//! Keeps a list of notes in /data/notes.json and publishes them as
//! /public/notes.txt.
use serde_json::{Value, json};
use std::io::{BufRead, Write};

const DATA: &str = "/data/notes.json";

fn save(notes: &[String]) {
    std::fs::write(DATA, serde_json::to_string(notes).unwrap()).unwrap();
    std::fs::write("/public/notes.txt", notes.join("\n") + "\n").unwrap();
}

fn main() {
    let mut notes: Vec<String> = std::fs::read_to_string(DATA)
        .ok()
        .and_then(|s| serde_json::from_str(&s).ok())
        .unwrap_or_default();
    let mut out = std::io::stdout().lock();
    for line in std::io::stdin().lock().lines() {
        let Ok(line) = line else { break };
        let Ok(msg) = serde_json::from_str::<Value>(&line) else { continue };
        let body = &msg["body"];
        let reply = match body["type"].as_str() {
            Some("shutdown") => break,
            Some("add") => {
                notes.push(body["text"].as_str().unwrap_or_default().to_string());
                save(&notes);
                json!({"type": "added", "count": notes.len()})
            }
            Some("list") => json!({"type": "notes", "items": notes}),
            Some("crash") => panic!("asked to crash"),
            _ => json!({"type": "error", "reason": "unknown message"}),
        };
        writeln!(out, "{}", json!({"to": msg["from"], "reply_to": msg["id"], "body": reply})).unwrap();
        out.flush().unwrap();
    }
}