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

import {
  Box,
  Button,
  Checkbox,
  FormControl,
  FormControlLabel,
  InputLabel,
  MenuItem,
  Paper,
  Select,
  Tab,
  Tabs,
  Typography,
} from "@mui/material";

import { useNavigate } from "react-router-dom";

import { JobTableColumns } from "./JobTable";
import ImportExportJobs from "./ImportExportJobs";
import RulesSettingsCard from "./RulesSettingsCard";
import BackupCard from "./BackupCard";
import QuickCaptureCard from "./QuickCaptureCard";
import AiUsageCard from "./AiUsageCard";
import AiPrivacySettingsCard from "./AiPrivacySettingsCard";
import { ThemeModePref } from "../themePrefs";
import { useI18n } from "../i18n/I18nProvider";

interface Props {
  pageSize: 15 | 20 | 25;
  onPageSizeChange: (n: 15 | 20 | 25) => void;
  columns: JobTableColumns;
  onColumnsChange: (next: JobTableColumns) => void;
  themeMode: ThemeModePref;
  onThemeModeChange: (v: ThemeModePref) => void;
}

function TabPanel({ value, index, children }: { value: number; index: number; children: React.ReactNode }) {
  if (value !== index) return null;
  return <Box sx={{ mt: 2.5 }}>{children}</Box>;
}

function SectionCard({ title, subtitle, children }: { title: string; subtitle?: string; children: React.ReactNode }) {
  return (
    <Paper sx={{ p: 2.5, borderRadius: 4, border: "none", boxShadow: "0px 1px 2px 0px rgba(15,23,42,0.04), 0px 8px 24px -12px rgba(15,23,42,0.12)" }}>
      <Typography variant="overline" sx={{ color: "text.secondary", fontWeight: 800 }}>{title}</Typography>
      {subtitle ? <Typography variant="body2" sx={{ color: "text.secondary", mt: 0.25, mb: 1.5 }}>{subtitle}</Typography> : <Box sx={{ mb: 1.5 }} />}
      {children}
    </Paper>
  );
}

const NOTIFICATION_PREFS_KEY = "settings.notificationPrefs";

type NotificationPrefs = {
  emailFollowUpReminders: boolean;
  emailGhostedJobAlerts: boolean;
  inAppReminderHighlights: boolean;
};

function loadNotificationPrefs(): NotificationPrefs {
  try {
    const raw = window.localStorage.getItem(NOTIFICATION_PREFS_KEY);
    if (!raw) {
      return {
        emailFollowUpReminders: true,
        emailGhostedJobAlerts: true,
        inAppReminderHighlights: true,
      };
    }
    return {
      emailFollowUpReminders: true,
      emailGhostedJobAlerts: true,
      inAppReminderHighlights: true,
      ...JSON.parse(raw),
    };
  } catch {
    return {
      emailFollowUpReminders: true,
      emailGhostedJobAlerts: true,
      inAppReminderHighlights: true,
    };
  }
}

export default function SettingsView({
  pageSize,
  onPageSizeChange,
  columns,
  onColumnsChange,
  themeMode,
  onThemeModeChange,
}: Props) {
  const navigate = useNavigate();
  const [tab, setTab] = useState(0);
  const { language, setLanguage, t } = useI18n();
  const [notificationPrefs, setNotificationPrefs] = useState<NotificationPrefs>(() => loadNotificationPrefs());

  useEffect(() => {
    window.localStorage.setItem(NOTIFICATION_PREFS_KEY, JSON.stringify(notificationPrefs));
  }, [notificationPrefs]);

  return (
    <Paper sx={{ mt: 0, p: 2.5, borderRadius: 4, border: "none", boxShadow: "0px 1px 2px 0px rgba(15,23,42,0.04), 0px 8px 24px -12px rgba(15,23,42,0.12)" }}>
      <Typography variant="h5" sx={{ mb: 0.5, fontWeight: 900 }}>
        {t("settingsTitle")}
      </Typography>
      <Typography sx={{ color: "text.secondary", mb: 2 }}>
        {t("settingsSubtitle")}
      </Typography>

      <Tabs value={tab} onChange={(_, v) => setTab(v)} variant="scrollable" scrollButtons="auto" allowScrollButtonsMobile sx={{ mb: 1 }}>
        <Tab label={t("settingsTabGeneral")} />
        <Tab label={t("settingsTabFollowUps")} />
        <Tab label={t("settingsTabNotifications")} />
        <Tab label={t("settingsTabBackup")} />
      </Tabs>

      <TabPanel value={tab} index={0}>
        <Box sx={{ display: "grid", gap: 2.5 }}>
          <Box sx={{ display: "grid", gridTemplateColumns: { xs: "1fr", md: "1fr 1fr" }, gap: 2.5 }}>
            <SectionCard title={t("settingsAppearance")}>
              <FormControl fullWidth>
                <InputLabel id="theme-mode-label">{t("settingsTheme")}</InputLabel>
                <Select
                  labelId="theme-mode-label"
                  value={themeMode}
                  label={t("settingsTheme")}
                  onChange={(e) => onThemeModeChange(e.target.value as ThemeModePref)}
                >
                  <MenuItem value="system">{t("settingsThemeSystem")}</MenuItem>
                  <MenuItem value="dark">{t("settingsThemeDark")}</MenuItem>
                  <MenuItem value="light">{t("settingsThemeLight")}</MenuItem>
                </Select>
              </FormControl>
            </SectionCard>

