use std::env;
use std::fs::File;
use std::io::Write;
use std::path::{Path, PathBuf};

use anyhow::Result;
use schemafy_lib::Expander;
use schemafy_lib::Schema;

fn process_token_stream(input: proc_macro2::TokenStream) -> syn::File {
    let mut ast: syn::File = syn::parse2(input).unwrap();
    ast.items.insert(
        0,
        syn::parse_quote! {
          use serde::{Serialize, Deserialize};
        },
    );
    ast
}

fn main() -> Result<()> {
    println!("cargo:rerun-if-changed=src/schema.json");
    let path = Path::new("src/schema.json");
    let json = std::fs::read_to_string(path).unwrap();
    let schema: Schema = serde_json::from_str(&json)?;
    let path_str = path.to_str().unwrap();
    let mut expander = Expander::new(Some("lwjson"), path_str, &schema);
    let generated = process_token_stream(expander.expand(&schema));
    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
    let mut file = File::create(out_path.join("lwjson.rs"))?;
    file.write_all(prettyplease::unparse(&generated).as_bytes())?;
    Ok(())
}