// Copyright (c) 2020 Egor Tensin <Egor.Tensin@gmail.com>
// This file is part of the "winapi-common" project.
// For details, see https://github.com/egor-tensin/winapi-common.
// Distributed under the MIT License.

#include <winapi/cmd_line.hpp>
#include <winapi/error.hpp>
#include <winapi/utf8.hpp>
#include <winapi/utils.hpp>

#include <boost/algorithm/string.hpp>

// clang-format off
#include <windows.h>
#include <shellapi.h>
// clang-format on

#include <cstddef>
#include <memory>
#include <stdexcept>
#include <string>
#include <sstream>
#include <utility>
#include <vector>

namespace winapi {
namespace {

std::vector<std::string> narrow_all(int argc, wchar_t** argv) {
    std::vector<std::string> utf;
    utf.reserve(argc);
    for (int i = 0; i < argc; ++i)
        utf.emplace_back(narrow(argv[i]));
    return utf;
}

CommandLine do_parse(std::wstring src) {
    boost::trim(src);
    if (src.empty()) {
        throw std::runtime_error{"Command line cannot be an empty string"};
    }

    int argc = 0;
    std::unique_ptr<wchar_t*, LocalDelete> argv{::CommandLineToArgvW(src.c_str(), &argc)};

    if (argv.get() == NULL) {
        throw error::windows(GetLastError(), "CommandLineToArgvW");
    }
    if (argc == 0) {
        throw std::runtime_error{"Command line must contain at least one token"};
    }

    return CommandLine{narrow_all(argc, argv.get())};
}

std::string split_argv0(std::vector<std::string>& argv) {
    if (argv.empty()) {
        throw std::range_error{"argv must contain at least one element"};
    }
    const auto argv0 = argv[0];
    argv.erase(argv.begin());
    return argv0;
}

std::vector<std::string> escape_all(const std::vector<std::string>& xs) {
    std::vector<std::string> escaped;
    escaped.reserve(xs.size());
    for (const auto& x : xs)
        escaped.emplace_back(CommandLine::escape(x));
    return escaped;
}

} // namespace

CommandLine CommandLine::query() {
    return do_parse(::GetCommandLineW());
}

CommandLine CommandLine::parse(const std::string& src) {
    return do_parse(widen(src));
}

CommandLine CommandLine::from_main(int argc, wchar_t* argv[]) {
    if (argc < 1)
        throw std::range_error{"argc must be a positive number"};
    return CommandLine{narrow_all(argc, argv)};
}

CommandLine::CommandLine(const std::vector<std::string>& argv) : m_args{argv} {
    m_argv0 = split_argv0(m_args);
}

CommandLine::CommandLine(std::vector<std::string>&& argv) : m_args{std::move(argv)} {
    m_argv0 = split_argv0(m_args);
}

std::string CommandLine::escape(const std::string& arg) {
    std::ostringstream safe;
    safe << '"';

    for (auto it = arg.cbegin(); it != arg.cend(); ++it) {
        std::size_t numof_backslashes = 0;

        for (; it != arg.cend() && *it == '\\'; ++it)
            ++numof_backslashes;

        if (it == arg.cend()) {
            safe << std::string(2 * numof_backslashes, '\\');
            break;
        }

        switch (*it) {
            case L'"':
                safe << std::string(2 * numof_backslashes + 1, '\\');
                break;

            default:
                safe << std::string(numof_backslashes, '\\');
                break;
        }

        safe << *it;
    }

    safe << '"';
    return safe.str();
}

std::string CommandLine::escape_cmd(const std::string& arg) {
    static constexpr auto escape_symbol = '^';
    static const std::string dangerous_symbols{"^!\"%&()<>|"};

    auto safe = escape(arg);
    for (const auto danger : dangerous_symbols) {
        std::ostringstream replacement;
        replacement << escape_symbol << danger;
        boost::replace_all(safe, std::string{danger}, replacement.str());
    }
    return safe;
}

std::string CommandLine::to_string() const {
    return boost::algorithm::join(escape_argv(), std::string{token_sep()});
}

std::string CommandLine::args_to_string() const {
    return boost::algorithm::join(escape_args(), std::string{token_sep()});
}

std::vector<std::string> CommandLine::get_argv() const {
    auto argv = get_args();
    argv.emplace(argv.begin(), get_argv0());
    return argv;
}

std::vector<std::string> CommandLine::escape_args() const {
    return escape_all(get_args());
}

std::vector<std::string> CommandLine::escape_argv() const {
    return escape_all(get_argv());
}

} // namespace winapi