use std::fs;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom};
use xrust::{Error, ErrorKind};

//mod relaxng;
mod xml;
mod xml_id;

use encoding_rs::UTF_16BE;
use encoding_rs::UTF_16LE;
use encoding_rs::UTF_8;
use encoding_rs::WINDOWS_1252;
use encoding_rs_io::DecodeReaderBytesBuilder;

fn dtdfileresolve() -> fn(Option<String>, String) -> Result<String, Error> {
    move |locdir, uri| {
        let u = match locdir {
            None => uri,
            Some(ld) => ld + uri.as_str(),
        };
        match fs::read_to_string(u) {
            Err(_) => Err(Error::new(
                ErrorKind::Unknown,
                "Unable to read external DTD".to_string(),
            )),
            Ok(s) => Ok(s),
        }
    }
}

fn non_utf8_file_reader(filedir: &str) -> String {
    /*
       xRust itself will most likely be UTF-8 only, but there are UTF-16 files in the conformance
       suite. I could change them, but best leave as-is in case we do try to support later.
    */
    let mut file_in = File::open(filedir).unwrap();
    let mut buffer = [0; 4];

    // read exactly 4 bytes
    let _ = file_in.read_exact(&mut buffer);
    let _ = file_in.seek(SeekFrom::Start(0));

    let enc = match buffer {
        //[0, 0, 254, 255] => {} //UCS-4, big-endian machine (1234 order)
        //[255, 254, 0, 0] => {} //UCS-4, little-endian machine (4321 order)
        //[0, 0, 255, 254] => {} //UCS-4, unusual octet order (2143)
        //[254, 255, 0, 0] => {} //UCS-4, unusual octet order (3412)
        [254, 255, _, _] => Some(UTF_16BE), //UTF-16, big-endian
        [255, 254, _, _] => Some(UTF_16LE), //UTF-16, little-endian
        [239, 187, 191, _] => Some(UTF_8),  //UTF-8
        [60, 63, 120, 109] => Some(WINDOWS_1252), //UTF-8
        _ => Some(UTF_8),                   //Other
    };

    let mut decoded_stream = DecodeReaderBytesBuilder::new().encoding(enc).build(file_in);

    let mut dest = String::new();
    let _ = decoded_stream.read_to_string(&mut dest);

    dest
}