/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *   SPDX-License-Identifier: Apache-2.0
 */

package org.apache.jena.atlas.lib;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;

import java.io.StringWriter;

import org.junit.jupiter.api.Test;

import org.apache.jena.atlas.AtlasException;
import org.apache.jena.atlas.io.AWriter;
import org.apache.jena.atlas.io.IO;

// Testing is a bit light here but the RDF term output and
// the language level output covers the ground as well.

public class TestEscapeStr {

    private static char S_QUOTE = '\'';
    private static char D_QUOTE = '"';

    // General, for double quoted strings.
    @Test public void escape_str_01()   { test_esc("", ""); }
    @Test public void escape_str_02()   { test_esc("A", "A"); }
    @Test public void escape_str_03()   { test_esc("\n", "\\n"); }
    @Test public void escape_str_04()   { test_esc("A\tB", "A\\tB"); }
    @Test public void escape_str_05()   { test_esc("\"", "\\\""); }
    @Test public void escape_str_06()   { test_esc("'", "'"); }

    private static void test_esc(String input, String expected) {
        String output = EscapeStr.stringEsc(input);
        assertEquals(expected, output, ()->"Failed at escape");
        String output2 = EscapeStr.unescapeStr(output);
        assertEquals(input, output2, ()->"Failed at unescape");
    }

    // Single line
    @Test public void escape_str_single_01()   { test_esc1("a'x",  S_QUOTE,  "a\\'x"); }
    @Test public void escape_str_single_02()   { test_esc1("a\"x", D_QUOTE,  "a\\\"x"); }

    @Test public void escape_str_single_03()   { test_esc1("a\"x", S_QUOTE,  "a\"x"); }
    @Test public void escape_str_single_04()   { test_esc1("a'x",  D_QUOTE,  "a'x"); }

    @Test public void escape_str_single_05()   { test_esc1("a'",   S_QUOTE,  "a\\'"); }
    @Test public void escape_str_single_06()   { test_esc1("a\"",  D_QUOTE,  "a\\\""); }

    @Test public void escape_str_single_07()   { test_esc1("\"",  S_QUOTE,  "\""); }
    @Test public void escape_str_single_08()   { test_esc1("'",   D_QUOTE,  "'"); }

    private static void test_esc1(String input, char quoteChar, String expected) {
        StringWriter sw = new StringWriter();
        AWriter w = IO.wrap(sw);
        EscapeStr.stringEsc(w, input, quoteChar, true);
        w.flush();
        String output = sw.toString();
        assertEquals(expected, output);
    }

    // Multiline quoting.
    // One character
    @Test public void escape_str_multi_01()    { test_esc3("a'x",  S_QUOTE,  "a'x"); }
    @Test public void escape_str_multi_02()    { test_esc3("a\"x", D_QUOTE,  "a\"x"); }

    @Test public void escape_str_multi_03()    { test_esc3("'x", S_QUOTE, "'x"); }
    @Test public void escape_str_multi_04()    { test_esc3("'x", D_QUOTE, "'x"); }

    // Last character
    @Test public void escape_str_multi_05()    { test_esc3("a'", S_QUOTE, "a\\'"); }
    @Test public void escape_str_multi_06()    { test_esc3("a'", D_QUOTE, "a'"); }

    @Test public void escape_str_multi_07()    { test_esc3("a\"", S_QUOTE, "a\""); }
    @Test public void escape_str_multi_08()    { test_esc3("a\"", D_QUOTE, "a\\\""); }

    @Test public void escape_str_multi_09()    { test_esc3("'", S_QUOTE, "\\'"); }
    @Test public void escape_str_multi_10()    { test_esc3("'", D_QUOTE, "'"); }

    @Test public void escape_str_multi_11()    { test_esc3("\"", S_QUOTE, "\""); }
    @Test public void escape_str_multi_12()    { test_esc3("\"", D_QUOTE, "\\\""); }

