#ifndef NOMINMAX
#define NOMINMAX
#endif

#include <windows.h>

#include <chrono>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <string_view>
#include <system_error>
#include <vector>

namespace {

constexpr auto kLaunchTimeout = std::chrono::seconds(20);
constexpr auto kShutdownTimeout = std::chrono::seconds(25);
constexpr auto kPollInterval = std::chrono::milliseconds(100);
constexpr const char* kReadyTrace = "[app] shell runtime initialized:";

struct ProcessWindowSearch {
    DWORD processId = 0;
    HWND hwnd = nullptr;
    bool requireVisible = false;
};

std::wstring QuoteCommandLine(const std::filesystem::path& executablePath) {
    return L"\"" + executablePath.wstring() + L"\"";
}

void PrintFailure(std::string_view message) {
    std::cerr << "[xceditor_smoke] " << message << '\n';
}

std::string ReadTextFile(const std::filesystem::path& path) {
    std::ifstream stream(path, std::ios::in | std::ios::binary);
    if (!stream.is_open()) {
        return {};
    }

    std::ostringstream buffer = {};
    buffer << stream.rdbuf();
    return buffer.str();
}

bool FileContains(const std::filesystem::path& path, std::string_view needle) {
    const std::string content = ReadTextFile(path);
    return !content.empty() && content.find(needle) != std::string::npos;
}

BOOL CALLBACK FindProcessWindowProc(HWND hwnd, LPARAM lParam) {
    auto& search = *reinterpret_cast<ProcessWindowSearch*>(lParam);

    DWORD processId = 0;
    GetWindowThreadProcessId(hwnd, &processId);
    if (processId != search.processId) {
        return TRUE;
    }

    if (search.requireVisible && !IsWindowVisible(hwnd)) {
        return TRUE;
    }

    RECT clientRect = {};
    if (!GetClientRect(hwnd, &clientRect)) {
        return TRUE;
    }

    const LONG width = clientRect.right - clientRect.left;
    const LONG height = clientRect.bottom - clientRect.top;
    if (width <= 0 || height <= 0) {
        return TRUE;
    }

    search.hwnd = hwnd;
    return FALSE;
}

HWND FindProcessWindow(DWORD processId, bool requireVisible) {
    ProcessWindowSearch search = {};
    search.processId = processId;
    search.requireVisible = requireVisible;
    EnumWindows(&FindProcessWindowProc, reinterpret_cast<LPARAM>(&search));
    return search.hwnd;
}

bool RemoveFileIfPresent(const std::filesystem::path& path) {
    std::error_code errorCode = {};
    if (!std::filesystem::exists(path, errorCode)) {
        return true;
    }

    std::filesystem::remove(path, errorCode);
    return !errorCode;
}

bool PrepareLogDirectory(
    const std::filesystem::path& logDirectory,
    const std::filesystem::path& runtimeLogPath,
    const std::filesystem::path& crashLogPath) {
    std::error_code errorCode = {};
    std::filesystem::create_directories(logDirectory, errorCode);
    if (errorCode) {
        PrintFailure("failed to create log directory: " + logDirectory.string());
        return false;
    }

    if (!RemoveFileIfPresent(runtimeLogPath)) {
        PrintFailure("failed to clear runtime log: " + runtimeLogPath.string());
        return false;
    }

    if (!RemoveFileIfPresent(crashLogPath)) {
        PrintFailure("failed to clear crash log: " + crashLogPath.string());
        return false;
    }

    return true;
}

bool LaunchEditorProcess(
    const std::filesystem::path& executablePath,
    PROCESS_INFORMATION& outProcessInfo) {
    SetEnvironmentVariableW(L"XCUI_AUTO_CAPTURE_ON_STARTUP", L"0");
    SetEnvironmentVariableW(L"XCUIEDITOR_SMOKE_TEST", L"1");
    SetEnvironmentVariableW(L"XCUIEDITOR_SMOKE_TEST_DURATION_SECONDS", L"12");
    SetEnvironmentVariableW(L"XCUIEDITOR_SMOKE_TEST_FRAME_LIMIT", nullptr);

    STARTUPINFOW startupInfo = {};
    startupInfo.cb = sizeof(startupInfo);

    std::wstring commandLine = QuoteCommandLine(executablePath);
    std::vector<wchar_t> mutableCommandLine(commandLine.begin(), commandLine.end());
    mutableCommandLine.push_back(L'\0');

    ZeroMemory(&outProcessInfo, sizeof(outProcessInfo));
    return CreateProcessW(
        executablePath.c_str(),
        mutableCommandLine.data(),
        nullptr,
        nullptr,
        FALSE,
        0,
        nullptr,
        nullptr,
        &startupInfo,
        &outProcessInfo) == TRUE;
}

bool WaitForEditorReady(
    HANDLE processHandle,
    const std::filesystem::path& runtimeLogPath) {
    const auto deadline = std::chrono::steady_clock::now() + kLaunchTimeout;

    while (std::chrono::steady_clock::now() < deadline) {
        if (WaitForSingleObject(processHandle, 0) == WAIT_OBJECT_0) {
            return false;
        }

        if (FileContains(runtimeLogPath, kReadyTrace)) {
            return true;
        }

