import { useState, useCallback, useEffect } from 'react';
import toast from 'react-hot-toast';
import { useAuthenticatedFetch } from './useAuthenticatedFetch';
import type { UserPreferences } from '../types';
import { COLOR_SCHEMES } from '../types';

const DEFAULT_PREFERENCES: UserPreferences = {
  colorScheme: 'blue',
};

export const applyColorScheme = (schemeId: string) => {
  const scheme = COLOR_SCHEMES.find(s => s.id === schemeId) || COLOR_SCHEMES[0];
  document.documentElement.style.setProperty('--theme-primary', scheme.primary);
  document.documentElement.style.setProperty('--theme-primary-dark', scheme.primaryDark);
  document.documentElement.style.setProperty('--theme-primary-darker', scheme.primaryDarker);
};

interface UseUserPreferencesReturn {
  preferences: UserPreferences;
  hasAIAccess: boolean;
  loading: boolean;
  saving: boolean;
  fetchPreferences: () => Promise<void>;
  savePreferences: (prefs: UserPreferences) => Promise<void>;
  applyColorScheme: (schemeId: string) => void;
}

export const useUserPreferences = (): UseUserPreferencesReturn => {
  const { authFetch, isAuthenticated } = useAuthenticatedFetch();
  const [preferences, setPreferences] = useState<UserPreferences>(DEFAULT_PREFERENCES);
  const [hasAIAccess, setHasAIAccess] = useState(false);
  const [loading, setLoading] = useState(false);
  const [saving, setSaving] = useState(false);

  const fetchPreferences = useCallback(async () => {
    if (!isAuthenticated) return;

    setLoading(true);
    try {
      const response = await authFetch('/api/users/me/preferences');
      if (response.ok) {
        const data = await response.json();
        const prefs: UserPreferences = {
          colorScheme: data.colorScheme || 'blue',
          geminiApiKey: data.geminiApiKey || undefined,
        };
        setPreferences(prefs);
        setHasAIAccess(data.hasAIAccess || false);
        applyColorScheme(prefs.colorScheme);
      }
    } catch {
    } finally {
      setLoading(false);
    }
  }, [authFetch, isAuthenticated]);

  const savePreferences = useCallback(async (prefs: UserPreferences) => {
    setSaving(true);
    try {
      const response = await authFetch('/api/users/me/preferences', {
        method: 'PUT',
        body: JSON.stringify(prefs),
      });

      if (!response.ok) {
        throw new Error('Failed to save preferences');
      }

      setPreferences(prefs);
      applyColorScheme(prefs.colorScheme);
      toast.success('Preferences saved!');
    } catch (err) {
      const message = err instanceof Error ? err.message : 'Failed to save preferences';
      toast.error(message);
      throw err;
    } finally {
      setSaving(false);
    }
  }, [authFetch]);

  useEffect(() => {
    fetchPreferences();
  }, [fetchPreferences]);

  return {
    preferences,
    hasAIAccess,
    loading,
    saving,
    fetchPreferences,
    savePreferences,
    applyColorScheme,
  };
};