import type {
	MasterDriver,
	ConnectionStatus,
	RobotCommand,
	CommandSequence,
	RemoteServerMasterConfig,
	CommandCallback,
	SequenceCallback,
	StatusChangeCallback,
	UnsubscribeFn
} from "$lib/types/robotDriver";
import { getWebSocketConfig } from "$lib/configs/performanceConfig";

/**
 * Remote Server Master Driver
 * Connects to FastAPI WebSocket server for remote robot control
 */
export class RemoteServerMaster implements MasterDriver {
	readonly type = "master" as const;
	readonly id: string;
	readonly name: string;

	private _status: ConnectionStatus = { isConnected: false };
	private config: RemoteServerMasterConfig;
	private robotId: string;

	// WebSocket connection
	private ws?: WebSocket;
	private reconnectAttempts = 0;
	private maxReconnectAttempts = getWebSocketConfig().MAX_RECONNECT_ATTEMPTS;
	private reconnectDelay = getWebSocketConfig().INITIAL_RECONNECT_DELAY_MS;
	private heartbeatInterval?: number;

	// Event callbacks
	private commandCallbacks: CommandCallback[] = [];
	private sequenceCallbacks: SequenceCallback[] = [];
	private statusCallbacks: StatusChangeCallback[] = [];

	constructor(config: RemoteServerMasterConfig, robotId: string) {
		this.config = config;
		this.robotId = robotId;
		this.id = `remote-master-${robotId}-${Date.now()}`;
		this.name = `Remote Server Master (${robotId})`;

		console.log(`Created RemoteServerMaster for robot ${robotId}`);
	}

	get status(): ConnectionStatus {
		return this._status;
	}

	async connect(): Promise<void> {
		console.log(`Connecting ${this.name} to ${this.config.url}...`);

		try {
			// Build WebSocket URL
			const wsUrl = this.buildWebSocketUrl();

			// Create WebSocket connection
			this.ws = new WebSocket(wsUrl);

			// Set up event handlers
			this.setupWebSocketHandlers();

			// Wait for connection
			await this.waitForConnection();

			// Start heartbeat
			this.startHeartbeat();

			this._status = {
				isConnected: true,
				lastConnected: new Date(),
				error: undefined
			};
			this.notifyStatusChange();

			console.log(`${this.name} connected successfully`);
		} catch (error) {
			this._status = {
				isConnected: false,
				error: `Connection failed: ${error}`
			};
			this.notifyStatusChange();
			throw error;
		}
	}

	async disconnect(): Promise<void> {
		console.log(`Disconnecting ${this.name}...`);

		this.stopHeartbeat();

		if (this.ws) {
			this.ws.close();
			this.ws = undefined;
		}

		this._status = { isConnected: false };
		this.notifyStatusChange();

		console.log(`${this.name} disconnected`);
	}

	async start(): Promise<void> {
		if (!this._status.isConnected) {
			throw new Error("Cannot start: master not connected");
		}

		console.log(`Starting remote control for robot ${this.robotId}`);

		// Send start command to server
		await this.sendMessage({
			type: "start_control",
			timestamp: new Date().toISOString(),
			data: { robotId: this.robotId }
		});
	}

	async stop(): Promise<void> {
		console.log(`Stopping remote control for robot ${this.robotId}`);

		if (this._status.isConnected && this.ws) {
			await this.sendMessage({
				type: "stop_control",
				timestamp: new Date().toISOString(),
				data: { robotId: this.robotId }
			});
		}
	}

	async pause(): Promise<void> {
		console.log(`Pausing remote control for robot ${this.robotId}`);

		if (this._status.isConnected && this.ws) {
			await this.sendMessage({
				type: "pause_control",
				timestamp: new Date().toISOString(),
				data: { robotId: this.robotId }
			});
		}
	}

	async resume(): Promise<void> {
		console.log(`Resuming remote control for robot ${this.robotId}`);

		if (this._status.isConnected && this.ws) {
			await this.sendMessage({
				type: "resume_control",
				timestamp: new Date().toISOString(),
				data: { robotId: this.robotId }
			});
		}
	}

	// Event subscription methods
	onCommand(callback: CommandCallback): UnsubscribeFn {
		this.commandCallbacks.push(callback);
		return () => {
			const index = this.commandCallbacks.indexOf(callback);
			if (index >= 0) {
				this.commandCallbacks.splice(index, 1);
			}
		};
	}

	onSequence(callback: SequenceCallback): UnsubscribeFn {
		this.sequenceCallbacks.push(callback);
		return () => {
			const index = this.sequenceCallbacks.indexOf(callback);
			if (index >= 0) {
				this.sequenceCallbacks.splice(index, 1);
			}
		};
	}

	onStatusChange(callback: StatusChangeCallback): UnsubscribeFn {
		this.statusCallbacks.push(callback);
		return () => {
			const index = this.statusCallbacks.indexOf(callback);
			if (index >= 0) {
				this.statusCallbacks.splice(index, 1);
			}
		};
	}

