//! Provider de filesystem local. Crate puro: cero dependencia de UI.
//! Implementa `yahweh_core::DataProvider` listando hijos de un path con
//! `std::fs::read_dir` y leyendo archivos a `Vec<u8>` via `tokio::io`.

use async_trait::async_trait;
use std::fs;
use std::io::Cursor;
use std::path::Path;
use std::pin::Pin;
use tokio::io::{AsyncRead, AsyncWrite};
use yahweh_core::{DataProvider, DisplayType, EntityNode};

pub const PROVIDER_ID: &str = "local_fs";

pub struct FileDataProvider;

#[async_trait]
impl DataProvider for FileDataProvider {
    fn provider_id(&self) -> String {
        PROVIDER_ID.to_string()
    }

    async fn list_children(&self, parent_id: Option<&str>) -> Result<Vec<EntityNode>, String> {
        let path = parent_id.unwrap_or(".");
        let mut children = Vec::new();

        if let Ok(entries) = fs::read_dir(path) {
            for entry in entries.filter_map(|e| e.ok()) {
                let path = entry.path();
                let name = path
                    .file_name()
                    .unwrap_or_default()
                    .to_string_lossy()
                    .into_owned();
                let display_type = if path.is_dir() {
                    DisplayType::Folder
                } else {
                    DisplayType::File
                };

                children.push(EntityNode {
                    id: path.to_string_lossy().into_owned(),
                    name,
                    display_type,
                    mime_type: None,
                });
            }
        }

        Ok(children)
    }

    async fn get_read_stream(
        &self,
        entity_id: &str,
    ) -> Result<Pin<Box<dyn AsyncRead + Send>>, String> {
        let content = fs::read(Path::new(entity_id)).map_err(|e| e.to_string())?;
        Ok(Box::pin(Cursor::new(content)))
    }

    async fn get_write_stream(
        &self,
        _entity_id: &str,
    ) -> Result<Pin<Box<dyn AsyncWrite + Send>>, String> {
        Err("Escritura en streaming no implementada para FS".to_string())
    }
}