#include <stddef.h>
#include <uefi/types.h>

#include "kernel_memory.h"

#include "console.h"
#include "error.h"
#include "memory.h"
#include "paging.h"
#include "status.h"

namespace boot {
namespace memory {

using mem_entry = kernel::args::mem_entry;
using mem_type = kernel::args::mem_type;

size_t fixup_pointer_index = 0;
void **fixup_pointers[64];

static const wchar_t *memory_type_names[] = {
	L"reserved memory type",
	L"loader code",
	L"loader data",
	L"boot services code",
	L"boot services data",
	L"runtime services code",
	L"runtime services data",
	L"conventional memory",
	L"unusable memory",
	L"acpi reclaim memory",
	L"acpi memory nvs",
	L"memory mapped io",
	L"memory mapped io port space",
	L"pal code",
	L"persistent memory"
};

static const wchar_t *
memory_type_name(uefi::memory_type t)
{
	if (t < uefi::memory_type::max_memory_type) {
		return memory_type_names[static_cast<uint32_t>(t)];
	}

	switch(t) {
		/*
		case args_type:		return L"jsix kernel args";
		case module_type:	return L"jsix bootloader module";
		case program_type:	return L"jsix kernel or program code";
		case table_type:	return L"jsix page tables";
		*/
		default: return L"Bad Type Value";
	}
}

void
update_marked_addresses(uefi::event, void *context)
{
	uefi::runtime_services *rs =
		reinterpret_cast<uefi::runtime_services*>(context);

	for (size_t i = 0; i < fixup_pointer_index; ++i) {
		if (fixup_pointers[i])
			rs->convert_pointer(0, fixup_pointers[i]);
	}
}

void
init_pointer_fixup(uefi::boot_services *bs, uefi::runtime_services *rs)
{
	status_line status(L"Initializing pointer virtualization event");

	uefi::event event;
	bs->set_mem(&fixup_pointers, sizeof(fixup_pointers), 0);
	fixup_pointer_index = 0;

	try_or_raise(
		bs->create_event(
			uefi::evt::signal_virtual_address_change,
			uefi::tpl::callback,
			(uefi::event_notify)&update_marked_addresses,
			rs,
			&event),
		L"Error creating memory virtualization event");
}

void
mark_pointer_fixup(void **p)
{
	fixup_pointers[fixup_pointer_index++] = p;
}

bool
can_merge(mem_entry &prev, mem_type type, uefi::memory_descriptor *next)
{
	return
		prev.type == type &&
		prev.start + (page_size * prev.pages) == next->physical_start &&
		prev.attr == (next->attribute & 0xffffffff);
}

void
get_uefi_mappings(efi_mem_map *map, bool allocate, uefi::boot_services *bs)
{
	size_t length = 0;
	uefi::status status = bs->get_memory_map(
		&length, nullptr, &map->key, &map->size, &map->version);

	if (status != uefi::status::buffer_too_small)
		error::raise(status, L"Error getting memory map size");

	map->length = length;

	if (allocate) {
		map->length += 10*map->size;

		try_or_raise(
			bs->allocate_pool(
				uefi::memory_type::loader_data, map->length,
				reinterpret_cast<void**>(&map->entries)),
			L"Allocating space for memory map");

		try_or_raise(
			bs->get_memory_map(&map->length, map->entries, &map->key, &map->size, &map->version),
			L"Getting UEFI memory map");
	}
}

efi_mem_map
build_kernel_mem_map(kernel::args::header *args, uefi::boot_services *bs)
{
	status_line status {L"Creating kernel memory map"};

	efi_mem_map map;
	get_uefi_mappings(&map, false, bs);

	size_t map_size = map.num_entries() * sizeof(mem_entry);

	kernel::args::mem_entry *kernel_map = nullptr;
	try_or_raise(
		bs->allocate_pages(
			uefi::allocate_type::any_pages,
			module_type,
			bytes_to_pages(map_size),
			reinterpret_cast<void**>(&kernel_map)),
		L"Error allocating kernel memory map module space");

	bs->set_mem(kernel_map, map_size, 0);
	get_uefi_mappings(&map, true, bs);

	size_t i = 0;
	bool first = true;
	for (auto desc : map) {
		/*
		console::print(L"   Range %lx (%lx) %x(%s) [%lu]\r\n",
			desc->physical_start, desc->attribute, desc->type, memory_type_name(desc->type), desc->number_of_pages);
		*/

		mem_type type;
		switch (desc->type) {
			case uefi::memory_type::reserved:
			case uefi::memory_type::unusable_memory:
			case uefi::memory_type::acpi_memory_nvs:
			case uefi::memory_type::pal_code:
				continue;

			case uefi::memory_type::loader_code:
			case uefi::memory_type::loader_data:
			case uefi::memory_type::boot_services_code:
			case uefi::memory_type::boot_services_data:
			case uefi::memory_type::conventional_memory:
				type = mem_type::free;
				break;

			case uefi::memory_type::runtime_services_code:
			case uefi::memory_type::runtime_services_data:
				type = mem_type::uefi_runtime;
				break;

			case uefi::memory_type::acpi_reclaim_memory:
				type = mem_type::acpi;
				break;

			case uefi::memory_type::memory_mapped_io:
			case uefi::memory_type::memory_mapped_io_port_space:
				type = mem_type::mmio;
				break;

			case uefi::memory_type::persistent_memory:
				type = mem_type::persistent;
				break;

				/*
			case args_type:
				type = mem_type::args;
				break;

			case module_type:
				type = mem_type::module;
				break;

			case program_type:
				type = mem_type::program;
				break;

			case table_type:
				type = mem_type::table;
				break;
			*/

			default:
				error::raise(
					uefi::status::invalid_parameter,
					L"Got an unexpected memory type from UEFI memory map");
		}

		// TODO: validate uefi's map is sorted
		if (first) {
			first = false;
			kernel_map[i].start = desc->physical_start;
			kernel_map[i].pages = desc->number_of_pages;
			kernel_map[i].type = type;
			kernel_map[i].attr = (desc->attribute & 0xffffffff);
			continue;
		}

		mem_entry &prev = kernel_map[i];
		if (can_merge(prev, type, desc)) {
			prev.pages += desc->number_of_pages;
		} else {
			mem_entry &next = kernel_map[++i];
			next.start = desc->physical_start;
			next.pages = desc->number_of_pages;
			next.type = type;
			next.attr = (desc->attribute & 0xffffffff);
		}
	}

	// Give just the actually-set entries in the header
	args->mem_map = kernel_map;
	args->map_count = i;

	return map;
}

void
virtualize(void *pml4, efi_mem_map &map, uefi::runtime_services *rs)
{
	paging::add_current_mappings(reinterpret_cast<paging::page_table*>(pml4));

	for (auto desc : map)
		desc->virtual_start = desc->physical_start + ::memory::page_offset;

	// Write our new PML4 pointer to CR3
	asm volatile ( "mov %0, %%cr3" :: "r" (pml4) );
	__sync_synchronize();

	try_or_raise(
		rs->set_virtual_address_map(
			map.length, map.size, map.version, map.entries),
		L"Error setting virtual address map");
}


} // namespace boot
} // namespace memory