/**
 * Enhanced Router
 * 
 * Provides enhanced routing with guards, middleware, lazy loading, and analytics.
 */

import { Logger } from '../../core/logger.js';
import { RouteGuard, BuiltInGuards } from './RouteGuard.js';
import { RouteMiddleware, BuiltInMiddleware } from './RouteMiddleware.js';

/**
 * Router - Enhanced routing system
 */
export class Router {
    constructor(config = {}) {
        this.config = {
            mode: config.mode || 'history', // 'history' | 'hash'
            base: config.base || '/',
            enableAnalytics: config.enableAnalytics ?? true,
            ...config
        };
        
        this.routes = new Map();
        this.guards = new Map();
        this.middleware = [];
        this.beforeEachHooks = [];
        this.afterEachHooks = [];
        this.currentRoute = null;
        this.analytics = {
            navigations: [],
            errors: []
        };
        
        // Initialize
        this.init();
    }
    
    /**
     * Create a new Router instance
     */
    static create(config = {}) {
        return new Router(config);
    }
    
    /**
     * Initialize router
     */
    init() {
        // Handle browser navigation
        window.addEventListener('popstate', (event) => {
            this.handlePopState(event);
        });
        
        Logger.info('[Router] Initialized', {
            mode: this.config.mode,
            base: this.config.base
        });
    }
    
    /**
     * Register a route
     */
    route(path, config) {
        const route = {
            path: this.normalizePath(path),
            component: config.component,
            name: config.name || path,
            title: config.title || null,
            meta: config.meta || {},
            guards: config.guards || [],
            middleware: config.middleware || [],
            lazy: config.lazy ?? false,
            ...config
        };
        
        this.routes.set(route.path, route);
        
        Logger.debug('[Router] Route registered', route);
        return this;
    }
    
    /**
     * Register multiple routes
     */
    routes(routesConfig) {
        routesConfig.forEach(route => {
            this.route(route.path, route);
        });
        return this;
    }
    
    /**
     * Register a guard
     */
    guard(name, guardFn) {
        const guard = RouteGuard.create(name, guardFn);
        this.guards.set(name, guard);
        return this;
    }
    
    /**
     * Register middleware
     */
    use(middleware) {
        if (typeof middleware === 'function') {
            this.middleware.push(RouteMiddleware.create('anonymous', middleware));
        } else if (middleware instanceof RouteMiddleware) {
            this.middleware.push(middleware);
        } else if (typeof middleware === 'string' && BuiltInMiddleware[middleware]) {
            this.middleware.push(BuiltInMiddleware[middleware]);
        }
        return this;
    }
    
    /**
     * Add beforeEach hook
     */
    beforeEach(hook) {
        this.beforeEachHooks.push(hook);
        return this;
    }
    
    /**
     * Add afterEach hook
     */
    afterEach(hook) {
        this.afterEachHooks.push(hook);
        return this;
    }
    
    /**
     * Navigate to a route
     */
    async navigate(path, options = {}) {
        const normalizedPath = this.normalizePath(path);
        const route = this.routes.get(normalizedPath);
        
        if (!route) {
            Logger.warn('[Router] Route not found', normalizedPath);
            return false;
        }
        
        const from = this.currentRoute;
        const to = {
            path: normalizedPath,
            name: route.name,
            title: route.title,
            meta: route.meta,
            component: route.component
        };
        
        // Execute beforeEach hooks
        for (const hook of this.beforeEachHooks) {
            const result = await hook(to, from);
            if (result === false || typeof result === 'string') {
                if (typeof result === 'string') {
                    return await this.navigate(result);
                }
                return false;
            }
        }
        
        // Execute guards
        for (const guardName of route.guards) {
            const guard = this.guards.get(guardName) || BuiltInGuards[guardName];
            if (!guard) {
                Logger.warn('[Router] Guard not found', guardName);
                continue;
            }
            
            const result = await guard.execute(to, from);
            if (!result.allowed) {
                if (result.redirect) {
                    return await this.navigate(result.redirect);
                }
                Logger.warn('[Router] Navigation blocked by guard', guardName);
                return false;
            }
        }
        
