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    use std::io::{BufReader, Read};

    /// Struct containing information about a file, without reading the actual data of the file.
    /// This should be used in cases where file information is needed to be retrieved quickly
    /// (e.g. when listing files in an archive).
    pub struct FarFileInfo {
        pub name: String,
        pub size: u32,
        offset: u32,
    }

    /// Struct containing a file, whether or not it's in an archive.
    /// This should be used when creating a file from a buffer, or when getting files from an archive.
    ///
    /// Should be created by calling `FarFile::new_from_archive` if extracting from an archive, or
    /// `FarFile::new_from_file` if reading from a buffer.
    ///
    /// # Examples
    /// ```
    /// // buffer is a Vec<u8> containing the contents of a file
    /// // fileA_name is the name of the file
    /// use libfar::farlib::FarFile;
    /// let fileA = FarFile::new_from_file(fileA_name, buffer.len() as u32, buffer);
    ///
    /// // archive_buf is a Vec<u8> containing the contents of a .far file
    /// // fileB_name is the name of the file that we got from reading the manifest
    /// // fileB_size is the size of the file that we got from reading the manifest
    /// // fileB_offset is the offset of the file that we got from reading the manifest
    /// let fileB = FarFile::new_from_archive(fileB_name, fileB_size, fileB_offset, archive_buf);
    /// ```
    pub struct FarFile {
        pub name: String,
        pub size: u32,
        pub data: Vec<u8>,
    }

    /// Struct containing information about an archive.
    ///
    /// Should be created by one of two ways:
    /// 1. Calling `FarArchive::new_from_files` if creating an archive from a list of FarFile structs
    /// 2. Calling `farlib::test(buffer)` if loading an archive from a file/buffer
    pub struct FarArchive {
        pub version: u32,
        pub file_count: u32,
        pub file_list: Vec<FarFileInfo>,
        pub file_data: Vec<FarFile>,
    }

    impl FarFile {
        /// Creates a new FarFile struct from an offset, size, and archive buffer.
        ///
        /// # Examples
        /// ```
        /// // archive_buf is a Vec<u8> containing the contents of a .far file
        /// // file_name is the name of the file that we got from reading the manifest
        /// // file_size is the size of the file that we got from reading the manifest
        /// // file_offset is the offset of the file that we got from reading the manifest
        /// use libfar::farlib::FarFile;
        /// let file = FarFile::new_from_archive(file_name, file_size, file_offset, archive_buf);
        /// ```
        pub fn new_from_archive(name : String, size : u32, offset : u32, original_file : &Vec<u8>) -> FarFile {
            let mut reader = BufReader::new(&original_file[offset as usize..(offset + size) as usize]);
            let mut data = Vec::new();
            reader.read_to_end(&mut data).expect("Failed to read file data");
            FarFile {
                name,
                size,
                data,
            }
        }

        /// Creates a new FarFile struct from a size, and data buffer.
        ///
        /// # Examples
        /// ```
        /// // buffer is a Vec<u8> containing the contents of a file
        /// // file_name is the name of the file
        /// use libfar::farlib::FarFile;
        /// let file = FarFile::new_from_file(file_name, buffer.len() as u32, buffer);
        /// ```
        pub fn new_from_file(name : String, size : u32, data : Vec<u8>) -> FarFile {
            FarFile {
                name,
                size,
                data,
            }
        }
    }

    impl FarArchive {
        /// Creates a new FarArchive struct from a list of FarFile structs.
        /// Important when creating a new archive.
        ///
        /// # Examples
        /// ```
        /// // file_names is a Vec<String> containing the names of the files
        /// use std::fs;
        /// use libfar::farlib;
        /// let mut file_list = Vec::new();
        /// for file in file_names {
        ///     let file_name = file.split("/").last().unwrap();
        ///     let file_size = fs::metadata(file.clone()).expect("Failed to get file size").len();
        ///     let file_data = fs::read(file.clone()).expect("Failed to read file");
        ///     let file_obj = farlib::FarFile {
        ///     name: file_name.to_string(),
        ///     size: file_size as u32,
        ///     data: file_data
        ///     };
        ///     file_list.push(file_obj);
        /// }
        ///
        /// let archive = farlib::FarArchive::new_from_files(file_list);
        /// ```
        pub fn new_from_files(files : Vec<FarFile>) -> FarArchive {
            let mut file_list = Vec::new();
            let mut file_data = Vec::new();
            let mut offset = 0;
            for file in files {
                offset += &file.size;
                file_list.push(FarFileInfo {
                    name: file.name.clone(),
                    size: file.size,
                    offset,
                });
                file_data.push(file);
            }
            FarArchive {
                version: 1,
                file_count: file_list.len() as u32,
                file_list,
                file_data,
            }
        }

        /// Loads file data into a FarArchive struct, used if a FarFileInfo struct is not sufficient.
        ///
        /// # Examples
        /// ```
        /// // buffer is a Vec<u8> containing the contents of a .far file
        /// use libfar::farlib;
        /// let test = farlib::test(&buffer);
        /// match test {
        ///    Ok(archive) => {
        ///        let archive = archive.load_file_data(&buffer);
        ///   }
        ///   Err(e) => {
        ///     println!("{} is not a valid archive: {}", archive_name, e);
        ///   }
        /// }
        /// ```
        pub fn load_file_data(self, original_file : &Vec<u8>) -> FarArchive {
            let mut new_file_data = Vec::new();
            for i in 0..self.file_list.len() {
                new_file_data.push(FarFile::new_from_archive(
                    self.file_list[i].name.clone(),
                    self.file_list[i].size,
                    self.file_list[i].offset,
                    original_file,
                ));
            }
            FarArchive {
                version: self.version,
                file_count: self.file_count,
                file_list: self.file_list,
                file_data: new_file_data,
            }
        }

