'use strict';
/**
 * paste_view.js — Logic for the paste view page.
 * Depends on: crypto.js (PasteCrypto), app.js (copyToClipboard)
 *
 * Reads the site name from <meta name="site-name"> so no Jinja injection
 * is needed in this external file.
 */

let _decryptedPaste = null;

document.addEventListener('DOMContentLoaded', async () => {
    let rawPayload;
    try {
        const island = document.getElementById('encryptedPayload');
        if (!island) return; // Not a paste view page
        rawPayload = JSON.parse(island.textContent);
    } catch (e) {
        showError('Bad Data', 'Could not read the paste payload.');
        return;
    }

    // Detect format from the data itself.
    // Encrypted pastes: "base64url:base64url" string.
    // Plaintext pastes: a JSON object.
    const isEncrypted = typeof rawPayload === 'string' &&
        /^[A-Za-z0-9_-]+:[A-Za-z0-9_-]+$/.test(rawPayload);

    if (isEncrypted) {
        const keyBase64 = window.location.hash.slice(1);
        if (!keyBase64) {
            showError('No Key',
                'The decryption key is missing from the URL. ' +
                'Use the full link including the # part.');
            return;
        }
        try {
            const key       = await PasteCrypto.importKey(keyBase64);
            const plaintext = await PasteCrypto.decrypt(rawPayload, key);
            _decryptedPaste = JSON.parse(plaintext);
        } catch (e) {
            showError('Decryption Failed', 'Wrong key or tampered data.');
            return;
        }
    } else {
        // Plaintext paste — rawPayload is already the parsed JSON object.
        try {
            _decryptedPaste = (typeof rawPayload === 'object')
                ? rawPayload
                : JSON.parse(rawPayload);
        } catch (e) {
            showError('Bad Data', 'Could not parse paste data.');
            return;
        }
    }

    renderPaste(_decryptedPaste);
    initPasteActions();
    initLineHighlight(); // register Prism hook before initLineNumbers triggers Prism
    initLineNumbers();
    initDeletion();
});

function initPasteActions() {
    const rawBtn = document.getElementById('rawBtn');
    const copyBtn = document.getElementById('copyBtn');
    const downloadBtn = document.getElementById('downloadBtn');

    if (rawBtn)      rawBtn.addEventListener('click', rawView);
    if (copyBtn)     copyBtn.addEventListener('click', copyPaste);
    if (downloadBtn) downloadBtn.addEventListener('click', downloadPaste);
}

function initLineNumbers() {
    const toggle = document.getElementById('lineNoToggle');
    const viewPre = document.getElementById('viewPre');
    if (!toggle || !viewPre) return;

    // Load preference from localStorage (default to checked)
    const stored = localStorage.getItem('show_line_numbers');
    const isEnabled = (stored === null) ? true : (stored === 'true');
    toggle.checked = isEnabled;

    const updateLines = () => {
        const checked = toggle.checked;
        if (checked) {
            viewPre.classList.add('line-numbers');
        } else {
            viewPre.classList.remove('line-numbers');
            const existing = viewPre.querySelector('.line-numbers-rows');
            if (existing) existing.remove();
        }
        localStorage.setItem('show_line_numbers', checked);

        // Always re-highlight so Prism's line-numbers plugin runs (works for plain text too)
        const code = document.getElementById('codeBlock');
        if (code) {
            Prism.highlightElement(code);
        }
    };

    toggle.addEventListener('change', updateLines);

    // Apply initial state (calls Prism so line numbers render without needing a toggle)
    updateLines();
}

function renderPaste(paste) {
    const siteName = document.querySelector('meta[name="site-name"]')?.content || '';
    const title    = paste.title || 'Untitled';
    document.title = title + (siteName ? ' \u2014 ' + siteName : '');
    document.getElementById('navPasteTitle').textContent = title;

    const lang        = paste.language || 'text';
    const prismLangMap = { text: false, html: 'markup', xml: 'markup', docker: 'docker' };
    const prismLang   = (lang in prismLangMap) ? prismLangMap[lang] : lang;

