import { Button, icon, Input } from "@mariozechner/mini-lit";
import "@mariozechner/mini-lit/dist/ThemeToggle.js";
import { getModel } from "@mariozechner/pi-ai";
import {
	Agent,
	type AgentState,
	ApiKeyPromptDialog,
	ApiKeysTab,
	type AppMessage,
	AppStorage,
	ChatPanel,
	// PersistentStorageDialog, // TODO: Fix - currently broken
	ProviderTransport,
	ProxyTab,
	SessionIndexedDBBackend,
	SessionListDialog,
	setAppStorage,
	SettingsDialog,
} from "@mariozechner/pi-web-ui";
import { html, render } from "lit";
import { Bell, History, Plus, Settings } from "lucide";
import "./app.css";
import { createSystemNotification, customMessageTransformer, registerCustomMessageRenderers } from "./custom-messages.js";

// Register custom message renderers
registerCustomMessageRenderers();

const storage = new AppStorage({
	sessions: new SessionIndexedDBBackend("pi-web-ui-sessions"),
});
setAppStorage(storage);

let currentSessionId: string | undefined;
let currentTitle = "";
let isEditingTitle = false;
let agent: Agent;
let chatPanel: ChatPanel;
let agentUnsubscribe: (() => void) | undefined;

const generateTitle = (messages: AppMessage[]): string => {
	const firstUserMsg = messages.find((m) => m.role === "user");
	if (!firstUserMsg || firstUserMsg.role !== "user") return "";

	let text = "";
	const content = firstUserMsg.content;

	if (typeof content === "string") {
		text = content;
	} else {
		const textBlocks = content.filter((c: any) => c.type === "text");
		text = textBlocks.map((c: any) => c.text || "").join(" ");
	}

	text = text.trim();
	if (!text) return "";

	const sentenceEnd = text.search(/[.!?]/);
	if (sentenceEnd > 0 && sentenceEnd <= 50) {
		return text.substring(0, sentenceEnd + 1);
	}
	return text.length <= 50 ? text : text.substring(0, 47) + "...";
};

const shouldSaveSession = (messages: AppMessage[]): boolean => {
	const hasUserMsg = messages.some((m: any) => m.role === "user");
	const hasAssistantMsg = messages.some((m: any) => m.role === "assistant");
	return hasUserMsg && hasAssistantMsg;
};

const saveSession = async () => {
	if (!storage.sessions || !currentSessionId || !agent || !currentTitle) return;

	const state = agent.state;
	if (!shouldSaveSession(state.messages)) return;

	try {
		await storage.sessions.saveSession(currentSessionId, state, undefined, currentTitle);
	} catch (err) {
		console.error("Failed to save session:", err);
	}
};

const updateUrl = (sessionId: string) => {
	const url = new URL(window.location.href);
	url.searchParams.set("session", sessionId);
	window.history.replaceState({}, "", url);
};

const createAgent = async (initialState?: Partial<AgentState>) => {
	if (agentUnsubscribe) {
		agentUnsubscribe();
	}

	const transport = new ProviderTransport();

	agent = new Agent({
		initialState: initialState || {
			systemPrompt: `You are a helpful AI assistant with access to various tools.

Available tools:
- JavaScript REPL: Execute JavaScript code in a sandboxed browser environment (can do calculations, get time, process data, create visualizations, etc.)
- Artifacts: Create interactive HTML, SVG, Markdown, and text artifacts

Feel free to use these tools when needed to provide accurate and helpful responses.`,
			model: getModel("anthropic", "claude-sonnet-4-5-20250929"),
			thinkingLevel: "off",
			messages: [],
			tools: [],
		},
		transport,
		// Custom transformer: convert system notifications to user messages with <system> tags
		messageTransformer: customMessageTransformer,
	});

	agentUnsubscribe = agent.subscribe((event: any) => {
		if (event.type === "state-update") {
			const messages = event.state.messages;

			// Generate title after first successful response
			if (!currentTitle && shouldSaveSession(messages)) {
				currentTitle = generateTitle(messages);
			}

			// Create session ID on first successful save
			if (!currentSessionId && shouldSaveSession(messages)) {
				currentSessionId = crypto.randomUUID();
				updateUrl(currentSessionId);
			}

			// Auto-save
			if (currentSessionId) {
				saveSession();
			}

			renderApp();
		}
	});

	await chatPanel.setAgent(agent);
};

const loadSession = async (sessionId: string): Promise<boolean> => {
	if (!storage.sessions) return false;

	const sessionData = await storage.sessions.loadSession(sessionId);
	if (!sessionData) {
		console.error("Session not found:", sessionId);
		return false;
	}

	currentSessionId = sessionId;
	const metadata = await storage.sessions.getMetadata(sessionId);
	currentTitle = metadata?.title || "";

	await createAgent({
		model: sessionData.model,
		thinkingLevel: sessionData.thinkingLevel,
		messages: sessionData.messages,
		tools: [],
	});

	updateUrl(sessionId);
	renderApp();
	return true;
};

const newSession = () => {
	const url = new URL(window.location.href);
	url.search = "";
	window.location.href = url.toString();
};

