#pragma once

#include "Common.h"
#include "../CPU/CPUThread.h"
#include "../Memory/vm.h"
#include "Utilities/lockless.h"

enum class ppu_cmd : u32
{
	null,

	opcode, // Execute PPU instruction from arg
	set_gpr, // Set gpr[arg] (+1 cmd)
	set_args, // Set general-purpose args (+arg cmd)
	lle_call, // Load addr and rtoc at *arg or *gpr[arg] and execute
	hle_call, // Execute function by index (arg)
	initialize, // ppu_initialize()
	sleep,
};

class ppu_thread : public cpu_thread
{
public:
	static const u32 id_base = 0x01000000; // TODO (used to determine thread type)
	static const u32 id_step = 1;
	static const u32 id_count = 2048;

	virtual std::string get_name() const override;
	virtual std::string dump() const override;
	virtual void cpu_task() override;
	virtual void cpu_sleep() override;
	virtual ~ppu_thread() override;

	ppu_thread(const std::string& name, u32 prio = 0, u32 stack = 0x10000);

	u64 gpr[32] = {}; // General-Purpose Registers
	f64 fpr[32] = {}; // Floating Point Registers
	v128 vr[32] = {}; // Vector Registers

	alignas(16) bool cr[32] = {}; // Condition Registers (abstract representation)

	// Pack CR bits
	u32 cr_pack() const
	{
		u32 result{};

		for (u32 bit : cr)
		{
			result = (result << 1) | bit;
		}

		return result;
	}

	// Unpack CR bits
	void cr_unpack(u32 value)
	{
		for (bool& b : cr)
		{
			b = (value & 0x1) != 0;
			value >>= 1;
		}
	}

	// Fixed-Point Exception Register (abstract representation)
	struct
	{
		bool so{}; // Summary Overflow
		bool ov{}; // Overflow
		bool ca{}; // Carry
		u8 cnt{};  // 0..6
	}
	xer;
	
	/*
		Saturation. A sticky status bit indicating that some field in a saturating instruction saturated since the last
		time SAT was cleared. In other words when SAT = '1' it remains set to '1' until it is cleared to '0' by an
		mtvscr instruction.
		1	The vector saturate instruction implicitly sets when saturation has occurred on the results one of
			the vector instructions having saturate in its name:
			Move To VSCR (mtvscr)
			Vector Add Integer with Saturation (vaddubs, vadduhs, vadduws, vaddsbs, vaddshs,
			vaddsws)
			Vector Subtract Integer with Saturation (vsububs, vsubuhs, vsubuws, vsubsbs, vsubshs,
			vsubsws)
			Vector Multiply-Add Integer with Saturation (vmhaddshs, vmhraddshs)
			Vector Multiply-Sum with Saturation (vmsumuhs, vmsumshs, vsumsws)
			Vector Sum-Across with Saturation (vsumsws, vsum2sws, vsum4sbs, vsum4shs,
			vsum4ubs)
			Vector Pack with Saturation (vpkuhus, vpkuwus, vpkshus, vpkswus, vpkshss, vpkswss)
			Vector Convert to Fixed-Point with Saturation (vctuxs, vctsxs)
		0	Indicates no saturation occurred; mtvscr can explicitly clear this bit.
	*/
	bool sat{};

	/*
		Non-Java. A mode control bit that determines whether vector floating-point operations will be performed
		in a Java-IEEE-C9X-compliant mode or a possibly faster non-Java/non-IEEE mode.
		0	The Java-IEEE-C9X-compliant mode is selected. Denormalized values are handled as specified
			by Java, IEEE, and C9X standard.
		1	The non-Java/non-IEEE-compliant mode is selected. If an element in a source vector register
			contains a denormalized value, the value '0' is used instead. If an instruction causes an underflow
			exception, the corresponding element in the target vr is cleared to '0'. In both cases, the '0'
			has the same sign as the denormalized or underflowing value.
	*/
	bool nj = true;

