/*
	This file is part of Fennix Kernel.

	Fennix Kernel is free software: you can redistribute it and/or
	modify it under the terms of the GNU General Public License as
	published by the Free Software Foundation, either version 3 of
	the License, or (at your option) any later version.

	Fennix Kernel is distributed in the hope that 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 Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/

#include "../crashhandler.hpp"
#include "chfcts.hpp"

#include <display.hpp>
#include <printf.h>
#include <debug.h>
#include <smp.hpp>
#include <cpu.hpp>

#if defined(a64)
#include "../../arch/amd64/cpu/gdt.hpp"
#elif defined(a32)
#elif defined(aa64)
#endif

#include "../../kernel.h"

static const char *PageFaultDescriptions[8] = {
	"Supervisory process tried to read a non-present page entry\n",
	"Supervisory process tried to read a page and caused a protection fault\n",
	"Supervisory process tried to write to a non-present page entry\n",
	"Supervisory process tried to write a page and caused a protection fault\n",
	"User process tried to read a non-present page entry\n",
	"User process tried to read a page and caused a protection fault\n",
	"User process tried to write to a non-present page entry\n",
	"User process tried to write a page and caused a protection fault\n"};

SafeFunction void DivideByZeroExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Divide by zero exception\n");
	UNUSED(Frame);
}

SafeFunction void DebugExceptionHandler(CHArchTrapFrame *Frame)
{
	CrashHandler::EHPrint("Kernel triggered debug exception.\n");
	UNUSED(Frame);
}

SafeFunction void NonMaskableInterruptExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("NMI exception");
	UNUSED(Frame);
}

SafeFunction void BreakpointExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Breakpoint exception");
	UNUSED(Frame);
}

SafeFunction void OverflowExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Overflow exception");
	UNUSED(Frame);
}

SafeFunction void BoundRangeExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Bound range exception");
	UNUSED(Frame);
}

SafeFunction void InvalidOpcodeExceptionHandler(CHArchTrapFrame *Frame)
{
	CrashHandler::EHPrint("Kernel tried to execute an invalid opcode.\n");
	UNUSED(Frame);
}

SafeFunction void DeviceNotAvailableExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Device not available exception");
	UNUSED(Frame);
}

SafeFunction void DoubleFaultExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Double fault exception");
	UNUSED(Frame);
}

SafeFunction void CoprocessorSegmentOverrunExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Coprocessor segment overrun exception");
	UNUSED(Frame);
}

SafeFunction void InvalidTSSExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Invalid TSS exception");
	UNUSED(Frame);
}

SafeFunction void SegmentNotPresentExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Segment not present exception");
	UNUSED(Frame);
}

SafeFunction void StackFaultExceptionHandler(CHArchTrapFrame *Frame)
{
	CPU::x64::SelectorErrorCode SelCode = {.raw = Frame->ErrorCode};
#if defined(a64)
	CrashHandler::EHPrint("Stack segment fault at address %#lx\n", Frame->rip);
#elif defined(a32)
	CrashHandler::EHPrint("Stack segment fault at address %#lx\n", Frame->eip);
#elif defined(aa64)
#endif
	CrashHandler::EHPrint("External: %d\n", SelCode.External);
	CrashHandler::EHPrint("Table: %d\n", SelCode.Table);
	CrashHandler::EHPrint("Index: %#x\n", SelCode.Idx);
	CrashHandler::EHPrint("Error code: %#lx\n", Frame->ErrorCode);
}

SafeFunction void GeneralProtectionExceptionHandler(CHArchTrapFrame *Frame)
{
	CPU::x64::SelectorErrorCode SelCode = {.raw = Frame->ErrorCode};
	// switch (SelCode.Table)
	// {
	// case CPU::x64::0b00:
	//     memcpy(desc_tmp, "GDT", 3);
	//     break;
	// case CPU::x64::0b01:
	//     memcpy(desc_tmp, "IDT", 3);
	//     break;
	// case CPU::x64::0b10:
	//     memcpy(desc_tmp, "LDT", 3);
	//     break;
	// case CPU::x64::0b11:
	//     memcpy(desc_tmp, "IDT", 3);
	//     break;
	// default:
	//     memcpy(desc_tmp, "Unknown", 7);
	//     break;
	// }
	CrashHandler::EHPrint("Kernel performed an illegal operation.\n");
	CrashHandler::EHPrint("External: %d\n", SelCode.External);
	CrashHandler::EHPrint("Table: %d\n", SelCode.Table);
	CrashHandler::EHPrint("Index: %#x\n", SelCode.Idx);
}

