/* -------------------------------------------

	Copyright SoftwareLabs

------------------------------------------- */

#include <Builtins/ACPI/ACPIFactoryInterface.hxx>
#include <HALKit/AMD64/Processor.hpp>
#include <NewKit/KernelCheck.hpp>
#include <ArchKit/ArchKit.hpp>

#define kAPIC_ICR_Low	  0x300
#define kAPIC_ICR_High	  0x310
#define kAPIC_SIPI_Vector 0x00500
#define kAPIC_EIPI_Vector 0x00400

///////////////////////////////////////////////////////////////////////////////////////

//! NOTE: fGSI stands 'Field Global System Interrupt'

///////////////////////////////////////////////////////////////////////////////////////

namespace NewOS::HAL
{
	constexpr Int32 kThreadAPIC	  = 0;
	constexpr Int32 kThreadLAPIC  = 1;
	constexpr Int32 kThreadIOAPIC = 2;
	constexpr Int32 kThreadAPIC64 = 3;
	constexpr Int32 kThreadBoot	  = 4;

	/*
	 *
	 * this is used to store info about the current running thread
	 * we use this struct to determine if we can use it, or mark it as used or on
	 * sleep.
	 *
	 */

	struct ProcessorInfoAMD64 final
	{
		Int32	ThreadType;
		UIntPtr JumpAddress;

		struct
		{
			UInt32 Code;
			UInt32 Data;
			UInt32 BSS;
		} Selector;
	};

	STATIC voidPtr	   kApicMadt	  = nullptr;
	STATIC const char* kApicSignature = "APIC";

	/// @brief Multiple APIC Descriptor Table.
	struct MadtType final : public SDT
	{
		struct MadtAddress final
		{
			Char RecordType;
			Char RecordLen; // record length

			UInt32 Address;
			UInt32 Flags; // 1 = Dual Legacy PICs installed
		} MadtRecords[];
	};

	struct MadtProcessorLocalApic final
	{
		Char   AcpiProcessorId;
		Char   ApicId;
		UInt32 Flags;
	};

	struct MadtIOApic final
	{
		Char   ApicId;
		Char   Reserved;
		UInt32 Address;
		UInt32 SystemInterruptBase;
	};

	struct MadtInterruptSource final
	{
		Char   BusSource;
		Char   IrqSource;
		UInt32 GSI;
		UInt16 Flags;
	};

	struct MadtInterruptNmi final
	{
		Char   NmiSource;
		Char   Reserved;
		UInt16 Flags;
		UInt32 GSI;
	};

	struct MadtLocalApicAddressOverride final
	{
		UInt16	Resvered;
		UIntPtr Address;
	};

	///////////////////////////////////////////////////////////////////////////////////////

	STATIC MadtType* kApicInfoBlock = nullptr;

	///////////////////////////////////////////////////////////////////////////////////////

	/// @brief Send start IPI for CPU.
	/// @param apicId
	/// @param vector
	/// @param targetAddress
	/// @return
	Void hal_send_start_ipi(UInt32 apicId, UInt8 vector, UInt32 targetAddress)
	{
		NewOS::ke_dma_write(targetAddress, kAPIC_ICR_High, apicId << 24);
		NewOS::ke_dma_write(targetAddress, kAPIC_ICR_Low, kAPIC_SIPI_Vector | vector);
	}

	/// @brief Send end IPI for CPU.
	/// @param apicId
	/// @param vector
	/// @param targetAddress
	/// @return
	Void hal_send_end_ipi(UInt32 apicId, UInt8 vector, UInt32 targetAddress)
	{
		NewOS::ke_dma_write(targetAddress, kAPIC_ICR_High, apicId << 24);
		NewOS::ke_dma_write(targetAddress, kAPIC_ICR_Low, kAPIC_EIPI_Vector | vector);
	}

	Void hal_system_get_cores(voidPtr rsdPtr)
	{
		auto acpi = ACPIFactoryInterface(rsdPtr);
		kApicMadt = acpi.Find(kApicSignature).Leak().Leak();

		if (kApicMadt != nullptr)
		{
			auto madt = (SDT*)kApicMadt;

			const UInt8* madt_end  = (const UInt8*)madt + madt->Length;
			const UInt8* entry_ptr = (const UInt8*)(madt + 1);

			while (entry_ptr < madt_end)
			{
				const MadtType::MadtAddress* entry_header = (const MadtType::MadtAddress*)entry_ptr;

				switch (entry_header->Flags)
				{
				case 0: {
					const MadtProcessorLocalApic* local_apic = (const MadtProcessorLocalApic*)entry_ptr;
					if (local_apic->Flags & 1)
					{
						// Processor is enabled
						kcout << "Processor ID: %d, APIC ID: %d\n"
							  << number(local_apic->AcpiProcessorId) << number(local_apic->ApicId);
					}
					break;
				}
				default:
					break;
				}

				entry_ptr += entry_header->RecordLen;
			}

			while (true)
			{
			}
		}
		else
		{
			kcout << "New OS: APIC is not present! it is a vital component.\r";
			ke_stop(RUNTIME_CHECK_FAILED);
		}
	}
} // namespace NewOS::HAL

///////////////////////////////////////////////////////////////////////////////////////