// Copyright 2015-2016 Mozilla Foundation. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use handles::*;
use variant::*;
use super::*;

pub struct UserDefinedDecoder;

impl UserDefinedDecoder {
    pub fn new() -> VariantDecoder {
        VariantDecoder::UserDefined(UserDefinedDecoder)
    }

    pub fn max_utf16_buffer_length(&self, byte_length: usize) -> Option<usize> {
        Some(byte_length)
    }

    pub fn max_utf8_buffer_length_without_replacement(&self, byte_length: usize) -> Option<usize> {
        byte_length.checked_mul(3)
    }

    pub fn max_utf8_buffer_length(&self, byte_length: usize) -> Option<usize> {
        byte_length.checked_mul(3)
    }

    decoder_functions!(
        {},
        {},
        {},
        {
            if b < 0x80 {
                // XXX optimize ASCII
                destination_handle.write_ascii(b);
                continue;
            }
            destination_handle.write_upper_bmp((b as usize + 0xF700usize) as u16);
            continue;
        },
        self,
        src_consumed,
        dest,
        source,
        b,
        destination_handle,
        _unread_handle,
        check_space_bmp
    );
}

pub struct UserDefinedEncoder;

impl UserDefinedEncoder {
    pub fn new(encoding: &'static Encoding) -> Encoder {
        Encoder::new(encoding, VariantEncoder::UserDefined(UserDefinedEncoder))
    }

    pub fn max_buffer_length_from_utf16_without_replacement(&self,
                                                            u16_length: usize)
                                                            -> Option<usize> {
        Some(u16_length)
    }

    pub fn max_buffer_length_from_utf8_without_replacement(&self,
                                                           byte_length: usize)
                                                           -> Option<usize> {
        Some(byte_length)
    }

    encoder_functions!(
        {},
        {
            if c <= '\u{7F}' {
                // TODO optimize ASCII run
                destination_handle.write_one(c as u8);
                continue;
            }
            if c < '\u{F780}' || c > '\u{F7FF}' {
                return (EncoderResult::Unmappable(c),
                        unread_handle.consumed(),
                        destination_handle.written());
            }
            destination_handle.write_one((c as usize - 0xF700usize) as u8);
            continue;
        },
        self,
        src_consumed,
        source,
        dest,
        c,
        destination_handle,
        unread_handle,
        check_space_one
    );
}

// Any copyright to the test code below this comment is dedicated to the
// Public Domain. http://creativecommons.org/publicdomain/zero/1.0/

#[cfg(test)]
mod tests {
    use super::super::testing::*;
    use super::super::*;

    fn decode_x_user_defined(bytes: &[u8], expect: &str) {
        decode(X_USER_DEFINED, bytes, expect);
    }

    fn encode_x_user_defined(string: &str, expect: &[u8]) {
        encode(X_USER_DEFINED, string, expect);
    }

    #[test]
    fn test_x_user_defined_decode() {
        // Empty
        decode_x_user_defined(b"", "");

        // ASCII
        decode_x_user_defined(b"\x61\x62", "\u{0061}\u{0062}");

        decode_x_user_defined(b"\x80\xFF", "\u{F780}\u{F7FF}");
    }

    #[test]
    fn test_x_user_defined_encode() {
        // Empty
        encode_x_user_defined("", b"");

        // ASCII
        encode_x_user_defined("\u{0061}\u{0062}", b"\x61\x62");

        encode_x_user_defined("\u{F780}\u{F7FF}", b"\x80\xFF");
        encode_x_user_defined("\u{F77F}\u{F800}", b"&#63359;&#63488;");
    }

}
