import React, { useState, useEffect, useCallback } from 'react';
import { useNavigate, useParams } from 'react-router-dom';
import { DismissibleAlert } from '../../../../../components/ui/dismissible-alert';
import { Spacer } from '../../../../../components/ui/spacer';
import { useForm, FormProvider } from 'react-hook-form';
import { CareTeam, Organization } from 'fhir/r4';
import { Check, FileText } from 'lucide-react';

import {
    useAuthServiceContext,
    useCareTeamServiceContext,
    usePatientServiceContext
} from '../../../../../services';
import { AppHeader, AppSpinner, ProfileLayoutContainer, ScrollableTab, HistoryNavigator, FhirCareTeam, FhirCareTeamDisplay } from '../../../../../components';
import { PrintableRegion, PrintRecord } from '../../../../../components/ui/print-record';
import { useFhirCareTeamTargetedBroadcast } from '../../../../../hooks';
import { useArchive } from '../../../../../hooks/useArchive';
import { careTeamScopeAdmitted, useCareTeamReadScope } from '../../../../../hooks/useCareTeamReadScope';
import { useScopeLifetime } from '../../../../../hooks/useScopeLifetime';
import ArchiveConfirmModal from '../../../../../components/ArchiveConfirmModal/ArchiveConfirmModal';
import { describeWriteFailure } from '../../../../../utils/fetchFailureMessage';

const EditCareTeamPage: React.FC = () => {
    const { careTeamId } = useParams<{ careTeamId: string }>();
    const navigate = useNavigate();
    const { userRole, USER_ROLES, wpOrganization, currentOrganization } = useAuthServiceContext();
    const { patientState, encounterState } = usePatientServiceContext();
    const {
        fetchCareTeam,
        transformToFhirCareTeam,
        transformFromFhirCareTeam,
        createCareTeam,
        updateCareTeam,
        archiveCareTeam,
        careTeamsList,
        ownedScope
    } = useCareTeamServiceContext();
    const readScope = useCareTeamReadScope(patientState?.id);

    const [loading, setLoading] = useState(false);
    const [submitting, setSubmitting] = useState(false);
    const [success, setSuccess] = useState<string | undefined>();
    const [error, setError] = useState<string | undefined>();
    const { generation, isLive } = useScopeLifetime(readScope);
    // The open team belongs to the viewer, practice and patient it was opened for, and to that opening's lifetime.
    const [opened, setOpened] = useState<{ generation: number; team: CareTeam } | undefined>();
    const careTeam = opened?.generation === generation ? opened.team : undefined;

    // A write is sent only for the practice and opening it was made in; a switch, even back again, refuses it.
    const writeTransport = () => {
        const organization = currentOrganization;
        if (!organization) throw new Error('No practice in context');
        const opening = generation;
        return { organization, admission: { isLive: () => isLive(opening) && wpOrganization.current?.id === organization.id } };
    };

    const archive = useArchive((reason, note) => archiveCareTeam(careTeam!, reason, note, writeTransport()));

    const isPatient = [USER_ROLES.PATIENT, USER_ROLES.RELATED_PERSON].includes(userRole as string);
    const isNew = careTeamId === 'new';
    const spacerMargin = '24px';

    const methods = useForm({
        defaultValues: {
            identifier: [],
            status: '',
            category: [],
            name: '',
            subject: null,
            encounter: null,
            participant: [{ member: [{}] }],
            reasonCode: [],
            reasonReference: [],
            managingOrganization: [],
            telecom: [],
            note: []
        }
    });

    const { handleSubmit, reset } = methods;

    const init = useCallback((team: CareTeam) => {
        reset(transformFromFhirCareTeam(team));
        setOpened({ generation, team });
    }, [transformFromFhirCareTeam, generation]);

    useFhirCareTeamTargetedBroadcast({
        careTeam,
        careTeamId,
        onUpdate: init,
        onDelete: () => navigate('..', { relative: 'path' })
    });

    useEffect(() => {
        const loadCareTeam = async () => {
            if (isNew || careTeam || !careTeamScopeAdmitted(readScope)) return;
            const opening = generation;

