// router.js - Simple SPA router
import { renderHomePage, getHomePageSidebar } from './pages/HomePage.js';
import { renderAreaPage, getAreaPageSidebar } from './pages/AreaPage.js';
import { renderResourcesPage, getResourcesPageSidebar } from './pages/ResourcesPage.js';

class Router {
    constructor() {
        this.routes = {
            '/': 'home',
            '/home': 'home',
            '/efficiency': 'efficiency',
            '/personal': 'personal', 
            '/rights': 'rights',
            '/ecosystems': 'ecosystems',
            '/about': 'resources'
        };
        
        this.currentPage = null;
        this.init();
    }

    init() {
        // Handle initial page load
        this.loadPage(window.location.pathname);
        
        // Handle browser back/forward
        window.addEventListener('popstate', (e) => {
            const path = window.location.pathname;
            const hash = window.location.hash;
            const fullUrl = path + hash;
            
            // Use navigateToUrl to ensure proper scroll behavior
            this.navigateToUrl(fullUrl);
        });
        
        // Handle hash changes for navigation
        window.addEventListener('hashchange', (e) => {
            const hash = window.location.hash.substring(1);
            if (hash) {
                // Scroll to the section after a short delay to ensure content is loaded
                setTimeout(() => this.scrollToSection(hash), 100);
            }
        });
        
        // Handle initial hash if present
        const initialHash = window.location.hash.substring(1);
        if (initialHash) {
            setTimeout(() => this.scrollToSection(initialHash), 200);
        }
        
        // Initialize unified navigation handling
        this.initializeNavigation();
    }

    async loadPage(path) {
        const route = this.routes[path] || 'home';
        
        if (this.currentPage === route) {
            // Same page, no need to reload
            return;
        }
        
        this.currentPage = route;

        try {
            switch (route) {
                case 'home':
                    await this.loadHomePage();
                    break;
                case 'efficiency':
                case 'personal':
                case 'rights':
                case 'ecosystems':
                    await this.loadAreaPage(route);
                    break;
                case 'resources':
                    await this.loadResourcesPage();
                    break;
                default:
                    await this.loadHomePage();
            }
            
        } catch (error) {
            console.error('Error loading page:', error);
            // Fallback to home page
            await this.loadHomePage();
        }
        
        return Promise.resolve();
    }

    async loadHomePage() {
        const mainContent = document.getElementById('main-content');
        const leftSidebar = document.getElementById('left-sidebar');
        
        if (!mainContent) {
            return;
        }

        try {
            // Get page content and sidebar
            const homePage = renderHomePage();
            
            // Update content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = homePage.content;
            
            // Update sidebar if it exists
            if (leftSidebar) {
                leftSidebar.innerHTML = getHomePageSidebar();
            }
            
            // Initialize page
            if (homePage.init) {
                homePage.init();
            }
            
            // Update navigation state
            this.updateNavigation('home');
        } catch (error) {
            // Fallback to error content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = `
                <div class="bg-white rounded-lg shadow-sm p-8">
                    <h1 class="text-3xl font-bold text-red-600 mb-6">Error Loading Page</h1>
                    <p class="text-gray-700">Sorry, there was an error loading the home page.</p>
                </div>
            `;
        }
    }

    async loadAreaPage(area) {
        const mainContent = document.getElementById('main-content');
        const leftSidebar = document.getElementById('left-sidebar');
        
        if (!mainContent) {
            return;
        }

        try {
            // Get area page content and sidebar
            const areaPage = renderAreaPage(area);
            
            // Update content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = areaPage.content;
            
            // Update sidebar
            if (leftSidebar) {
                leftSidebar.innerHTML = getAreaPageSidebar(area);
            }
            
            // Initialize page
            if (areaPage.init) {
                areaPage.init();
            }
        } catch (error) {
            console.error(`Error loading ${area} page:`, error);
            
