import { router, usePage } from '@inertiajs/react';
import { useEffect, useRef, useState } from 'react';
import { Button } from '@/components/ui/button';
import {
    Dialog,
    DialogContent,
    DialogDescription,
    DialogTitle,
} from '@/components/ui/dialog';

export function WorkContextChange() {
    const page = usePage();
    const dirty = useRef(new Set<HTMLFormElement>());
    const pending = useRef(false);
    const savingForm = useRef<HTMLFormElement | null>(null);
    const [open, setOpen] = useState(false);
    const [message, setMessage] = useState('');
    useEffect(() => {
        dirty.current.clear();
    }, [page.url]);
    useEffect(() => {
        const formChanged = (event: Event) => {
            if (
                !(event instanceof CustomEvent) ||
                !(event.detail.form instanceof HTMLFormElement)
            )
                return;
            if (event.detail.dirty) dirty.current.add(event.detail.form);
            else dirty.current.delete(event.detail.form);
        };
        const changed = (event: Event) => {
            const input = event.target;
            if (
                input instanceof HTMLInputElement ||
                input instanceof HTMLTextAreaElement ||
                input instanceof HTMLSelectElement
            ) {
                if (input.form) dirty.current.add(input.form);
            }
        };
        const click = (event: MouseEvent) => {
            if (!(event.target instanceof Element)) return;
            const link = event.target.closest('a');
            if (
                !link ||
                new URL(link.href).pathname !== '/dashboard' ||
                !dirty.current.size
            )
                return;
            event.preventDefault();
            event.stopPropagation();
            setMessage('');
            setOpen(true);
        };
        const unload = (event: BeforeUnloadEvent) => {
            if (dirty.current.size) {
                event.preventDefault();
                event.returnValue = '';
            }
        };
        const saved = (event: Event) => {
            if (!(event instanceof CustomEvent)) return;
            if (event.detail.success) dirty.current.delete(event.detail.form);
            if (!pending.current || event.detail.form !== savingForm.current)
                return;
            if (event.detail.success) {
                pending.current = false;
                dirty.current.clear();
                setOpen(false);
                router.visit('/dashboard');
            } else {
                pending.current = false;
                setOpen(true);
                setMessage(
                    'A gravação falhou. O contexto actual foi mantido. Corrija os campos antes de mudar.',
                );
            }
        };
        const failure = () => {
            if (pending.current) {
                pending.current = false;
                setOpen(true);
                setMessage(
                    'Não foi possível concluir a gravação. O contexto actual foi mantido.',
                );
            }
        };
        const offException = router.on('httpException', failure);
        const offNetwork = router.on('networkError', failure);
        document.addEventListener('input', changed);
        document.addEventListener('change', changed);
        document.addEventListener('click', click, true);
        window.addEventListener('beforeunload', unload);
        window.addEventListener('sgc:context-save-result', saved);
        window.addEventListener('sgc:context-dirty', formChanged);
        return () => {
            document.removeEventListener('input', changed);
            document.removeEventListener('change', changed);
            document.removeEventListener('click', click, true);
            window.removeEventListener('beforeunload', unload);
            window.removeEventListener('sgc:context-save-result', saved);
            window.removeEventListener('sgc:context-dirty', formChanged);
            offException();
            offNetwork();
        };
    }, []);
    return (
        <Dialog open={open} onOpenChange={setOpen}>
            <DialogContent>
                <DialogTitle>Alterações por guardar</DialogTitle>
                <DialogDescription>
                    Guarde as alterações antes de escolher outro contexto, ou
                    descarte-as.
                </DialogDescription>
                {message && <p role="alert">{message}</p>}
                <div className="flex flex-wrap gap-3">
                    <Button
                        onClick={() => {
                            const forms = [...dirty.current].filter(
                                (form) => form.isConnected,
                            );
                            if (forms.length !== 1) {
                                setMessage(
                                    'Existem alterações em vários formulários. Cancele a mudança e guarde cada formulário antes de continuar.',
                                );
                                return;
                            }
                            if (!forms[0].hasAttribute('data-context-save')) {
                                setMessage(
                                    'Cancele a mudança e conclua este formulário pela sua acção própria. A mudança de contexto não executa aprovações ou outras decisões.',
                                );
                                return;
                            }
                            if (!forms[0].reportValidity()) {
                                setOpen(false);
                                return;
                            }
                            pending.current = true;
                            savingForm.current = forms[0];
                            setOpen(false);
                            forms[0].requestSubmit();
                        }}
                    >
                        Guardar
                    </Button>
                    <Button
                        variant="outline"
                        onClick={() => {
                            dirty.current.clear();
                            pending.current = false;
                            setOpen(false);
                            router.visit('/dashboard');
                        }}
                    >
                        Descartar
                    </Button>
                    <Button
                        variant="outline"
                        onClick={() => {
                            pending.current = false;
                            setOpen(false);
                        }}
                    >
                        Cancelar
                    </Button>
                </div>
            </DialogContent>
        </Dialog>
    );
}