    // 2 in a row
    @Test public void escape_str_multi_2q_1()  { test_esc3("a''z", S_QUOTE, "a''z"); }
    @Test public void escape_str_multi_2q_2()  { test_esc3("a''z", D_QUOTE, "a''z"); }
    @Test public void escape_str_multi_2q_3()  { test_esc3("a''",  S_QUOTE, "a'\\'"); }
    @Test public void escape_str_multi_2q_4()  { test_esc3("a''",  D_QUOTE, "a''"); }

    // 3 in a row.
    @Test public void escape_str_multi_3q_1()  { test_esc3("a'''z", S_QUOTE, "a''\\'z"); }
    @Test public void escape_str_multi_3q_2()  { test_esc3("a'''z", D_QUOTE, "a'''z"); }
    @Test public void escape_str_multi_3q_3()  { test_esc3("a'''",  S_QUOTE, "a''\\'"); }
    @Test public void escape_str_multi_3q_4()  { test_esc3("a'''",  D_QUOTE, "a'''"); }

    // 4 in a row.
    @Test public void escape_str_multi_4q_1()    { test_esc3("a''''z", S_QUOTE, "a''\\''z"); }
    @Test public void escape_str_multi_4q_2()    { test_esc3("a''''z", D_QUOTE, "a''''z"); }

    @Test public void escape_str_multi_4q_3()    { test_esc3("a''''", S_QUOTE, "a''\\'\\'"); }
    @Test public void escape_str_multi_4q_4()    { test_esc3("a''''", D_QUOTE, "a''''"); }

    // Unicode replacement char U+FFFD - write in Unicode escape form.
    @Test public void escape_str_repacementChar_1()    { test_esc1("abc\uFFFDdef", S_QUOTE, "abc\\uFFFDdef"); }
    @Test public void escape_str_repacementChar_2()    { test_esc3("abc\uFFFDdef", D_QUOTE, "abc\\uFFFDdef"); }

    private static void test_esc3(String input, char quoteChar, String expected) {
        StringWriter sw = new StringWriter();
        AWriter w = IO.wrap(sw);
        EscapeStr.stringEsc(w, input, quoteChar, false);
        w.flush();
        String output = sw.toString();
        assertEquals(expected, output);
    }

    // Unescape
    @Test public void unescape_str_10()   { test_unesc("\\u0041", "A"); }
    @Test public void unescape_str_11()   { test_unesc("\\U00000041", "A"); }
    @Test public void unescape_str_12()   { test_unesc("12\\u004134", "12A34"); }
    @Test public void unescape_str_13()   { test_unesc("12\\U0000004134", "12A34"); }

    private void test_unesc(String input, String expected) {
        String output = EscapeStr.unescapeStr(input);
        assertEquals(expected, output);
    }

    private void test_escape_string(String input, String expected) {
        String output = EscapeStr.stringEsc(input);
        assertEquals(expected, output);
    }

    @Test public void unescape_unicode_1()   { test_unesc_unicode("", ""); }
    @Test public void unescape_unicode_2()   { test_unesc_unicode("abc\\u0020def", "abc def"); }
    @Test public void unescape_unicode_3()   { test_unesc_unicode("\\u0020", " "); }
    @Test public void unescape_unicode_4()   { test_unesc_unicode("abc\\U00000020def", "abc def"); }
    @Test public void unescape_unicode_5()   { test_unesc_unicode("\\U00000020", " "); }

    // Leaves non-unicode untouched.
    @Test public void unescape_unicode_10()   { test_unesc_unicode("\\1\\2", "\\1\\2"); }
    @Test public void unescape_unicode_11()   { test_unesc_unicode("\\n\\t", "\\n\\t"); }
    @Test public void unescape_unicode_12()   { test_unesc_unicode("\\(\\)", "\\(\\)"); }
    @Test public void unescape_unicode_13()   { test_unesc_unicode("\\\\", "\\\\"); }