        // Execute middleware
        let middlewareBlocked = false;
        for (const middleware of [...this.middleware, ...route.middleware]) {
            await new Promise((resolve) => {
                middleware.execute(to, from, (allowed) => {
                    if (allowed === false) {
                        middlewareBlocked = true;
                    }
                    resolve();
                });
            });
            
            if (middlewareBlocked) {
                return false;
            }
        }
        
        // Load component if lazy
        if (route.lazy && typeof route.component === 'function') {
            try {
                route.component = await route.component();
            } catch (error) {
                Logger.error('[Router] Failed to load lazy component', error);
                return false;
            }
        }
        
        // Update current route
        this.currentRoute = to;
        
        // Update browser history
        if (this.config.mode === 'history') {
            history.pushState({ route: to }, route.title || '', normalizedPath);
        } else {
            window.location.hash = normalizedPath;
        }
        
        // Update page title
        if (route.title) {
            document.title = route.title;
        }
        
        // Track analytics
        if (this.config.enableAnalytics) {
            this.trackNavigation(to, from);
        }
        
        // Execute afterEach hooks
        for (const hook of this.afterEachHooks) {
            await hook(to, from);
        }
        
        // Render component
        await this.renderComponent(route, options);
        
        Logger.info('[Router] Navigated', { to: normalizedPath });
        return true;
    }
    
    /**
     * Render component
     */
    async renderComponent(route, options = {}) {
        const container = options.container || document.querySelector('main');
        
        if (!container) {
            Logger.error('[Router] Container not found');
            return;
        }
        
        if (typeof route.component === 'function') {
            // Component is a function (render function)
            const content = await route.component(route, options);
            if (typeof content === 'string') {
                container.innerHTML = content;
            } else if (content instanceof HTMLElement) {
                container.innerHTML = '';
                container.appendChild(content);
            }
        } else if (typeof route.component === 'string') {
            // Component is a selector or HTML
            const element = document.querySelector(route.component);
            if (element) {
                container.innerHTML = '';
                container.appendChild(element.cloneNode(true));
            } else {
                container.innerHTML = route.component;
            }
        }
        
        // Re-initialize modules in new content
        this.reinitializeModules(container);
    }
    
    /**
     * Re-initialize modules in container
     */
    reinitializeModules(container) {
        // Trigger module re-initialization
        const event = new CustomEvent('router:content-updated', {
            detail: { container },
            bubbles: true
        });
        document.dispatchEvent(event);
    }
    
    /**
     * Handle popstate event
     */
    handlePopState(event) {
        const path = this.config.mode === 'history' 
            ? window.location.pathname 
            : window.location.hash.slice(1);
        
        this.navigate(path, { updateHistory: false });
    }
    
    /**
     * Normalize path
     */
    normalizePath(path) {
        // Remove base if present
        if (path.startsWith(this.config.base)) {
            path = path.slice(this.config.base.length);
        }
        
        // Ensure leading slash
        if (!path.startsWith('/')) {
            path = '/' + path;
        }
        
        // Remove trailing slash (except root)
        if (path !== '/' && path.endsWith('/')) {
            path = path.slice(0, -1);
        }
        
        return path;
    }
    
    /**
     * Track navigation for analytics
     */
    trackNavigation(to, from) {
        const navigation = {
            to: to.path,
            from: from?.path || null,
            timestamp: Date.now(),
            duration: from ? Date.now() - (from.timestamp || Date.now()) : 0
        };
        
        this.analytics.navigations.push(navigation);
        
        // Limit analytics size
        if (this.analytics.navigations.length > 100) {
            this.analytics.navigations.shift();
        }
        
        // Trigger analytics event
        const event = new CustomEvent('router:navigation', {
            detail: navigation,
            bubbles: true
        });
        window.dispatchEvent(event);
    }
    
    /**
     * Get current route
     */
    getCurrentRoute() {
        return this.currentRoute;
    }
    
    /**
     * Get analytics
     */
    getAnalytics() {
        return {
            ...this.analytics,
            totalNavigations: this.analytics.navigations.length,
            totalErrors: this.analytics.errors.length
        };
    }
    
    /**
     * Destroy router
     */
    destroy() {
        this.routes.clear();
        this.guards.clear();
        this.middleware = [];
        this.beforeEachHooks = [];
        this.afterEachHooks = [];
        this.currentRoute = null;
        
        Logger.info('[Router] Destroyed');
    }
}