/**
* Claude (Anthropic) integration for image-based ad copy generation
*/
import type { Anthropic } from "@anthropic-ai/sdk";
import { parseAIResponse } from "../utils/json-parser";
import type { AdCopyResult, GenerateAdCopyOptions } from "./types";
const MAX_TOKENS = 2048;
type ClaudeImageMimeType =
| "image/jpeg"
| "image/png"
| "image/gif"
| "image/webp";
/**
* Validates if MIME type is supported by Claude vision API
*/
function isValidClaudeImageType(
mimeType: string
): mimeType is ClaudeImageMimeType {
const validTypes: ClaudeImageMimeType[] = [
"image/jpeg",
"image/png",
"image/gif",
"image/webp",
];
return validTypes.includes(mimeType as ClaudeImageMimeType);
}
/**
* Converts ArrayBuffer to base64 string
*/
function arrayBufferToBase64(buffer: ArrayBuffer): string {
const bytes = new Uint8Array(buffer);
let binary = "";
for (let i = 0; i < bytes.byteLength; i++) {
binary += String.fromCharCode(bytes[i]);
}
return btoa(binary);
}
/**
* Generates ad copy from an image using Claude's vision API
*/
export async function generateAdCopyFromImage(
anthropic: Anthropic,
imageBuffer: ArrayBuffer,
mimeType: string,
options: GenerateAdCopyOptions
): Promise<AdCopyResult> {
// Validate MIME type
if (!isValidClaudeImageType(mimeType)) {
throw new Error(
`Image type '${mimeType}' is not supported by Claude vision API. ` +
`Supported types: image/jpeg, image/png, image/gif, image/webp`
);
}
// Convert ArrayBuffer to base64
const base64Data = arrayBufferToBase64(imageBuffer);
// Prepare prompt with optional additional context
const promptText = options.additionalContext
? `${options.prompt}\n\nFurther specific instructions: ${options.additionalContext}`
: options.prompt;
console.log("[Claude] Generating ad copy from image...");
const response = await anthropic.beta.messages.parse({
model: "claude-sonnet-4-5",
betas: ["structured-outputs-2025-11-13"],
max_tokens: MAX_TOKENS,
messages: [
{
role: "user",
content: [
{
type: "image",
source: {
type: "base64",
media_type: mimeType,
data: base64Data,
},
},
{
type: "text",
text: promptText,
},
],
},
],
output_format: {
type: "json_schema",
schema: {
type: "object",
properties: {
headline: {
type: "string",
description: "The compelling ad headline that captures attention",
},
primaryText: {
type: "string",
description:
"The primary ad text that provides context and call-to-action",
},
},
required: ["headline", "primaryText"],
additionalProperties: false,
},
},
});
// Extract text from response - guaranteed to be valid JSON with structured outputs
const textContent = response.content.find((c) => c.type === "text");
if (!textContent || textContent.type !== "text") {
throw new Error("No text content in Claude response");
}
// Parse JSON response - with structured outputs, this is guaranteed to match schema
const result = parseAIResponse(textContent.text);
console.log("[Claude] Ad copy generated successfully");
return result;
}
