script.js

function openTab(evt, tabName) {
    const tabcontents = document.getElementsByClassName("tabcontent");
    for (let i = 0; i < tabcontents.length; i++) {
        tabcontents[i].style.display = "none";
        tabcontents[i].classList.remove("active-tab");
    }
    const tablinks = document.getElementsByClassName("tablinks");
    for (let i = 0; i < tablinks.length; i++) {
        tablinks[i].classList.remove("active");
    }
    const target = document.getElementById(tabName);
    target.style.display = "block";
    target.classList.add("active-tab");
    const btns = document.querySelectorAll('.tablinks');
    const labels = { 'splitTab': '分割', 'mergeTab': '結合', 'linkTab': '共有', 'shareTab': '共有' };
    btns.forEach(b => {
        if (b.innerText.includes(labels[tabName])) b.classList.add('active');
    });
}

function toggleCustomSize() {
    const s = document.getElementById('splitSize');
    document.getElementById('customSizeContainer').classList.toggle('hidden', s.value !== 'custom');
}

// URLパラメータによる自動処理
window.addEventListener('load', async () => {
    const p = new URLSearchParams(window.location.search);
    const z = p.get('zip');
    const d = p.get('data');

    if (z) {
        openTab(null, 'mergeTab');
        document.getElementById('mergeFromUrlAlert').classList.remove('hidden');
        document.getElementById('fileSelectionArea').classList.add('hidden');
        window.targetZipUrl = decodeURIComponent(z);
        updateStatus('mergeStatus', `共有URLからリモートZIPを検出しました。`, 'info');
    } else if (d) {
        openTab(null, 'mergeTab');
        document.getElementById('mergeFromUrlAlert').classList.remove('hidden');
        document.getElementById('fileSelectionArea').classList.add('hidden');
        try {
            updateStatus('mergeStatus', 'インラインデータを展開中...', 'info');
            const data = JSON.parse(decodeURIComponent(atob(d)));
            window.inlineMergeData = data;
            updateStatus('mergeStatus', `インラインデータ (${data.name}) 読込成功。`, 'success');
        } catch(e) { updateStatus('mergeStatus', '解析エラー。リンクが壊れている可能性があります。', 'error'); }
    }
});

document.getElementById('splitButton').addEventListener('click', async function() {
    const input = document.getElementById('fileToSplit');
    let sizeMB = document.getElementById('splitSize').value;
    if (sizeMB === 'custom') sizeMB = document.getElementById('customSplitSize').value;
    const splitSize = parseInt(sizeMB) * 1024 * 1024;
    const encOpt = document.getElementById('encryptOption').value;
    const pass = encOpt === 'aes256' ? document.getElementById('encryptPassword').value : null;

    if (!input.files[0]) return updateStatus('splitStatus', 'ファイルを選んでください', 'error');

    try {
        const file = input.files[0];
        updateStatus('splitStatus', '処理中...', 'info');
        document.getElementById('inlineShareArea').classList.add('hidden');

        const hash = await calculateSHA256MacroChunked(file, (p) => {
            document.getElementById('splitProgress').style.width = `${p * 0.2}%`;
        });

        // インラインURL生成
        if (file.size < 2 * 1024 * 1024) {
            updateStatus('splitStatus', 'インラインURLを生成中...', 'info');
            const ab = await readFileAsArrayBuffer(file);
            const uint8 = new Uint8Array(ab);
            let binary = '';
            for (let i = 0; i < uint8.byteLength; i++) binary += String.fromCharCode(uint8[i]);
            const b64 = btoa(binary);
            const shareData = { name: file.name, hash: hash, data: b64 };
            const encoded = btoa(encodeURIComponent(JSON.stringify(shareData)));
            const url = `${window.location.href.split('?')[0]}?data=${encoded}`;
            document.getElementById('quickShareResultInline').value = url;
            document.getElementById('inlineShareArea').classList.remove('hidden');
        }

        const count = Math.ceil(file.size / splitSize);
        const zip = new JSZip();
        zip.file("metadata.json", JSON.stringify({ originalName: file.name, totalChunkCount: count, fileSize: file.size, hash: hash, encrypted: encOpt === 'aes256' }));

        if (encOpt !== 'aes256') {
            for (let i = 0; i < count; i++) zip.file(`part${i+1}.bin`, file.slice(i*splitSize, (i+1)*splitSize));
        } else {
            const ab = await readFileAsArrayBuffer(file);
            const enc = await encryptData(ab, pass);
            const s = enc.byteLength / count;
            for (let i = 0; i < count; i++) zip.file(`part${i+1}.bin`, enc.slice(i*s, (i+1)*s));
        }

