/*
 * Copyright (c) 2018-2020 Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <mesosphere.hpp>

namespace ams::kern::svc {

    /* =============================    Common    ============================= */

    namespace {

        constexpr bool IsValidVirtualCoreId(int32_t core_id) {
            return (0 <= core_id && core_id < static_cast<int32_t>(cpu::NumVirtualCores));
        }

        Result CreateThread(ams::svc::Handle *out, ams::svc::ThreadFunc f, uintptr_t arg, uintptr_t stack_bottom, int32_t priority, int32_t core_id) {
            /* Adjust core id, if it's the default magic. */
            KProcess &process = GetCurrentProcess();
            if (core_id == ams::svc::IdealCoreUseProcessValue) {
                core_id = process.GetIdealCoreId();
            }

            /* Validate arguments. */
            R_UNLESS(IsValidVirtualCoreId(core_id),                   svc::ResultInvalidCoreId());
            R_UNLESS(((1ul << core_id) & process.GetCoreMask()) != 0, svc::ResultInvalidCoreId());

            R_UNLESS(ams::svc::HighestThreadPriority <= priority && priority <= ams::svc::LowestThreadPriority, svc::ResultInvalidPriority());
            R_UNLESS(process.CheckThreadPriority(priority),                                                     svc::ResultInvalidPriority());

            /* Reserve a new thread from the process resource limit (waiting up to 100ms). */
            KScopedResourceReservation thread_reservation(std::addressof(process), ams::svc::LimitableResource_ThreadCountMax, 1, KHardwareTimer::GetTick() + ams::svc::Tick(TimeSpan::FromMilliSeconds(100)));
            R_UNLESS(thread_reservation.Succeeded(), svc::ResultLimitReached());

            /* Create the thread. */
            KThread *thread = KThread::Create();
            R_UNLESS(thread != nullptr, svc::ResultOutOfResource());
            ON_SCOPE_EXIT { thread->Close(); };

            /* Initialize the thread. */
            {
                KScopedLightLock lk(process.GetStateLock());
                R_TRY(KThread::InitializeUserThread(thread, reinterpret_cast<KThreadFunction>(static_cast<uintptr_t>(f)), arg, stack_bottom, priority, core_id, std::addressof(process)));
            }

            /* Commit the thread reservation. */
            thread_reservation.Commit();

            /* Clone the current fpu status to the new thread. */
            thread->GetContext().CloneFpuStatus();

            /* Register the new thread. */
            KThread::Register(thread);

            /* Add the thread to the handle table. */
            R_TRY(process.GetHandleTable().Add(out, thread));

            return ResultSuccess();
        }

        Result StartThread(ams::svc::Handle thread_handle) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Try to start the thread. */
            return thread->Run();
        }

        void ExitThread() {
            GetCurrentThread().Exit();
            MESOSPHERE_PANIC("Thread survived call to exit");
        }

        void SleepThread(int64_t ns) {
            /* When the input tick is positive, sleep. */
            if (AMS_LIKELY(ns > 0)) {
                /* Convert the timeout from nanoseconds to ticks. */
                /* NOTE: Nintendo does not use this conversion logic in WaitSynchronization... */
                s64 timeout;

                const ams::svc::Tick offset_tick(TimeSpan::FromNanoSeconds(ns));
                if (AMS_LIKELY(offset_tick > 0)) {
                    timeout = KHardwareTimer::GetTick() + offset_tick + 2;
                    if (AMS_UNLIKELY(timeout <= 0)) {
                        timeout = std::numeric_limits<s64>::max();
                    }
                } else {
                    timeout = std::numeric_limits<s64>::max();
                }

                /* Sleep. */
                /* NOTE: Nintendo does not check the result of this sleep. */
                GetCurrentThread().Sleep(timeout);
            } else if (ns == ams::svc::YieldType_WithoutCoreMigration) {
                KScheduler::YieldWithoutCoreMigration();
            } else if (ns == ams::svc::YieldType_WithCoreMigration) {
                KScheduler::YieldWithCoreMigration();
            } else if (ns == ams::svc::YieldType_ToAnyThread) {
                KScheduler::YieldToAnyThread();
            } else {
                /* Nintendo does nothing at all if an otherwise invalid value is passed. */
            }
        }

        Result GetThreadPriority(int32_t *out_priority, ams::svc::Handle thread_handle) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Get the thread's priority. */
            *out_priority = thread->GetPriority();
            return ResultSuccess();
        }

        Result SetThreadPriority(ams::svc::Handle thread_handle, int32_t priority) {
            /* Get the current process. */
            KProcess &process = GetCurrentProcess();

            /* Get the thread from its handle. */
            KScopedAutoObject thread = process.GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Validate the thread is owned by the current process. */
            R_UNLESS(thread->GetOwnerProcess() == GetCurrentProcessPointer(), svc::ResultInvalidHandle());

