#![allow(dead_code, unused_variables)]

use serde::Serialize;
use std::io::Write;

#[derive(Debug, Serialize)]
pub struct LintMessage;
pub struct LintPath;

pub trait Linter {
    fn check_paths<'a>(&mut self, paths: impl Iterator<Item = &'a LintPath>);
}

pub trait Output {
    fn write(&mut self, msg: LintMessage);
}

impl<T: ?Sized + Output> Output for &'_ mut T {
    fn write(&mut self, msg: LintMessage) {
        (**self).write(msg);
    }
}

// Useful for tests.
impl Output for Vec<LintMessage> {
    fn write(&mut self, msg: LintMessage) {
        self.push(msg);
    }
}

struct PrintToStdout;
impl Output for PrintToStdout {
    fn write(&mut self, msg: LintMessage) {
        println!("{:?}", msg);
    }
}

// Stream JSON.
impl<W: Write> Output for serde_json::Serializer<W> {
    fn write(&mut self, msg: LintMessage) {
        let _ = msg.serialize(self);
    }
}

pub struct SignedSourceLinter<'a> {
    config: (/* ... */),
    out: Box<dyn Output + 'a>,
}

impl Linter for SignedSourceLinter<'_> {
    fn check_paths<'a>(&mut self, paths: impl Iterator<Item = &'a LintPath>) {
        for path in paths {
            // TODO
            self.out.write(LintMessage);
        }
    }
}

fn main() {}