    // \-u{...} style Unicode escapes
    @Test public void unescape_unicode_20()   { test_unesc_unicode("\\u{41}", "A"); }
    @Test public void unescape_unicode_21()   { test_unesc_unicode("\\u{000000}", "\u0000"); }
    @Test public void unescape_unicode_22()   { test_unesc_unicode("\\u{1F0A1}", "🂡"); }
    @Test public void unescape_unicode_23()   { test_unesc_unicode("\\u{01F0A1}", "🂡"); }
    @Test public void unescape_unicode_24()   { test_unesc_unicode("\\u{10FFFF}", 0x10FFFF); }

    @Test public void unescape_unicode_30()   { test_unesc_unicode_bad("\\u{}"); }
    @Test public void unescape_unicode_31()   { test_unesc_unicode_bad("\\u{123456789}"); }
    @Test public void unescape_unicode_32()   { test_unesc_unicode_bad("\\u{000000000}"); }
    // If the limit is 6
    @Test public void unescape_unicode_33()   { test_unesc_unicode_bad("\\u{1234567}"); }
    @Test public void unescape_unicode_34()   { test_unesc_unicode_bad("\\u{0000000}"); }

    // Surrogates via \-u, \-U and \-u{}
    @Test public void unescape_unicode_40()   { test_unesc_unicode_bad("\\uD83C\\uDCA1"); }
    @Test public void unescape_unicode_41()   { test_unesc_unicode_bad("\\U0000D83C\\U0000DCA1"); }
    @Test public void unescape_unicode_42()   { test_unesc_unicode_bad("\\u{00D83C}\\u{00DCA1}"); }

    // Not valid surrogate pairs.
    @Test public void unescape_unicode_50()   { test_unesc_unicode_bad("\\uD83Cxyz"); }
    @Test public void unescape_unicode_51()   { test_unesc_unicode_bad("\\U0000D83Cxyz"); }
    @Test public void unescape_unicode_52()   { test_unesc_unicode_bad("\\u{00D83C}xyz"); }

    @Test public void unescape_unicode_60()   { test_unesc_unicode_bad("abc\\uDCA1xyz"); }
    @Test public void unescape_unicode_61()   { test_unesc_unicode_bad("abc\\U0000DCA1xyz"); }
    @Test public void unescape_unicode_62()   { test_unesc_unicode_bad("abc\\u{00DCA1}xyz"); }

    // Escaped surrogates, good and bad.
    // Use java character escapes to put the surrogates into the java string.
    // 🂡 is U+D83C U+DCA1
    @Test public void escape_unicode_70()   { test_escape_string("\uD83C\uDCA1", "🂡"); }
    @Test public void escape_unicode_71()   { test_escape_string("abc\uD83C\uDCA1xyz", "abc🂡xyz"); }
    // low, then high -> illegal
    @Test public void escape_unicode_75()   { test_escape_string("\uDCA1\uD83C", "\\uFFFD\\uFFFD"); }
    @Test public void escape_unicode_76()   { test_escape_string("\uDCA1\uD83C@", "\\uFFFD\\uFFFD@"); }
    // Lone surrogate
    @Test public void escape_unicode_80()   { test_escape_string("\uD83C", "\\uFFFD"); }
    @Test public void escape_unicode_81()   { test_escape_string("abc\uD83Cxyz", "abc\\uFFFDxyz"); }
    @Test public void escape_unicode_82()   { test_escape_string("\uDCA1", "\\uFFFD"); }
    @Test public void escape_unicode_83()   { test_escape_string("abc\uDCA1xyz", "abc\\uFFFDxyz"); }
    // Illegal then legal
    @Test public void escape_unicode_84()   { test_escape_string("\uDCA1\uD83C\uDCA1", "\\uFFFD🂡"); }


    // low, then high/low -> one illegal, encode legal pair.

    private void test_unesc_unicode(String input, String expected) {
        String output = EscapeStr.unescapeUnicode(input);
        assertEquals(expected, output);
    }

    private void test_unesc_unicode(String input, int expected) {
        String output = EscapeStr.unescapeUnicode(input);
        int codepoint = output.codePointAt(0);
        assertEquals(expected, codepoint);
    }

    private void test_unesc_unicode_bad(String input) {
        assertThrows(AtlasException.class, ()->EscapeStr.unescapeUnicode(input));
    }
}