            /* Validate the priority. */
            R_UNLESS(ams::svc::HighestThreadPriority <= priority && priority <= ams::svc::LowestThreadPriority, svc::ResultInvalidPriority());
            R_UNLESS(process.CheckThreadPriority(priority),                                                     svc::ResultInvalidPriority());

            /* Set the thread priority. */
            thread->SetBasePriority(priority);
            return ResultSuccess();
        }

        Result GetThreadCoreMask(int32_t *out_core_id, uint64_t *out_affinity_mask, ams::svc::Handle thread_handle) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Get the core mask. */
            R_TRY(thread->GetCoreMask(out_core_id, out_affinity_mask));

            return ResultSuccess();
        }

        Result SetThreadCoreMask(ams::svc::Handle thread_handle, int32_t core_id, uint64_t affinity_mask) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Validate the thread is owned by the current process. */
            R_UNLESS(thread->GetOwnerProcess() == GetCurrentProcessPointer(), svc::ResultInvalidHandle());

            /* Determine the core id/affinity mask. */
            if (core_id == ams::svc::IdealCoreUseProcessValue) {
                core_id       = GetCurrentProcess().GetIdealCoreId();
                affinity_mask = (1ul << core_id);
            } else {
                /* Validate the affinity mask. */
                const u64 process_core_mask = GetCurrentProcess().GetCoreMask();
                R_UNLESS((affinity_mask | process_core_mask) == process_core_mask, svc::ResultInvalidCoreId());
                R_UNLESS(affinity_mask != 0,                                       svc::ResultInvalidCombination());

                /* Validate the core id. */
                if (IsValidVirtualCoreId(core_id)) {
                    R_UNLESS(((1ul << core_id) & affinity_mask) != 0, svc::ResultInvalidCombination());
                } else {
                    R_UNLESS(core_id == ams::svc::IdealCoreNoUpdate || core_id == ams::svc::IdealCoreDontCare, svc::ResultInvalidCoreId());
                }
            }

            /* Set the core mask. */
            R_TRY(thread->SetCoreMask(core_id, affinity_mask));

            return ResultSuccess();
        }

        Result GetThreadId(uint64_t *out_thread_id, ams::svc::Handle thread_handle) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Get the thread's id. */
            *out_thread_id = thread->GetId();
            return ResultSuccess();
        }

        Result GetThreadContext3(KUserPointer<ams::svc::ThreadContext *> out_context, ams::svc::Handle thread_handle) {
            /* Get the thread from its handle. */
            KScopedAutoObject thread = GetCurrentProcess().GetHandleTable().GetObject<KThread>(thread_handle);
            R_UNLESS(thread.IsNotNull(), svc::ResultInvalidHandle());

            /* Require the handle be to a non-current thread in the current process. */
            R_UNLESS(thread->GetOwnerProcess() == GetCurrentProcessPointer(), svc::ResultInvalidHandle());
            R_UNLESS(thread.GetPointerUnsafe() != GetCurrentThreadPointer(),  svc::ResultBusy());

            /* Get the thread context. */
            ams::svc::ThreadContext context = {};
            R_TRY(thread->GetThreadContext3(std::addressof(context)));

            /* Copy the thread context to user space. */
            R_TRY(out_context.CopyFrom(std::addressof(context)));

            return ResultSuccess();
        }

        Result GetThreadList(int32_t *out_num_threads, KUserPointer<uint64_t *> out_thread_ids, int32_t max_out_count, ams::svc::Handle debug_handle) {
            /* Validate that the out count is valid. */
            R_UNLESS((0 <= max_out_count && max_out_count <= static_cast<int32_t>(std::numeric_limits<int32_t>::max() / sizeof(u64))), svc::ResultOutOfRange());

            /* Validate that the pointer is in range. */
            if (max_out_count > 0) {
                R_UNLESS(GetCurrentProcess().GetPageTable().Contains(KProcessAddress(out_thread_ids.GetUnsafePointer()), max_out_count * sizeof(u64)), svc::ResultInvalidCurrentMemory());
            }

            if (debug_handle == ams::svc::InvalidHandle) {
                /* If passed invalid handle, we should return the global thread list. */
                R_TRY(KThread::GetThreadList(out_num_threads, out_thread_ids, max_out_count));
            } else {
                /* Get the handle table. */
                auto &handle_table = GetCurrentProcess().GetHandleTable();

                /* Try to get as a debug object. */
                KScopedAutoObject debug = handle_table.GetObject<KDebug>(debug_handle);
                if (debug.IsNotNull()) {
                    /* Get the debug object's process. */
                    KScopedAutoObject process = debug->GetProcess();
                    R_UNLESS(process.IsNotNull(), svc::ResultProcessTerminated());

