@extends('layouts.app')
@section('title', 'Primzahl-Check – Primzahltest & Primfaktorzerlegung | kotsch.tech')
@section('meta_description', 'Primzahl-Check online: Prüfe ob eine Zahl eine Primzahl ist. Primfaktorzerlegung, Teiler, nächste Primzahlen und Sieb des Eratosthenes. Kostenlos.')
@section('meta_extra')
<meta name="keywords" content="Primzahl Check, Primzahl Test, Primfaktorzerlegung, Sieb Eratosthenes, Primzahlen bis N, Teileranzahl">
@endsection
@section('content')
@include('tools._tool_base')
<style>
.prime-badge { display:flex; align-items:center; gap:14px; padding:18px 22px; border-radius:var(--radius-sm); margin-bottom:16px; }
.prime-badge.is-prime { background:#f0fdf4; border:2px solid #86efac; }
.prime-badge.not-prime { background:#fef2f2; border:2px solid #fca5a5; }
.badge-icon { font-size:2rem; line-height:1; }
.badge-text { font-size:1.1rem; font-weight:800; }
.prime-badge.is-prime .badge-text { color:#16a34a; }
.prime-badge.not-prime .badge-text { color:#dc2626; }
.prime-chip { display:inline-flex; align-items:center; justify-content:center; padding:6px 14px; border-radius:999px; background:var(--accent-soft); color:var(--accent); font-weight:800; font-size:0.88rem; cursor:pointer; border:1px solid var(--accent); transition:all 0.12s; margin:3px; }
.prime-chip:hover { background:var(--accent); color:#fff; }
.sieve-chip { display:inline-flex; align-items:center; justify-content:center; min-width:44px; padding:4px 8px; border-radius:6px; background:var(--accent-soft); color:var(--accent); font-weight:700; font-size:0.82rem; border:1px solid var(--accent); margin:2px; cursor:pointer; }
.sieve-chip:hover { background:var(--accent); color:#fff; }
</style>

<div class="tool-page">
<div class="tool-container">
    <div class="tool-header">
        <span class="t-tag"><i class="fas fa-superscript"></i> Mathematik</span>
        <h1 class="tool-h1">Primzahl<span>check.</span></h1>
        <p class="tool-sub">Primfaktorzerlegung, Teileranzahl, Nachbarprimzahlen und Sieb des Eratosthenes.</p>
    </div>

    <div class="t-panel">
        <div class="t-field">
            <label class="t-label">Zahl prüfen</label>
            <div class="t-copy-wrap">
                <input type="number" class="t-input" id="checkInput" placeholder="z.B. 97" min="1" max="999999999" oninput="checkPrime()" style="font-size:1.5rem;font-weight:800;text-align:center;font-family:'JetBrains Mono',monospace">
                <button class="t-copy-btn" onclick="checkInput.value=Math.floor(Math.random()*10000)+1;checkPrime()"><i class="fas fa-random"></i></button>
            </div>
            <div id="checkError" style="display:none;color:#ef4444;font-size:0.82rem;font-weight:700;margin-top:6px"></div>
        </div>

        <div id="resultPanel" style="display:none;margin-top:12px">
            <div id="primeBadge" class="prime-badge">
                <div class="badge-icon" id="badgeIcon"></div>
                <div class="badge-text" id="badgeText"></div>
            </div>

            <div class="t-grid-2" style="gap:10px;margin-bottom:12px">
                <div class="t-stat-card"><div class="t-stat-val" id="r-divcount">–</div><div class="t-stat-label">Teiler</div></div>
                <div class="t-stat-card"><div class="t-stat-val" id="r-digits">–</div><div class="t-stat-label">Stellen</div></div>
            </div>

            <div class="t-field" style="margin-bottom:10px">
                <label class="t-label">Primfaktorzerlegung</label>
                <div style="padding:12px;background:var(--bg);border:1px solid var(--line);border-radius:var(--radius-sm);font-family:'JetBrains Mono',monospace;font-weight:700;color:var(--accent)" id="r-factorization">–</div>
            </div>

            <div class="t-field" style="margin-bottom:10px">
                <label class="t-label">Alle Teiler</label>
                <div style="padding:12px;background:var(--bg);border:1px solid var(--line);border-radius:var(--radius-sm);font-family:'JetBrains Mono',monospace;font-size:0.82rem;max-height:100px;overflow-y:auto" id="r-divisors">–</div>
            </div>

            <div style="margin-top:8px">
                <div style="font-size:0.78rem;font-weight:700;color:var(--muted);text-transform:uppercase;margin-bottom:6px">Vorherige Primzahlen</div>
                <div id="prevPrimes"></div>
            </div>
            <div style="margin-top:10px">
                <div style="font-size:0.78rem;font-weight:700;color:var(--muted);text-transform:uppercase;margin-bottom:6px">Nächste Primzahlen</div>
                <div id="nextPrimes"></div>
            </div>
        </div>
    </div>

