// This is a part of encoding-next.
// Copyright (c) 2014-2015, Kang Seonghoon.
// See README.md and LICENSE.txt for details.

use encoding::label::encoding_from_whatwg_label;
use encoding::{DecoderTrap, EncoderTrap};
use getopts::Options;
use std::fs::File;
use std::io::{Read, Write};
use std::path::Path;
use std::{env, io};

fn main() {
    let args: Vec<_> = env::args().collect();

    let mut opts = Options::new();
    opts.optopt("f", "from-code", "set input encoding", "NAME");
    opts.optopt("t", "to-code", "set output encoding", "NAME");
    opts.optopt(
        "e",
        "error-policy",
        "set error policy (one of strict, ignore, replace, ncr-escape)",
        "POLICY",
    );
    opts.optflag("c", "", "same as `--error-policy=ignore`");
    opts.optopt("o", "output", "output file", "FILE");
    opts.optflag("h", "help", "print this help menu");

    let matches = match opts.parse(&args[1..]) {
        Ok(m) => m,
        Err(e) => panic!("{}", e.to_string()),
    };
    if matches.opt_present("h") {
        println!(
            "{}",
            opts.usage("Converts the character encoding using encoding-next.")
        );
        return;
    }

    let inencname = matches.opt_str("f");
    let outencname = matches.opt_str("t");
    let inenc = match inencname.as_ref().map(|s| &s[..]) {
        Some(name) => match encoding_from_whatwg_label(name) {
            Some(enc) => enc,
            None => panic!("invalid input encoding name {}", name),
        },
        None => encoding::all::UTF_8 as encoding::EncodingRef,
    };
    let outenc = match outencname.as_ref().map(|s| &s[..]) {
        Some(name) => match encoding_from_whatwg_label(name) {
            Some(enc) => enc,
            None => panic!("invalid output encoding name {}", name),
        },
        None => encoding::all::UTF_8 as encoding::EncodingRef,
    };

    let mut policy = matches.opt_str("e");
    if matches.opt_present("c") {
        policy = Some("ignore".to_string());
    }
    let (intrap, outtrap) = match policy.as_ref().map(|s| &s[..]) {
        Some("strict") | None => (DecoderTrap::Strict, EncoderTrap::Strict),
        Some("ignore") => (DecoderTrap::Ignore, EncoderTrap::Ignore),
        Some("replace") => (DecoderTrap::Replace, EncoderTrap::Replace),
        Some("ncr-escape") => (DecoderTrap::Replace, EncoderTrap::NcrEscape),
        Some(s) => panic!("invalid error policy {}", s),
    };

    let mut input = match matches.free.first().map(|s| &s[..]) {
        Some("-") | None => Box::new(io::stdin()) as Box<dyn Read>,
        Some(f) => match File::open(&Path::new(f)) {
            Ok(f) => Box::new(f) as Box<dyn Read>,
            Err(e) => panic!("cannot open the input {}: {}", f, e),
        },
    };
    let mut output = match matches.opt_str("o").as_ref().map(|s| &s[..]) {
        Some("-") | None => Box::new(io::stdout()) as Box<dyn Write>,
        Some(f) => match File::create(&Path::new(f)) {
            Ok(f) => Box::new(f) as Box<dyn Write>,
            Err(e) => panic!("cannot open the output {}: {}", f, e),
        },
    };

    // XXX should really use the incremental interface
    let mut ret = Vec::new();
    input
        .read_to_end(&mut ret)
        .expect("cannot read from the input");
    let decoded = match inenc.decode(&ret, intrap) {
        Ok(s) => s,
        Err(e) => panic!("decoder error: {}", e),
    };
    let encoded = match outenc.encode(&decoded, outtrap) {
        Ok(s) => s,
        Err(e) => panic!("encoder error: {}", e),
    };
    output.write_all(&encoded).unwrap();
}