use anyhow::Result;
use std::fs::File;
use std::io::{BufWriter, Write};
use std::path::Path;

use crate::router::RouteDecision;

pub struct RoutingLogWriter {
    inner: BufWriter<File>,
}

impl RoutingLogWriter {
    pub fn create<P: AsRef<Path>>(path: P) -> Result<Self> {
        let f = File::create(path)?;
        Ok(Self { inner: BufWriter::new(f) })
    }

    pub fn write(&mut self, decision: &RouteDecision) -> Result<()> {
        let line = serde_json::to_string(decision)?;
        self.inner.write_all(line.as_bytes())?;
        self.inner.write_all(b"\n")?;
        Ok(())
    }

    pub fn finish(mut self) -> Result<()> {
        self.inner.flush()?;
        Ok(())
    }
}