LingvAI/utils/replicate-translate.ts

import { readSettings } from "./settings-store";

type ReplicateOutput = string | string[] | { translation?: string; translated_text?: string; output?: string };

export async function replicateTranslate(
    text: string,
    targetLanguage: string
): Promise<string> {
    const settings = readSettings();

    if (!settings.replicateApiToken) {
        throw new Error("Replicate API token not configured");
    }
    if (!settings.jigsawApiKey) {
        throw new Error("JigsawStack API key not configured");
    }

    const body = {
        version: settings.modelVersion,
        input: {
            text,
            api_key: settings.jigsawApiKey,
            target_language: targetLanguage
        }
    };

    const response = await fetch("https://api.replicate.com/v1/predictions", {
        method: "POST",
        headers: {
            "Authorization": `Bearer ${settings.replicateApiToken}`,
            "Content-Type": "application/json",
            "Prefer": "wait"
        },
        body: JSON.stringify(body)
    });

    if (!response.ok) {
        const err = await response.text();
        throw new Error(`Replicate API error: ${response.status} ${err}`);
    }

    const data = await response.json();

    if (data.error) {
        throw new Error(`Replicate model error: ${data.error}`);
    }

    // Extract translated text from various output formats
    const output: ReplicateOutput = data.output;

    if (typeof output === "string") return output;
    if (Array.isArray(output)) return output.join("");
    if (output && typeof output === "object") {
        return output.translation ?? output.translated_text ?? output.output ?? String(output);
    }

    throw new Error("Unexpected output format from Replicate");
}

// Batch translate using separator trick to minimize API calls
const SEPARATOR = "\n{{SEP}}\n";

export async function replicateTranslateBatch(
    texts: string[],
    targetLanguage: string
): Promise<string[]> {
    if (texts.length === 0) return [];
    if (texts.length === 1) {
        return [await replicateTranslate(texts[0], targetLanguage)];
    }

    const joined = texts.join(SEPARATOR);
    const translated = await replicateTranslate(joined, targetLanguage);

    // Try to split on the separator; fall back to individual calls if it got translated
    const parts = translated.split(SEPARATOR);
    if (parts.length === texts.length) {
        return parts;
    }

    // Fallback: translate individually
    return Promise.all(texts.map(t => replicateTranslate(t, targetLanguage)));
}