/**
 * <rstack-identity> — Custom element for EncryptID sign-in/sign-out.
 *
 * Renders either a "Sign In" button or the user avatar + dropdown.
 * Contains the full WebAuthn auth modal (sign-in + register).
 * Refactored from lib/rspace-header.ts into a standalone web component.
 */

const SESSION_KEY = "encryptid_session";
const ENCRYPTID_URL = "https://auth.rspace.online";

interface SessionState {
	accessToken: string;
	claims: {
		sub: string;
		exp: number;
		username?: string;
		did?: string;
		eid: {
			authLevel: number;
			capabilities: { encrypt: boolean; sign: boolean; wallet: boolean };
		};
	};
}

// ── Session helpers (exported for use by other code) ──

export function getSession(): SessionState | null {
	try {
		const stored = localStorage.getItem(SESSION_KEY);
		if (!stored) return null;
		const session = JSON.parse(stored) as SessionState;
		if (Math.floor(Date.now() / 1000) >= session.claims.exp) {
			localStorage.removeItem(SESSION_KEY);
			localStorage.removeItem("rspace-username");
			return null;
		}
		return session;
	} catch {
		return null;
	}
}

export function clearSession(): void {
	localStorage.removeItem(SESSION_KEY);
	localStorage.removeItem("rspace-username");
}

export function isAuthenticated(): boolean {
	return getSession() !== null;
}

export function getAccessToken(): string | null {
	return getSession()?.accessToken ?? null;
}

export function getUserDID(): string | null {
	return getSession()?.claims.did ?? getSession()?.claims.sub ?? null;
}

export function getUsername(): string | null {
	return getSession()?.claims.username ?? null;
}

// ── Helpers ──

function base64urlToBuffer(b64url: string): ArrayBuffer {
	const b64 = b64url.replace(/-/g, "+").replace(/_/g, "/");
	const pad = "=".repeat((4 - (b64.length % 4)) % 4);
	const bin = atob(b64 + pad);
	const bytes = new Uint8Array(bin.length);
	for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
	return bytes.buffer;
}

function bufferToBase64url(buf: ArrayBuffer): string {
	const bytes = new Uint8Array(buf);
	let bin = "";
	for (let i = 0; i < bytes.byteLength; i++) bin += String.fromCharCode(bytes[i]);
	return btoa(bin).replace(/\+/g, "-").replace(/\//g, "_").replace(/=/g, "");
}

function parseJWT(token: string): Record<string, unknown> {
	const parts = token.split(".");
	if (parts.length < 2) return {};
	try {
		const b64 = parts[1].replace(/-/g, "+").replace(/_/g, "/");
		const pad = "=".repeat((4 - (b64.length % 4)) % 4);
		return JSON.parse(atob(b64 + pad));
	} catch {
		return {};
	}
}

function storeSession(token: string, username: string, did: string): void {
	const payload = parseJWT(token) as Record<string, any>;
	const session: SessionState = {
		accessToken: token,
		claims: {
			sub: payload.sub || "",
			exp: payload.exp || 0,
			username,
			did,
			eid: payload.eid || { authLevel: 3, capabilities: { encrypt: true, sign: true, wallet: false } },
		},
	};
	localStorage.setItem(SESSION_KEY, JSON.stringify(session));
	if (username) localStorage.setItem("rspace-username", username);
}

// ── The custom element ──

export class RStackIdentity extends HTMLElement {
	#shadow: ShadowRoot;

	constructor() {
		super();
		this.#shadow = this.attachShadow({ mode: "open" });
	}

	connectedCallback() {
		this.#render();
	}

	#render() {
		const session = getSession();
		const theme = this.closest("[data-theme]")?.getAttribute("data-theme") || "light";

		if (session) {
			const username = session.claims.username || "";
			const did = session.claims.did || session.claims.sub;
			const displayName = username || (did.length > 24 ? did.slice(0, 16) + "..." + did.slice(-6) : did);
			const initial = username ? username[0].toUpperCase() : did.slice(8, 10).toUpperCase();

			this.#shadow.innerHTML = `
				<style>${STYLES}</style>
				<div class="user ${theme}" id="user-toggle">
					<div class="avatar">${initial}</div>
					<span class="name">${displayName}</span>
					<div class="dropdown" id="dropdown">
						<button class="dropdown-item" data-action="profile">👤 Profile</button>
						<button class="dropdown-item" data-action="recovery">🛡️ Recovery</button>
						<div class="dropdown-divider"></div>
						<button class="dropdown-item dropdown-item--danger" data-action="signout">🚪 Sign Out</button>
					</div>
				</div>
			`;

