// Copyright 2023 PingCAP, Inc.
//
// Licensed 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
//
//     http://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.

#pragma once

#include <Core/Types.h>

#include <cmath>
#include <cstring>
#include <string>

#define UNICODE_BAR_CHAR_SIZE (strlen("█"))


/** Allows you to draw a unicode-art bar whose width is displayed with a resolution of 1/8 character.
  */


namespace UnicodeBar
{
using DB::Int64;

inline double getWidth(Int64 x, Int64 min, Int64 max, double max_width)
{
    if (x <= min)
        return 0;

    if (x >= max)
        return max_width;

    return (x - min) * max_width / (max - min);
}

inline size_t getWidthInBytes(double width)
{
    return ceil(width - 1.0 / 8) * UNICODE_BAR_CHAR_SIZE;
}

/// In `dst` there must be a space for barWidthInBytes(width) characters and a trailing zero.
inline void render(double width, char * dst)
{
    size_t floor_width = floor(width);

    for (size_t i = 0; i < floor_width; ++i)
    {
        memcpy(dst, "█", UNICODE_BAR_CHAR_SIZE);
        dst += UNICODE_BAR_CHAR_SIZE;
    }

    size_t remainder = floor((width - floor_width) * 8);

    if (remainder)
    {
        memcpy(dst, &"▏▎▍▌▋▋▊▉"[(remainder - 1) * UNICODE_BAR_CHAR_SIZE], UNICODE_BAR_CHAR_SIZE);
        dst += UNICODE_BAR_CHAR_SIZE;
    }

    *dst = 0;
}

inline std::string render(double width)
{
    std::string res(getWidthInBytes(width), '\0');
    render(width, &res[0]);
    return res;
}
} // namespace UnicodeBar