    const codeBlock = document.getElementById('codeBlock');
    const viewPre   = document.getElementById('viewPre');
    codeBlock.textContent = paste.content || '';
    if (prismLang) {
        codeBlock.className = 'language-' + prismLang;
        viewPre.className   = 'language-' + prismLang;
        Prism.highlightElement(codeBlock);
    }

    document.getElementById('viewFull').style.display = 'block';
}

function showError(title, detail) {
    document.getElementById('errorTitle').textContent   = title;
    document.getElementById('errorDetail').textContent  = detail;
    document.getElementById('errorState').style.display = 'block';
}

function rawView() {
    const key = window.location.hash;
    const url = window.location.href.split('?')[0].split('#')[0] + '/raw' + key;
    window.open(url, '_blank');
}

async function copyPaste() {
    if (!_decryptedPaste) return;
    const ok  = await copyToClipboard(_decryptedPaste.content);
    const btn = document.getElementById('copyBtn');
    if (btn) {
        const t = btn.textContent;
        btn.textContent = ok ? 'Copied!' : 'Failed';
        setTimeout(() => btn.textContent = t, 1500);
    }
}

function downloadPaste() {
    if (!_decryptedPaste) return;
    const { title = 'untitled', content = '', language = 'text' } = _decryptedPaste;
    const extMap = {
        javascript: '.js',  typescript: '.ts',  python:  '.py',   java:       '.java',
        c:          '.c',   cpp:        '.cpp',  csharp:  '.cs',   html:       '.html',
        css:        '.css', scss:       '.scss', sql:     '.sql',  json:       '.json',
        yaml:       '.yaml',xml:        '.xml',  bash:    '.sh',   powershell: '.ps1',
        php:        '.php', ruby:       '.rb',   go:      '.go',   rust:       '.rs',
        swift:      '.swift',kotlin:    '.kt',   markdown:'.md',   diff:       '.diff',
        docker:     '',     nginx:      '.conf', toml:    '.toml', ini:        '.ini',
    };
    const filename = title.replace(/[^a-z0-9.\-]/gi, '_') + (extMap[language] ?? '.txt');
    const blob = new Blob([content], { type: 'text/plain' });
    const url  = URL.createObjectURL(blob);
    const a    = Object.assign(document.createElement('a'), { href: url, download: filename });
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    URL.revokeObjectURL(url);
}

function initDeletion() {
    const pasteId = window.location.pathname.split('/').pop();
    const token = localStorage.getItem('del_' + pasteId);
    const deleteBtn = document.getElementById('deleteBtn');

    if (token && deleteBtn) {
        deleteBtn.style.display = 'inline-block';
        deleteBtn.addEventListener('click', async () => {
            if (!confirm('Are you sure you want to delete this paste? This action cannot be undone.')) return;
            
            deleteBtn.disabled = true;
            deleteBtn.textContent = '...';
            
            try {
                const resp = await fetch('/api/delete/' + pasteId, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify({ token })
                });
                const result = await resp.json();
                if (result.success) {
                    localStorage.removeItem('del_' + pasteId);
                    window.location.href = '/';
                } else {
                    alert('Error: ' + (result.error || 'Unknown error'));
                    deleteBtn.disabled = false;
                    deleteBtn.textContent = 'Delete';
                }
            } catch (err) {
                console.error(err);
                alert('Failed to delete paste. Connection error.');
                deleteBtn.disabled = false;
                deleteBtn.textContent = 'Delete';
            }
        });
    }
}

// ── Line highlight / linking ──────────────────────────────────────────────────

let _hlAnchor  = null; // anchor line for shift-click range
let _hlStart   = null;
let _hlEnd     = null;
let _hlScrolled = false;

function initLineHighlight() {
    // Parse ?L=5 or ?L=5-12 from the URL
    const lParam = new URLSearchParams(window.location.search).get('L');
    if (lParam) {
        const m = lParam.match(/^(\d+)(?:-(\d+))?$/);
        if (m) {
            _hlStart  = parseInt(m[1], 10);
            _hlEnd    = m[2] ? parseInt(m[2], 10) : _hlStart;
            _hlAnchor = _hlStart;
        }
    }