            // The shared list may still be another patient's, viewer's or practice's until this scope's read answers.
            const foundCareTeam = ownedScope === readScope ? careTeamsList?.find(ct => ct.id === careTeamId) : undefined;

            if (foundCareTeam) {
                init(foundCareTeam);
                return;
            }

            setLoading(true);

            try {
                const fetchedCareTeam = await fetchCareTeam(careTeamId as string, readScope);
                if (isLive(opening)) init(fetchedCareTeam);
            } catch (err) {
                console.error('Error loading care team:', err);
                setError('Could not load care team. Try again.');
            } finally {
                setLoading(false);
            }
        };

        loadCareTeam();
    }, [careTeam, careTeamsList, ownedScope, readScope, careTeamId, fetchCareTeam, init, generation, isLive]);

    const onSubmit = async (data: any) => {
        if (isPatient) return;

        if (!patientState) {
            setError('Patient information is missing. Please try again.');
            return;
        }

        setSubmitting(true);
        setSuccess(undefined);
        setError(undefined);

        try {
            if (isNew) {
                await createCareTeam(transformToFhirCareTeam(data, patientState, wpOrganization.current as Organization, encounterState));

                navigate('..', { relative: 'path' });
            } else {
                if (!careTeam) return;
                const opening = generation;
                const saved = await updateCareTeam({
                    id: careTeam.id,
                    ...transformToFhirCareTeam(data, patientState)
                }, careTeam.meta?.versionId, writeTransport());
                // The saved version is the next edit's baseline.
                if (isLive(opening)) init(saved);
            }

            setSuccess(`Care team ${isNew ? 'created' : 'updated'} successfully.`);
            setTimeout(() => setSuccess(undefined), 3_000);
        } catch (err: any) {
            console.error(`Error ${isNew ? 'creating' : 'updating'} care team:`, err);
            setError(describeWriteFailure(err, `Failed to ${isNew ? 'create' : 'update'} care team`));
        } finally {
            setSubmitting(false);
        }
    };

    if (loading) {
        return (
            <AppSpinner/>
        );
    }

    return (
        <HistoryNavigator<CareTeam> resourceType="CareTeam" resourceId={careTeamId || ''}>
            {(showHistory) => (
                <FormProvider {...methods}>

                    <form onSubmit={handleSubmit(onSubmit)}>
                        <AppHeader showBackButton={true}>

                            {!isNew && (
                                <button
                                    type="button"
                                    className="btn btn-blue"
                                    disabled={submitting}
                                    onClick={showHistory}
                                >
                                    <FileText />
                                    History
                                </button>
                            )}

                            {!isPatient && (
                                <button
                                    className={`btn btn-green${submitting ? ' btn-busy' : ''}`}
                                    disabled={submitting}
                                    type="submit"
                                >
                                    <Check />
                                    Save
                                </button>
                            )}

                            {!isNew && !isPatient && (
                                <button type="button"
                                        className="btn btn-green"
                                        onClick={archive.open}>
                                    Archive
                                </button>
                            )}

                            {/* The record has to be able to leave the screen. Without this a
                                patient sending it to somebody not on Akashic photographs a scrolling
                                page or prints the browser window, navigation and all. */}
                            {isPatient && careTeam && <PrintRecord/>}
                        </AppHeader>

                        {success && (
                            <>
                                <DismissibleAlert status="success" onDismiss={() => setSuccess(undefined)}>
                                    {success}
                                </DismissibleAlert>

                                <Spacer margin={spacerMargin}/>
                            </>
                        )}

                        {error && (
                            <>
                                <DismissibleAlert status="error" onDismiss={() => setError(undefined)}>
                                    <div style={{ whiteSpace: 'pre-line' }}>{error}</div>
                                </DismissibleAlert>

                                <Spacer margin={spacerMargin}/>
                            </>
                        )}

                        <ScrollableTab>
                            <ProfileLayoutContainer>
                                {/* THE READER GETS THE RECORD, NOT THE FORM SWITCHED OFF. `FhirCareTeamDisplay`
                                    already renders this resource for the history viewer, the reference
                                    preview and the patient snapshot, so a patient was the one audience shown
                                    the edit form instead of the view written for reading it. The old shape
                                    wrapped the form in `inert`, which is worse than it looks: the fields stay
                                    in the accessibility tree, so a screen reader still reads them as inputs,
                                    and a text range over the subtree returns an EMPTY STRING - a patient
                                    could not select or copy their own record. */}
                                {isPatient && careTeam ? (
                                    <PrintableRegion>
                                        <FhirCareTeamDisplay careTeam={careTeam}
                                                          isOpen={true}
                                                          onClose={() => undefined}/>
                                    </PrintableRegion>
                                ) : (
                                    <FhirCareTeam elevated={true}
                                                  disabled={submitting}/>
                                )}
                            </ProfileLayoutContainer>
                        </ScrollableTab>

                        {!isPatient && (
                            <ArchiveConfirmModal
                                open={archive.isOpen}
                                onOpenChange={(o) => { if (!o) archive.close(); }}
                                resourceLabel="Care Team"
                                submitting={archive.submitting}
                                error={archive.error}
                                onConfirm={async (reason, note) => {
                                    if (await archive.submit(reason, note)) {
                                        navigate('..', { relative: 'path' });
                                    }
                                }}
                            />
                        )}
                    </form>
                </FormProvider>
            )}
        </HistoryNavigator>
    );
};

export default EditCareTeamPage;