export default class Router {
    constructor(options = {}) {
        this.routes = new Map();
        this.currentRoute = null;
        this.basePath = options.basePath || '/';
        this.transitionEnabled = true;
        this.logger = options.logger || null;
        this.appState = options.appState || null;
        this._setupListeners();
    }

    register(path, handler, metadata = {}) {
        this.routes.set(path, { handler, metadata });
        return this;
    }

    async navigate(path, state = {}, skipTransition = false) {
        try {
            const route = this._matchRoute(path);

            if (!route) {
                this.logger?.warn(`No route found for: ${path}`);
                return;
            }

            if (this.currentRoute?.path === path) return;

            this.appState?.setState({ isLoading: true });

            const performTransition = () => {
                if (this.transitionEnabled && !skipTransition && document.startViewTransition) {
                    document.startViewTransition(() => {
                        this._executeRoute(path, route, state);
                    }).finished.then(() => {
                        this.appState?.setState({ isLoading: false });
                    }).catch(err => {
                        this.logger?.error('View transition failed', err);
                        this.appState?.setState({ isLoading: false });
                    });
                } else {
                    this._executeRoute(path, route, state);
                    this.appState?.setState({ isLoading: false });
                }
            };

            window.history.pushState(state, '', `${this.basePath}${path}`);
            performTransition();
        } catch (error) {
            this.logger?.error(`Navigation error: ${error.message}`);
            this.appState?.setState({ isLoading: false });
        }
    }

    _executeRoute(path, route, state) {
        const root = document.getElementById('app-root');
        if (!root) return;

        root.innerHTML = '';

        this.currentRoute = { path, ...route };

        try {
            const result = route.handler(state);

            if (result instanceof HTMLElement) {
                root.appendChild(result);
            } else if (typeof result === 'string') {
                root.innerHTML = result;
            }

            this.appState?.setState({ currentPage: path });
            window.dispatchEvent(new CustomEvent('route-changed', { detail: { path, state } }));
        } catch (error) {
            this.logger?.error(`Route handler failed for ${path}`, error);
            root.innerHTML = '<h1>Error loading page</h1>';
        }
    }

    _matchRoute(path) {
        if (this.routes.has(path)) {
            return this.routes.get(path);
        }

        for (const [routePath, route] of this.routes.entries()) {
            const regex = this._pathToRegex(routePath);
            if (regex.test(path)) {
                return route;
            }
        }

        return null;
    }

    _pathToRegex(path) {
        const pattern = path
            .replace(/\//g, '\\/')
            .replace(/:(\w+)/g, '(?<$1>[^/]+)')
            .replace(/\*/g, '.*');
        return new RegExp(`^${pattern}$`);
    }

    _setupListeners() {
        window.addEventListener('popstate', (event) => {
            const path = window.location.pathname.replace(this.basePath, '') || '/';
            this.navigate(path, event.state, true);
        });

        document.addEventListener('click', (event) => {
            const link = event.target.closest('a[data-nav]');
            if (link) {
                event.preventDefault();
                const path = link.getAttribute('href') || link.getAttribute('data-nav');
                this.navigate(path);
            }
        });
    }

    back() {
        window.history.back();
    }

    forward() {
        window.history.forward();
    }
}