/*
 * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc.
 * All rights reserved.
 * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
 * (http://www.torchmobile.com/)
 * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
 * Copyright (C) 2012 Intel Corporation. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "third_party/blink/renderer/core/css/css_markup.h"

#include "third_party/blink/renderer/core/css/css_url_data.h"
#include "third_party/blink/renderer/core/css/parser/css_parser_idioms.h"
#include "third_party/blink/renderer/core/css/properties/css_parsing_utils.h"
#include "third_party/blink/renderer/platform/font_family_names.h"
#include "third_party/blink/renderer/platform/fonts/font_family.h"
#include "third_party/blink/renderer/platform/wtf/text/character_visitor.h"
#include "third_party/blink/renderer/platform/wtf/text/format.h"
#include "third_party/blink/renderer/platform/wtf/text/strcat.h"
#include "third_party/blink/renderer/platform/wtf/text/string_buffer.h"
#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"

namespace blink {

// "ident" from the CSS tokenizer, minus backslash-escape sequences
bool IsCSSTokenizerIdentifier(const StringView& string) {
  unsigned length = string.length();

  if (!length) {
    return false;
  }

  return VisitCharacters(string, [](auto chars) {
    size_t index{0};

    // -?
    if (chars[index] == '-') {
      ++index;
    }

    // {nmstart}
    if (index == chars.size() || !IsNameStartCodePoint(chars[index])) {
      return false;
    }
    ++index;

    // {nmchar}*
    for (; index < chars.size(); ++index) {
      if (!IsNameCodePoint(chars[index])) {
        return false;
      }
    }
    return true;
  });
}

// Validates whether a string is a sequence of one or more space-separated CSS
// ident tokens (without backslash-escape sequences). This is used to determine
// whether a <family-name> can be serialized as unquoted space-separated idents
// per the CSSWG resolution. See
// https://github.com/w3c/csswg-drafts/issues/5846.
//
// Grammar: ident ( ' ' ident )*
// Each ident: -? {nmstart} {nmchar}*
bool IsCSSTokenizerIdentSequence(const StringView& string) {
  unsigned length = string.length();
  if (!length) {
    return false;
  }

  return VisitCharacters(string, [](auto chars) {
    size_t index = 0;

    // Reject leading space.
    if (chars[0] == ' ') {
      return false;
    }

    while (index < chars.size()) {
      // Parse one ident: -? {nmstart} {nmchar}*

      // Optional leading hyphen.
      if (chars[index] == '-') {
        ++index;
      }

      // {nmstart} is required.
      if (index >= chars.size() || !IsNameStartCodePoint(chars[index])) {
        return false;
      }
      ++index;

      // {nmchar}*
      while (index < chars.size() && IsNameCodePoint(chars[index])) {
        ++index;
      }

      // After an ident, we expect either end-of-string or a single space
      // followed by another ident.
      if (index < chars.size()) {
        if (chars[index] != ' ') {
          return false;  // Non-space, non-ident character.
        }
        ++index;
        // Reject trailing space or consecutive spaces (next char must start
        // a new ident, not be a space or end-of-string).
        if (index >= chars.size() || chars[index] == ' ') {
          return false;
        }
      }
    }

    return true;
  });
}

static void SerializeCharacter(UChar32 c, StringBuilder& append_to) {
  append_to.Append('\\');
  append_to.Append(c);
}

static void SerializeCharacterAsCodePoint(UChar32 c, StringBuilder& append_to) {
  FormatTo(append_to, "\\{:x} ", c);
}

void SerializeIdentifier(const String& identifier,
                         StringBuilder& append_to,
                         bool skip_start_checks) {
  bool is_first = !skip_start_checks;
  bool is_second = false;
  bool is_first_char_hyphen = false;
  unsigned index = 0;
  while (index < identifier.length()) {
    UChar32 c = identifier.CodePointAtOrZero(index);
    if (c == 0) {
      // Check for lone surrogate which CodePointAtOrZero() does not return.
      c = identifier[index];
    }

    index += U16_LENGTH(c);

    if (c == 0) {
      append_to.Append(0xfffd);
    } else if (c <= 0x1f || c == 0x7f ||
               (0x30 <= c && c <= 0x39 &&
                (is_first || (is_second && is_first_char_hyphen)))) {
      SerializeCharacterAsCodePoint(c, append_to);
    } else if (c == 0x2d && is_first && index == identifier.length()) {
      SerializeCharacter(c, append_to);
    } else if (0x80 <= c || c == 0x2d || c == 0x5f ||
               (0x30 <= c && c <= 0x39) || (0x41 <= c && c <= 0x5a) ||
               (0x61 <= c && c <= 0x7a)) {
      append_to.Append(c);
    } else {
      SerializeCharacter(c, append_to);
    }

    if (is_first) {
      is_first = false;
      is_second = true;
      is_first_char_hyphen = (c == 0x2d);
    } else if (is_second) {
      is_second = false;
    }
  }
}

void SerializeString(const String& string, StringBuilder& append_to) {
  append_to.Append('\"');

  unsigned index = 0;
  while (index < string.length()) {
    UChar32 c = string.CodePointAtOrZero(index);
    index += U16_LENGTH(c);

    if (c <= 0x1f || c == 0x7f) {
      SerializeCharacterAsCodePoint(c, append_to);
    } else if (c == 0x22 || c == 0x5c) {
      SerializeCharacter(c, append_to);
    } else {
      append_to.Append(c);
    }
  }

  append_to.Append('\"');
}

String SerializeString(const String& string) {
  StringBuilder builder;
  SerializeString(string, builder);
  return builder.ReleaseString();
}

String SerializeURI(const String& url,
                    const CSSUrlRequestModifiers& modifiers) {
  StringBuilder builder;
  builder.Append("url(");
  SerializeString(url, builder);
  if (!modifiers.IsEmpty()) {
    modifiers.AppendCssText(builder);
  }
  builder.Append(')');
  return builder.ReleaseString();
}

String SerializeFontFamily(const AtomicString& string) {
  // Some <font-family> values are serialized without quotes.
  // See https://github.com/w3c/csswg-drafts/issues/5846
  return css_parsing_utils::FontFamilyNeedsQuoting(string)
             ? SerializeString(string)
             : string;
}

}  // namespace blink