// This file Copyright © 2019-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.

#include <algorithm>
#include <iterator>
#include <string>
#include <string_view>

#include <event2/util.h> // evutil_ascii_strncasecmp

#include "file-info.h"
#include "utils.h"

using namespace std::literals;

static void appendSanitizedComponent(std::string& out, std::string_view in)
{
    // remove leading spaces
    auto constexpr leading_test = [](unsigned char ch)
    {
        return isspace(ch);
    };
    auto const it = std::find_if_not(std::begin(in), std::end(in), leading_test);
    in.remove_prefix(std::distance(std::begin(in), it));

    // remove trailing spaces and '.'
    auto constexpr trailing_test = [](unsigned char ch)
    {
        return (isspace(ch) != 0) || ch == '.';
    };
    auto const rit = std::find_if_not(std::rbegin(in), std::rend(in), trailing_test);
    in.remove_suffix(std::distance(std::rbegin(in), rit));

    // munge banned characters
    // https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file
    auto constexpr ensure_legal_char = [](auto ch)
    {
        auto constexpr Banned = std::string_view{ "<>:\"/\\|?*" };
        auto const banned = Banned.find(ch) != std::string_view::npos || (unsigned char)ch < 0x20;
        return banned ? '_' : ch;
    };
    auto const old_out_len = std::size(out);
    std::transform(std::begin(in), std::end(in), std::back_inserter(out), ensure_legal_char);

    // munge banned filenames
    // https://docs.microsoft.com/en-us/windows/desktop/FileIO/naming-a-file
    auto constexpr ReservedNames = std::array<std::string_view, 22>{
        "CON"sv,  "PRN"sv,  "AUX"sv,  "NUL"sv,  "COM1"sv, "COM2"sv, "COM3"sv, "COM4"sv, "COM5"sv, "COM6"sv, "COM7"sv,
        "COM8"sv, "COM9"sv, "LPT1"sv, "LPT2"sv, "LPT3"sv, "LPT4"sv, "LPT5"sv, "LPT6"sv, "LPT7"sv, "LPT8"sv, "LPT9"sv,
    };
    for (auto const& name : ReservedNames)
    {
        size_t const name_len = std::size(name);
        if (evutil_ascii_strncasecmp(out.c_str() + old_out_len, std::data(name), name_len) != 0 ||
            (out[old_out_len + name_len] != '\0' && out[old_out_len + name_len] != '.'))
        {
            continue;
        }

        out.insert(std::begin(out) + old_out_len + name_len, '_');
        break;
    }
}

std::string tr_file_info::sanitizePath(std::string_view in)
{
    auto out = std::string{};

    auto segment = std::string_view{};
    while (tr_strvSep(&in, &segment, '/'))
    {
        appendSanitizedComponent(out, segment);
        out += '/';
    }
    if (!std::empty(out)) // remove trailing slash
    {
        out.resize(std::size(out) - 1);
    }

    return out;
}