import initWasm, {
    decrypt_serialized_u64_radix_flat_wasm
} from './concrete-ml-extensions-wasm/concrete_ml_extensions_wasm.js';

const SERVER = 'https://backend-server.com';

let clientKey, serverKey;
let encTokens;
let encServerResult;
let keygenWorker;
let encryptWorker;
let sessionUid;

// Memory-efficient base64 encoding for large Uint8Array
function uint8ToBase64(uint8) {
    return new Promise((resolve, reject) => {
        const blob = new Blob([uint8]);
        const reader = new FileReader();
        reader.onload = function () {
            const base64 = reader.result.split(',')[1];
            resolve(base64);
        };
        reader.onerror = reject;
        reader.readAsDataURL(blob);
    });
}

const $ = id => document.getElementById(id);
const enable = (id, ok=true) => $(id).disabled = !ok;
const show = (id, visible=true) => $(id).hidden = !visible;

// Hide all spinners immediately
show('keygenSpin', false);
show('spin', false);
show('encIcon', false);
show('tokenizerSpin', false);

// Initialize WASM
(async () => {
    try {
        console.log('[Main] Initializing WASM module...');
        await initWasm();
        console.log('[Main] WASM module initialized successfully');

        // Initialize the keygen worker
        keygenWorker = new Worker(new URL('./keygen-worker.js', import.meta.url), { type: 'module' });
        keygenWorker.onmessage = async function(e) {
            if (e.data.type === 'success') {
                const res = e.data.result;
                console.log('[Main] Key generation successful');
                console.log(`[Main] Client key size: ${res.clientKey.length} bytes`);
                console.log(`[Main] Server key size: ${res.serverKey.length} bytes`);
                clientKey = res.clientKey; serverKey = res.serverKey;
                
                try {
                    // Initialize encryption worker
                    encryptWorker = new Worker(new URL('./encrypt-worker.js', import.meta.url), { type: 'module' });
                    encryptWorker.onmessage = function(e) {
                        if (e.data.type === 'ready') {
                            console.log('[Main] Encryption worker ready');
                        } else if (e.data.type === 'success') {
                            encTokens = e.data.result;
                            console.log(`[Main] Encryption completed: ${encTokens.length} bytes`);
                            show('encryptSpin', false);
                            show('encIcon', true);
                            enable('btnEncrypt', true);
                            enable('btnSend');
                            $('encStatus').textContent = 'Your text is encrypted 🔒';
                        } else if (e.data.type === 'error') {
                            console.error('[Main] Encryption error:', e.data.error);
                            show('encryptSpin', false);
                            enable('btnEncrypt', true);
                            $('encStatus').textContent = `Encryption failed: ${e.data.error}`;
                            alert(`Encryption failed: ${e.data.error}`);
                        }
                    };
                    
                    // Initialize the worker with the client key
                    encryptWorker.postMessage({ type: 'init', clientKey });
                    
                    console.log('[Main] Encoding server key to base64...');
                    const serverKeyB64 = await uint8ToBase64(serverKey);
                    console.log(`[Main] Server key base64 size: ${serverKeyB64.length} bytes`);
                    const handshakeResponse = await fetch(`${SERVER}/handshake`, {
                        method:'POST', 
                        headers:{'Content-Type':'application/json'},
                        body: JSON.stringify({
                            server_key_b64: serverKeyB64
                        })
                    });
                    
                    if (!handshakeResponse.ok) {
                        const errorText = await handshakeResponse.text();
                        throw new Error(`Server handshake failed: ${handshakeResponse.status} ${errorText}`);
                    }
                    
                    const { uid } = await handshakeResponse.json();
                    sessionUid = uid;
                    console.log('[Main] Server handshake successful');
                    $('keygenStatus').textContent = 'keys generated ✓';
                    enable('btnEncrypt');
                } catch (error) {
                    console.error('[Main] Server handshake error:', error);
                    $('keygenStatus').textContent = `Server handshake failed: ${error.message}`;
                    enable('btnEncrypt', false);
                }
            } else {
                console.error('[Main] Key generation error:', e.data.error);
                $('keygenStatus').textContent = `Error generating keys: ${e.data.error}`;
            }
            show('keygenSpin', false);
        };
    } catch (e) {
        console.error('[Main] Failed to initialize WASM module:', e);
        $('keygenStatus').textContent = `Initialization Error: ${e.message}`;
        throw e;
    }
})();

