use std::io::Write;

fn main() {
    let mut output_file = std::fs::File::create("src/registered_scripts.rs").unwrap();

    write!(
        output_file,
        r"// Autogenerated file. Do not edit.
 
use alloc::boxed::Box;
use pkmn_lib_interface::app_interface::{{get_hash, StringKey}};
use pkmn_lib_interface::handling::{{Script, ScriptCategory}};

macro_rules! resolve_match {{
    (
        $mid:expr,
        $(
            $script:ty,
        )*
    ) => (
        match $mid {{
            $(
                const {{ get_hash(<$script>::get_const_name()) }} => {{
                    return Some(Box::new(<$script>::new()))
                }}
            )*
            _ => {{}}
        }}
    )
}}

pub fn get_script(category: ScriptCategory, name: &StringKey) -> Option<Box<dyn Script>> {{
    match category {{"
    )
    .unwrap();

    write_category("moves", "Move", &mut output_file);
    write_category("abilities", "Ability", &mut output_file);
    write_category("status", "Status", &mut output_file);
    write_category("pokemon", "Pokemon", &mut output_file);
    write_category("battle", "Battle", &mut output_file);
    write_category("weather", "Weather", &mut output_file);
    write_category("side", "Side", &mut output_file);
    write_category(
        "item_battle_triggers",
        "ItemBattleTrigger",
        &mut output_file,
    );

    write!(
        output_file,
        r#"
    }}
    None
}} 
    "#
    )
    .unwrap();
}

fn write_category(path: &str, category: &str, output_file: &mut std::fs::File) {
    write!(
        output_file,
        r"
        ScriptCategory::{} => {{
            resolve_match! {{
                name.hash().unwrap(),
",
        category
    )
    .unwrap();
    write_scripts(path, output_file);

    write!(
        output_file,
        r"            }}
        }},"
    )
    .unwrap();
}

fn write_scripts(path: &str, output_file: &mut std::fs::File) {
    let move_files = std::fs::read_dir(format!("src/{}", path))
        .unwrap()
        .map(|f| f.unwrap().path())
        .filter(|f| f.extension().unwrap() == "rs")
        .map(|f| f.file_stem().unwrap().to_str().unwrap().to_string())
        .collect::<Vec<_>>();
    for file in move_files {
        println!("cargo:rerun-if-changed=src/{}/{}.rs", path, file);
        let parsed =
            syn::parse_file(&std::fs::read_to_string(format!("src/{}/{}.rs", path, file)).unwrap())
                .unwrap();
        // Now we need to find every impl Script for X { ... } block inside parsed
        let script_impls = parsed
            .items
            .iter()
            .filter_map(|item| match item {
                syn::Item::Impl(impl_block) => match impl_block.trait_ {
                    Some((_, ref path, _)) => {
                        if path.segments[0].ident == "Script" {
                            Some(impl_block)
                        } else {
                            None
                        }
                    }
                    None => None,
                },
                _ => None,
            })
            .collect::<Vec<_>>();
        for script_impl in script_impls {
            match script_impl.self_ty.as_ref() {
                syn::Type::Path(p) => {
                    let ident = p.path.segments[0].ident.to_string();
                    writeln!(
                        output_file,
                        "                crate::{}::{}::{},",
                        path, file, ident
                    )
                    .unwrap();
                }
                _ => {}
            }
        }
    }
}