import { useEffect, useState, useCallback } from 'react';
import { useQuestionnaireServiceContext } from '../services';

import { describeFetchFailure } from '../utils/fetchFailureMessage';

interface UseFhirQuestionnairesOptions {
    autoLoad?: boolean;
    errorMessage?: string;
    forceReload?: boolean;
    pageSize?: number;
}

interface UseFhirQuestionnairesReturn {
    loading: boolean;
    error: string | undefined;
    loadQuestionnaires: () => Promise<void>;
    clearError: () => void;
    questionnaireBundle: ReturnType<typeof useQuestionnaireServiceContext>['questionnaireBundle'];
    questionnaireList: ReturnType<typeof useQuestionnaireServiceContext>['questionnaireList'];
}

export const useFhirQuestionnaires = (options: UseFhirQuestionnairesOptions = {}): UseFhirQuestionnairesReturn => {
    const {
        autoLoad = true,
        errorMessage = "Failed to load questionnaires",
        forceReload = false,
        pageSize = 100
    } = options;

    const {
        fetchQuestionnairesWithPolling,
        questionnaireBundle,
        questionnaireList,
        shouldReload
    } = useQuestionnaireServiceContext();

    const [loading, setLoading] = useState(false);
    const [error, setError] = useState<string | undefined>();

    const loadQuestionnaires = useCallback(async () => {
        setLoading(true);
        setError(undefined);

        try {
            await fetchQuestionnairesWithPolling(pageSize);
        } catch (err) {
            console.error('Failed to load questionnaires:', err);
            setError(describeFetchFailure(err, errorMessage));
        } finally {
            setLoading(false);
        }
    }, [fetchQuestionnairesWithPolling, pageSize, errorMessage]);

    const clearError = useCallback(() => {
        setError(undefined);
    }, []);

    useEffect(() => {
        if (!autoLoad) return;

        // A write elsewhere marks the cached list stale; mounting on it would hand out the old copy.
        if (!questionnaireBundle || forceReload || shouldReload) {
            loadQuestionnaires();
        }
    }, [autoLoad, questionnaireBundle, forceReload, shouldReload, loadQuestionnaires]);

    return {
        loading,
        error,
        loadQuestionnaires,
        clearError,
        questionnaireBundle,
        questionnaireList
    };
};