SafeFunction void PageFaultExceptionHandler(CHArchTrapFrame *Frame)
{
	CPU::x64::PageFaultErrorCode params = {.raw = (uint32_t)Frame->ErrorCode};
#if defined(a64)
	CrashHandler::EHPrint("\eAFAFAFAn exception occurred at %#lx by %#lx\n", CrashHandler::PageFaultAddress, Frame->rip);
#elif defined(a32)
	CrashHandler::EHPrint("\eAFAFAFAn exception occurred at %#lx by %#lx\n", CrashHandler::PageFaultAddress, Frame->eip);
#elif defined(aa64)
#endif
	CrashHandler::EHPrint("Page: %s\n", params.P ? "Present" : "Not Present");
	CrashHandler::EHPrint("Write Operation: %s\n", params.W ? "Read-Only" : "Read-Write");
	CrashHandler::EHPrint("Processor Mode: %s\n", params.U ? "User-Mode" : "Kernel-Mode");
	CrashHandler::EHPrint("CPU Reserved Bits: %s\n", params.R ? "Reserved" : "Unreserved");
	CrashHandler::EHPrint("Caused By An Instruction Fetch: %s\n", params.I ? "Yes" : "No");
	CrashHandler::EHPrint("Caused By A Protection-Key Violation: %s\n", params.PK ? "Yes" : "No");
	CrashHandler::EHPrint("Caused By A Shadow Stack Access: %s\n", params.SS ? "Yes" : "No");
	CrashHandler::EHPrint("Caused By An SGX Violation: %s\n", params.SGX ? "Yes" : "No");
	if (Frame->ErrorCode & 0x00000008)
		CrashHandler::EHPrint("One or more page directory entries contain reserved bits which are set to 1.\n");
	else
		CrashHandler::EHPrint(PageFaultDescriptions[Frame->ErrorCode & 0b111]);

#ifdef DEBUG
	uintptr_t CheckPageFaultAddress = 0;
	CheckPageFaultAddress = CrashHandler::PageFaultAddress;
	if (CheckPageFaultAddress == 0)
#ifdef a64
		CheckPageFaultAddress = Frame->rip;
#elif defined(a32)
		CheckPageFaultAddress = Frame->eip;
#elif defined(aa64)
		CheckPageFaultAddress = 0;
#endif

#if defined(a64)
	Memory::Virtual vmm(((Memory::PageTable *)CPU::x64::readcr3().raw));
#elif defined(a32)
	Memory::Virtual vmm(((Memory::PageTable *)CPU::x32::readcr3().raw));
#elif defined(aa64)
	Memory::Virtual vmm();
#warning "TODO: aa64"
#endif

	bool PageAvailable = vmm.Check((void *)CheckPageFaultAddress);
	debug("Page available (Check(...)): %s. %s",
		  PageAvailable ? "Yes" : "No",
		  (params.P && !PageAvailable) ? "CR2 == Present; Check() != Present??????" : "CR2 confirms Check() result.");

	if (PageAvailable)
	{
		bool Present = vmm.Check((void *)CheckPageFaultAddress);
		bool ReadWrite = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::RW);
		bool User = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::US);
		bool WriteThrough = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::PWT);
		bool CacheDisabled = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::PCD);
		bool Accessed = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::A);
		bool Dirty = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::D);
		bool Global = vmm.Check((void *)CheckPageFaultAddress, Memory::PTFlag::G);
		/* ... */

		debug("Page available: %s", Present ? "Yes" : "No");
		debug("Page read/write: %s", ReadWrite ? "Yes" : "No");
		debug("Page user/kernel: %s", User ? "User" : "Kernel");
		debug("Page write-through: %s", WriteThrough ? "Yes" : "No");
		debug("Page cache disabled: %s", CacheDisabled ? "Yes" : "No");
		debug("Page accessed: %s", Accessed ? "Yes" : "No");
		debug("Page dirty: %s", Dirty ? "Yes" : "No");
		debug("Page global: %s", Global ? "Yes" : "No");

		if (Present)
		{
#if defined(a64)
			uintptr_t CheckPageFaultLinearAddress = (uintptr_t)CheckPageFaultAddress;
			CheckPageFaultLinearAddress &= 0xFFFFFFFFFFFFF000;
			debug("%#lx -> %#lx", CheckPageFaultAddress, CheckPageFaultLinearAddress);