	// Private methods
	private buildWebSocketUrl(): string {
		const baseUrl = this.config.url.replace(/^http/, "ws");
		return `${baseUrl}/ws/master/${this.robotId}`;
	}

	private setupWebSocketHandlers(): void {
		if (!this.ws) return;

		this.ws.onopen = () => {
			console.log(`WebSocket connected for robot ${this.robotId}`);
			this.reconnectAttempts = 0; // Reset on successful connection
		};

		this.ws.onmessage = (event) => {
			try {
				const message = JSON.parse(event.data);
				this.handleServerMessage(message);
			} catch (error) {
				console.error("Failed to parse WebSocket message:", error);
			}
		};

		this.ws.onclose = (event) => {
			console.log(`WebSocket closed for robot ${this.robotId}:`, event.code, event.reason);
			this.handleDisconnection();
		};

		this.ws.onerror = (error) => {
			console.error(`WebSocket error for robot ${this.robotId}:`, error);
			this._status = {
				isConnected: false,
				error: `WebSocket error: ${error}`
			};
			this.notifyStatusChange();
		};
	}

	private async waitForConnection(): Promise<void> {
		if (!this.ws) throw new Error("WebSocket not created");

		return new Promise((resolve, reject) => {
			const timeout = setTimeout(() => {
				reject(new Error("Connection timeout"));
			}, getWebSocketConfig().CONNECTION_TIMEOUT_MS);

			if (this.ws!.readyState === WebSocket.OPEN) {
				clearTimeout(timeout);
				resolve();
				return;
			}

			this.ws!.onopen = () => {
				clearTimeout(timeout);
				resolve();
			};

			this.ws!.onerror = (error) => {
				clearTimeout(timeout);
				reject(error);
			};
		});
	}

	private async sendMessage(message: Record<string, unknown>): Promise<void> {
		if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
			throw new Error("WebSocket not connected");
		}

		this.ws.send(JSON.stringify(message));
	}

	private handleServerMessage(message: Record<string, unknown>): void {
		const { type, data } = message;

		console.log(`🔍 RemoteServerMaster received: ${type}`, data);

		switch (type) {
			case "command":
				if (data) {
					this.notifyCommand([data as RobotCommand]);
				}
				break;

			case "sequence":
				if (data) {
					this.notifySequence(data as CommandSequence);
				}
				break;

			case "play_sequence":
				if (data) {
					console.log(`Playing sequence from server on robot ${this.robotId}`);
					this.notifySequence(data as CommandSequence);
				}
				break;

			case "robot_state":
				console.log(`Received robot state for ${this.robotId}:`, data);
				break;

			case "slave_status":
				console.log(`Slave status update for ${this.robotId}:`, data);
				// Status updates don't need to trigger robot movement
				break;

			case "joint_states":
				console.log(`Joint states update for ${this.robotId}:`, data);
				// Convert joint states from slave into robot commands to update local robot
				if (data && typeof data === "object" && "joints" in data) {
					const jointsData = data.joints as Array<{
						name: string;
						virtual_value: number;
						real_value?: number;
					}>;
					if (Array.isArray(jointsData) && jointsData.length > 0) {
						const command: RobotCommand = {
							timestamp: Date.now(),
							joints: jointsData.map((joint) => ({
								name: joint.name,
								value: joint.real_value !== undefined ? joint.real_value : joint.virtual_value
							})),
							metadata: { source: "remote_slave_joint_states" }
						};

						console.log(`🔄 Converting joint states to command:`, command);
						this.notifyCommand([command]);
					}
				}
				break;

			case "slave_error":
				console.error(`Slave error for ${this.robotId}:`, data);
				break;

			case "heartbeat_ack":
				// Heartbeat acknowledged, connection is alive
				break;

			default:
				console.warn(`Unknown message type from server: ${type}`);
		}
	}

	private handleDisconnection(): void {
		this._status = { isConnected: false };
		this.notifyStatusChange();
		this.stopHeartbeat();

		// Attempt reconnection if not manually disconnected
		if (this.reconnectAttempts < this.maxReconnectAttempts) {
			this.attemptReconnection();
		}
	}

	private async attemptReconnection(): Promise<void> {
		this.reconnectAttempts++;
		const maxDelay = getWebSocketConfig().MAX_RECONNECT_DELAY_MS;
		const delay = Math.min(
			this.reconnectDelay * Math.pow(1.5, this.reconnectAttempts - 1),
			maxDelay
		);

		console.log(
			`Attempting master reconnection ${this.reconnectAttempts}/${this.maxReconnectAttempts} in ${delay}ms...`
		);

		setTimeout(async () => {
			try {
				await this.connect();
			} catch (error) {
				console.error(`Master reconnection attempt ${this.reconnectAttempts} failed:`, error);
			}
		}, delay);
	}

	private startHeartbeat(): void {
		this.heartbeatInterval = setInterval(async () => {
			if (this._status.isConnected && this.ws) {
				try {
					await this.sendMessage({
						type: "heartbeat",
						timestamp: new Date().toISOString()
					});
				} catch (error) {
					console.error("Failed to send heartbeat:", error);
				}
			}
		}, getWebSocketConfig().HEARTBEAT_INTERVAL_MS);
	}

	private stopHeartbeat(): void {
		if (this.heartbeatInterval) {
			clearInterval(this.heartbeatInterval);
			this.heartbeatInterval = undefined;
		}
	}

	private notifyCommand(commands: RobotCommand[]): void {
		this.commandCallbacks.forEach((callback) => {
			try {
				callback(commands);
			} catch (error) {
				console.error("Error in command callback:", error);
			}
		});
	}

	private notifySequence(sequence: CommandSequence): void {
		this.sequenceCallbacks.forEach((callback) => {
			try {
				callback(sequence);
			} catch (error) {
				console.error("Error in sequence callback:", error);
			}
		});
	}

	private notifyStatusChange(): void {
		this.statusCallbacks.forEach((callback) => {
			try {
				callback(this._status);
			} catch (error) {
				console.error("Error in status callback:", error);
			}
		});
	}
}