    // After every Prism highlight, wire gutter clicks and redraw highlight bars.
    // initLineNumbers() calls Prism, which fires this hook.
    Prism.hooks.add('complete', function (env) {
        if (env.element && env.element.id === 'codeBlock') {
            _wireLineClicks();
            if (_hlStart !== null) {
                _drawHighlight(_hlStart, _hlEnd);
                if (!_hlScrolled) {
                    _scrollToLine(_hlStart);
                    _hlScrolled = true;
                }
            }
        }
    });
}

function _wireLineClicks() {
    const viewPre = document.getElementById('viewPre');
    if (!viewPre) return;
    viewPre.querySelectorAll('.line-numbers-rows > span').forEach((span, i) => {
        if (span.dataset.lineWired) return;
        span.dataset.lineWired = '1';
        const lineNum = i + 1;
        span.title = `Line ${lineNum}`;
        span.addEventListener('click', (e) => {
            if (e.shiftKey && _hlAnchor !== null) {
                const a = Math.min(_hlAnchor, lineNum);
                const b = Math.max(_hlAnchor, lineNum);
                _hlStart = a; _hlEnd = b;
                _drawHighlight(a, b);
                _updateLineUrl(a, b);
            } else if (_hlStart === lineNum && _hlEnd === lineNum) {
                // Clicking the sole highlighted line → clear
                _hlAnchor = null; _hlStart = null; _hlEnd = null;
                _clearHighlight();
                _clearLineUrl();
            } else {
                _hlAnchor = lineNum;
                _hlStart  = lineNum;
                _hlEnd    = lineNum;
                _drawHighlight(lineNum, lineNum);
                _updateLineUrl(lineNum, lineNum);
            }
        });
    });
}

function _clearHighlight() {
    const viewPre = document.getElementById('viewPre');
    if (!viewPre) return;
    viewPre.querySelectorAll('.line-hl').forEach(el => el.remove());
    viewPre.querySelectorAll('.line-numbers-rows > span').forEach(
        s => s.classList.remove('hl-active')
    );
}

function _clearLineUrl() {
    const url = new URL(window.location.href);
    url.searchParams.delete('L');
    history.replaceState(null, '', url.toString());
}

function _drawHighlight(start, end) {
    const viewPre = document.getElementById('viewPre');
    const code    = document.getElementById('codeBlock');
    if (!viewPre || !code) return;

    // Remove old bars and gutter classes
    viewPre.querySelectorAll('.line-hl').forEach(el => el.remove());
    viewPre.querySelectorAll('.line-numbers-rows > span').forEach(
        (s, i) => s.classList.toggle('hl-active', i + 1 >= start && i + 1 <= end)
    );

    const lineH  = parseFloat(getComputedStyle(code).lineHeight) || 22.4;
    const padTop = parseFloat(getComputedStyle(viewPre).paddingTop) || 16;

    const frag = document.createDocumentFragment();
    for (let i = start; i <= end; i++) {
        const bar = document.createElement('div');
        bar.className = 'line-hl';
        bar.style.top    = (padTop + (i - 1) * lineH) + 'px';
        bar.style.height = lineH + 'px';
        frag.appendChild(bar);
    }
    // Insert before <code> so bars sit below code text in z-order
    viewPre.insertBefore(frag, viewPre.firstChild);
}

function _scrollToLine(lineNum) {
    const code    = document.getElementById('codeBlock');
    const viewPre = document.getElementById('viewPre');
    const scroller = document.querySelector('.view-full');
    if (!code || !viewPre || !scroller) return;
    const lineH  = parseFloat(getComputedStyle(code).lineHeight) || 22.4;
    const padTop = parseFloat(getComputedStyle(viewPre).paddingTop) || 16;
    scroller.scrollTop = Math.max(0, padTop + (lineNum - 1) * lineH - 80);
}

function _updateLineUrl(start, end) {
    const url = new URL(window.location.href);
    url.searchParams.set('L', start === end ? String(start) : `${start}-${end}`);
    history.replaceState(null, '', url.toString());
}