/**
 * g1wallet.js — Ğ1 Wallet client-side skeleton.
 *
 * At this stage:
 *   - The g1wallet namespace and session object are declared.
 *   - The unlock button is wired — it intercepts the click but does NOT derive keys yet.
 *   - The event API stubs are in place for cry01 and poll01 to listen to.
 *   - bip39 is loaded (vendor/bip39-3.1.0.min.js, English wordlist only) for
 *     mnemonic validation and entropy extraction, but full key derivation is
 *     not yet called.
 *
 * DERIVATION (not yet implemented — see RFC 0015):
 *   Per Duniter HD Wallet RFC 0015 (Dubp_HD_Wallet, git.duniter.org/documents/rfcs),
 *   the wallet's keypair is derived from a 12-word BIP39 mnemonic (English
 *   wordlist). The mnemonic's ENTROPY (16 bytes for 12 words) — not a PBKDF2
 *   seed — is the input to a BIP32-Ed25519 derivation (Khovratovich/Law
 *   construction, same family as Cardano's HD wallets).
 *
 *   The exact BIP32-Ed25519 derivation path used by Ğecko/Cesium2 has not yet
 *   been confirmed against RFC 0015 and MUST be verified before this stub is
 *   replaced with real derivation code. Do not implement against assumptions.
 *
 * CRITICAL RULES (never relax these):
 *   - The private key NEVER leaves the browser.
 *   - The mnemonic NEVER leaves the browser.
 *   - No key material in localStorage, sessionStorage, or cookies.
 *   - The private key object is marked non-extractable in WebCrypto.
 *   - One document, one confirmation, one click — no batch signing.
 */

(function () {
    'use strict';

    // ------------------------------------------------------------------------
    // SESSION STATE
    // Session is held in module-scope memory only.
    // It is gone when the page is closed or navigated away from.
    // ------------------------------------------------------------------------

    var _session = {
        unlocked:   false,
        pubkey:     null,   // base58-encoded Ed25519 public key
        // _privkey is intentionally not stored here — it lives only in the
        // WebCrypto CryptoKey object (non-extractable) once derivation is implemented.
        _cryptoKey: null    // CryptoKey (non-extractable) — null until derivation
    };

    // ------------------------------------------------------------------------
    // PUBLIC API
    // Exposed on window.g1wallet for other addons to use.
    // ------------------------------------------------------------------------

    window.g1wallet = {

        /**
         * Returns true if the wallet is currently unlocked.
         */
        isUnlocked: function () {
            return _session.unlocked;
        },

        /**
         * Returns the current session pubkey (base58 string), or null if locked.
         */
        getPubkey: function () {
            return _session.unlocked ? _session.pubkey : null;
        },

        /**
         * Requests a signature from the wallet for a given document.
         * If the wallet is locked, dispatches 'g1wallet:sign_request_blocked' instead.
         * Once signing is implemented, dispatches the result via the callback event.
         *
         * @param {string} document    - The document string to sign
         * @param {string} callback    - Event name to dispatch with the signed result
         */
        requestSignature: function (document, callback) {
            if (!_session.unlocked || !_session._cryptoKey) {
                window.dispatchEvent(new CustomEvent('g1wallet:sign_request_blocked', {
                    detail: { reason: 'Wallet is locked. Please unlock your wallet first.' }
                }));
                return;
            }
            // TODO: implement signing via SubtleCrypto.sign() with Ed25519,
            // using the key derived per RFC 0015 (BIP32-Ed25519 over mnemonic entropy).
            // The signed bytes are base64-encoded and dispatched via the callback event.
            console.warn('[g1wallet] requestSignature: signing not yet implemented.');
        }
    };

    // ------------------------------------------------------------------------
    // WIDGET API
    // Used by Widget/G1wallet.php inline script to register widget instances.
    // ------------------------------------------------------------------------

    window.G1WalletWidget = {
        init: function (uid, walletUrl) {
            // Listen for session events and update the widget DOM.
            window.addEventListener('g1wallet:unlocked', function (e) {
                var statusEl = document.getElementById(uid + '-status');
                if (!statusEl) return;
                var pubkey = e.detail.pubkey || '';
                var short  = pubkey.substring(0, 12) + '…';
                statusEl.innerHTML =
                    '<div class="g1wallet-status g1wallet-status-unlocked">' +
                    '<span class="g1wallet-status-indicator">&#x1F513;</span> ' +
                    '<span class="text-success small">Unlocked</span>' +
                    '<div class="g1wallet-cached-key text-muted small font-monospace mt-1">' +
                    _escHtml(short) +
                    '</div></div>';
            });

            window.addEventListener('g1wallet:locked', function () {
                var statusEl = document.getElementById(uid + '-status');
                if (!statusEl) return;
                statusEl.innerHTML =
                    '<div class="g1wallet-status g1wallet-status-locked">' +
                    '<span class="g1wallet-status-indicator">&#x1F512;</span> ' +
                    '<span class="text-muted small">Locked</span>' +
                    '<div class="mt-1"><a href="' + _escHtml(walletUrl) + '" ' +
                    'class="btn btn-xs btn-outline-secondary btn-sm">Unlock</a></div>' +
                    '</div>';
            });
        }
    };

