//! `DiMAS` observation example
//! Copyright © 2024 Stephan Kunz

use dimas::prelude::*;

#[derive(Debug)]
struct AgentProps {
	limit: u128,
	sequence: Vec<u128>,
}

/// request structure for observer and observable
#[derive(Debug, Encode, Decode)]
pub struct FibonacciRequest {
	/// limit
	pub limit: u128,
}

async fn control_callback(ctx: Context<AgentProps>, msg: Message) -> Result<ControlResponse> {
	let message: FibonacciRequest = msg.decode()?;
	// check wanted limit
	if message.limit > 2 && message.limit <= 20 {
		// accept
		println!("Accepting Fibonacci sequence up to {}", message.limit);
		ctx.write()?.limit = message.limit;
		Ok(ControlResponse::Accepted)
	} else {
		// decline
		println!("Declining Fibonacci sequence up to {}", message.limit);
		Ok(ControlResponse::Declined)
	}
}

async fn feedback_callback(ctx: Context<AgentProps>) -> Result<Message> {
	let seq = ctx.read()?.sequence.clone();
	let message = Message::encode(&seq);
	println!("Sending feedback: {:?}", &seq);
	Ok(message)
}

async fn fibonacci(ctx: Context<AgentProps>) -> Result<Message> {
	let limit = ctx.read()?.limit;
	// clear any existing result
	ctx.write()?.sequence.clear();
	// create and add first two elements
	let mut n_2 = 0;
	ctx.write()?.sequence.push(n_2);
	let mut n_1 = 1;
	ctx.write()?.sequence.push(n_1);
	for _ in 2..limit {
		let next = n_2 + n_1;
		n_2 = n_1;
		n_1 = next;
		ctx.write()?.sequence.push(next);
		// artificial time consumption
		tokio::time::sleep(Duration::from_millis(1000)).await;
	}
	let sequence = ctx.read()?.sequence.clone();
	let result = Message::encode(&sequence);
	println!("Sending result: {:?}", &sequence);
	Ok(result)
}

#[dimas::main]
async fn main() -> Result<()> {
	// create & initialize agents properties
	let properties = AgentProps {
		limit: 0u128,
		sequence: Vec::new(),
	};

	// create an agent with the properties and the prefix 'examples'
	let agent = Agent::new(properties)
		.prefix("examples")
		.name("observable")
		.config(&Config::default())?;

	// create the observable for fibonacci
	agent
		.observable()
		.topic("fibonacci")
		.control_callback(control_callback)
		.feedback_callback(feedback_callback)
		.feedback_interval(Duration::from_secs(2))
		.execution_callback(fibonacci)
		.add()?;

	// run agent
	agent.start().await?;

	Ok(())
}