#include "memory_string_searcher.h"
#include "Emu/Memory/vm.h"
#include "Emu/Memory/vm_reservation.h"
#include "Emu/CPU/CPUDisAsm.h"
#include "Emu/Cell/SPUDisAsm.h"
#include "Emu/IdManager.h"

#include "Utilities/Thread.h"
#include "Utilities/StrUtil.h"

#include <QLabel>
#include <QLineEdit>
#include <QPushButton>
#include <QHBoxLayout>
#include <QComboBox>
#include <QCheckBox>

#include <charconv>
#include <unordered_map>

#include "util/logs.hpp"
#include "util/sysinfo.hpp"
#include "util/asm.hpp"

LOG_CHANNEL(gui_log, "GUI");

constexpr auto qstr = QString::fromStdString;

enum search_mode : int
{
	no_mode          = 1,
	as_string        = 2,
	as_hex           = 4,
	as_f64           = 8,
	as_f32           = 16,
	as_inst          = 32,
	as_fake_spu_inst = 64,
};

template <>
void fmt_class_string<search_mode>::format(std::string& out, u64 arg)
{
	if (!arg)
	{
		out += "No search modes have been selected";
	}

	for (int modes = static_cast<int>(arg); modes; modes &= modes - 1)
	{
		const int mode = modes & ~(modes - 1);

		auto mode_s = [&]() -> std::string_view
		{
			switch (mode)
			{
			case as_string: return "String"; 
			case as_hex: return "HEX bytes/integer"; 
			case as_f64: return "Double"; 
			case as_f32: return "Float"; 
			case as_inst: return "Instruction"; 
			case as_fake_spu_inst: return "SPU Instruction"; 
			default: return "";
			}
		}();

		if (mode_s.empty())
		{
			break;
		}

		if (modes != static_cast<int>(arg))
		{
			out += ", ";
		}

		out += mode_s;
	}
}

memory_string_searcher::memory_string_searcher(QWidget* parent, std::shared_ptr<CPUDisAsm> disasm, std::string_view title)
	: QDialog(parent)
	, m_disasm(std::move(disasm))
{
	if (title.empty())
	{
		setWindowTitle(tr("Memory Searcher"));
	}
	else
	{
		setWindowTitle(tr("Memory Searcher Of %1").arg(title.data()));
	}

	setObjectName("memory_string_searcher");
	setAttribute(Qt::WA_DeleteOnClose);

	// Extract memory view from the disassembler
	std::tie(m_ptr, m_size) = m_disasm->get_memory_span();

	m_addr_line = new QLineEdit(this);
	m_addr_line->setFixedWidth(QLabel("This is the very length of the lineedit due to hidpi reasons.").sizeHint().width());
	m_addr_line->setPlaceholderText(tr("Search..."));
	m_addr_line->setMaxLength(4096);

	QPushButton* button_search = new QPushButton(tr("&Search"), this);

	m_chkbox_case_insensitive = new QCheckBox(tr("Case Insensitive"), this);
	m_chkbox_case_insensitive->setCheckable(true);
	m_chkbox_case_insensitive->setToolTip(tr("When using string mode, the characters' case will not matter both in string and in memory."
		"\nWarning: this may reduce performance of the search."));

	m_cbox_input_mode = new QComboBox(this);
	m_cbox_input_mode->addItem(tr("Select search mode(s).."), QVariant::fromValue(+no_mode));
	m_cbox_input_mode->addItem(tr("String"), QVariant::fromValue(+as_string));
	m_cbox_input_mode->addItem(tr("HEX bytes/integer"), QVariant::fromValue(+as_hex));
	m_cbox_input_mode->addItem(tr("Double"), QVariant::fromValue(+as_f64));
	m_cbox_input_mode->addItem(tr("Float"), QVariant::fromValue(+as_f32));
	m_cbox_input_mode->addItem(tr("Instruction"), QVariant::fromValue(+as_inst));

	QString tooltip = tr("String: search the memory for the specified string."
		"\nHEX bytes/integer: search the memory for hexadecimal values. Spaces, commas, \"0x\", \"0X\", \"\\x\", \"h\", \"H\" ensure separation of bytes but they are not mandatory."
		"\nDouble: reinterpret the string as 64-bit precision floating point value. Values are searched for exact representation, meaning -0 != 0."
		"\nFloat: reinterpret the string as 32-bit precision floating point value. Values are searched for exact representation, meaning -0 != 0."
		"\nInstruction: search an instruction contains the text of the string.");

	if (m_size != 0x40000/*SPU_LS_SIZE*/)
	{
		m_cbox_input_mode->addItem("SPU Instruction", QVariant::fromValue(+as_fake_spu_inst));
		tooltip.append(tr("\nSPU Instruction: Search an SPU instruction contains the text of the string. For searching instructions within embedded SPU images.\nTip: SPU floats are commented along forming instructions."));
	}

	connect(m_cbox_input_mode, QOverload<int>::of(&QComboBox::currentIndexChanged), this, [this](int index)
	{
		if (index < 0) return;

		if ((1 << index) == no_mode)
		{
			m_modes = {};
		}
		else
		{
			m_modes = search_mode{m_modes | (1 << index)};
		}

		m_modes_label->setText(qstr(fmt::format("%s.", m_modes)));
	});

	m_cbox_input_mode->setToolTip(tooltip);

	m_modes_label = new QLabel(qstr(fmt::format("%s.", m_modes)));

	QHBoxLayout* hbox_panel = new QHBoxLayout();
	hbox_panel->addWidget(m_addr_line);
	hbox_panel->addWidget(m_cbox_input_mode);
	hbox_panel->addWidget(m_chkbox_case_insensitive);
	hbox_panel->addWidget(button_search);