    // ------------------------------------------------------------------------
    // UNLOCK BUTTON — wired on the wallet landing page
    // ------------------------------------------------------------------------

    document.addEventListener('DOMContentLoaded', function () {
        var unlockBtn    = document.getElementById('g1wallet-unlock-btn');
        var lockedView   = document.getElementById('g1wallet-locked-view');
        var unlockedView = document.getElementById('g1wallet-unlocked-view');
        var spinner      = document.getElementById('g1wallet-unlock-spinner');
        var errorEl      = document.getElementById('g1wallet-unlock-error');
        var lockBtn      = document.getElementById('g1wallet-lock-btn');

        if (!unlockBtn) return; // Not on the wallet page.

        unlockBtn.addEventListener('click', function () {
            var mnemonicEl = document.getElementById('g1wallet-mnemonic');
            var mnemonic   = (mnemonicEl || {}).value || '';

            // Normalize whitespace: collapse multiple spaces/newlines to single spaces, trim.
            mnemonic = mnemonic.trim().replace(/\s+/g, ' ').toLowerCase();

            _clearError();

            if (!mnemonic) {
                _showError('Mnemonic phrase is required.');
                return;
            }

            var words = mnemonic.split(' ');
            if (words.length !== 12) {
                _showError('Mnemonic phrase must be exactly 12 words. You entered ' + words.length + '.');
                return;
            }

            // Validate against the BIP39 English wordlist and checksum.
            if (window.bip39 && typeof window.bip39.validateMnemonic === 'function') {
                if (!window.bip39.validateMnemonic(mnemonic)) {
                    _showError('Invalid mnemonic phrase. Check the words and try again.');
                    return;
                }
            } else {
                _showError('Mnemonic validation library not available. Please reload the page.');
                return;
            }

            // TODO: derive keypair from mnemonic entropy per RFC 0015 (BIP32-Ed25519).
            // var entropy = window.bip39.mnemonicToEntropy(mnemonic);
            // ... BIP32-Ed25519 derivation (path TBD, pending RFC 0015 confirmation) ...
            // ... resulting Ed25519 keypair imported as non-extractable CryptoKey ...
            console.log('[g1wallet] Unlock clicked. Mnemonic validated. Derivation not yet implemented.');

            if (spinner) spinner.style.display = 'inline';
            unlockBtn.disabled = true;

            // Simulate async derivation (placeholder).
            setTimeout(function () {
                if (spinner) spinner.style.display = 'none';
                unlockBtn.disabled = false;
                _showError('Mnemonic is valid. Key derivation not yet implemented. This is a skeleton build.');
            }, 500);
        });

        if (lockBtn) {
            lockBtn.addEventListener('click', function () {
                _lockWallet();
                if (lockedView)   lockedView.style.display   = '';
                if (unlockedView) unlockedView.style.display = 'none';
                // Clear the mnemonic field.
                var mnemonicEl = document.getElementById('g1wallet-mnemonic');
                if (mnemonicEl) mnemonicEl.value = '';
            });
        }

        // Listen for wallet:unlocked event (dispatched by _unlockWallet below).
        window.addEventListener('g1wallet:unlocked', function (e) {
            if (lockedView)   lockedView.style.display   = 'none';
            if (unlockedView) unlockedView.style.display = '';
            var pubkeyDisplay = document.getElementById('g1wallet-pubkey-display');
            if (pubkeyDisplay) pubkeyDisplay.textContent = e.detail.pubkey || '—';
        });
    });

    // ------------------------------------------------------------------------
    // INTERNAL HELPERS
    // ------------------------------------------------------------------------

    function _unlockWallet(pubkey, cryptoKey) {
        _session.unlocked   = true;
        _session.pubkey     = pubkey;
        _session._cryptoKey = cryptoKey;
        window.dispatchEvent(new CustomEvent('g1wallet:unlocked', {
            detail: { pubkey: pubkey }
        }));
    }

    function _lockWallet() {
        _session.unlocked   = false;
        _session.pubkey     = null;
        _session._cryptoKey = null;
        window.dispatchEvent(new CustomEvent('g1wallet:locked'));
    }

    function _showError(message) {
        var el = document.getElementById('g1wallet-unlock-error');
        if (el) {
            el.textContent   = message;
            el.style.display = '';
        }
    }

    function _clearError() {
        var el = document.getElementById('g1wallet-unlock-error');
        if (el) {
            el.textContent   = '';
            el.style.display = 'none';
        }
    }

    function _escHtml(str) {
        return String(str)
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;');
    }

    // ------------------------------------------------------------------------
    // AUTO-POPULATE: cry01 and poll01 form fields
    // Other addons place data-g1wallet-target="pubkey" on their pubkey input fields.
    // When the wallet unlocks, those fields are populated automatically.
    // ------------------------------------------------------------------------

    window.addEventListener('g1wallet:unlocked', function (e) {
        var pubkey  = e.detail.pubkey || '';
        var targets = document.querySelectorAll('[data-g1wallet-target="pubkey"]');
        targets.forEach(function (el) {
            el.value = pubkey;
        });
    });

    window.addEventListener('g1wallet:locked', function () {
        var targets = document.querySelectorAll('[data-g1wallet-target="pubkey"]');
        targets.forEach(function (el) {
            el.value = '';
        });
    });

}());