// @name Link Collector
// @description Collect unique web links from your selection or the whole page. Copy them as Markdown or plain URLs without changing their query parameters.
(function () {
    'use strict';

    /** @template {keyof HTMLElementTagNameMap} T @param {T} tag @param {string} [text] */
    function element(tag, text = '') {
        const node = document.createElement(tag);
        node.textContent = text;
        return node;
    }

    /** @param {HTMLElement} parent @param {string} label @param {() => void} action */
    function button(parent, label, action) {
        const node = element('button', label);
        node.type = 'button';
        node.addEventListener('click', action);
        parent.append(node);
        return node;
    }

    /** @param {string} id @param {string} title */
    function panel(id, title) {
        const existing = document.getElementById(id);
        if (existing) {
            existing.dispatchEvent(new Event('getbookmarklets:close'));
            return null;
        }
        const previous = document.activeElement;
        const host = element('div');
        host.id = id;
        host.style.setProperty('display', 'block', 'important');
        const shadow = host.attachShadow({ mode: 'open' });
        const style = element('style', ':host{all:initial}dialog{box-sizing:border-box;width:min(92vw,850px);max-height:90vh;padding:20px;border:1px solid #aaa;border-radius:12px;background:var(--bg,#fff);color:var(--fg,#17202a);font:16px/1.5 system-ui}dialog::backdrop{background:#0008}header,.toolbar{display:flex;gap:10px;align-items:center;flex-wrap:wrap}header{justify-content:space-between}h2{margin:0;font-size:21px}.content{margin:16px 0;overflow:auto;max-height:65vh}textarea{box-sizing:border-box;width:100%;height:45vh;font:14px/1.5 monospace;padding:10px}button,select{font:inherit;padding:6px 12px;cursor:pointer}label{display:inline-flex;align-items:center;gap:7px}p[role=status]{min-height:1.5em;margin-bottom:0}pre{white-space:pre-wrap}a{color:inherit;text-decoration:underline}table{border-collapse:collapse}td,th{border:1px solid #999;padding:5px}img{max-width:100%}');
        const dialog = element('dialog');
        dialog.setAttribute('aria-label', title);
        const header = element('header');
        header.append(element('h2', title));
        button(header, 'Close', () => dialog.close());
        const content = element('div');
        content.className = 'content';
        const toolbar = element('div');
        toolbar.className = 'toolbar';
        const status = element('p');
        status.setAttribute('role', 'status');
        status.setAttribute('aria-live', 'polite');
        dialog.append(header, content, toolbar, status);
        shadow.append(style, dialog);
        dialog.addEventListener('close', () => {
            host.remove();
            if (previous instanceof HTMLElement && previous.isConnected) previous.focus({ preventScroll: true });
        });
        host.addEventListener('getbookmarklets:close', () => dialog.close());
        document.documentElement.append(host);
        dialog.showModal();
        return { host, dialog, content, toolbar, status };
    }

    /** @param {string} id @param {string} title @param {string} text */
    function textPanel(id, title, text) {
        const view = panel(id, title);
        if (!view) return null;
        const textarea = element('textarea');
        textarea.setAttribute('aria-label', 'Output');
        textarea.readOnly = true;
        textarea.value = text;
        view.content.append(textarea);
        button(view.toolbar, 'Copy', async () => {
            try {
                await navigator.clipboard.writeText(textarea.value);
                view.status.textContent = 'Copied.';
            } catch {
                textarea.focus();
                textarea.select();
                view.status.textContent = 'Copy unavailable here. The text is selected for manual copying.';
            }
        });
        return { ...view, textarea };
    }

    /** @param {string} text */
    const escapeMarkdown = text => text.replace(/[\\`*_[\]<>#|]/g, '\\$&');

    /** @param {string} href */
    function safeLink(href) {
        try {
            const url = new URL(href, document.baseURI);
            return ['http:', 'https:', 'mailto:', 'tel:'].includes(url.protocol) ? url.href.replace(/</g, '%3C').replace(/>/g, '%3E') : null;
        } catch {
            return null;
        }
    }

    const selection = window.getSelection();
    const ranges = selection && !selection.isCollapsed ? Array.from({ length: selection.rangeCount }, (_, i) => selection.getRangeAt(i).cloneRange()) : [];
    const links = new Map();
    for (const anchor of document.querySelectorAll('a[href]')) {
        if (ranges.length && !ranges.some(range => range.intersectsNode(anchor))) continue;
        const style = getComputedStyle(anchor);
        if (style.display === 'none' || style.visibility === 'hidden' || !anchor.getClientRects().length || anchor.closest('[hidden],[aria-hidden="true"]')) continue;
        const href = safeLink(anchor.getAttribute('href') || '');
        if (!href) continue;
        const url = new URL(href);
        if (!['http:', 'https:'].includes(url.protocol) || links.has(url.href)) continue;
        links.set(url.href, (anchor.innerText || anchor.querySelector('img')?.alt || url.href).replace(/\s+/g, ' ').trim());
    }
    const markdown = [...links].map(([url, label]) => `- [${escapeMarkdown(label)}](<${url}>)`).join('\n');
    const view = textPanel('__getbookmarklets_links__', 'Link Collector', markdown);
    if (view) {
        const label = element('label', 'Format ');
        const format = element('select');
        format.setAttribute('aria-label', 'Format');
        for (const [value, text] of [['markdown', 'Markdown'], ['urls', 'URLs only']]) {
            const option = element('option', text);
            option.value = value;
            format.append(option);
        }
        label.append(format);
        view.toolbar.prepend(label);
        format.addEventListener('change', () => {
            view.textarea.value = format.value === 'urls' ? [...links.keys()].join('\n') : markdown;
        });
        view.status.textContent = `${links.size} unique links${ranges.length ? ' from your selection' : ' on this page'}.`;
    }

})();