// modules/core/click-manager.js
import { Logger } from './logger.js';
import { useEvent } from './useEvent.js';
import { navigateTo } from "./navigateTo";
import { LinkPrefetcher } from './LinkPrefetcher.js';

let callback = null;
let unsubscribes = [];
let prefetcher = null;

function isInternal(link) {
    return link.origin === location.origin;
}

function handleClick(e) {
    const link = e.target.closest('a');
    if (!link || e.defaultPrevented) return;

    const href = link.getAttribute('href');
    if (!href || href.startsWith('#')) return;

    // Skip conditions
    if (
        link.target === '_blank' ||
        link.hasAttribute('download') ||
        link.getAttribute('rel')?.includes('external') ||
        link.hasAttribute('data-skip')
    ) {
        Logger.info(`[click-manager] skipped: ${href}`);
        return;
    }

    if (isInternal(link)) {
        e.preventDefault();

        const cached = prefetcher ? prefetcher.getCached(href) : null;

        const options = {
            viewTransition: link.hasAttribute('data-view-transition'),
            replace: link.hasAttribute('data-replace'),
            modal: link.hasAttribute('data-modal'),
            prefetched: cached !== null,
            data: cached,
        };

        Logger.info(`[click-manager] internal: ${href}`, options);

        if(options.modal) {
            callback?.(href, link, options);
        } else {
            navigateTo(href, options);
        }
    }
}

function handleMouseOver(e) {
    const link = e.target.closest('a[href]');
    if (!link || !prefetcher) return;
    
    prefetcher.handleHover(link);
}

function handleMouseOut(e) {
    const link = e.target.closest('a[href]');
    if (!link || !prefetcher) return;
    
    prefetcher.handleMouseLeave();
}

function handlePopState() {
    const href = location.pathname;
    Logger.info(`[click-manager] popstate: ${href}`);
    navigateTo(href, { replace: true });
}

export function getPrefetched(href) {
    return prefetcher ? prefetcher.getCached(href) : null;
}

export function prefetchHref(href) {
    if (!href || !prefetcher) return;
    prefetcher.prefetch(href, { priority: 'high' });
}

export function prefetchUrls(urls) {
    if (!prefetcher) return;
    prefetcher.prefetchEager(urls);
}

export function init(onNavigate, prefetchOptions = {}) {
    callback = onNavigate;
    
    // Initialize prefetcher with options
    prefetcher = new LinkPrefetcher({
        strategies: ['hover', 'visible'],
        hoverDelay: 150,
        observerMargin: '50px',
        maxCacheSize: 20,
        cacheTTL: 60000,
        ...prefetchOptions
    });
    
    unsubscribes = [
        useEvent(document, 'click', handleClick),
        useEvent(document, 'mouseover', handleMouseOver),
        useEvent(document, 'mouseout', handleMouseOut),
        useEvent(window, 'popstate', handlePopState),
    ];
    
    // Observe all initial links if visible strategy is enabled
    if (prefetchOptions.strategies?.includes('visible') !== false) {
        // Wait for DOM to be ready
        if (document.readyState === 'loading') {
            document.addEventListener('DOMContentLoaded', () => {
                prefetcher.observeLinks();
            });
        } else {
            prefetcher.observeLinks();
        }
    }
    
    // Support for eager prefetching via data attributes
    document.querySelectorAll('a[data-prefetch="eager"]').forEach(link => {
        const href = link.getAttribute('href');
        if (href) {
            prefetcher.prefetch(href, { priority: 'high' });
        }
    });

    Logger.info('[click-manager] ready with prefetching');
}

export function destroy() {
    callback = null;
    
    if (prefetcher) {
        prefetcher.destroy();
        prefetcher = null;
    }
    
    unsubscribes.forEach(unsub => unsub());
    unsubscribes = [];
    
    Logger.info('[click-manager] destroyed');
}

// Export prefetcher for advanced usage
export function getPrefetcher() {
    return prefetcher;
}