// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <cstring>

#include "common/logging/log.h"

#include "core/memory.h"
#include "core/hle/kernel/memory.h"
#include "core/hle/kernel/shared_memory.h"

namespace Kernel {

SharedMemory::SharedMemory() {}
SharedMemory::~SharedMemory() {}

SharedPtr<SharedMemory> SharedMemory::Create(SharedPtr<Process> owner_process, u32 size, MemoryPermission permissions,
        MemoryPermission other_permissions, VAddr address, MemoryRegion region, std::string name) {
    SharedPtr<SharedMemory> shared_memory(new SharedMemory);

    shared_memory->owner_process = owner_process;
    shared_memory->name = std::move(name);
    shared_memory->size = size;
    shared_memory->permissions = permissions;
    shared_memory->other_permissions = other_permissions;

    if (address == 0) {
        // We need to allocate a block from the Linear Heap ourselves.
        // We'll manually allocate some memory from the linear heap in the specified region.
        MemoryRegionInfo* memory_region = GetMemoryRegion(region);
        auto& linheap_memory = memory_region->linear_heap_memory;

        ASSERT_MSG(linheap_memory->size() + size <= memory_region->size, "Not enough space in region to allocate shared memory!");

        shared_memory->backing_block = linheap_memory;
        shared_memory->backing_block_offset = linheap_memory->size();
        // Allocate some memory from the end of the linear heap for this region.
        linheap_memory->insert(linheap_memory->end(), size, 0);
        memory_region->used += size;

        shared_memory->linear_heap_phys_address = Memory::FCRAM_PADDR + memory_region->base + shared_memory->backing_block_offset;

        // Refresh the address mappings for the current process.
        if (Kernel::g_current_process != nullptr) {
            Kernel::g_current_process->vm_manager.RefreshMemoryBlockMappings(linheap_memory.get());
        }
    } else {
        auto& vm_manager = shared_memory->owner_process->vm_manager;
        // The memory is already available and mapped in the owner process.
        auto vma = vm_manager.FindVMA(address)->second;
        // Copy it over to our own storage
        shared_memory->backing_block = std::make_shared<std::vector<u8>>(vma.backing_block->data() + vma.offset,
                                                                         vma.backing_block->data() + vma.offset + size);
        // Unmap the existing pages
        vm_manager.UnmapRange(address, size);
        // Map our own block into the address space
        vm_manager.MapMemoryBlock(address, shared_memory->backing_block, 0, size, MemoryState::Shared);
    }

    shared_memory->base_address = address;
    return shared_memory;
}

ResultCode SharedMemory::Map(Process* target_process, VAddr address, MemoryPermission permissions,
        MemoryPermission other_permissions) {

    // TODO(Subv): Return E0E01BEE when permissions and other_permissions don't
    // match what was specified when the memory block was created.

    // TODO(Subv): Check for the Shared Device Mem flag in the creator process.
    /*if (was_created_with_shared_device_mem && address != 0) {
        return ResultCode(ErrorDescription::InvalidCombination, ErrorModule::OS, ErrorSummary::InvalidArgument, ErrorLevel::Usage);
    }*/

    // TODO(Subv): The same process that created a SharedMemory object
    // can not map it in its own address space unless it was created with addr=0, result 0xD900182C.

    if (address < Memory::HEAP_VADDR || address + size >= Memory::SHARED_MEMORY_VADDR_END) {
        LOG_ERROR(Kernel, "cannot map id=%u, address=0x%08X name=%s, invalid address",
                GetObjectId(), address, name.c_str());
        return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::OS,
                ErrorSummary::InvalidArgument, ErrorLevel::Usage);
    }

    VAddr target_address = address;

    if (base_address == 0 && target_address == 0) {
        // Calculate the address at which to map the memory block.
        target_address = Memory::PhysicalToVirtualAddress(linear_heap_phys_address);
    }

    // Map the memory block into the target process
    target_process->vm_manager.MapMemoryBlock(target_address, backing_block, backing_block_offset, size, MemoryState::Shared);

    return RESULT_SUCCESS;
}

ResultCode SharedMemory::Unmap(Process* target_process, VAddr address) {
    // TODO(Subv): Verify what happens if the application tries to unmap an address that is not mapped to a SharedMemory.
    return target_process->vm_manager.UnmapRange(address, size);
}

u8* SharedMemory::GetPointer(u32 offset) {
    return backing_block->data() + backing_block_offset + offset;
}

} // namespace