use bendy::decoding::{Error as BencodeError, FromBencode, Object};
use sha1::{Digest, Sha1};
use std::fs;
use std::path::Path;

fn calculate_infohash<P: AsRef<Path>>(path: P) -> Result<[u8; 20], BencodeError> {
    // Read and decode the torrent file
    let data = fs::read(path)?;
    let torrent = Object::decode(&data)?;

    // Find the "info" dictionary
    let info = torrent
        .lookup("info")
        .ok_or(BencodeError::Unspecified)?
        .to_owned();

    // Encode the "info" dictionary into bytes
    let info_bytes = info.encode()?;

    // Calculate the SHA-1 hash
    let mut hasher = Sha1::new();
    hasher.update(&info_bytes);
    let result = hasher.finalize();

    // Convert the hash to a 20-byte array and return
    Ok(result.into())
}

fn main() {
    let path = "path_to_torrent_file.torrent";
    match calculate_infohash(path) {
        Ok(hash) => {
            println!("Infohash: {:?}", hash);
        }
        Err(e) => {
            eprintln!("Error: {}", e);
        }
    }
}

use bip_bencode::{Bencode, BencodeRef, BencodeConvert};
use sha1::{Digest, Sha1};
use std::fs;
use std::io::{self, Read};
use std::path::Path;

fn calculate_infohash<P: AsRef<Path>>(path: P) -> io::Result<[u8; 20]> {
    // Read the torrent file
    let mut data = Vec::new();
    let mut file = fs::File::open(path)?;
    file.read_to_end(&mut data)?;

    // Decode the torrent file
    let torrent = BencodeRef::decode(&data).unwrap();

    // Extract the "info" dictionary
    let info = match torrent.dict().unwrap().lookup(b"info") {
        Some(info) => info,
        None => return Err(io::Error::new(io::ErrorKind::Other, "Missing info dictionary")),
    };

    // Re-encode the "info" dictionary into bytes
    let info_bytes = info.encode();

    // Calculate the SHA-1 hash
    let mut hasher = Sha1::new();
    hasher.update(&info_bytes);
    let result = hasher.finalize();

    Ok(result.into())
}

fn main() {
    let path = "path_to_torrent_file.torrent";
    match calculate_infohash(path) {
        Ok(hash) => {
            println!("Infohash: {:?}", hash);
        }
        Err(e) => {
            eprintln!("Error: {}", e);
        }
    }
}