged = mergeConfig(merged, HTML_CONFIG);
+	}
+
+	return merged;
+}
+
+/** Used for synchronous `getHeadings()` function */
+export function setupConfigSync(
+	userConfig: AstroMarkdocConfig = {},
+	options: MarkdocIntegrationOptions | undefined,
+): MergedConfig {
+	const defaultConfig: AstroMarkdocConfig = setupHeadingConfig();
+
+	let merged = mergeConfig(defaultConfig, userConfig);
+
+	if (options?.allowHTML) {
+		merged = mergeConfig(merged, HTML_CONFIG);
+	}
+
+	return merged;
+}
+
+type MergedConfig = Required<Omit<AstroMarkdocConfig, 'extends'>>;
+
+/** Merge function from `@markdoc/markdoc` internals */
+export function mergeConfig(
+	configA: AstroMarkdocConfig,
+	configB: AstroMarkdocConfig,
+): MergedConfig {
+	return {
+		...configA,
+		...configB,
+		ctx: {
+			...configA.ctx,
+			...configB.ctx,
+		},
+		tags: {
+			...configA.tags,
+			...configB.tags,
+		},
+		nodes: {
+			...configA.nodes,
+			...configB.nodes,
+		},
+		functions: {
+			...configA.functions,
+			...configB.functions,
+		},
+		variables: {
+			...configA.variables,
+			...configB.variables,
+		},
+		partials: {
+			...configA.partials,
+			...configB.partials,
+		},
+		validation: {
+			...configA.validation,
+			...configB.validation,
+		},
+	};
+}
+
+export function resolveComponentImports(
+	markdocConfig: Required<Pick<AstroMarkdocConfig, 'tags' | 'nodes'>>,
+	tagComponentMap: Record<string, AstroInstance['default']>,
+	nodeComponentMap: Record<NodeType, AstroInstance['default']>,
+) {
+	for (const [tag, render] of Object.entries(tagComponentMap)) {
+		const config = markdocConfig.tags[tag];
+		if (config) config.render = render;
+	}
+	for (const [node, render] of Object.entries(nodeComponentMap)) {
+		const config = markdocConfig.nodes[node as NodeType];
+		if (config) config.render = render;
+	}
+	return markdocConfig;
+}
+
+/**
+ * Get text content as a string from a Markdoc transform AST
+ */
+export function getTextContent(childNodes: RenderableTreeNode[]): string {
+	let text = '';
+	for (const node of childNodes) {
+		if (typeof node === 'string' || typeof node === 'number') {
+			text += node;
+		} else if (typeof node === 'object' && Markdoc.Tag.isTag(node)) {
+			text += getTextContent(node.children);
+		}
+	}
+	return text;
+}
+
+const headingLevels = [1, 2, 3, 4, 5, 6] as const;
+
+/**
+ * Collect headings from Markdoc transform AST
+ * for `headings` result on `render()` return value
+ */
+export function collectHeadings(
+	children: RenderableTreeNode[],
+	collectedHeadings: MarkdownHeading[],
+) {
+	for (const node of children) {
+		if (typeof node !== 'object' || !Markdoc.Tag.isTag(node)) continue;
+
+		if (node.attributes.__collectHeading === true && typeof node.attributes.level === 'number') {
+			collectedHeadings.push({
+				slug: node.attributes.id,
+				depth: node.attributes.level,
+				text: getTextContent(node.children),
+			});
+			continue;
+		}
+
+		for (const level of headingLevels) {
+			if (node.name === 'h' + level) {
+				collectedHeadings.push({
+					slug: node.attributes.id,
+					depth: level,
+					text: getTextContent(node.children),
+				});
+			}
+		}
+		collectHeadings(node.children, collectedHeadings);
+	}
+}
+
+export function createGetHeadings(
+	stringifiedAst: string,
+	userConfig: AstroMarkdocConfig,
+	options: MarkdocIntegrationOptions | undefined,
+) {
+	return function getHeadings() {
+		/* Yes, we are transforming twice (once from `getHeadings()` and again from <Content /> in case of variables).
+			TODO: propose new `render()` API to allow Markdoc variable passing to `render()` itself,
+			instead of the Content component. Would remove double-transform and unlock variable resolution in heading slugs. */
+		const config = setupConfigSync(userConfig, options);
+		const ast = Markdoc.Ast.fromJSON(stringifiedAst);
+		const content = Markdoc.transform(ast as Node, config as ConfigType);
+		let collectedHeadings: MarkdownHeading[] = [];
+		collectHeadings(Array.isArray(content) ? content : [content], collectedHeadings);
+		return collectedHeadings;
+	};
+}
+
+export function createContentComponent(
+	Renderer: AstroInstance['default'],
+	stringifiedAst: string,
+	userConfig: AstroMarkdocConfig,
+	options: MarkdocIntegrationOptions | undefined,
+	tagComponentMap: Record<string, AstroInstance['default']>,
+	nodeComponentMap: Record<NodeType, AstroInstance['default']>,
+) {
+	return createComponent({
+		async factory(result: any, props: Record<string, any>) {
+			const withVariables = mergeConfig(userConfig, { variables: props });
+			const config = resolveComponentImports(
+				await setupConfig(withVariables, options),
+				tagComponentMap,
+				nodeComponentMap,
+			);
+
+			return renderComponent(result, Renderer.name, Renderer, { stringifiedAst, config }, {});
+		},
+		propagation: 'self',
+	} as any);
+}
+
+// statically define a partial MarkdocConfig which registers the required "html-tag" Markdoc tag when the "allowHTML" feature is enabled
+const HTML_CONFIG: AstroMarkdocConfig = {
+	tags: {
+		'html-tag': htmlTag,
+	},
+};