//! Example on how to use the ab-code-gen library to generate the code by parsing and modifying a file.

use std::{
    io::{self, Write},
    thread::spawn,
};

use ab_code_gen::Config;
use log::warn;
use syn::*;

fn main() {
    expand_file("examples/hello_world.rs");
    expand_file("examples/print_stuff.rs");
    expand_file("examples/quick.rs");
}

fn expand_file(file_path: &str) {
    // extract file_name from file_path
    let the_path = std::path::Path::new(file_path);
    let file_name = the_path.file_stem().unwrap();
    let file_extension = the_path.extension().unwrap();

    let content: String = std::fs::read_to_string(the_path).unwrap();
    let mut ast = syn::parse_file(&content).unwrap();
    // search for the module
    let module = ast
        .items
        .iter_mut()
        .find_map(|item| match item {
            Item::Mod(module) => Some(module),
            _ => None,
        })
        .unwrap();
    let config = Config::default();
    let actor_module = ab_code_gen::ActorModule::new(module, &config).unwrap();

    let code = actor_module.generate().unwrap();
    // add produced code
    module
        .content
        .as_mut()
        .unwrap()
        .1
        .push(syn::Item::Verbatim(code));
    // remove the actor_module attribute
    module
        .attrs
        .retain(|attr| attr.path().segments.last().unwrap().ident != "actor_module");
    let expanded_code = quote::quote! {#ast}.to_string();

    // pass to cargo fmt
    let mut child = std::process::Command::new("rustfmt")
        .arg("--edition")
        .arg("2018")
        .stdin(std::process::Stdio::piped())
        .stdout(std::process::Stdio::piped())
        .spawn()
        .unwrap();
    let mut child_stdin = child.stdin.take().unwrap();
    let mut child_stdout = child.stdout.take().unwrap();

    spawn(move || {
        let _ = child_stdin.write_all(expanded_code.as_bytes());
    });

    let mut output = vec![];
    std::io::copy(&mut child_stdout, &mut output).unwrap();

    let status = child.wait().unwrap();

    let res = match String::from_utf8(output) {
        Ok(out_str) => match status.code() {
            Some(0) => Ok(out_str),
            Some(2) => Err(io::Error::new(
                io::ErrorKind::Other,
                "Rustfmt parsing errors.".to_string(),
            )),
            Some(3) => {
                warn!("Rustfmt could not format some lines.");
                Ok(out_str)
            }
            _ => Err(io::Error::new(
                io::ErrorKind::Other,
                "Internal rustfmt error".to_string(),
            )),
        },
        _ => unimplemented!("Rustfmt output is not utf8"),
    };
    let new_path = the_path.with_file_name(format!(
        "{}_expanded.{}",
        file_name.to_str().unwrap(),
        file_extension.to_str().unwrap()
    ));
    std::fs::write(new_path, res.unwrap()).unwrap();
}