import { writable } from 'svelte/store';
import { browser } from '$app/environment';

/**
 * User preferences store
 * Persisted to localStorage
 */

export interface UserPreferences {
	theme: 'cs2dark' | 'cs2light' | 'auto';
	language: string;
	favoriteMap?: string;
	favoritePlayers: string[]; // Steam IDs as strings to preserve uint64 precision
	showAdvancedStats: boolean;
	dateFormat: 'relative' | 'absolute';
	timezone: string;
}

const defaultPreferences: UserPreferences = {
	theme: 'cs2dark',
	language: 'en',
	favoritePlayers: [],
	showAdvancedStats: false,
	dateFormat: 'relative',
	timezone: Intl.DateTimeFormat().resolvedOptions().timeZone
};

// Load preferences from localStorage
const loadPreferences = (): UserPreferences => {
	if (!browser) return defaultPreferences;

	try {
		const stored = localStorage.getItem('cs2wtf-preferences');
		if (stored) {
			return { ...defaultPreferences, ...JSON.parse(stored) };
		}
	} catch (error) {
		console.error('Failed to load preferences:', error);
	}

	return defaultPreferences;
};

// Create the store
const createPreferencesStore = () => {
	const { subscribe, set, update } = writable<UserPreferences>(loadPreferences());

	return {
		subscribe,
		set: (value: UserPreferences) => {
			if (browser) {
				localStorage.setItem('cs2wtf-preferences', JSON.stringify(value));
			}
			set(value);
		},
		update: (fn: (value: UserPreferences) => UserPreferences) => {
			update((current) => {
				const newValue = fn(current);
				if (browser) {
					localStorage.setItem('cs2wtf-preferences', JSON.stringify(newValue));
				}
				return newValue;
			});
		},
		reset: () => {
			if (browser) {
				localStorage.removeItem('cs2wtf-preferences');
			}
			set(defaultPreferences);
		},

		// Convenience methods
		setTheme: (theme: UserPreferences['theme']) => {
			update((prefs) => ({ ...prefs, theme }));
		},
		setLanguage: (language: string) => {
			update((prefs) => ({ ...prefs, language }));
		},
		addFavoritePlayer: (playerId: string) => {
			update((prefs) => ({
				...prefs,
				favoritePlayers: [...new Set([...prefs.favoritePlayers, playerId])]
			}));
		},
		removeFavoritePlayer: (playerId: string) => {
			update((prefs) => ({
				...prefs,
				favoritePlayers: prefs.favoritePlayers.filter((id) => id !== playerId)
			}));
		},
		toggleAdvancedStats: () => {
			update((prefs) => ({
				...prefs,
				showAdvancedStats: !prefs.showAdvancedStats
			}));
		}
	};
};

export const preferences = createPreferencesStore();