mod checked;
mod chunk;
mod uploading;

use std::{
    ffi::OsStr,
    fs,
    io::{self, Read},
    path::Path,
};

use base64ct::{Base64, Encoding};
use blake2b_simd::Params as Blake2b;

pub use checked::Checked;
pub use chunk::Chunk;
use log::debug;
pub use uploading::Uploading;

fn compute_file_hash(path: &Path, size: u64, on_progress: impl Fn(u64)) -> io::Result<String> {
    let mut file = fs::File::open(path)?;
    let mut hasher = Blake2b::new().hash_length(64).to_state();

    let mut buf = vec![0u8; 4 * 1024 * 1024];
    let mut bytes_read = 0;

    loop {
        let n = file.read(&mut buf)?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);

        bytes_read += n as u64;
        on_progress(n as u64);
    }

    if bytes_read != size {
        return Err(io::Error::other(format!(
            "Hashed {bytes_read:?} bytes, known file size {size:?}!"
        )));
    }

    let result = Base64::encode_string(hasher.finalize().as_bytes());
    debug!("hashed {:?}: {result:?}", path.display());
    Ok(result)
}

fn check_file_hash(
    path: &Path,
    size: u64,
    hash: Option<&String>,
    on_progress: impl Fn(u64),
) -> io::Result<bool> {
    let Some(hash) = hash else {
        debug!("no hash to check for {:?}!", path.display());
        return Ok(false);
    };

    let result = *hash == compute_file_hash(path, size, on_progress)?;
    debug!("matches {:?}: {result:?}", *hash);
    Ok(result)
}

pub trait FileTrait<'t> {
    /// extract the filename part of a `Path` reference
    ///
    /// # Panics
    ///
    /// Expects `path::Path::file_name` and `ffi::OsStr::to_str` to succeed on the given path
    fn extract_file_name(p: &'t Path) -> &'t str {
        p.file_name()
            .and_then(OsStr::to_str)
            .expect("bad file name")
    }

    /// get a reference to the file's name
    fn get_name(&'t self) -> &'t str;

    /// get the file's size
    fn get_size(&self) -> u64;

    fn check_hash(&self, on_progress: impl Fn(u64)) -> io::Result<bool>;
}