        /// Creates a buffer representing the contents of a FarArchive struct.
        /// Can be written to a file to create a .far archive.
        ///
        /// # Examples
        /// ```
        /// // archive is a FarArchive struct
        /// // archive_name is the name of the file we will write the archive to
        /// use std::fs;
        /// use std::io::Write;
        /// use libfar::farlib;
        /// let buffer = archive.to_vec();
        /// let mut file = fs::File::create(archive_name.clone()).expect("Failed to create file");
        /// file.write_all(&*archive_obj.to_vec()).expect("Failed to write file");
        /// ```
        pub fn to_vec(self) -> Vec<u8> {
            // write header
            let mut header = Vec::new();
            for c in "FAR!byAZ".chars() {
                header.push(c as u8);
            }
            header.extend(&self.version.to_le_bytes());
            // wait to write manifest offset until calculated later
            // write file data
            let mut file_data = Vec::new(); // actual data to be written to file
            let mut file_list = Vec::new(); // file list used for making manifest later on
            let mut bytes_written = 16; // where we should start putting files
            for i in 0..self.file_data.len() {
                let mut file_data_bytes = Vec::new();
                file_data_bytes.extend_from_slice(&self.file_data[i].data);
                file_data.extend_from_slice(&file_data_bytes);
                file_list.push(FarFileInfo {
                    name: self.file_data[i].name.clone(),
                    size: self.file_data[i].size,
                    offset: bytes_written,
                });
                bytes_written += self.file_data[i].size;
            }
            // write manifest
            let mut manifest = Vec::new();
            // write file count
            manifest.extend_from_slice(&self.file_count.to_le_bytes());
            // for each file, write (size, size, offset, name length, name)
            for i in 0..self.file_list.len() {
                manifest.extend_from_slice(&file_list[i].size.to_le_bytes());
                manifest.extend_from_slice(&file_list[i].size.to_le_bytes());
                manifest.extend_from_slice(&file_list[i].offset.to_le_bytes());
                manifest.extend_from_slice(&(file_list[i].name.len() as u32).to_le_bytes());
                manifest.extend_from_slice(&file_list[i].name.as_bytes());
            }
            // write manifest offset
            let manifest_offset = bytes_written;
            header.extend_from_slice(&manifest_offset.to_le_bytes());

            // join vecs together
            let mut output = Vec::new();
            output.extend_from_slice(&header);
            output.extend_from_slice(&file_data);
            output.extend_from_slice(&manifest);
            output
        }
    }

    /// Tests if a buffer is a valid FarArchive.
    /// Returns a FarArchive struct if it is, or an error if it is not.
    ///
    /// # Examples
    /// ```
    /// use std::fs;
    /// use libfar::farlib;
    /// let buffer = fs::read("test.far").expect("Failed to read file");
    /// let test = farlib::test(&buffer);
    /// match test {
    ///     Ok(archive) => {
    ///         println!("test.far is a valid archive");
    ///     },
    ///     Err(e) => {
    ///         println!("test.far is not a valid archive: {}", e);
    ///     }
    /// }
    /// ```
    pub fn test(file : &Vec<u8>) -> Result<FarArchive, String> {
        let mut reader = BufReader::new(&file[..]);
        let mut magic = [0u8; 8];
        reader.read_exact(&mut magic).unwrap();
        if magic != *b"FAR!byAZ" {
            return Err("Not a Far archive".to_string());
        }
        let mut version = [0; 4];
        reader.read_exact(&mut version).unwrap();
        let version = u32::from_le_bytes(version);
        // get list of files
        let files = list_files(file).expect("Failed to list files");
        Ok(FarArchive {
            version,
            file_count: files.len() as u32,
            file_list: files,
            file_data: vec![],
        })
    }

    fn list_files(file : &Vec<u8>) -> Result<Vec<FarFileInfo>, String> {
        // manifest offset is at 12 bytes (u32)
        let mut reader = BufReader::new(&file[12..]);
        let mut offset = [0u8; 4];
        reader.read_exact(&mut offset).unwrap();
        let offset = u32::from_le_bytes(offset);
        // move to manifest
        reader = BufReader::new(&file[offset as usize..]);
        // read u32 for number of files
        let mut num_files = [0u8; 4];
        reader.read_exact(&mut num_files).unwrap();
        let num_files = u32::from_le_bytes(num_files);
        // for each file, read u32 for size, u32 for size again (stored twice for some reason), u32 for offset, u32 for name length, name
        let mut files = Vec::new();
        for i in 0..num_files {
            let mut size = [0u8; 4];
            reader.read_exact(&mut size).expect(format!("Failed to read size for file {}", i).as_str());
            let size = u32::from_le_bytes(size);
            let mut size2 = [0u8; 4];
            reader.read_exact(&mut size2).expect(format!("Failed to read size for file {}", i).as_str());
            let _size2 = u32::from_le_bytes(size2); // why is this stored twice? f*** you EA
            let mut offset = [0u8; 4];
            reader.read_exact(&mut offset).expect(format!("Failed to read offset for file {}", i).as_str());
            let offset = u32::from_le_bytes(offset);
            let mut name_len = [0u8; 4];
            reader.read_exact(&mut name_len).expect(format!("Failed to read name length for file {}", i).as_str());
            let name_len = u32::from_le_bytes(name_len);
            let mut name = vec![0u8; name_len as usize];
            reader.read_exact(&mut name).expect(format!("Failed to read name for file {}", i).as_str());
            files.push(FarFileInfo {
                name: String::from_utf8(name).unwrap(),
                size,
                offset,
            });
        }
        Ok(files)
    }