/*

 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <AK/ByteBuffer.h>

#include <AK/ByteString.h>

#include <AK/DeprecatedFlyString.h>

#include <AK/Format.h>

#include <AK/Function.h>

#include <AK/StdLibExtras.h>

#include <AK/StringView.h>

#include <AK/Utf8View.h>

#include <AK/Vector.h>

namespace AK {

bool ByteString::operator==(DeprecatedFlyString const& fly_string) const

{

    return m_impl == fly_string.impl() || view() == fly_string.view();

}

bool ByteString::operator==(ByteString const& other) const

{

    return m_impl == other.impl() || view() == other.view();

}

bool ByteString::operator==(StringView other) const

{

    if (other.is_null())

        return is_empty();

    return view() == other;

}

bool ByteString::operator<(ByteString const& other) const

{

    return view() < other.view();

}

bool ByteString::operator>(ByteString const& other) const

{

    return view() > other.view();

}

bool ByteString::copy_characters_to_buffer(char* buffer, size_t buffer_size) const

{

    // We must fit at least the NUL-terminator.

    VERIFY(buffer_size > 0);

    size_t characters_to_copy = min(length(), buffer_size - 1);

    __builtin_memcpy(buffer, characters(), characters_to_copy);

    buffer[characters_to_copy] = 0;

    return characters_to_copy == length();

}

ByteString ByteString::isolated_copy() const

{

    if (m_impl->length() == 0)

        return empty();

    char* buffer;

    auto impl = StringImpl::create_uninitialized(length(), buffer);

    memcpy(buffer, m_impl->characters(), m_impl->length());

    return ByteString(move(*impl));

}

ByteString ByteString::substring(size_t start, size_t length) const

{

    if (!length)

        return ByteString::empty();

    VERIFY(!Checked<size_t>::addition_would_overflow(start, length));

    VERIFY(start + length <= m_impl->length());

    return { characters() + start, length };

}

ByteString ByteString::substring(size_t start) const

{

    VERIFY(start <= length());

    return { characters() + start, length() - start };

}

StringView ByteString::substring_view(size_t start, size_t length) const&

{

    VERIFY(!Checked<size_t>::addition_would_overflow(start, length));

    VERIFY(start + length <= m_impl->length());

    return { characters() + start, length };

}

StringView ByteString::substring_view(size_t start) const&

{

    VERIFY(start <= length());

    return { characters() + start, length() - start };

}

Vector<ByteString> ByteString::split(char separator, SplitBehavior split_behavior) const

{

    return split_limit(separator, 0, split_behavior);

}

Vector<ByteString> ByteString::split_limit(char separator, size_t limit, SplitBehavior split_behavior) const

{

    if (is_empty())

        return {};

    Vector<ByteString> v;

    size_t substart = 0;

    bool keep_empty = has_flag(split_behavior, SplitBehavior::KeepEmpty);

    bool keep_separator = has_flag(split_behavior, SplitBehavior::KeepTrailingSeparator);

    for (size_t i = 0; i < length() && (v.size() + 1) != limit; ++i) {

        char ch = characters()[i];

        if (ch == separator) {

            size_t sublen = i - substart;

            if (sublen != 0 || keep_empty)

                v.append(substring(substart, keep_separator ? sublen + 1 : sublen));

            substart = i + 1;

        }

    }

    size_t taillen = length() - substart;

    if (taillen != 0 || keep_empty)

        v.append(substring(substart, taillen));

    return v;

}

Vector<StringView> ByteString::split_view(Function<bool(char)> separator, SplitBehavior split_behavior) const&

{

    if (is_empty())

        return {};

    Vector<StringView> v;

    size_t substart = 0;

    bool keep_empty = has_flag(split_behavior, SplitBehavior::KeepEmpty);

    bool keep_separator = has_flag(split_behavior, SplitBehavior::KeepTrailingSeparator);

    for (size_t i = 0; i < length(); ++i) {

        char ch = characters()[i];

        if (separator(ch)) {

            size_t sublen = i - substart;

            if (sublen != 0 || keep_empty)

                v.append(substring_view(substart, keep_separator ? sublen + 1 : sublen));

            substart = i + 1;

        }

    }

    size_t taillen = length() - substart;

    if (taillen != 0 || keep_empty)

        v.append(substring_view(substart, taillen));

    return v;

}

Vector<StringView> ByteString::split_view(char const separator, SplitBehavior split_behavior) const&

{

    return split_view([separator](char ch) { return ch == separator; }, split_behavior);

}

ByteBuffer ByteString::to_byte_buffer() const

{

    // FIXME: Handle OOM failure.

    return ByteBuffer::copy(bytes()).release_value_but_fixme_should_propagate_errors();

}

bool ByteString::starts_with(StringView str, CaseSensitivity case_sensitivity) const

{

    return StringUtils::starts_with(*this, str, case_sensitivity);

}

bool ByteString::starts_with(char ch) const

{

    if (is_empty())

        return false;

    return characters()[0] == ch;

}

bool ByteString::ends_with(StringView str, CaseSensitivity case_sensitivity) const

{

    return StringUtils::ends_with(*this, str, case_sensitivity);

}

bool ByteString::ends_with(char ch) const

{

    if (is_empty())

        return false;

    return characters()[length() - 1] == ch;

}

ByteString ByteString::repeated(char ch, size_t count)

{

    if (!count)

        return empty();

    char* buffer;

    auto impl = StringImpl::create_uninitialized(count, buffer);

    memset(buffer, ch, count);

    return *impl;

}

ByteString ByteString::repeated(StringView string, size_t count)

{

    if (!count || string.is_empty())

        return empty();

    char* buffer;

    auto impl = StringImpl::create_uninitialized(count * string.length(), buffer);

    for (size_t i = 0; i < count; i++)

        __builtin_memcpy(buffer + i * string.length(), string.characters_without_null_termination(), string.length());

    return *impl;

}

ByteString ByteString::bijective_base_from(size_t value, unsigned base, StringView map)

{

    value++;

    if (map.is_null())

        map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"sv;

    VERIFY(base >= 2 && base <= map.length());

    // The '8 bits per byte' assumption may need to go?