            // Fallback content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = `
                <div class="bg-white rounded-lg shadow-sm p-8">
                    <h1 class="text-3xl font-bold text-red-600 mb-6">Error Loading Page</h1>
                    <p class="text-gray-700">Sorry, there was an error loading the ${area} page.</p>
                </div>
            `;
        }
        
        this.updateNavigation(area);
    }

    async loadResourcesPage() {
        const mainContent = document.getElementById('main-content');
        const leftSidebar = document.getElementById('left-sidebar');
        
        if (!mainContent) return;

        try {
            // Get resources page content and sidebar
            const resourcesPage = renderResourcesPage();
            
            // Update content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = resourcesPage.content;
            
            // Update sidebar
            if (leftSidebar) {
                leftSidebar.innerHTML = getResourcesPageSidebar();
            }
            
            // Initialize page
            if (resourcesPage.init) {
                resourcesPage.init();
            }
        } catch (error) {
            // Fallback content
            const contentContainer = mainContent.querySelector('.max-w-4xl') || mainContent;
            contentContainer.innerHTML = `
                <div class="bg-white rounded-lg shadow-sm p-8">
                    <h1 class="text-3xl font-bold text-red-600 mb-6">Error Loading Page</h1>
                    <p class="text-gray-700">Sorry, there was an error loading the resources page.</p>
                </div>
            `;
        }
        
        this.updateNavigation('resources');
    }

    updateNavigation(currentPage) {
        // Update header navigation active states
        const navLinks = document.querySelectorAll('header nav a');
        navLinks.forEach(link => {
            link.classList.remove('text-blue-600', 'bg-blue-50');
            link.classList.add('text-gray-700');
            
            const href = link.getAttribute('href');
            if ((currentPage === 'home' && (href === '/' || href === '/home')) ||
                (currentPage === 'resources' && href === '/about') ||
                (currentPage !== 'home' && currentPage !== 'resources' && href === `/${currentPage}`)) {
                link.classList.remove('text-gray-700');
                link.classList.add('text-blue-600', 'bg-blue-50');
            }
        });
    }


    initializeNavigation() {
        // Use event delegation to handle all navigation links
        document.addEventListener('click', (e) => {
            const link = e.target.closest('a');
            if (!link) return;
            
            const href = link.getAttribute('href');
            if (!href) return;
            
            // Handle different types of links
            if (href.startsWith('/') && !href.startsWith('/js/') && !href.startsWith('/css/') && !href.startsWith('/images/')) {
                // Check if this is a known SPA route
                const path = href.split('#')[0];
                if (this.routes[path]) {
                    e.preventDefault();
                    this.navigateToUrl(href);
                }
            } else if (href.startsWith('#')) {
                // Same-page hash navigation
                e.preventDefault();
                this.scrollToSection(href.substring(1));
            }
            // External links are handled normally by browser
        });
    }

    navigateToUrl(fullUrl) {
        // Parse URL into path and hash
        const [path, hash] = fullUrl.split('#');
        
        // Update browser URL
        window.history.pushState({}, '', fullUrl);
        
        // Load page and then handle hash
        this.loadPage(path).then(() => {
            if (hash) {
                setTimeout(() => this.scrollToSection(hash), 100);
            } else {
                // No hash - scroll to top of page with a delay to ensure content is rendered
                setTimeout(() => {
                    window.scrollTo({ top: 0, behavior: 'smooth' });
                }, 100);
            }
        });
    }

    scrollToSection(sectionId) {
        const element = document.getElementById(sectionId);
        if (element) {
            // Scroll to element with offset to show title
            const elementRect = element.getBoundingClientRect();
            const absoluteElementTop = elementRect.top + window.pageYOffset;
            const offset = 120; // Account for fixed header + some padding
            
            window.scrollTo({
                top: absoluteElementTop - offset,
                behavior: 'smooth'
            });
        }
    }

}

// Export router instance
export const router = new Router();