    <div class="t-panel">
        <div class="t-panel-title"><i class="fas fa-th"></i> Sieb des Eratosthenes</div>
        <div class="t-grid-2" style="gap:12px;margin-bottom:12px">
            <div class="t-field">
                <label class="t-label">Primzahlen bis N</label>
                <input type="number" class="t-input" id="sieveInput" placeholder="z.B. 100" min="2" max="10000" value="100">
            </div>
            <div style="display:flex;align-items:flex-end">
                <button class="t-btn full" onclick="runSieve()"><i class="fas fa-calculator"></i> Berechnen</button>
            </div>
        </div>
        <div id="sieveError" style="display:none;color:#ef4444;font-size:0.82rem;font-weight:700;margin-bottom:8px"></div>
        <div id="sieveResult" style="display:none">
            <div style="font-size:0.82rem;font-weight:700;color:var(--muted);margin-bottom:8px" id="sieveCount"></div>
            <div style="display:flex;flex-wrap:wrap;max-height:300px;overflow-y:auto" id="sievePrimes"></div>
        </div>
    </div>
</div>
@include('tools._ads_banner')
</div>

<script>
function isPrime(n) {
    if (n<2) return false;
    if (n===2) return true;
    if (n%2===0) return false;
    for (let i=3;i<=Math.sqrt(n);i+=2) if (n%i===0) return false;
    return true;
}

function primeFactors(n) {
    const f={}; let d=2;
    while(n>1){while(n%d===0){f[d]=(f[d]||0)+1;n/=d;}d++;if(d*d>n&&n>1){f[n]=(f[n]||0)+1;break;}}
    return f;
}

function countDivisors(n) {
    let c=0;
    for(let i=1;i<=Math.sqrt(n);i++) if(n%i===0){c++;if(i!==n/i)c++;}
    return c;
}

function getDivisors(n) {
    const d=[];
    for(let i=1;i<=Math.min(n,1000);i++) if(n%i===0) d.push(i);
    return d;
}

function getNeighbourPrimes(n, dir, count) {
    const result=[]; let c=n+dir;
    while(result.length<count&&c>=2&&c<=n+10000){if(isPrime(c))result.push(c);c+=dir;}
    return dir>0?result:result.reverse();
}

function checkPrime() {
    const raw = document.getElementById('checkInput').value.trim();
    const err = document.getElementById('checkError');
    if(!raw){document.getElementById('resultPanel').style.display='none';err.style.display='none';return;}
    const n = parseInt(raw);
    if(isNaN(n)||n<1){err.textContent='Positive ganze Zahl eingeben.';err.style.display='';return;}
    if(n>999999999){err.textContent='Maximal 999.999.999.';err.style.display='';return;}
    err.style.display='none';

    const prime = isPrime(n);
    document.getElementById('primeBadge').className = 'prime-badge ' + (prime?'is-prime':'not-prime');
    document.getElementById('badgeIcon').textContent = prime?'✓':'✗';
    document.getElementById('badgeText').textContent = prime?`${n.toLocaleString('de')} ist eine Primzahl!`:`${n.toLocaleString('de')} ist keine Primzahl.`;

    const factors = primeFactors(n);
    const factHtml = prime ? String(n) : Object.entries(factors).map(([p,e])=>e>1?`${p}<sup>${e}</sup>`:p).join(' × ');
    document.getElementById('r-factorization').innerHTML = factHtml;

    const divCount = countDivisors(n);
    document.getElementById('r-divcount').textContent = divCount;
    document.getElementById('r-digits').textContent = String(n).length;

    const divs = getDivisors(n);
    document.getElementById('r-divisors').textContent = divs.join(', ') + (n>1000?'…':'');

    document.getElementById('prevPrimes').innerHTML = getNeighbourPrimes(n,-1,5).map(p=>
        `<span class="prime-chip" onclick="document.getElementById('checkInput').value=${p};checkPrime()">${p.toLocaleString('de')}</span>`).join('');
    document.getElementById('nextPrimes').innerHTML = getNeighbourPrimes(n,1,5).map(p=>
        `<span class="prime-chip" onclick="document.getElementById('checkInput').value=${p};checkPrime()">${p.toLocaleString('de')}</span>`).join('');

    document.getElementById('resultPanel').style.display='';
}

function runSieve() {
    const err = document.getElementById('sieveError');
    err.style.display='none';
    const limit = parseInt(document.getElementById('sieveInput').value)||0;
    if(limit<2){err.textContent='Bitte ≥ 2 eingeben.';err.style.display='';return;}
    if(limit>10000){err.textContent='Maximal 10.000 erlaubt.';err.style.display='';return;}

    const sieve = new Array(limit+1).fill(true);
    sieve[0]=sieve[1]=false;
    for(let i=2;i*i<=limit;i++) if(sieve[i]) for(let j=i*i;j<=limit;j+=i) sieve[j]=false;
    const primes = [];
    for(let i=2;i<=limit;i++) if(sieve[i]) primes.push(i);

    document.getElementById('sieveCount').textContent = `${primes.length} Primzahlen bis ${limit.toLocaleString('de')} gefunden.`;
    document.getElementById('sievePrimes').innerHTML = primes.map(p=>
        `<span class="sieve-chip" onclick="document.getElementById('checkInput').value=${p};checkPrime()">${p}</span>`).join('');
    document.getElementById('sieveResult').style.display='';
}

document.getElementById('checkInput').addEventListener('keydown',e=>{if(e.key==='Enter')checkPrime();});
document.getElementById('sieveInput').addEventListener('keydown',e=>{if(e.key==='Enter')runSieve();});
document.getElementById('checkInput').value='97';
checkPrime();
runSieve();
</script>

@include('tools._seo_content', ['toolSlug' => 'primzahl-check', 'toolName' => 'Primzahl-Check'])

@endsection