    Array<char, round_up_to_power_of_two(sizeof(size_t) * 8 + 1, 2)> buffer;

    size_t i = 0;

    do {

        auto remainder = value % base;

        auto new_value = value / base;

        if (remainder == 0) {

            new_value--;

            remainder = map.length();

        }

        buffer[i++] = map[remainder - 1];

        value = new_value;

    } while (value > 0);

    for (size_t j = 0; j < i / 2; ++j)

        swap(buffer[j], buffer[i - j - 1]);

    return ByteString { ReadonlyBytes(buffer.data(), i) };

}

ByteString ByteString::roman_number_from(size_t value)

{

    if (value > 3999)

        return ByteString::number(value);

    StringBuilder builder;

    while (value > 0) {

        if (value >= 1000) {

            builder.append('M');

            value -= 1000;

        } else if (value >= 900) {

            builder.append("CM"sv);

            value -= 900;

        } else if (value >= 500) {

            builder.append('D');

            value -= 500;

        } else if (value >= 400) {

            builder.append("CD"sv);

            value -= 400;

        } else if (value >= 100) {

            builder.append('C');

            value -= 100;

        } else if (value >= 90) {

            builder.append("XC"sv);

            value -= 90;

        } else if (value >= 50) {

            builder.append('L');

            value -= 50;

        } else if (value >= 40) {

            builder.append("XL"sv);

            value -= 40;

        } else if (value >= 10) {

            builder.append('X');

            value -= 10;

        } else if (value == 9) {

            builder.append("IX"sv);

            value -= 9;

        } else if (value >= 5 && value <= 8) {

            builder.append('V');

            value -= 5;

        } else if (value == 4) {

            builder.append("IV"sv);

            value -= 4;

        } else if (value <= 3) {

            builder.append('I');

            value -= 1;

        }

    }

    return builder.to_byte_string();

}

bool ByteString::matches(StringView mask, Vector<MaskSpan>& mask_spans, CaseSensitivity case_sensitivity) const

{

    return StringUtils::matches(*this, mask, case_sensitivity, &mask_spans);

}

bool ByteString::matches(StringView mask, CaseSensitivity case_sensitivity) const

{

    return StringUtils::matches(*this, mask, case_sensitivity);

}

bool ByteString::contains(StringView needle, CaseSensitivity case_sensitivity) const

{

    return StringUtils::contains(*this, needle, case_sensitivity);

}

bool ByteString::contains(char needle, CaseSensitivity case_sensitivity) const

{

    return StringUtils::contains(*this, StringView(&needle, 1), case_sensitivity);

}

bool ByteString::equals_ignoring_ascii_case(StringView other) const

{

    return StringUtils::equals_ignoring_ascii_case(view(), other);

}

ByteString ByteString::reverse() const

{

    StringBuilder reversed_string(length());

    for (size_t i = length(); i-- > 0;) {

        reversed_string.append(characters()[i]);

    }

    return reversed_string.to_byte_string();

}

ByteString escape_html_entities(StringView html)

{

    StringBuilder builder;

    for (size_t i = 0; i < html.length(); ++i) {

        if (html[i] == '<')

            builder.append("<"sv);

        else if (html[i] == '>')

            builder.append(">"sv);

        else if (html[i] == '&')

            builder.append("&"sv);

        else if (html[i] == '"')

            builder.append("""sv);

        else

            builder.append(html[i]);

    }

    return builder.to_byte_string();

}

ByteString::ByteString(DeprecatedFlyString const& string)

    : m_impl(string.impl())

{

}

ByteString ByteString::to_lowercase() const

{

    return m_impl->to_lowercase();

}

ByteString ByteString::to_uppercase() const

{

    return m_impl->to_uppercase();

}

ByteString ByteString::to_snakecase() const

{

    return StringUtils::to_snakecase(*this);

}

ByteString ByteString::to_titlecase() const

{

    return StringUtils::to_titlecase(*this);

}

ByteString ByteString::invert_case() const

{

    return StringUtils::invert_case(*this);

}

bool ByteString::operator==(char const* cstring) const

{

    if (!cstring)

        return is_empty();

    return view() == cstring;

}

ByteString ByteString::vformatted(StringView fmtstr, TypeErasedFormatParams& params)

{

    StringBuilder builder;

    MUST(vformat(builder, fmtstr, params));

    return builder.to_byte_string();

}

Vector<size_t> ByteString::find_all(StringView needle) const

{

    return StringUtils::find_all(*this, needle);

}

DeprecatedStringCodePointIterator ByteString::code_points() const

{

    return DeprecatedStringCodePointIterator(*this);

}

ErrorOr<ByteString> ByteString::from_utf8(ReadonlyBytes bytes)

{

    if (!Utf8View(bytes).validate())

        return Error::from_string_literal("ByteString::from_utf8: Input was not valid UTF-8");

    return ByteString { *StringImpl::create(bytes) };

}

}