			Memory::Virtual::PageMapIndexer Index = Memory::Virtual::PageMapIndexer((uintptr_t)CheckPageFaultLinearAddress);
			debug("Index for %#lx is PML:%d PDPTE:%d PDE:%d PTE:%d",
				  CheckPageFaultLinearAddress,
				  Index.PMLIndex,
				  Index.PDPTEIndex,
				  Index.PDEIndex,
				  Index.PTEIndex);
#if defined(a64)
			Memory::PageMapLevel4 PML4 = ((Memory::PageTable *)CPU::x64::readcr3().raw)->Entries[Index.PMLIndex];
#elif defined(a32)
			Memory::PageMapLevel4 PML4 = ((Memory::PageTable *)CPU::x32::readcr3().raw)->Entries[Index.PMLIndex];
#elif defined(aa64)
			Memory::PageMapLevel4 PML4 = {.raw = 0};
#warning "TODO: aa64"
#endif

			Memory::PageDirectoryPointerTableEntryPtr *PDPTE = (Memory::PageDirectoryPointerTableEntryPtr *)((uintptr_t)PML4.GetAddress() << 12);
			Memory::PageDirectoryEntryPtr *PDE = (Memory::PageDirectoryEntryPtr *)((uintptr_t)PDPTE->Entries[Index.PDPTEIndex].GetAddress() << 12);
			Memory::PageTableEntryPtr *PTE = (Memory::PageTableEntryPtr *)((uintptr_t)PDE->Entries[Index.PDEIndex].GetAddress() << 12);

			debug("# %03d-%03d-%03d-%03d: P:%s RW:%s US:%s PWT:%s PCB:%s A:%s NX:%s Address:%#lx",
				  Index.PMLIndex, 0, 0, 0,
				  PML4.Present ? "1" : "0",
				  PML4.ReadWrite ? "1" : "0",
				  PML4.UserSupervisor ? "1" : "0",
				  PML4.WriteThrough ? "1" : "0",
				  PML4.CacheDisable ? "1" : "0",
				  PML4.Accessed ? "1" : "0",
				  PML4.ExecuteDisable ? "1" : "0",
				  PML4.GetAddress() << 12);

			debug("# %03d-%03d-%03d-%03d: P:%s RW:%s US:%s PWT:%s PCB:%s A:%s NX:%s Address:%#lx",
				  Index.PMLIndex, Index.PDPTEIndex, 0, 0,
				  PDPTE->Entries[Index.PDPTEIndex].Present ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].ReadWrite ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].UserSupervisor ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].WriteThrough ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].CacheDisable ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].Accessed ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].ExecuteDisable ? "1" : "0",
				  PDPTE->Entries[Index.PDPTEIndex].GetAddress() << 12);

			debug("# %03d-%03d-%03d-%03d: P:%s RW:%s US:%s PWT:%s PCB:%s A:%s NX:%s Address:%#lx",
				  Index.PMLIndex, Index.PDPTEIndex, Index.PDEIndex, 0,
				  PDE->Entries[Index.PDEIndex].Present ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].ReadWrite ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].UserSupervisor ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].WriteThrough ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].CacheDisable ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].Accessed ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].ExecuteDisable ? "1" : "0",
				  PDE->Entries[Index.PDEIndex].GetAddress() << 12);

			debug("# %03d-%03d-%03d-%03d: P:%s RW:%s US:%s PWT:%s PCB:%s A:%s D:%s PAT:%s G:%s PK:%d NX:%s Address:%#lx",
				  Index.PMLIndex, Index.PDPTEIndex, Index.PDEIndex, Index.PTEIndex,
				  PTE->Entries[Index.PTEIndex].Present ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].ReadWrite ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].UserSupervisor ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].WriteThrough ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].CacheDisable ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].Accessed ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].Dirty ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].PageAttributeTable ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].Global ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].ProtectionKey,
				  PTE->Entries[Index.PTEIndex].ExecuteDisable ? "1" : "0",
				  PTE->Entries[Index.PTEIndex].GetAddress() << 12);
#endif
		}
	}
#endif
}

SafeFunction void x87FloatingPointExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("x87 floating point exception");
	UNUSED(Frame);
}

SafeFunction void AlignmentCheckExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Alignment check exception");
	UNUSED(Frame);
}

SafeFunction void MachineCheckExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Machine check exception");
	UNUSED(Frame);
}

SafeFunction void SIMDFloatingPointExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("SIMD floating point exception");
	UNUSED(Frame);
}

SafeFunction void VirtualizationExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Virtualization exception");
	UNUSED(Frame);
}

SafeFunction void SecurityExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Security exception");
	UNUSED(Frame);
}

SafeFunction void UnknownExceptionHandler(CHArchTrapFrame *Frame)
{
	fixme("Unknown exception");
	UNUSED(Frame);
}