use std::error::Error;
use std::fmt::Display;
use std::io::Read;
use pkgfile::PKGFile;
use reqwest::blocking::get;
use crate::package::identifier::PackageLocator;

#[derive(Debug)]
pub enum FetchError {
    HTTPError(reqwest::Error),
    IOError(std::io::Error),
    ParseError,
}

impl Display for FetchError {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        match self {
            FetchError::HTTPError(e) => write!(f, "HTTP Error: {}", e),
            FetchError::IOError(e) => write!(f, "IO Error: {}", e),
            FetchError::ParseError => write!(f, "Parse Error"),
        }
    }
}

impl Error for FetchError {}

pub fn fetch_by_path<S: Into<String>>(path: S) -> Result<PKGFile, FetchError> {
    std::fs::read(path.into())
        .map_err(|e| FetchError::IOError(e)).and_then(|bytes| {
        PKGFile::try_from(bytes).map_err(|_| FetchError::ParseError)
    })
}

pub fn fetch_by_uri<S: Into<String>>(uri: S) -> Result<PKGFile, FetchError> {
    // get file contents as bytes
    let mut bytes = Vec::new();
    match get(uri.into()) {
        Ok(mut response) => {
            match response.take(1024 * 1024).read_to_end(&mut bytes) {
                Ok(_) => (),
                Err(e) => return Err(FetchError::IOError(e)),
            };
        }
        Err(e) => return Err(FetchError::HTTPError(e)),
    };
    // parse bytes as PKGFile
    match PKGFile::try_from(bytes) {
        Ok(pkgfile) => Ok(pkgfile),
        Err(e) => Err(FetchError::ParseError),
    }
}

pub fn fetch_by_package_locator(package_locator: PackageLocator) -> Result<PKGFile, FetchError> {
    // TODO: search index for package locator
    Ok(PKGFile::default())
}