			const toggle = this.#shadow.getElementById("user-toggle")!;
			const dropdown = this.#shadow.getElementById("dropdown")!;

			toggle.addEventListener("click", (e) => {
				e.stopPropagation();
				dropdown.classList.toggle("open");
			});

			document.addEventListener("click", () => dropdown.classList.remove("open"));

			this.#shadow.querySelectorAll("[data-action]").forEach((el) => {
				el.addEventListener("click", (e) => {
					e.stopPropagation();
					const action = (el as HTMLElement).dataset.action;
					dropdown.classList.remove("open");
					if (action === "signout") {
						clearSession();
						this.#render();
						this.dispatchEvent(new CustomEvent("auth-change", { bubbles: true, composed: true }));
					} else if (action === "profile") {
						window.open(ENCRYPTID_URL, "_blank");
					} else if (action === "recovery") {
						window.open(`${ENCRYPTID_URL}/recover`, "_blank");
					}
				});
			});
		} else {
			this.#shadow.innerHTML = `
				<style>${STYLES}</style>
				<button class="signin-btn ${theme}" id="signin-btn">🔑 Sign In</button>
			`;

			this.#shadow.getElementById("signin-btn")!.addEventListener("click", () => {
				this.showAuthModal();
			});
		}
	}

	/** Public method: show the auth modal programmatically */
	showAuthModal(callbacks?: { onSuccess?: () => void; onCancel?: () => void }): void {
		if (document.querySelector(".rstack-auth-overlay")) return;

		const overlay = document.createElement("div");
		overlay.className = "rstack-auth-overlay";
		let mode: "signin" | "register" = "signin";

		const render = () => {
			overlay.innerHTML = mode === "signin" ? signinHTML() : registerHTML();
			attachListeners();
		};

		const signinHTML = () => `
			<style>${MODAL_STYLES}</style>
			<div class="auth-modal">
				<h2>Sign in with EncryptID</h2>
				<p>Use your passkey to sign in. No passwords needed.</p>
				<div class="actions">
					<button class="btn btn--secondary" data-action="cancel">Cancel</button>
					<button class="btn btn--primary" data-action="signin">🔑 Sign In with Passkey</button>
				</div>
				<div class="error" id="auth-error"></div>
				<div class="toggle">Don't have an account? <a data-action="switch-register">Create one</a></div>
			</div>
		`;

		const registerHTML = () => `
			<style>${MODAL_STYLES}</style>
			<div class="auth-modal">
				<h2>Create your EncryptID</h2>
				<p>Set up a secure, passwordless identity.</p>
				<input class="input" id="auth-username" type="text" placeholder="Choose a username" autocomplete="username webauthn" maxlength="32" />
				<div class="actions">
					<button class="btn btn--secondary" data-action="cancel">Cancel</button>
					<button class="btn btn--primary" data-action="register">🔐 Create Passkey</button>
				</div>
				<div class="error" id="auth-error"></div>
				<div class="toggle">Already have an account? <a data-action="switch-signin">Sign in</a></div>
			</div>
		`;

		const close = () => {
			overlay.remove();
		};

		const handleSignIn = async () => {
			const errEl = overlay.querySelector("#auth-error") as HTMLElement;
			const btn = overlay.querySelector('[data-action="signin"]') as HTMLButtonElement;
			errEl.textContent = "";
			btn.disabled = true;
			btn.innerHTML = '<span class="spinner"></span> Authenticating...';

			try {
				const startRes = await fetch(`${ENCRYPTID_URL}/api/auth/start`, {
					method: "POST",
					headers: { "Content-Type": "application/json" },
					body: JSON.stringify({}),
				});
				if (!startRes.ok) throw new Error("Failed to start authentication");
				const { options: serverOptions } = await startRes.json();

				const credential = (await navigator.credentials.get({
					publicKey: {
						challenge: new Uint8Array(base64urlToBuffer(serverOptions.challenge)),
						rpId: serverOptions.rpId || "rspace.online",
						userVerification: "required",
						timeout: 60000,
					},
				})) as PublicKeyCredential;
				if (!credential) throw new Error("Authentication failed");

				const completeRes = await fetch(`${ENCRYPTID_URL}/api/auth/complete`, {
					method: "POST",
					headers: { "Content-Type": "application/json" },
					body: JSON.stringify({
						challenge: serverOptions.challenge,
						credential: { credentialId: bufferToBase64url(credential.rawId) },
					}),
				});
				const data = await completeRes.json();
				if (!completeRes.ok || !data.success) throw new Error(data.error || "Authentication failed");

