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

namespace Kernel {

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

SharedPtr<SharedMemory> SharedMemory::Create(SharedPtr<Process> owner_process, u64 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 +
            static_cast<PAddr>(shared_memory->backing_block_offset);

        // Increase the amount of used linear heap memory for the owner process.
        if (shared_memory->owner_process != nullptr) {
            shared_memory->owner_process->linear_heap_used += size;
        }

        // Refresh the address mappings for the current process.
        if (Core::CurrentProcess() != nullptr) {
            Core::CurrentProcess()->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);
        ASSERT_MSG(vma != vm_manager.vma_map.end(), "Invalid memory address");
        ASSERT_MSG(vma->second.backing_block, "Backing block doesn't exist for address");

        // The returned VMA might be a bigger one encompassing the desired address.
        auto vma_offset = address - vma->first;
        ASSERT_MSG(vma_offset + size <= vma->second.size,
                   "Shared memory exceeds bounds of mapped block");

        shared_memory->backing_block = vma->second.backing_block;
        shared_memory->backing_block_offset = vma->second.offset + vma_offset;
    }

    shared_memory->base_address = address;
    return shared_memory;
}

SharedPtr<SharedMemory> SharedMemory::CreateForApplet(std::shared_ptr<std::vector<u8>> heap_block,
                                                      u32 offset, u32 size,
                                                      MemoryPermission permissions,
                                                      MemoryPermission other_permissions,
                                                      std::string name) {
    SharedPtr<SharedMemory> shared_memory(new SharedMemory);

    shared_memory->owner_process = nullptr;
    shared_memory->name = std::move(name);
    shared_memory->size = size;
    shared_memory->permissions = permissions;
    shared_memory->other_permissions = other_permissions;
    shared_memory->backing_block = heap_block;
    shared_memory->backing_block_offset = offset;
    shared_memory->base_address = Memory::HEAP_VADDR + offset;

    return shared_memory;
}

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

    MemoryPermission own_other_permissions =
        target_process == owner_process ? this->permissions : this->other_permissions;

    // Automatically allocated memory blocks can only be mapped with other_permissions = DontCare
    if (base_address == 0 && other_permissions != MemoryPermission::DontCare) {
        return ERR_INVALID_COMBINATION;
    }

    // Error out if the requested permissions don't match what the creator process allows.
    if (static_cast<u32>(permissions) & ~static_cast<u32>(own_other_permissions)) {
        LOG_ERROR(Kernel, "cannot map id=%u, address=0x%lx name=%s, permissions don't match",
                  GetObjectId(), address, name.c_str());
        return ERR_INVALID_COMBINATION;
    }

    // Error out if the provided permissions are not compatible with what the creator process needs.
    if (other_permissions != MemoryPermission::DontCare &&
        static_cast<u32>(this->permissions) & ~static_cast<u32>(other_permissions)) {
        LOG_ERROR(Kernel, "cannot map id=%u, address=0x%lx name=%s, permissions don't match",
                  GetObjectId(), address, name.c_str());
        return ERR_WRONG_PERMISSION;
    }

    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).value();
    }

    // Map the memory block into the target process
    auto result = target_process->vm_manager.MapMemoryBlock(
        target_address, backing_block, backing_block_offset, size, MemoryState::Shared);
    if (result.Failed()) {
        LOG_ERROR(Kernel,
                  "cannot map id=%u, target_address=0x%lx name=%s, error mapping to virtual memory",
                  GetObjectId(), target_address, name.c_str());
        return result.Code();
    }

    return target_process->vm_manager.ReprotectRange(target_address, size,
                                                     ConvertPermissions(permissions));
}

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);
}

VMAPermission SharedMemory::ConvertPermissions(MemoryPermission permission) {
    u32 masked_permissions =
        static_cast<u32>(permission) & static_cast<u32>(MemoryPermission::ReadWriteExecute);
    return static_cast<VMAPermission>(masked_permissions);
};

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

} // namespace Kernel