        Sleep(static_cast<DWORD>(kPollInterval.count()));
    }

    return false;
}

bool WaitForEditorExit(HANDLE processHandle, DWORD timeoutMilliseconds, DWORD& outExitCode) {
    if (WaitForSingleObject(processHandle, timeoutMilliseconds) != WAIT_OBJECT_0) {
        return false;
    }

    outExitCode = 0;
    return GetExitCodeProcess(processHandle, &outExitCode) == TRUE;
}

std::string BuildEarlyExitReason(
    HANDLE processHandle,
    const std::filesystem::path& runtimeLogPath,
    const std::filesystem::path& crashLogPath) {
    DWORD exitCode = 0;
    GetExitCodeProcess(processHandle, &exitCode);

    std::ostringstream message = {};
    message << "editor exited before ready, code=" << exitCode;

    const std::string runtimeLog = ReadTextFile(runtimeLogPath);
    if (!runtimeLog.empty()) {
        message << "\nruntime.log:\n" << runtimeLog;
    }

    const std::string crashLog = ReadTextFile(crashLogPath);
    if (!crashLog.empty()) {
        message << "\ncrash.log:\n" << crashLog;
    }

    return message.str();
}

std::string BuildTimeoutReason(
    const std::filesystem::path& runtimeLogPath,
    const std::filesystem::path& crashLogPath) {
    std::ostringstream message = {};
    message << "editor did not reach ready state within "
            << std::chrono::duration_cast<std::chrono::milliseconds>(kLaunchTimeout).count()
            << "ms";

    const std::string runtimeLog = ReadTextFile(runtimeLogPath);
    if (!runtimeLog.empty()) {
        message << "\nruntime.log:\n" << runtimeLog;
    }

    const std::string crashLog = ReadTextFile(crashLogPath);
    if (!crashLog.empty()) {
        message << "\ncrash.log:\n" << crashLog;
    }

    return message.str();
}

void CloseProcessHandles(PROCESS_INFORMATION& processInfo) {
    if (processInfo.hThread != nullptr) {
        CloseHandle(processInfo.hThread);
        processInfo.hThread = nullptr;
    }
    if (processInfo.hProcess != nullptr) {
        CloseHandle(processInfo.hProcess);
        processInfo.hProcess = nullptr;
    }
}

} // namespace

int wmain(int argc, wchar_t* argv[]) {
    if (argc < 2 || argv[1] == nullptr || argv[1][0] == L'\0') {
        PrintFailure("missing XCEditor path");
        return 1;
    }

    const std::filesystem::path executablePath = std::filesystem::path(argv[1]).lexically_normal();
    if (!std::filesystem::exists(executablePath)) {
        PrintFailure("XCEditor not found: " + executablePath.string());
        return 1;
    }

    const std::filesystem::path logDirectory =
        (executablePath.parent_path() / "logs").lexically_normal();
    const std::filesystem::path runtimeLogPath =
        (logDirectory / "runtime.log").lexically_normal();
    const std::filesystem::path crashLogPath =
        (logDirectory / "crash.log").lexically_normal();
    if (!PrepareLogDirectory(logDirectory, runtimeLogPath, crashLogPath)) {
        return 1;
    }

    PROCESS_INFORMATION processInfo = {};
    if (!LaunchEditorProcess(executablePath, processInfo)) {
        PrintFailure("failed to launch XCEditor");
        return 1;
    }

    if (!WaitForEditorReady(
            processInfo.hProcess,
            runtimeLogPath)) {
        const DWORD waitState = WaitForSingleObject(processInfo.hProcess, 0);
        const std::string message =
            waitState == WAIT_OBJECT_0
            ? BuildEarlyExitReason(processInfo.hProcess, runtimeLogPath, crashLogPath)
            : BuildTimeoutReason(runtimeLogPath, crashLogPath);
        PrintFailure(message);
        TerminateProcess(processInfo.hProcess, 2);
        CloseProcessHandles(processInfo);
        return 1;
    }

    DWORD exitCode = 0;
    if (!WaitForEditorExit(
            processInfo.hProcess,
            static_cast<DWORD>(
                std::chrono::duration_cast<std::chrono::milliseconds>(kShutdownTimeout).count()),
            exitCode)) {
        PrintFailure("editor did not exit after WM_CLOSE");
        TerminateProcess(processInfo.hProcess, 4);
        CloseProcessHandles(processInfo);
        return 1;
    }

    CloseProcessHandles(processInfo);

    if (exitCode != 0) {
        PrintFailure("editor exited with non-zero code: " + std::to_string(exitCode));
        return 1;
    }

    const std::string crashLog = ReadTextFile(crashLogPath);
    if (!crashLog.empty()) {
        PrintFailure("crash log was generated:\n" + crashLog);
        return 1;
    }

    return 0;
}