// ── Utilities ──

export function esc(s) {
    const d = document.createElement('div');
    d.textContent = s;
    return d.innerHTML;
}

export function escRe(s) {
    return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

let csrfToken = '';
export function setCsrf(token) { csrfToken = token; }
export function getCsrf() { return csrfToken; }

export async function api(path, opts = {}) {
    const headers = { 'Content-Type': 'application/json' };
    if (csrfToken) headers['X-CSRF-Token'] = csrfToken;
    const res = await fetch(path, {
        headers,
        ...opts,
        body: opts.body ? JSON.stringify(opts.body) : undefined,
    });
    return res.json();
}

export function $(id) { return document.getElementById(id); }

export function fuzzyMatch(needle, haystack) {
    if (needle.length < 3) return null;
    let ni = 0, hi = 0, score = 0, streak = 0;
    while (ni < needle.length && hi < haystack.length) {
        if (needle[ni] === haystack[hi]) {
            streak++; score += streak * 2;
            if (hi === 0 || /[\s\-_./]/.test(haystack[hi - 1])) score += 10;
            if (hi < 5) score += 5 - hi;
            ni++;
        } else { streak = 0; }
        hi++;
    }
    if (ni < needle.length) return null;
    return score - (haystack.length - needle.length) * 0.3;
}

export function countSubstring(str, sub) {
    let c = 0, p = 0;
    while ((p = str.indexOf(sub, p)) !== -1) { c++; p += sub.length; }
    return c;
}

export function highlight(html, words) {
    let result = html;
    for (const w of words) result = result.replace(new RegExp('(' + escRe(w) + ')', 'gi'), '<mark>$1</mark>');
    if (!result.includes('<mark>')) {
        const full = words.join('');
        let fi = 0, out = '';
        for (let i = 0; i < html.length && fi < full.length; i++) {
            if (html[i].toLowerCase() === full[fi]) { out += '<mark>' + html[i] + '</mark>'; fi++; } else { out += html[i]; }
        }
        out += html.substring(out.replace(/<\/?mark>/g, '').length);
        result = out;
    }
    return result;
}