            <SectionCard title={t("settingsLanguageTitle")} subtitle={t("settingsLanguageBody")}>
              <FormControl fullWidth>
                <InputLabel id="language-label">{t("settingsPreferredLanguage")}</InputLabel>
                <Select
                  labelId="language-label"
                  value={language}
                  label={t("settingsPreferredLanguage")}
                  onChange={(e) => setLanguage(e.target.value as "en" | "no")}
                >
                  <MenuItem value="en">{t("settingsEnglish")}</MenuItem>
                  <MenuItem value="no">{t("settingsNorwegian")}</MenuItem>
                </Select>
              </FormControl>
            </SectionCard>
          </Box>

          <SectionCard title={t("settingsJobs")}>
            <Box sx={{ display: "flex", gap: 4, flexWrap: "wrap" }}>
              <Box sx={{ minWidth: 240 }}>
                <Typography variant="subtitle2" sx={{ mb: 1, fontWeight: 700 }}>
                  {t("settingsPagination")}
                </Typography>
                <FormControl fullWidth>
                  <InputLabel id="page-size-label">{t("settingsRowsPerPage")}</InputLabel>
                  <Select
                    labelId="page-size-label"
                    value={pageSize}
                    label={t("settingsRowsPerPage")}
                    onChange={(e) => onPageSizeChange(e.target.value as 15 | 20 | 25)}
                  >
                    <MenuItem value={15}>15</MenuItem>
                    <MenuItem value={20}>20</MenuItem>
                    <MenuItem value={25}>25</MenuItem>
                  </Select>
                </FormControl>
              </Box>

              <Box sx={{ minWidth: 240 }}>
                <Typography variant="subtitle2" sx={{ mb: 1, fontWeight: 700 }}>
                  {t("settingsColumns")}
                </Typography>
                {(
                  [
                    ["status", t("settingsColumnStatus")],
                    ["dateApplied", t("settingsColumnDateApplied")],
                    ["daysSince", t("settingsColumnDays")],
                    ["jobUrl", t("settingsColumnJobUrl")],
                  ] as const
                ).map(([key, label]) => (
                  <FormControlLabel
                    key={key}
                    control={<Checkbox checked={columns[key]} onChange={() => onColumnsChange({ ...columns, [key]: !columns[key] })} />}
                    label={label}
                  />
                ))}
              </Box>
            </Box>

            <Box sx={{ mt: 2 }}>
              <ImportExportJobs />
            </Box>
          </SectionCard>

          <AiPrivacySettingsCard />
          <AiUsageCard />
          <QuickCaptureCard />
          <SectionCard title="Connected accounts" subtitle="Manage inbox connections separately from your account and security settings.">
            <Button variant="outlined" onClick={() => navigate("/settings/connected-accounts")}>Manage connected accounts</Button>
          </SectionCard>
        </Box>
      </TabPanel>

      <TabPanel value={tab} index={1}>
        <RulesSettingsCard />
      </TabPanel>

      <TabPanel value={tab} index={2}>
        <SectionCard title={t("settingsNotificationsTitle")} subtitle={t("settingsNotificationsBody")}>
          <Box sx={{ display: "grid", gap: 1 }}>
            <FormControlLabel
              control={<Checkbox checked={notificationPrefs.emailFollowUpReminders} onChange={(e) => setNotificationPrefs((prev) => ({ ...prev, emailFollowUpReminders: e.target.checked }))} />}
              label={t("settingsNotificationsFollowUpReminders")}
            />
            <FormControlLabel
              control={<Checkbox checked={notificationPrefs.emailGhostedJobAlerts} onChange={(e) => setNotificationPrefs((prev) => ({ ...prev, emailGhostedJobAlerts: e.target.checked }))} />}
              label={t("settingsNotificationsGhostedJobs")}
            />
            <FormControlLabel
              control={<Checkbox checked={notificationPrefs.inAppReminderHighlights} onChange={(e) => setNotificationPrefs((prev) => ({ ...prev, inAppReminderHighlights: e.target.checked }))} />}
              label={t("settingsNotificationsInAppReminders")}
            />
          </Box>
          <Typography variant="caption" sx={{ color: "text.secondary", display: "block", mt: 1.5 }}>
            {t("settingsNotificationsDelivery")}
          </Typography>
          <Box sx={{ display: "flex", gap: 1, flexWrap: "wrap", mt: 1.5 }}>
            <Button variant="outlined" onClick={() => navigate("/reminders")}>{t("settingsOpenReminderInbox")}</Button>
          </Box>
        </SectionCard>
      </TabPanel>

      <TabPanel value={tab} index={3}>
        <BackupCard />
      </TabPanel>
    </Paper>
  );
}