import React, { useEffect, useState } from "react";

import { Alert, Box, Button, Divider, Typography } from "@mui/material";
import { PageSection } from "../layout/PageLayout";
import { api, getApiErrorMessage } from "../api";
import { clearAuthClientState } from "../auth";
import { useToast } from "../toast";
import { useI18n } from "../i18n/I18nProvider";
import { usePrompt } from "../prompt";

type AccountLifecycleStatus = {
  deletionEnabled: boolean;
  deletionStatus: string;
  requiredConfirmation: string;
  request?: { status: string; stage: string } | null;
};

export default function BackupCard() {
  const { toast } = useToast();
  const { t } = useI18n();
  const { prompt } = usePrompt();
  const [downloading, setDownloading] = useState(false);
  const [exportingAccount, setExportingAccount] = useState(false);
  const [deletingAccount, setDeletingAccount] = useState(false);
  const [lifecycle, setLifecycle] = useState<AccountLifecycleStatus | null>(null);

  useEffect(() => {
    let active = true;
    api.get<AccountLifecycleStatus>("/account-lifecycle/status")
      .then((response) => { if (active) setLifecycle(response.data); })
      .catch(() => { if (active) setLifecycle(null); });
    return () => { active = false; };
  }, []);

  const downloadBlob = (blob: Blob, contentDisposition: string | undefined, fallbackName: string) => {
    const url = URL.createObjectURL(blob);
    const match = /filename="?([^";]+)"?/i.exec(contentDisposition || "");
    const link = document.createElement("a");
    link.href = url;
    link.download = match?.[1] ?? fallbackName;
    document.body.appendChild(link);
    link.click();
    link.remove();
    window.setTimeout(() => URL.revokeObjectURL(url), 5000);
  };

  const downloadAccountExport = async () => {
    setExportingAccount(true);
    try {
      const res = await api.post("/export/account", null, { responseType: "blob" });
      downloadBlob(res.data as Blob, res.headers?.["content-disposition"] as string | undefined, `jobjakt-account-export-${new Date().toISOString().slice(0, 10)}.zip`);
      toast(t("accountExportDownloaded"), "success");
    } catch (error: any) {
      toast(getApiErrorMessage(error, t("accountExportFailed")), "error");
    } finally {
      setExportingAccount(false);
    }
  };

  const downloadEncrypted = async () => {
    setDownloading(true);
    try {
      const res = await api.post("/backup/encrypted", null, { responseType: "blob" });
      downloadBlob(res.data as Blob, res.headers?.["content-disposition"] as string | undefined, `jobtracker_backup_${new Date().toISOString().slice(0, 10)}.jtbackup`);
      toast(t("backupDownloaded"), "success");
    } catch (error: any) {
      toast(getApiErrorMessage(error, t("backupFailed")), "error");
    } finally {
      setDownloading(false);
    }
  };

  const deleteAccount = async () => {
    if (!lifecycle?.deletionEnabled || lifecycle.deletionStatus !== "active") return;
    const confirmation = await prompt({
      title: t("accountDeleteTitle"),
      message: t("accountDeletePrompt", { confirmation: lifecycle.requiredConfirmation }),
      confirmLabel: t("accountDeleteButton"),
      cancelLabel: t("cancel"),
    });
    if (confirmation === null) return;
    if (confirmation.trim() !== lifecycle.requiredConfirmation) {
      toast(t("accountDeleteConfirmationMismatch"), "error");
      return;
    }
    setDeletingAccount(true);
    try {
      const response = await api.post("/account-lifecycle/delete", { confirmation });
      setLifecycle((current) => current ? { ...current, deletionStatus: "pending", request: response.data } : current);
      clearAuthClientState();
      window.location.assign("/login");
    } catch (error: any) {
      toast(getApiErrorMessage(error, t("accountDeleteFailed")), "error");
      setDeletingAccount(false);
    }
  };

  return (
    <PageSection surface title={t("backupTitle")}>
      <Typography sx={{ color: "text.secondary", mb: 1 }}>
        {t("accountExportBody")}
      </Typography>
      <Box sx={{ display: "flex", gap: 1, flexWrap: "wrap" }}>
        <Button variant="contained" onClick={downloadAccountExport} disabled={exportingAccount || downloading}>
          {exportingAccount ? t("accountExportPreparing") : t("accountExportDownload")}
        </Button>
      </Box>
      <Alert severity="info" sx={{ mt: 1.5 }}>{t("accountExportRecentSignIn")}</Alert>
      <Divider sx={{ my: 2 }} />
      <Typography component="h3" variant="sectionTitle">{t("backupEncryptedTitle")}</Typography>
      <Typography sx={{ color: "text.secondary", mb: 1 }}>
        {t("backupBody")}
      </Typography>
      <Box sx={{ display: "flex", gap: 1, flexWrap: "wrap" }}>
        <Button variant="contained" onClick={downloadEncrypted} disabled={downloading || exportingAccount}>
          {downloading ? t("backupPreparing") : t("backupDownload")}
        </Button>
      </Box>
      <Divider sx={{ my: 2 }} />
      <Typography component="h3" variant="sectionTitle">{t("accountDeleteTitle")}</Typography>
      {lifecycle?.deletionStatus === "pending" ? (
        <Alert severity="warning">{t("accountDeletePending", { stage: lifecycle.request?.stage ?? "pending" })}</Alert>
      ) : lifecycle?.deletionEnabled ? (
        <Box>
          <Alert severity="error" sx={{ mb: 1.5 }}>{t("accountDeleteWarning")}</Alert>
          <Button color="error" variant="outlined" onClick={() => void deleteAccount()} disabled={deletingAccount}>
            {deletingAccount ? t("accountDeleteStarting") : t("accountDeleteButton")}
          </Button>
        </Box>
      ) : (
        <Alert severity="info">{t("accountDeleteDisabled")}</Alert>
      )}
    </PageSection>
  );
}