$('btnKeygen').onclick = async () => {
    if ($('keygenSpin').hidden === false) {
        console.log('[Main] Keygen already in progress, ignoring click');
        return;
    }
    show('keygenSpin', true);
    $('keygenStatus').textContent = 'generating…';
    try {
        keygenWorker.postMessage({});
    } catch (e) {
        console.error('[Main] Key generation error:', e);
        $('keygenStatus').textContent = `Error generating keys: ${e.message}`;
        show('keygenSpin', false);
    }
};

$('btnEncrypt').onclick = async () => {
    const text = $('tokenInput').value.trim();
    if (!text) {
        console.error('[Main] No text provided for tokenization/encryption');
        alert('Please enter text to encrypt.');
        return;
    }
    if (!encryptWorker) {
        console.error('[Main] Encryption worker not initialized');
        alert('Encryption worker is not ready. Please generate keys first.');
        return;
    }

    show('encryptSpin', true);
    show('encIcon', false);
    enable('btnEncrypt', false);

    try {
        console.log('[Main] Tokenizing text:', text);
        const tokenIds = llama3Tokenizer.encode(text);
        console.log('[Main] Token IDs:', tokenIds);

        encryptWorker.postMessage({ type: 'encrypt', tokenIds });
    } catch (error) {
        console.error('[Main] Tokenization or encryption initiation error:', error);
        show('encryptSpin', false);
        enable('btnEncrypt', true);
        alert(`Error during tokenization/encryption: ${error.message}`);
    }
};

$('btnSend').onclick = async () => {
    if ($('spin').hidden === false) {
        console.log('[Main] Send already in progress, ignoring click');
        return;
    }
    show('encIcon', false);
    show('spin', true);
    $('srvStatus').textContent = 'Preparing request…';
    $('srvComputing').hidden = true;
    const startTime = performance.now();
    try {
        const ciphertext_b64 = await uint8ToBase64(encTokens);

        $('srvStatus').textContent = 'Sending…';
        console.log('[Main] Sending request to server...');
        const response = await fetch(`${SERVER}/detect`, {
            method:'POST', 
            headers:{'Content-Type':'application/json'},
            body: JSON.stringify({
                uid: sessionUid,
                ciphertext_b64
            })
        }).catch(error => {
            throw new Error(`Server unreachable: ${error.message}`);
        });
        
        console.log(`[Main] Server response status: ${response.status}`);
        if (!response.ok) {
            const errorText = await response.text();
            throw new Error(`Server error: ${response.status} ${errorText}`);
        }

        $('srvStatus').textContent = '✓ sent';
        $('srvComputing').hidden = false;
        
        const {result_b64} = await response.json();
        const endTime = performance.now();
        const duration = ((endTime - startTime) / 1000).toFixed(2);
        console.log(`[Main] Server request completed in ${duration}s`);
        console.log('[Main] Processing server response...');
        encServerResult = Uint8Array.from(atob(result_b64), c=>c.charCodeAt(0));
        console.log(`[Main] Received encrypted result: ${encServerResult.length} bytes`);
        $('encResult').value = `(${encServerResult.length} B)`;
        $('srvComputing').hidden = true;
        $('srvStatus').textContent = `✓ received (${duration}s)`;
        enable('btnDecrypt');
    } catch (e) {
        const endTime = performance.now();
        const duration = ((endTime - startTime) / 1000).toFixed(2);
        console.error(`[Main] Server request failed after ${duration}s:`, e);
        $('srvComputing').hidden = true;
        $('srvStatus').textContent = `Server error: ${e.message} (${duration}s)`;
        show('spin', false);
    }
};

$('btnDecrypt').onclick = () => {
    try {
        console.log('[Main] Starting decryption...');
        const dec = decrypt_serialized_u64_radix_flat_wasm(encServerResult, clientKey);
        const [flag, score_scaled, total_g] = Array.from(dec);
        const score = (Number(score_scaled) / 1e6).toFixed(6);
        console.log('[Main] Decryption successful');
        console.log(`[Main] Result - flag: ${flag}, score: ${score}, total_g: ${total_g}`);
        $('decResult').textContent = `flag=${flag}, score=${score}, total_g=${total_g}`;
    } catch (e) {
        console.error('[Main] Decryption error:', e);
        $('decResult').textContent = `Error decrypting result: ${e.message}`;
    }
};