/***
    Copyright (C) 2021 Jamie Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuOpen.Win32.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuProcesses.hpp"
#include "AuOpen.Win32.hpp"
#include <Source/IO/FS/FS.hpp>

#define COINIT_APARTMENTTHREADED  0x2
#define COINIT_DISABLE_OLE1DDE    0x4

namespace Aurora::Processes
{
    static AuList<AuPair<AuString, bool>> gOpenItems;
    static AuConditionMutex gCondMutex;
    static AuConditionVariable gCondVariable(AuUnsafeRaiiToShared(gCondMutex.AsPointer()));
    static AuThreads::ThreadUnique_t gOpenerThread;

    static void RunTasks()
    {
        AU_LOCK_GUARD(gCondMutex);

        while (AuIsThreadRunning())
        {
            try
            {
                while (gOpenItems.size())
                {
                    auto &[uri, type] = gOpenItems[0];

                    bool bDirExists {};
                    bool bFileExists {};

                    if (uri.empty())
                    {
                        continue;
                    }

                    if (!pShellExecuteW)
                    {
                        SysPushErrorUninitialized("Cannot open URIs yet");
                        continue;
                    }

                    bFileExists = AuIOFS::FileExists(uri);

                    if (!type)
                    {
                        bDirExists = AuIOFS::DirExists(uri);

                        if (!bFileExists &&
                            !bDirExists)
                        {
                            SysPushErrorGeneric("Exploit attempt? Attempted to open non-existent file/directory. (request: {})", uri);
                            continue;
                        }

                        if (bFileExists)
                        {
                            if (AuFS::IsFileBlocked(uri))
                            {
                                SysPushErrorGeneric("Exploit attempt? Attempted to open untrusted file/directory. (request: {})", uri);
                                continue;
                            }
                        }
                    }
                    else
                    {
                        if (bFileExists)
                        {
                            SysPushErrorGeneric("Exploit attempt? Attempted to open existing file/directory via URI ({})", uri);
                            continue;
                        }
                    }

                    auto u16OpenURI = Locale::ConvertFromUTF8(uri);
                    auto pOpenType  = bDirExists ? L"explore" : L"open";

                    gCondMutex->Unlock();
                    pShellExecuteW(nullptr,
                                   pOpenType,
                                   u16OpenURI.c_str(),
                                   nullptr,
                                   nullptr,
                                   SW_SHOWNORMAL);
                    gCondMutex->Lock();

                    // Move all N-1 elements for each N, vs clearing later (requires lock?), vs making a copy of the work (requires another alloc?).
                    // We can just do ShellExecuteW outside of the lock, and access a locally owned U16-translated string container, without bothering the write side mutex or mutable work container.
                    // A work queue buffer could solve this, but eh.
                    gOpenItems.erase(gOpenItems.begin());
                }

                gCondVariable->WaitForSignal();
            }
            catch (...)
            {
                SysPushErrorCatch("An error occurred while dispatching a ShellExecute runner frame");
            }
        }
    }

    static void OpenerThread()
    {
        if (pCoInitializeEx)
        {
            (void)pCoInitializeEx(nullptr, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
        }

        RunTasks();
        
        if (pCoUninitialize)
        {
            pCoUninitialize();
        }
    }

    void InitWin32Opener()
    {
        gOpenerThread = AuThreads::ThreadUnique(AuThreads::ThreadInfo(
            AuMakeShared<AuThreads::IThreadVectorsFunctional>(AuThreads::IThreadVectorsFunctional::OnEntry_t(std::bind(OpenerThread)),
                                                              AuThreads::IThreadVectorsFunctional::OnExit_t{}),
            "COM ShellExecute Runner"
        ));
        SysAssert(gOpenerThread);

        gOpenerThread->Run();
    }

    void DeinitWin32Opener()
    {
        if (!gOpenerThread)
        {
            return;
        }
        gOpenerThread->SendExitSignal();
        gCondVariable->Signal();
        gOpenerThread.reset();
    }

    AUKN_SYM void OpenUri(const AuROString &uri)
    {
        AU_LOCK_GLOBAL_GUARD(gCondMutex);
        AuTryInsert(gOpenItems, AuMakePair(AuString(uri), true));
        gCondVariable->Signal();
    }

    AUKN_SYM void OpenFile(const AuROString &file)
    {
        auto path = AuIOFS::NormalizePathRet(file);

        if (path.empty())
        {
            SysPushErrorMemory();
            return;
        }

        {
            AU_LOCK_GLOBAL_GUARD(gCondMutex);
            AuTryInsert(gOpenItems, AuMove(AuMakePair(AuMove(path), false)));
            gCondVariable->Signal();
        }
    }
}