import { S3Client, GetObjectCommand } from "@aws-sdk/client-s3";
import { auth } from "~~/lib/auth";
import { verifyFileToken } from "~~/server/utils/file-token";

export default defineEventHandler(async (event) => {
    const key = getRouterParam(event, 'key');
    if (!key) {
        throw createError({ statusCode: 400, statusMessage: 'Missing file key' });
    }

    const query = getQuery(event);
    const exp = query.exp ? Number(query.exp) : undefined;
    const sig = query.sig as string | undefined;

    let authorized = false;

    // Path 1: HMAC token (for AI model access)
    if (exp && sig && process.env.BETTER_AUTH_SECRET) {
        authorized = verifyFileToken(key, exp, sig, process.env.BETTER_AUTH_SECRET);
    }

    // Path 2: Session auth (for client-side access)
    if (!authorized) {
        try {
            const sessionData = await auth.api.getSession(event);
            if (sessionData) {
                event.context.user = sessionData.user;
                authorized = true;
            }
        } catch {
            // No valid session
        }
    }

    if (!authorized) {
        throw createError({ statusCode: 401, statusMessage: 'Unauthorized' });
    }

    const config = useRuntimeConfig();

    const s3 = new S3Client({
        region: config.s3.region || 'us-east-1',
        endpoint: config.s3.endpoint!,
        credentials: {
            accessKeyId: config.s3.accessKeyId!,
            secretAccessKey: config.s3.secret!,
        },
        forcePathStyle: true,
    });

    try {
        const response = await s3.send(new GetObjectCommand({
            Bucket: config.s3.bucket!,
            Key: key,
        }));

        setHeaders(event, {
            'Content-Type': response.ContentType || 'application/octet-stream',
            'Content-Length': response.ContentLength?.toString() || '',
            'Cache-Control': 'public, max-age=3600',
        });

        return response.Body;
    } catch (error: any) {
        if (error.name === 'NoSuchKey') {
            throw createError({ statusCode: 404, statusMessage: 'File not found' });
        }
        throw createError({ statusCode: 500, statusMessage: 'Error fetching file' });
    }
});