        const blob = await zip.generateAsync({type:'blob', zip64:true, compression: file.size > 500*1024*1024 ? 'STORE':'DEFLATE'}, (m) => {
            document.getElementById('splitProgress').style.width = `${20 + m.percent * 0.8}%`;
        });

        updateStatus('splitStatus', '完了！', 'success');
        document.getElementById('splitResults').style.display = 'block';
        document.getElementById('splitFilesList').innerHTML = `<p><span>ファイル:</span> ${file.name}</p><p><span>サイズ:</span> ${formatFileSize(file.size)}</p>`;
        
        const url = URL.createObjectURL(blob);
        document.getElementById('downloadAllButton').onclick = () => {
            const a = document.createElement('a'); a.href = url; a.download = `${file.name}_all.zip`; a.click();
        };
        document.getElementById('postSplitShareArea').classList.remove('hidden');
    } catch(e) { updateStatus('splitStatus', `エラー: ${e.message}`, 'error'); }
});

document.getElementById('mergeButton').addEventListener('click', async function() {
    try {
        let meta, pMap = {};
        if (window.targetZipUrl) {
            updateStatus('mergeStatus', 'リモートから読込中...', 'info');
            const res = await fetch(window.targetZipUrl);
            const blob = await res.blob();
            const zip = await JSZip.loadAsync(blob);
            meta = JSON.parse(await zip.file("metadata.json").async('text'));
            zip.file(/part\d+\.bin$/).forEach(f => pMap[parseInt(f.name.match(/\d+/)[0])] = f);
            meta.count = meta.totalChunkCount;
        } else if (window.inlineMergeData) {
            updateStatus('mergeStatus', '展開中...', 'info');
            meta = window.inlineMergeData;
            const b64 = meta.data;
            const binary = atob(b64);
            const bytes = new Uint8Array(binary.length);
            for (let i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
            const resultBlob = new Blob([bytes]);
            const h = await calculateSHA256MacroChunked(resultBlob);
            if (h !== meta.hash) throw new Error('ハッシュ不一致');
            updateStatus('mergeStatus', '成功！', 'success');
            document.getElementById('mergeResults').style.display = 'block';
            const url = URL.createObjectURL(resultBlob);
            document.getElementById('downloadMergedButton').onclick = () => {
                const a = document.createElement('a'); a.href = url; a.download = meta.name; a.click();
            };
            return;
        } else {
            const input = document.getElementById('zipToMerge');
            for (let i = 0; i < input.files.length; i++) {
                const zip = await JSZip.loadAsync(input.files[i]);
                const m = JSON.parse(await zip.file("metadata.json").async('text'));
                if (!meta) meta = m;
                zip.file(/part\d+\.bin$/).forEach(f => pMap[parseInt(f.name.match(/\d+/)[0])] = f);
            }
            if (!meta) throw new Error('ファイルが未選択です。');
            meta.count = meta.totalChunkCount || meta.chunkCount;
        }

        updateStatus('mergeStatus', '結合中...', 'info');
        const blobs = [];
        for (let i = 1; i <= meta.count; i++) blobs.push(await pMap[i].async('blob'));
        
        let result;
        if (meta.encrypted) {
            const pass = document.getElementById('decryptPassword').value;
            if (!pass) { document.getElementById('decryptContainer').style.display = 'block'; throw new Error('パスワード必要'); }
            result = await decryptData(await readFileAsArrayBuffer(new Blob(blobs)), pass);
        } else result = new Blob(blobs);

        updateStatus('mergeStatus', '検証中...', 'info');
        const h = await calculateSHA256MacroChunked(result instanceof Blob ? result : new Blob([result]));
        if (h !== meta.hash) throw new Error('ハッシュ不一致');
        updateStatus('mergeStatus', '成功！', 'success');
        document.getElementById('mergeResults').style.display = 'block';
        const url = URL.createObjectURL(result instanceof Blob ? result : new Blob([result]));
        document.getElementById('downloadMergedButton').onclick = () => {
            const a = document.createElement('a'); a.href = url; a.download = meta.originalName || meta.name; a.click();
        };
    } catch(e) { updateStatus('mergeStatus', `エラー: ${e.message}`, 'error'); }
});

document.getElementById('generateQuickLink').addEventListener('click', () => {
    const url = document.getElementById('inputZipUrl').value;
    if (!url) return alert('URLを入れてください');
    const shareUrl = `${window.location.href.split('?')[0]}?zip=${encodeURIComponent(url)}`;
    document.getElementById('quickShareResult').value = shareUrl;
    document.getElementById('quickShareArea').classList.remove('hidden');
});

