feat: content engine

packages/thumbnail-generator/src/generator.ts

@@ -0,0 +1,84 @@
+import Replicate from "replicate";
+import * as fs from "node:fs/promises";
+import * as path from "node:path";
+
+export interface ThumbnailGeneratorConfig {
+  replicateApiKey: string;
+}
+
+export class ThumbnailGenerator {
+  private replicate: Replicate;
+
+  constructor(config: ThumbnailGeneratorConfig) {
+    this.replicate = new Replicate({
+      auth: config.replicateApiKey,
+    });
+  }
+
+  public async generateImage(
+    topic: string,
+    outputPath: string,
+  ): Promise<string> {
+    const systemPrompt = `Technical blueprint / architectural illustration — clean lines, monochrome base with one highlighter accent color (yellow, pink, or green). Abstract, geometric, or diagrammatic illustrations only. 'Engineering notebook sketch' — precise, minimal, professional. No text in images. No people or realistic photos.`;
+
+    const prompt = `${systemPrompt}\n\nTopic to illustrate abstractly: ${topic}`;
+
+    console.log(`🎨 Generating thumbnail for topic: "${topic}"...`);
+
+    const output = await this.replicate.run("black-forest-labs/flux-1.1-pro", {
+      input: {
+        prompt,
+        aspect_ratio: "16:9",
+        output_format: "png",
+        output_quality: 90,
+        prompt_upsampling: false,
+      },
+    });
+
+    // Replicate returns a ReadableStream for the output of flux-1.1-pro in newer Node SDKs
+    // Or a string URL in older ones. We handle both.
+    let buffer: Buffer;
+
+    if (output instanceof ReadableStream) {
+      console.log(`⬇️ Downloading generated stream from Replicate...`);
+      const chunks: Uint8Array[] = [];
+      const reader = output.getReader();
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        if (value) chunks.push(value);
+      }
+      buffer = Buffer.concat(chunks);
+    } else if (
+      typeof output === "string" ||
+      (Array.isArray(output) && typeof output[0] === "string")
+    ) {
+      const imageUrl = Array.isArray(output) ? output[0] : output;
+      console.log(
+        `⬇️ Downloading generated image from URL: ${imageUrl.substring(0, 50)}...`,
+      );
+      const response = await fetch(imageUrl);
+      if (!response.ok) {
+        throw new Error(`Failed to download image: ${response.statusText}`);
+      }
+      const arrayBuffer = await response.arrayBuffer();
+      buffer = Buffer.from(arrayBuffer);
+    } else if (Buffer.isBuffer(output)) {
+      buffer = output;
+    } else if (typeof output === "object") {
+      console.log("Raw output object:", output);
+      throw new Error("Unexpected output format from Replicate.");
+    } else {
+      throw new Error("Unknown output format from Replicate.");
+    }
+
+    const absPath = path.isAbsolute(outputPath)
+      ? outputPath
+      : path.resolve(process.cwd(), outputPath);
+    await fs.mkdir(path.dirname(absPath), { recursive: true });
+    await fs.writeFile(absPath, buffer);
+
+    console.log(`✅ Saved thumbnail to: ${absPath}`);
+    return absPath;
+  }
+}

packages/thumbnail-generator/src/index.ts

@@ -0,0 +1 @@
+export * from "./generator";