// ============================================================================
// RENDER
// ============================================================================
const renderApp = () => {
	const app = document.getElementById("app");
	if (!app) return;

	const appHtml = html`
		<div class="w-full h-screen flex flex-col bg-background text-foreground overflow-hidden">
			<!-- Header -->
			<div class="flex items-center justify-between border-b border-border shrink-0">
				<div class="flex items-center gap-2 px-4 py-">
					${Button({
						variant: "ghost",
						size: "sm",
						children: icon(History, "sm"),
						onClick: () => {
							SessionListDialog.open(
								async (sessionId) => {
									await loadSession(sessionId);
								},
								(deletedSessionId) => {
									// Only reload if the current session was deleted
									if (deletedSessionId === currentSessionId) {
										newSession();
									}
								},
							);
						},
						title: "Sessions",
					})}
					${Button({
						variant: "ghost",
						size: "sm",
						children: icon(Plus, "sm"),
						onClick: newSession,
						title: "New Session",
					})}

					${currentTitle
						? isEditingTitle
							? html`<div class="flex items-center gap-2">
									${Input({
										type: "text",
										value: currentTitle,
										className: "text-sm w-64",
										onChange: async (e: Event) => {
											const newTitle = (e.target as HTMLInputElement).value.trim();
											if (newTitle && newTitle !== currentTitle && storage.sessions && currentSessionId) {
												await storage.sessions.updateTitle(currentSessionId, newTitle);
												currentTitle = newTitle;
											}
											isEditingTitle = false;
											renderApp();
										},
										onKeyDown: async (e: KeyboardEvent) => {
											if (e.key === "Enter") {
												const newTitle = (e.target as HTMLInputElement).value.trim();
												if (newTitle && newTitle !== currentTitle && storage.sessions && currentSessionId) {
													await storage.sessions.updateTitle(currentSessionId, newTitle);
													currentTitle = newTitle;
												}
												isEditingTitle = false;
												renderApp();
											} else if (e.key === "Escape") {
												isEditingTitle = false;
												renderApp();
											}
										},
									})}
								</div>`
							: html`<button
									class="px-2 py-1 text-sm text-foreground hover:bg-secondary rounded transition-colors"
									@click=${() => {
										isEditingTitle = true;
										renderApp();
										requestAnimationFrame(() => {
											const input = app?.querySelector('input[type="text"]') as HTMLInputElement;
											if (input) {
												input.focus();
												input.select();
											}
										});
									}}
									title="Click to edit title"
								>
									${currentTitle}
								</button>`
						: html`<span class="text-base font-semibold text-foreground">Pi Web UI Example</span>`}
				</div>
				<div class="flex items-center gap-1 px-2">
					${Button({
						variant: "ghost",
						size: "sm",
						children: icon(Bell, "sm"),
						onClick: () => {
							// Demo: Inject custom message
							if (agent) {
								agent.appendMessage(
									createSystemNotification("This is a custom message! It appears in the UI but is never sent to the LLM."),
								);
							}
						},
						title: "Demo: Add Custom Notification",
					})}
					<theme-toggle></theme-toggle>
					${Button({
						variant: "ghost",
						size: "sm",
						children: icon(Settings, "sm"),
						onClick: () => SettingsDialog.open([new ApiKeysTab(), new ProxyTab()]),
						title: "Settings",
					})}
				</div>
			</div>

			<!-- Chat Panel -->
			${chatPanel}
		</div>
	`;

	render(appHtml, app);
};

// ============================================================================
// INIT
// ============================================================================
async function initApp() {
	const app = document.getElementById("app");
	if (!app) throw new Error("App container not found");

	// Show loading
	render(
		html`
			<div class="w-full h-screen flex items-center justify-center bg-background text-foreground">
				<div class="text-muted-foreground">Loading...</div>
			</div>
		`,
		app,
	);

	// TODO: Fix PersistentStorageDialog - currently broken
	// Request persistent storage
	// if (storage.sessions) {
	// 	await PersistentStorageDialog.request();
	// }

	// Create ChatPanel
	chatPanel = new ChatPanel();
	chatPanel.onApiKeyRequired = async (provider: string) => {
		return await ApiKeyPromptDialog.prompt(provider);
	};

	// Check for session in URL
	const urlParams = new URLSearchParams(window.location.search);
	const sessionIdFromUrl = urlParams.get("session");

	if (sessionIdFromUrl) {
		const loaded = await loadSession(sessionIdFromUrl);
		if (!loaded) {
			// Session doesn't exist, redirect to new session
			newSession();
			return;
		}
	} else {
		await createAgent();
	}

	renderApp();
}

initApp();