				storeSession(data.token, data.username || "", data.did || "");
				close();
				this.#render();
				this.dispatchEvent(new CustomEvent("auth-change", { bubbles: true, composed: true }));
				callbacks?.onSuccess?.();
			} catch (err: any) {
				btn.disabled = false;
				btn.innerHTML = "🔑 Sign In with Passkey";
				errEl.textContent = err.name === "NotAllowedError" ? "Authentication was cancelled." : err.message || "Authentication failed.";
			}
		};

		const handleRegister = async () => {
			const usernameInput = overlay.querySelector("#auth-username") as HTMLInputElement;
			const errEl = overlay.querySelector("#auth-error") as HTMLElement;
			const btn = overlay.querySelector('[data-action="register"]') as HTMLButtonElement;
			const username = usernameInput.value.trim();

			if (!username) {
				errEl.textContent = "Please enter a username.";
				usernameInput.focus();
				return;
			}

			errEl.textContent = "";
			btn.disabled = true;
			btn.innerHTML = '<span class="spinner"></span> Creating passkey...';

			try {
				const startRes = await fetch(`${ENCRYPTID_URL}/api/register/start`, {
					method: "POST",
					headers: { "Content-Type": "application/json" },
					body: JSON.stringify({ username, displayName: username }),
				});
				if (!startRes.ok) throw new Error("Failed to start registration");
				const { options: serverOptions, userId } = await startRes.json();

				const credential = (await navigator.credentials.create({
					publicKey: {
						challenge: new Uint8Array(base64urlToBuffer(serverOptions.challenge)),
						rp: { id: serverOptions.rp?.id || "rspace.online", name: serverOptions.rp?.name || "EncryptID" },
						user: { id: new Uint8Array(base64urlToBuffer(serverOptions.user.id)), name: username, displayName: username },
						pubKeyCredParams: serverOptions.pubKeyCredParams || [
							{ alg: -7, type: "public-key" as const },
							{ alg: -257, type: "public-key" as const },
						],
						authenticatorSelection: { residentKey: "required", requireResidentKey: true, userVerification: "required" },
						attestation: "none",
						timeout: 60000,
					},
				})) as PublicKeyCredential;
				if (!credential) throw new Error("Failed to create credential");

				const response = credential.response as AuthenticatorAttestationResponse;
				const publicKey = response.getPublicKey?.();

				const completeRes = await fetch(`${ENCRYPTID_URL}/api/register/complete`, {
					method: "POST",
					headers: { "Content-Type": "application/json" },
					body: JSON.stringify({
						challenge: serverOptions.challenge,
						credential: {
							credentialId: bufferToBase64url(credential.rawId),
							publicKey: publicKey ? bufferToBase64url(publicKey) : "",
							transports: response.getTransports?.() || [],
						},
						userId,
						username,
					}),
				});
				const data = await completeRes.json();
				if (!completeRes.ok || !data.success) throw new Error(data.error || "Registration failed");

				storeSession(data.token, username, data.did || "");
				close();
				this.#render();
				this.dispatchEvent(new CustomEvent("auth-change", { bubbles: true, composed: true }));
				callbacks?.onSuccess?.();
			} catch (err: any) {
				btn.disabled = false;
				btn.innerHTML = "🔐 Create Passkey";
				errEl.textContent = err.name === "NotAllowedError" ? "Passkey creation was cancelled." : err.message || "Registration failed.";
			}
		};

		const attachListeners = () => {
			overlay.querySelector('[data-action="cancel"]')?.addEventListener("click", () => {
				close();
				callbacks?.onCancel?.();
			});
			overlay.querySelector('[data-action="signin"]')?.addEventListener("click", handleSignIn);
			overlay.querySelector('[data-action="register"]')?.addEventListener("click", handleRegister);
			overlay.querySelector('[data-action="switch-register"]')?.addEventListener("click", () => {
				mode = "register";
				render();
				setTimeout(() => (overlay.querySelector("#auth-username") as HTMLInputElement)?.focus(), 50);
			});
			overlay.querySelector('[data-action="switch-signin"]')?.addEventListener("click", () => {
				mode = "signin";
				render();
			});
			overlay.querySelector("#auth-username")?.addEventListener("keydown", (e) => {
				if ((e as KeyboardEvent).key === "Enter") handleRegister();
			});
			overlay.addEventListener("click", (e) => {
				if (e.target === overlay) {
					close();
					callbacks?.onCancel?.();
				}
			});
		};

		document.body.appendChild(overlay);
		render();
	}

	static define(tag = "rstack-identity") {
		if (!customElements.get(tag)) customElements.define(tag, RStackIdentity);
	}
}

// ── Require auth helper (for use by module code) ──

export function requireAuth(onAuthenticated: () => void): boolean {
	if (isAuthenticated()) return true;
	const el = document.querySelector("rstack-identity") as RStackIdentity | null;
	if (el) {
		el.showAuthModal({ onSuccess: onAuthenticated });
	}
	return false;
}

