import React, { useEffect, useRef, useState } from "react";
import { useBlocker, useBeforeUnload } from "react-router-dom";
import { Alert, Box, Button, Checkbox, FormControlLabel, Stack, Typography } from "@mui/material";
import { arrangeDashboardWidgets, DashboardLayout, defaultDashboardLayout, WIDGETS } from "../dashboardLayout";
import { useI18n } from "../i18n/I18nProvider";
import { useConfirm } from "../confirm";
import { PageSection } from "../layout/PageLayout";

export function DashboardNavigationGuard({ dirty, saving }: { dirty: boolean; saving: boolean }) {
  const { t } = useI18n();
  const { confirm } = useConfirm();
  const blocker = useBlocker(dirty || saving);
  const [waiting, setWaiting] = useState(false);
  const pending = useRef(false);
  useBeforeUnload(React.useCallback(event => {
    if (!dirty) return;
    event.preventDefault(); event.returnValue = "";
  }, [dirty]));
  useEffect(() => {
    if (blocker.state !== "blocked") { pending.current = false; return; }
    if (saving) { setWaiting(true); blocker.reset(); return; }
    if (pending.current) return;
    pending.current = true;
    void confirm({ title: t("dashboardDiscardTitle"), message: t("dashboardDiscardBody"), confirmLabel: t("dashboardDiscard"), cancelLabel: t("workspaceKeepEditing"), destructive: true })
      .then(approved => { if (approved) blocker.proceed(); else blocker.reset(); });
  }, [blocker, confirm, saving, t]);
  return waiting && saving ? <Typography role="status">{t("dashboardWaitForSave")}</Typography> : null;
}

type Props = {
  draft: DashboardLayout;
  dirty: boolean;
  saving: boolean;
  saveError: string | null;
  conflict: boolean;
  onChange: (next: DashboardLayout) => void;
  onSave: () => void;
  onCancel: () => void;
  onReload: () => void;
};

export default function DashboardLayoutEditor({ draft, dirty, saving, saveError, conflict, onChange, onSave, onCancel, onReload }: Props) {
  const { t } = useI18n();
  const { confirm } = useConfirm();
  const panel = useRef<HTMLDivElement>(null);
  useEffect(() => {
    panel.current?.focus({ preventScroll: true });
    panel.current?.scrollIntoView?.({ block: "start" });
  }, []);
  const cancel = async () => {
    if (!dirty || await confirm({ title: t("dashboardDiscardTitle"), message: t("dashboardDiscardBody"), confirmLabel: t("dashboardDiscard"), destructive: true })) onCancel();
  };
  const reset = async () => {
    if (await confirm({ title: t("dashboardReset"), message: t("dashboardResetBody"), confirmLabel: t("dashboardReset") })) onChange({ ...defaultDashboardLayout(), revision: draft.revision });
  };
  const reload = async () => {
    if (await confirm({ title: t("dashboardReload"), message: t("dashboardReloadBody"), confirmLabel: t("dashboardReload"), destructive: true })) onReload();
  };
  return <Box ref={panel} tabIndex={-1} role="group" aria-label={t("dashboardEditing")} sx={{ scrollMarginTop: "calc(var(--app-shell-header-height, 124px) + 16px)" }} onKeyDown={event => {
    if (event.key === "Escape" && !saving && !event.defaultPrevented) { event.preventDefault(); void cancel(); }
  }}>
    <PageSection surface title={t("dashboardEditing")} description={t("dashboardEditingBody")}>
      <Stack direction="row" useFlexGap flexWrap="wrap" spacing={1} sx={{ mb: 2 }}>
        <Button variant="contained" disabled={saving || conflict} onClick={onSave}>{t(saving ? "dashboardSaving" : "dashboardSave")}</Button>
        <Button disabled={saving} onClick={() => void cancel()}>{t("cancel")}</Button>
        <Button disabled={saving} onClick={() => void reset()}>{t("dashboardReset")}</Button>
      </Stack>
      {saveError ? <Alert severity="error" sx={{ mb: 2 }}>{t(conflict ? "dashboardConflict" : "dashboardSaveFailed")}
        {conflict ? <Button disabled={saving} onClick={() => void reload()}>{t("dashboardReload")}</Button> : null}
      </Alert> : null}
      <Typography role="status" aria-live="polite" variant="body2" sx={{ mb: 1 }}>{t(dirty ? "assetsUnsavedChanges" : "dashboardDraftSaved")}</Typography>
      <Box component="details">
        <Box component="summary" sx={{ p: 1, cursor: "pointer", minHeight: 44 }}>{t("dashboardManageWidgets")}</Box>
        <Stack direction="row" useFlexGap flexWrap="wrap" role="group" aria-label={t("dashboardManageWidgets")}>
        {draft.widgets.map(widget => {
          const entry = WIDGETS.find(item => item.id === widget.id)!;
          const name = t(entry.titleKey);
          return <FormControlLabel key={widget.id} sx={{ minWidth: 0, overflowWrap: "anywhere" }} label={name}
            control={<Checkbox checked={widget.visible} disabled={saving || conflict} onChange={event => onChange({ ...draft,
              widgets: arrangeDashboardWidgets(draft.widgets.map(item => item.id === widget.id ? { ...item, visible: event.target.checked } : item)) })} />} />;
        })}
        </Stack>
      </Box>
    </PageSection>
  </Box>;
}