import { useState, useEffect } from 'react';
import { Attachment } from 'fhir/r4';
import { getFhirPhotoUrl, isScannedPhoto } from '../utils/fhirPhoto';
import { usePhotoUploadService } from '../services/PhotoUploadService';

// Links are stamped with their photo, so a changed photo never shows the old link or its late answer. Inline bytes show
// only when the server marked them clean; otherwise a reader who may open the file sees it through a checked link.
export const usePhotoUrl = (photo?: Attachment | null, type?: string): { url: string; loading: boolean } => {
    const { getPresignedDownloadUrl } = usePhotoUploadService();
    const defaultUrl = getFhirPhotoUrl(null, type);
    const remoteKey = !isScannedPhoto(photo) && photo?.url && !/^[a-z][a-z0-9+.-]*:/i.test(photo.url) ? photo.url : undefined;

    const [resolved, setResolved] = useState<{ key: string; url: string } | undefined>();

    useEffect(() => {
        if (!remoteKey) return;
        let current = true;
        getPresignedDownloadUrl(remoteKey)
            .then((url) => { if (current) setResolved({ key: remoteKey, url }); })
            .catch(() => { if (current) setResolved({ key: remoteKey, url: defaultUrl }); });
        return () => { current = false; };
    }, [remoteKey, type]);

    if (isScannedPhoto(photo)) return { url: getFhirPhotoUrl(photo, type), loading: false };
    if (!remoteKey) return { url: defaultUrl, loading: false };
    if (resolved?.key === remoteKey) return { url: resolved.url, loading: false };
    return { url: defaultUrl, loading: true };
};