	struct // Floating-Point Status and Control Register (abstract representation)
	{
		bool fl{}; // FPCC.FL
		bool fg{}; // FPCC.FG
		bool fe{}; // FPCC.FE
		bool fu{}; // FPCC.FU
	}
	fpscr;

	u32 cia{}; // Current Instruction Address
	u64 lr{}; // Link Register
	u64 ctr{}; // Counter Register
	u32 vrsave{0xffffffff}; // VR Save Register (almost unused)

	atomic_t<u32> prio{0}; // Thread priority (0..3071)
	const u32 stack_size; // Stack size
	const u32 stack_addr; // Stack address
	
	atomic_t<u32> joiner{~0u}; // Joining thread (-1 if detached)

	lf_fifo<atomic_t<cmd64>, 127> cmd_queue; // Command queue for asynchronous operations.

	void cmd_push(cmd64);
	void cmd_list(std::initializer_list<cmd64>);
	void cmd_pop(u32 = 0);
	cmd64 cmd_wait(); // Empty command means caller must return, like true from cpu_thread::check_status().
	cmd64 cmd_get(u32 index) { return cmd_queue[cmd_queue.peek() + index].load(); }

	const char* last_function{}; // Last function name for diagnosis, optimized for speed.

	const std::string m_name; // Thread name

	u64 get_next_arg(u32& g_count)
	{
		if (g_count < 8)
		{
			return gpr[g_count++ + 3];
		}
		else
		{
			return *get_stack_arg(++g_count);
		}
	}

	be_t<u64>* get_stack_arg(s32 i, u64 align = alignof(u64));
	void exec_task();
	void fast_call(u32 addr, u32 rtoc);

	static u32 stack_push(u32 size, u32 align_v);
	static void stack_pop_verbose(u32 addr, u32 size) noexcept;
};

template<typename T, typename = void>
struct ppu_gpr_cast_impl
{
	static_assert(!sizeof(T), "Invalid type for ppu_gpr_cast<>");
};

template<typename T>
struct ppu_gpr_cast_impl<T, std::enable_if_t<std::is_integral<T>::value || std::is_enum<T>::value>>
{
	static_assert(sizeof(T) <= 8, "Too big integral type for ppu_gpr_cast<>()");
	static_assert(std::is_same<std::decay_t<T>, bool>::value == false, "bool type is deprecated in ppu_gpr_cast<>(), use b8 instead");

	static inline u64 to(const T& value)
	{
		return static_cast<u64>(value);
	}

	static inline T from(const u64 reg)
	{
		return static_cast<T>(reg);
	}
};

template<>
struct ppu_gpr_cast_impl<b8, void>
{
	static inline u64 to(const b8& value)
	{
		return value;
	}

	static inline b8 from(const u64 reg)
	{
		return static_cast<u32>(reg) != 0;
	}
};

template<>
struct ppu_gpr_cast_impl<error_code, void>
{
	static inline u64 to(const error_code& code)
	{
		return code;
	}

	static inline error_code from(const u64 reg)
	{
		return not_an_error(reg);
	}
};

template<typename T, typename AT>
struct ppu_gpr_cast_impl<vm::_ptr_base<T, AT>, void>
{
	static inline u64 to(const vm::_ptr_base<T, AT>& value)
	{
		return ppu_gpr_cast_impl<AT>::to(value.addr());
	}

	static inline vm::_ptr_base<T, AT> from(const u64 reg)
	{
		return vm::cast(ppu_gpr_cast_impl<AT>::from(reg));
	}
};

template<typename T, typename AT>
struct ppu_gpr_cast_impl<vm::_ref_base<T, AT>, void>
{
	static inline u64 to(const vm::_ref_base<T, AT>& value)
	{
		return ppu_gpr_cast_impl<AT>::to(value.addr());
	}

	static inline vm::_ref_base<T, AT> from(const u64 reg)
	{
		return vm::cast(ppu_gpr_cast_impl<AT>::from(reg));
	}
};

template<typename To = u64, typename From>
inline To ppu_gpr_cast(const From& value)
{
	return ppu_gpr_cast_impl<To>::from(ppu_gpr_cast_impl<From>::to(value));
}