                    /* Get the thread list. */
                    R_TRY(process->GetThreadList(out_num_threads, out_thread_ids, max_out_count));
                } else {
                    /* Try to get as a process. */
                    KScopedAutoObject process = handle_table.GetObjectWithoutPseudoHandle<KProcess>(debug_handle);
                    R_UNLESS(process.IsNotNull(), svc::ResultInvalidHandle());

                    /* Get the thread list. */
                    R_TRY(process->GetThreadList(out_num_threads, out_thread_ids, max_out_count));
                }
            }

            return ResultSuccess();
        }

    }

    /* =============================    64 ABI    ============================= */

    Result CreateThread64(ams::svc::Handle *out_handle, ams::svc::ThreadFunc func, ams::svc::Address arg, ams::svc::Address stack_bottom, int32_t priority, int32_t core_id) {
        return CreateThread(out_handle, func, arg, stack_bottom, priority, core_id);
    }

    Result StartThread64(ams::svc::Handle thread_handle) {
        return StartThread(thread_handle);
    }

    void ExitThread64() {
        return ExitThread();
    }

    void SleepThread64(int64_t ns) {
        return SleepThread(ns);
    }

    Result GetThreadPriority64(int32_t *out_priority, ams::svc::Handle thread_handle) {
        return GetThreadPriority(out_priority, thread_handle);
    }

    Result SetThreadPriority64(ams::svc::Handle thread_handle, int32_t priority) {
        return SetThreadPriority(thread_handle, priority);
    }

    Result GetThreadCoreMask64(int32_t *out_core_id, uint64_t *out_affinity_mask, ams::svc::Handle thread_handle) {
        return GetThreadCoreMask(out_core_id, out_affinity_mask, thread_handle);
    }

    Result SetThreadCoreMask64(ams::svc::Handle thread_handle, int32_t core_id, uint64_t affinity_mask) {
        return SetThreadCoreMask(thread_handle, core_id, affinity_mask);
    }

    Result GetThreadId64(uint64_t *out_thread_id, ams::svc::Handle thread_handle) {
        return GetThreadId(out_thread_id, thread_handle);
    }

    Result GetThreadContext364(KUserPointer<ams::svc::ThreadContext *> out_context, ams::svc::Handle thread_handle) {
        return GetThreadContext3(out_context, thread_handle);
    }

    Result GetThreadList64(int32_t *out_num_threads, KUserPointer<uint64_t *> out_thread_ids, int32_t max_out_count, ams::svc::Handle debug_handle) {
        return GetThreadList(out_num_threads, out_thread_ids, max_out_count, debug_handle);
    }

    /* ============================= 64From32 ABI ============================= */

    Result CreateThread64From32(ams::svc::Handle *out_handle, ams::svc::ThreadFunc func, ams::svc::Address arg, ams::svc::Address stack_bottom, int32_t priority, int32_t core_id) {
        return CreateThread(out_handle, func, arg, stack_bottom, priority, core_id);
    }

    Result StartThread64From32(ams::svc::Handle thread_handle) {
        return StartThread(thread_handle);
    }

    void ExitThread64From32() {
        return ExitThread();
    }

    void SleepThread64From32(int64_t ns) {
        return SleepThread(ns);
    }

    Result GetThreadPriority64From32(int32_t *out_priority, ams::svc::Handle thread_handle) {
        return GetThreadPriority(out_priority, thread_handle);
    }

    Result SetThreadPriority64From32(ams::svc::Handle thread_handle, int32_t priority) {
        return SetThreadPriority(thread_handle, priority);
    }

    Result GetThreadCoreMask64From32(int32_t *out_core_id, uint64_t *out_affinity_mask, ams::svc::Handle thread_handle) {
        return GetThreadCoreMask(out_core_id, out_affinity_mask, thread_handle);
    }

    Result SetThreadCoreMask64From32(ams::svc::Handle thread_handle, int32_t core_id, uint64_t affinity_mask) {
        return SetThreadCoreMask(thread_handle, core_id, affinity_mask);
    }

    Result GetThreadId64From32(uint64_t *out_thread_id, ams::svc::Handle thread_handle) {
        return GetThreadId(out_thread_id, thread_handle);
    }

    Result GetThreadContext364From32(KUserPointer<ams::svc::ThreadContext *> out_context, ams::svc::Handle thread_handle) {
        return GetThreadContext3(out_context, thread_handle);
    }

    Result GetThreadList64From32(int32_t *out_num_threads, KUserPointer<uint64_t *> out_thread_ids, int32_t max_out_count, ams::svc::Handle debug_handle) {
        return GetThreadList(out_num_threads, out_thread_ids, max_out_count, debug_handle);
    }

}