// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import "package:expect/expect.dart";
import 'dart:convert';

String decode(List<int> inputBytes) {
  List<int> bytes;
  ChunkedConversionSink byteSink =
      new ByteConversionSink.withCallback((result) => bytes = result);
  var stringConversionSink = new Utf8Encoder().startChunkedConversion(byteSink);
  ByteConversionSink inputByteSink = stringConversionSink.asUtf8Sink(false);
  inputByteSink.add(inputBytes);
  inputByteSink.close();
  return UTF8.decode(bytes);
}

String decode2(List<int> inputBytes) {
  List<int> bytes;
  ChunkedConversionSink byteSink =
      new ByteConversionSink.withCallback((result) => bytes = result);
  var stringConversionSink = new Utf8Encoder().startChunkedConversion(byteSink);
  ByteConversionSink inputByteSink = stringConversionSink.asUtf8Sink(false);
  inputBytes.forEach((b) => inputByteSink.addSlice([0, b, 1], 1, 2, false));
  inputByteSink.close();
  return UTF8.decode(bytes);
}

String decodeAllowMalformed(List<int> inputBytes) {
  List<int> bytes;
  ChunkedConversionSink byteSink =
      new ByteConversionSink.withCallback((result) => bytes = result);
  var stringConversionSink = new Utf8Encoder().startChunkedConversion(byteSink);
  ByteConversionSink inputByteSink = stringConversionSink.asUtf8Sink(true);
  inputByteSink.add(inputBytes);
  inputByteSink.close();
  return UTF8.decode(bytes);
}

String decodeAllowMalformed2(List<int> inputBytes) {
  List<int> bytes;
  ChunkedConversionSink byteSink =
      new ByteConversionSink.withCallback((result) => bytes = result);
  var stringConversionSink = new Utf8Encoder().startChunkedConversion(byteSink);
  ByteConversionSink inputByteSink = stringConversionSink.asUtf8Sink(true);
  inputBytes.forEach((b) => inputByteSink.addSlice([0, b, 1], 1, 2, false));
  inputByteSink.close();
  return UTF8.decode(bytes);
}


final TESTS = [
  // Unfinished UTF-8 sequences.
  [ 0xc3 ],
  [ 0xE2, 0x82 ],
  [ 0xF0, 0xA4, 0xAD ],
  // Overlong encoding of euro-sign.
  [ 0xF0, 0x82, 0x82, 0xAC ],
  // Other overlong/unfinished sequences.
  [ 0xC0 ],
  [ 0xC1 ],
  [ 0xF5 ],
  [ 0xF6 ],
  [ 0xF7 ],
  [ 0xF8 ],
  [ 0xF9 ],
  [ 0xFA ],
  [ 0xFB ],
  [ 0xFC ],
  [ 0xFD ],
  [ 0xFE ],
  [ 0xFF ],
  [ 0xC0, 0x80 ],
  [ 0xC1, 0x80 ],
  // Outside valid range.
  [ 0xF4, 0xBF, 0xBF, 0xBF ]];

final TESTS2 = [
  // Test that 0xC0|1, 0x80 does not eat the next character.
  [[ 0xC0, 0x80, 0x61 ], "Xa" ],
  [[ 0xC1, 0x80, 0x61 ], "Xa" ],
  // 0xF5 .. 0xFF never appear in valid UTF-8 sequences.
  [[ 0xF5, 0x80 ], "XX" ],
  [[ 0xF6, 0x80 ], "XX" ],
  [[ 0xF7, 0x80 ], "XX" ],
  [[ 0xF8, 0x80 ], "XX" ],
  [[ 0xF9, 0x80 ], "XX" ],
  [[ 0xFA, 0x80 ], "XX" ],
  [[ 0xFB, 0x80 ], "XX" ],
  [[ 0xFC, 0x80 ], "XX" ],
  [[ 0xFD, 0x80 ], "XX" ],
  [[ 0xFE, 0x80 ], "XX" ],
  [[ 0xFF, 0x80 ], "XX" ],
  [[ 0xF5, 0x80, 0x61 ], "XXa" ],
  [[ 0xF6, 0x80, 0x61 ], "XXa" ],
  [[ 0xF7, 0x80, 0x61 ], "XXa" ],
  [[ 0xF8, 0x80, 0x61 ], "XXa" ],
  [[ 0xF9, 0x80, 0x61 ], "XXa" ],
  [[ 0xFA, 0x80, 0x61 ], "XXa" ],
  [[ 0xFB, 0x80, 0x61 ], "XXa" ],
  [[ 0xFC, 0x80, 0x61 ], "XXa" ],
  [[ 0xFD, 0x80, 0x61 ], "XXa" ],
  [[ 0xFE, 0x80, 0x61 ], "XXa" ],
  [[ 0xFF, 0x80, 0x61 ], "XXa" ],
  // Characters outside the valid range.
  [[ 0xF5, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xF6, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xF7, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xF8, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xF9, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFA, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFB, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFC, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFD, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFE, 0x80, 0x80, 0x61 ], "XXXa" ],
  [[ 0xFF, 0x80, 0x80, 0x61 ], "XXXa" ]];

main() {
  var allTests = TESTS.expand((test) {
    // Pairs of test and expected string output when malformed strings are
    // allowed. Replacement character: U+FFFD
    return [[ test, "\u{FFFD}" ],
            [ new List.from([0x61])..addAll(test), "a\u{FFFD}" ],
            [ new List.from([0x61])..addAll(test)..add(0x61), "a\u{FFFD}a" ],
            [ new List.from(test)..add(0x61), "\u{FFFD}a" ],
            [ new List.from(test)..addAll(test), "\u{FFFD}\u{FFFD}" ],
            [ new List.from(test)..add(0x61)..addAll(test),
              "\u{FFFD}a\u{FFFD}" ],
            [ new List.from([0xc3, 0xa5])..addAll(test), "å\u{FFFD}" ],
            [ new List.from([0xc3, 0xa5])..addAll(test)..addAll([0xc3, 0xa5]),
              "å\u{FFFD}å" ],
            [ new List.from(test)..addAll([0xc3, 0xa5]), "\u{FFFD}å" ],
            [ new List.from(test)..addAll([0xc3, 0xa5])..addAll(test),
              "\u{FFFD}å\u{FFFD}" ]];
  });

  var allTests2 = TESTS2.map((test) {
    // Pairs of test and expected string output when malformed strings are
    // allowed. Replacement character: U+FFFD
    String expected = test[1].replaceAll("X", "\u{FFFD}");
    return [test[0], expected];
  });

  for (var test in []..addAll(allTests)..addAll(allTests2)) {
    List<int> bytes = test[0];
    Expect.throws(() => decode(bytes), (e) => e is FormatException);
    Expect.throws(() => decode2(bytes), (e) => e is FormatException);

    String expected = test[1];
    Expect.equals(expected, decodeAllowMalformed(bytes));
    Expect.equals(expected, decodeAllowMalformed2(bytes));
  }
}