// Copyright (c) 2011-2016 Ryan Prichard
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.

#include "AgentLocation.h"

#include <windows.h>

#include <string>

#include "../shared/WinptyAssert.h"

#include "LibWinptyException.h"

#define AGENT_EXE L"winpty-agent.exe"

static HMODULE getCurrentModule() {
    HMODULE module;
    if (!GetModuleHandleExW(
                GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
                GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
                reinterpret_cast<LPCWSTR>(getCurrentModule),
                &module)) {
        ASSERT(false && "GetModuleHandleEx failed");
    }
    return module;
}

static std::wstring getModuleFileName(HMODULE module) {
    const int bufsize = 4096;
    wchar_t path[bufsize];
    int size = GetModuleFileNameW(module, path, bufsize);
    ASSERT(size != 0 && size != bufsize);
    return std::wstring(path);
}

static std::wstring dirname(const std::wstring &path) {
    std::wstring::size_type pos = path.find_last_of(L"\\/");
    if (pos == std::wstring::npos) {
        return L"";
    } else {
        return path.substr(0, pos);
    }
}

static bool pathExists(const std::wstring &path) {
    return GetFileAttributesW(path.c_str()) != 0xFFFFFFFF;
}

std::wstring findAgentProgram() {
    std::wstring progDir = dirname(getModuleFileName(getCurrentModule()));
    std::wstring ret = progDir + (L"\\" AGENT_EXE);
    if (!pathExists(ret)) {
        throw LibWinptyException(
            WINPTY_ERROR_AGENT_EXE_MISSING,
            (L"agent executable does not exist: '" + ret + L"'").c_str());
    }
    return ret;
}