'use client';

import {useState} from 'react';
import {VStack, HStack} from '@astryxdesign/core/Layout';
import {FormLayout} from '@astryxdesign/core/FormLayout';
import {Selector} from '@astryxdesign/core/Selector';
import {Button} from '@astryxdesign/core/Button';
import {Text} from '@astryxdesign/core/Text';
import {useToast} from '@astryxdesign/core/Toast';
import {StaticPanel} from '@/shared/components/patterns/PanelCard';
import {useThemeMode} from '@/shared/providers/ThemeModeProvider';
import type {ThemeMode} from '@/shared/theme/themeMode';

/** Theme mode is deliberately absent — it lives in ThemeModeProvider. */
export interface SystemPreferences {
  currency: 'INR' | 'USD' | 'EUR' | 'GBP';
  language: 'en' | 'hi' | 'kn' | 'ta';
  dateFormat: 'DD/MM/YYYY' | 'MM/DD/YYYY' | 'YYYY-MM-DD';
  defaultLanding: '/dashboard' | '/stores' | '/lyts' | '/staff';
}

const DEFAULT_PREFS: SystemPreferences = {
  currency: 'INR',
  language: 'en',
  dateFormat: 'DD/MM/YYYY',
  defaultLanding: '/dashboard',
};

export function PreferencesForm() {
  const toast = useToast();
  /**
   * Theme is the one preference that does NOT go through the save cycle.
   * It repaints the workspace the instant it changes and persists itself to
   * the theme-mode cookie, so there is nothing left for Save to commit — and
   * a mode you can see but have not "saved" would be the confusing state.
   * The rest of the form is still mock local state.
   */
  const {mode: themeMode, setMode: setThemeMode} = useThemeMode();
  const [prefs, setPrefs] = useState<SystemPreferences>(DEFAULT_PREFS);
  const [savedPrefs, setSavedPrefs] = useState<SystemPreferences>(DEFAULT_PREFS);
  const [isSaving, setIsSaving] = useState(false);

  const set = <K extends keyof SystemPreferences>(
    key: K,
    val: SystemPreferences[K],
  ) => setPrefs((p) => ({...p, [key]: val}));

  const isDirty = JSON.stringify(prefs) !== JSON.stringify(savedPrefs);

  const handleSave = () => {
    setIsSaving(true);
    setTimeout(() => {
      setSavedPrefs(prefs);
      setIsSaving(false);
      toast({body: 'Workspace preferences updated'});
    }, 400);
  };

  return (
    <StaticPanel
      title="Workspace Display & Formatting Preferences"
      subtitle="Customize theme mode, reporting currency, language and default start screen."
      actions={
        <HStack gap={2} vAlign="center">
          {isDirty ? (
            <Text size="sm" color="secondary">
              Unsaved changes
            </Text>
          ) : null}
          <Button
            variant="secondary"
            size="sm"
            label="Reset"
            isDisabled={!isDirty || isSaving}
            onClick={() => setPrefs(savedPrefs)}
          />
          <Button
            variant="primary"
            size="sm"
            label="Save Preferences"
            isDisabled={!isDirty}
            isLoading={isSaving}
            onClick={handleSave}
          />
        </HStack>
      }
    >
      <VStack gap={5}>
        <FormLayout direction="horizontal">
          <Selector
            label="Theme Interface Mode"
            value={themeMode}
            onChange={(v) => setThemeMode(v as ThemeMode)}
            options={[
              {label: 'Light Mode', value: 'light'},
              {label: 'Dark Mode (Monochrome Premium)', value: 'dark'},
              {label: 'System OS Preference', value: 'system'},
            ]}
          />
          <Selector
            label="Reporting Base Currency"
            value={prefs.currency}
            onChange={(v) => set('currency', v as SystemPreferences['currency'])}
            options={[
              {label: 'INR (₹ Indian Rupee)', value: 'INR'},
              {label: 'USD ($ US Dollar)', value: 'USD'},
              {label: 'EUR (€ Euro)', value: 'EUR'},
              {label: 'GBP (£ British Pound)', value: 'GBP'},
            ]}
          />
        </FormLayout>

        <FormLayout direction="horizontal">
          <Selector
            label="Workspace Language"
            value={prefs.language}
            onChange={(v) => set('language', v as SystemPreferences['language'])}
            options={[
              {label: 'English (US & India)', value: 'en'},
              {label: 'Hindi (हिंदी)', value: 'hi'},
              {label: 'Kannada (ಕನ್ನಡ)', value: 'kn'},
              {label: 'Tamil (தமிழ்)', value: 'ta'},
            ]}
          />
          <Selector
            label="Date Formatting"
            value={prefs.dateFormat}
            onChange={(v) => set('dateFormat', v as SystemPreferences['dateFormat'])}
            options={[
              {label: 'DD/MM/YYYY (e.g. 05/08/2026)', value: 'DD/MM/YYYY'},
              {label: 'MM/DD/YYYY (e.g. 08/05/2026)', value: 'MM/DD/YYYY'},
              {label: 'YYYY-MM-DD (e.g. 2026-08-05)', value: 'YYYY-MM-DD'},
            ]}
          />
        </FormLayout>

        <FormLayout direction="horizontal">
          <Selector
            label="Default Home Landing Module"
            value={prefs.defaultLanding}
            onChange={(v) => set('defaultLanding', v as SystemPreferences['defaultLanding'])}
            options={[
              {label: 'Dashboard Overview', value: '/dashboard'},
              {label: 'Store Locations', value: '/stores'},
              {label: 'Lyts & Rewards Catalogue', value: '/lyts'},
              {label: 'Staff Roster & Performance', value: '/staff'},
            ]}
          />
        </FormLayout>
      </VStack>
    </StaticPanel>
  );
}