import pf.Stdin

import pf.Stdout

import pf.Stderr

Helpers :: [].{

encode_json : a -> Str where [a.encoder_for : _]

encode_json = |a| Json.to_str(a)

decode_json : Str -> a where [a.parser_for : _]

decode_json = |str| {

match Json.parse(str) {

Ok(p) => p

Err(_) => {

crash "Json.parse(str)"

}

}

}

NodeState(a) : { node_id : Str, msg_id : U64, ..a }

reply! = |state, msg, body| {

send_message!(state, msg.src, { ..body, in_reply_to: msg.body.msg_id })

}

send_message! = |state, dest, body| {

payload = encode_json({ src: state.node_id, dest, body: { ..body, msg_id: state.msg_id } })

Stdout.line!(payload)?

Ok({ ..state, msg_id: state.msg_id + 1 })

}

Payload(body) : {

src : Str,

dest : Str,

body : body,

}

LoopState(a) : [WaitingForInit, ..a]

run! = |handle_input!| {

initial_state : LoopState(_)

initial_state = WaitingForInit

run_internal!(handle_input!, initial_state)

}

run_internal! = |handle_input!, state| {

line_str = Stdin.line!()?

Stderr.line!(line_str)?

new_state = handle_input!(line_str, state)?

run_internal!(handle_input!, new_state)

}

}