// ── Styles ──

const STYLES = `
:host { display: contents; }

.signin-btn {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 20px; border-radius: 8px; border: none;
  font-size: 0.875rem; font-weight: 600; cursor: pointer;
  transition: all 0.2s; text-decoration: none;
}
.signin-btn.light {
  background: linear-gradient(135deg, #06b6d4, #0891b2); color: white;
}
.signin-btn.dark {
  background: linear-gradient(135deg, #06b6d4, #7c3aed); color: white;
}
.signin-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(6,182,212,0.3); }

.user {
  display: flex; align-items: center; gap: 10px;
  position: relative; cursor: pointer;
}
.avatar {
  width: 34px; height: 34px; border-radius: 50%;
  background: linear-gradient(135deg, #06b6d4, #7c3aed);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.8rem; color: white;
}
.name {
  font-size: 0.8rem; max-width: 140px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.user.light .name { color: #64748b; }
.user.dark .name { color: #94a3b8; }

.dropdown {
  position: absolute; top: 100%; right: 0; margin-top: 8px;
  min-width: 200px; border-radius: 10px; overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,0.2); display: none; z-index: 100;
}
.dropdown.open { display: block; }
.user.light .dropdown { background: white; border: 1px solid rgba(0,0,0,0.1); }
.user.dark .dropdown { background: #1e293b; border: 1px solid rgba(255,255,255,0.1); }

.dropdown-item {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 16px; font-size: 0.875rem; cursor: pointer;
  transition: background 0.15s; border: none; background: none;
  width: 100%; text-align: left;
}
.user.light .dropdown-item { color: #374151; }
.user.light .dropdown-item:hover { background: #f1f5f9; }
.user.dark .dropdown-item { color: #e2e8f0; }
.user.dark .dropdown-item:hover { background: rgba(255,255,255,0.05); }
.dropdown-item--danger { color: #ef4444 !important; }

.dropdown-divider { height: 1px; margin: 4px 0; }
.user.light .dropdown-divider { background: rgba(0,0,0,0.08); }
.user.dark .dropdown-divider { background: rgba(255,255,255,0.08); }
`;

const MODAL_STYLES = `
.rstack-auth-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px); display: flex; align-items: center;
  justify-content: center; z-index: 10000; animation: fadeIn 0.2s;
}
.auth-modal {
  background: #1e293b; border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px; padding: 2rem; max-width: 420px; width: 90%;
  text-align: center; color: white; box-shadow: 0 20px 60px rgba(0,0,0,0.4);
  animation: slideUp 0.3s;
}
.auth-modal h2 {
  font-size: 1.5rem; margin-bottom: 0.5rem;
  background: linear-gradient(135deg, #06b6d4, #7c3aed);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.auth-modal p { color: #94a3b8; font-size: 0.95rem; line-height: 1.6; margin-bottom: 1.5rem; }
.input {
  width: 100%; padding: 12px 16px; border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.15); background: rgba(255,255,255,0.05);
  color: white; font-size: 1rem; margin-bottom: 1rem; outline: none;
  transition: border-color 0.2s; box-sizing: border-box;
}
.input:focus { border-color: #06b6d4; }
.input::placeholder { color: #64748b; }
.actions { display: flex; gap: 12px; margin-top: 0.5rem; }
.btn {
  flex: 1; padding: 12px 20px; border-radius: 8px; border: none;
  font-size: 0.95rem; font-weight: 600; cursor: pointer; transition: all 0.2s;
}
.btn--primary { background: linear-gradient(135deg, #06b6d4, #7c3aed); color: white; }
.btn--primary:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(6,182,212,0.3); }
.btn--primary:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn--secondary { background: rgba(255,255,255,0.08); color: #94a3b8; border: 1px solid rgba(255,255,255,0.1); }
.btn--secondary:hover { background: rgba(255,255,255,0.12); color: white; }
.error { color: #ef4444; font-size: 0.85rem; margin-top: 0.5rem; min-height: 1.2em; }
.toggle { margin-top: 1rem; font-size: 0.85rem; color: #64748b; }
.toggle a { color: #06b6d4; cursor: pointer; text-decoration: none; }
.toggle a:hover { text-decoration: underline; }
.spinner {
  display: inline-block; width: 18px; height: 18px;
  border: 2px solid transparent; border-top-color: currentColor;
  border-radius: 50%; animation: spin 0.7s linear infinite;
  vertical-align: middle; margin-right: 6px;
}
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
@keyframes spin { to { transform: rotate(360deg); } }
`;