use crate::symbols::Symbol;
use async_trait::async_trait;
use std::error::Error;
use std::fs::File as FsFile;
use std::io::{Read, Write};
use std::path::Path;

#[derive(Debug)]
pub struct File<D, C> {
  path: D,
  content: C,
}

impl<D, C> File<D, C> {
  pub const fn new(path: D, content: C) -> Self {
    Self { path, content }
  }
}

#[async_trait(?Send)]
impl<D: AsRef<Path>, C: AsRef<str>> Symbol for File<D, C> {
  async fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    if !self.path.as_ref().exists() {
      return Ok(false);
    }
    let file = FsFile::open(self.path.as_ref())?;
    // Check if content is the same
    let mut file_content = file.bytes();
    let mut target_content = self.content.as_ref().bytes();
    loop {
      match (file_content.next(), target_content.next()) {
        (None, None) => return Ok(true),
        (Some(Ok(a)), Some(b)) if a == b => {}
        (Some(Err(e)), _) => return Err(Box::new(e)),
        (_, _) => return Ok(false),
      }
    }
  }

  async fn execute(&self) -> Result<(), Box<dyn Error>> {
    let mut file = FsFile::create(self.path.as_ref())?;
    file.write_all(self.content.as_ref().as_bytes())?;
    Ok(())
  }
}