use crate::resources::resource_filesystem::FilesystemResource;
use crate::resources::ResourceWrapper;
use mlua::{MetaMethod, UserData, UserDataMethods};
use std::fs::{read_dir, ReadDir};
use std::path::PathBuf;

pub struct DirectorySource {
    path: PathBuf,
    read_dir: ReadDir,
}

impl From<String> for DirectorySource {
    fn from(path: String) -> Self {
        let path = PathBuf::from(path);
        let read_dir = std::fs::read_dir(&path).expect("could not read dir");
        DirectorySource { path, read_dir }
    }
}

impl Iterator for DirectorySource {
    type Item = FilesystemResource;

    fn next(&mut self) -> Option<Self::Item> {
        self.read_dir
            .next()
            .map(|entry| entry.expect("Could not read directory content").path())
            .map(|path| FilesystemResource::from(path))
    }
}

impl UserData for DirectorySource {
    fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) {
        methods.add_meta_method(MetaMethod::ToString, |_, this, _: ()| {
            Ok(this.path.display().to_string())
        });
        methods.add_meta_method_mut(MetaMethod::Call, |_, this, _: ()| {
            Ok(this.next().map(|entry| ResourceWrapper::from(entry)))
        });
    }
}