// コピー機能の改善
async function copyToClipboard(id) {
    const el = document.getElementById(id);
    const text = el.value || el.innerText;
    
    try {
        // モダンなAPIを第一選択とする
        if (navigator.clipboard) {
            await navigator.clipboard.writeText(text);
        } else {
            // フォールバック: display:none ではなく画面外で見えない状態にしてコピー
            el.style.display = 'block';
            el.style.position = 'absolute';
            el.style.left = '-9999px';
            el.select();
            document.execCommand('copy');
            el.style.display = 'none';
        }
        alert('URLをコピーしました！');
    } catch (err) {
        console.error('コピー失敗:', err);
        alert('コピーに失敗しました。お手数ですが、手動でコピーしてください。');
    }
}

function updateStatus(id, msg, type) {
    const el = document.getElementById(id); el.textContent = msg;
    el.style.color = type === 'error' ? '#ed4245' : type === 'success' ? '#3ba55c' : '#ffffff';
}

function readFileAsArrayBuffer(f) { return new Promise((r, j) => { const rd = new FileReader(); rd.onload = () => r(rd.result); rd.onerror = j; rd.readAsArrayBuffer(f); }); }

async function calculateSHA256MacroChunked(blob, onProgress) {
    const macroSize = 100 * 1024 * 1024;
    const sha256 = CryptoJS.algo.SHA256.create();
    for (let offset = 0; offset < blob.size; offset += macroSize) {
        const slice = blob.slice(offset, offset + macroSize);
        const buffer = await readFileAsArrayBuffer(slice);
        sha256.update(CryptoJS.lib.WordArray.create(buffer));
        if (onProgress) onProgress((offset + slice.size) / blob.size * 100);
        await new Promise(r => setTimeout(r, 0));
    }
    return sha256.finalize().toString();
}

async function encryptData(d, p) {
    const s = crypto.getRandomValues(new Uint8Array(16));
    const m = await crypto.subtle.importKey('raw', new TextEncoder().encode(p), {name: 'PBKDF2'}, false, ['deriveKey']);
    const k = await crypto.subtle.deriveKey({name: 'PBKDF2', salt: s, iterations: 100000, hash: 'SHA-256'}, m, {name: 'AES-CBC', length: 256}, false, ['encrypt', 'decrypt']);
    const iv = crypto.getRandomValues(new Uint8Array(16));
    const enc = await crypto.subtle.encrypt({name: 'AES-CBC', iv: iv}, k, d);
    const res = new Uint8Array(s.length + iv.length + enc.byteLength);
    res.set(s, 0); res.set(iv, s.length); res.set(new Uint8Array(enc), s.length + iv.length);
    return res.buffer;
}

async function decryptData(d, p) {
    const da = new Uint8Array(d); const s = da.slice(0, 16); const iv = da.slice(16, 32); const enc = da.slice(32);
    const m = await crypto.subtle.importKey('raw', new TextEncoder().encode(p), {name: 'PBKDF2'}, false, ['deriveKey']);
    const k = await crypto.subtle.deriveKey({name: 'PBKDF2', salt: s, iterations: 100000, hash: 'SHA-256'}, m, {name: 'AES-CBC', length: 256}, false, ['encrypt', 'decrypt']);
    return await crypto.subtle.decrypt({name: 'AES-CBC', iv: iv}, k, enc);
}

function formatFileSize(b) { if (b === 0) return '0 Bytes'; const k = 1024; const s = ['Bytes', 'KB', 'MB', 'GB', 'TB']; const i = Math.floor(Math.log(b) / Math.log(k)); return parseFloat((b / Math.pow(k, i)).toFixed(2)) + ' ' + s[i]; }

function getMimeType(f) { const ext = f.split('.').pop().toLowerCase(); const m = { 'jpg': 'image/jpeg', 'png': 'image/png', 'gif': 'image/gif', 'webp': 'image/webp', 'mp4': 'video/mp4', 'webm': 'video/webm', 'mp3': 'audio/mpeg', 'wav': 'audio/wav', 'pdf': 'application/pdf', 'zip': 'application/zip' }; return m[ext] || 'application/octet-stream'; }