	QVBoxLayout* vbox_panel = new QVBoxLayout();
	vbox_panel->addLayout(hbox_panel);
	vbox_panel->addWidget(m_modes_label);

	setLayout(vbox_panel);

	connect(button_search, &QAbstractButton::clicked, this, [this]()
	{
		std::string wstr = m_addr_line->text().toStdString();

		if (wstr.empty() || wstr.size() >= 4096u)
		{
			gui_log.error("String is empty or too long (size=%u)", wstr.size());
			return;
		}

		gui_log.notice("Searching for %s (mode: %s)", wstr, m_modes);

		u64 found = 0;

		for (int modes = m_modes; modes; modes &= modes - 1)
		{
			found += OnSearch(wstr, modes & ~(modes - 1));
		}

		gui_log.success("Search completed (found %u matches)", +found);
	});

	layout()->setSizeConstraint(QLayout::SetFixedSize);

	// Show by default
	show();

	// Expected to be created by IDM, emulation stop will close it
	connect(this, &memory_string_searcher::finished, [id = idm::last_id()](int)
	{
		idm::remove<memory_searcher_handle>(id);
	});
}

u64 memory_string_searcher::OnSearch(std::string wstr, int mode)
{
	bool case_insensitive = false;

	// First characters for case insensitive search
	const char first_chars[2]{ static_cast<char>(::tolower(wstr[0])), static_cast<char>(::toupper(wstr[0])) };
	std::string_view insensitive_search{first_chars, 2};

	if (insensitive_search[0] == insensitive_search[1])
	{
		// Optimization
		insensitive_search.remove_suffix(1);
	}

	switch (mode)
	{
	case as_inst:
	case as_string:
	case as_fake_spu_inst:
	{
		case_insensitive = m_chkbox_case_insensitive->isChecked();

		if (case_insensitive)
		{
			std::transform(wstr.begin(), wstr.end(), wstr.begin(), ::tolower);
		}

		break;
	}
	case as_hex:
	{
		constexpr std::string_view hex_chars = "0123456789ABCDEFabcdef";

		// Split
		std::vector<std::string> parts = fmt::split(wstr, {" ", ",", "0x", "0X", "\\x", "h", "H"});

		// Pad zeroes
		for (std::string& part : parts)
		{
			if (part.size() % 2)
			{
				gui_log.warning("Padding string part with '0' at front due to odd hexadeciaml characters count.");
				part.insert(part.begin(), '0');
			}
		}

		// Concat strings
		wstr.clear();
		for (const std::string& part : parts)
		{
			wstr += part;
		}

		if (const usz pos = wstr.find_first_not_of(hex_chars); pos != umax)
		{
			gui_log.error("String '%s' cannot be interpreted as hexadecimal byte string due to unknown character '%c'.",
				m_addr_line->text().toStdString(), wstr[pos]);
			return 0;
		}

		std::string dst;
		dst.resize(wstr.size() / 2);

		for (usz pos = 0; pos < wstr.size() / 2; pos++)
		{
			uchar value = 0;
			std::from_chars(wstr.data() + pos * 2, wstr.data() + (pos + 1) * 2, value, 16);
			std::memcpy(dst.data() + pos, &value, 1);
		}

		wstr = std::move(dst);
		break;
	}
	case as_f64:
	{
		// Remove trailing 'f' letters
		wstr = wstr.substr(0, wstr.find_last_not_of("Ff") + 1);

		char* end{};
		be_t<f64> value = std::strtod(wstr.data(), &end);

		if (wstr.empty() || end != wstr.data() + wstr.size())
		{
			gui_log.error("String '%s' cannot be interpreted as double.", wstr);
			return 0;
		}

		wstr.resize(sizeof(value));
		std::memcpy(wstr.data(), &value, sizeof(value));
		break;
	}
	case as_f32:
	{
		wstr = wstr.substr(0, wstr.find_last_not_of("Ff") + 1);

		char* end{};
		be_t<f32> value = std::strtof(wstr.data(), &end);

		if (wstr.empty() || end != wstr.data() + wstr.size())
		{
			gui_log.error("String '%s' cannot be interpreted as float.", wstr);
			return 0;
		}

		wstr.resize(sizeof(value));
		std::memcpy(wstr.data(), &value, sizeof(value));
		break;
	}
	default: ensure(false);
	}

	// Search the address space for the string
	atomic_t<u32> found = 0;
	atomic_t<u32> avail_addr = 0;

	// There's no need for so many threads (except for instructions searching)
	const u32 max_threads = utils::aligned_div(utils::get_thread_count(), mode < as_inst ? 2 : 1);

	static constexpr u32 block_size = 0x2000000;

	vm::reader_lock rlock;

	const named_thread_group workers("Memory Searcher "sv, max_threads, [&]()
	{
		if (mode == as_inst || mode == as_fake_spu_inst)
		{
			auto disasm = m_disasm->copy_type_erased();
			disasm->change_mode(cpu_disasm_mode::normal);

			SPUDisAsm spu_dis(cpu_disasm_mode::normal, static_cast<const u8*>(m_ptr));

			const usz limit = std::min(m_size, m_ptr == vm::g_sudo_addr ? 0xFFFF'0000 : m_size);

			while (true)
			{
				u32 addr;

				const bool ok = avail_addr.fetch_op([&](u32& val)
				{
					if (val < limit && val != umax)
					{
						while (m_ptr == vm::g_sudo_addr && !vm::check_addr(val, mode == as_inst ? vm::page_executable : 0))
						{
							// Skip unmapped memory
							val = utils::align(val + 1, 0x10000);

							if (!val)
							{
								return false;
							}
						}

						addr = val;

						// Iterate 16k instructions at a time
						val += 0x10000;

						if (!val)
						{
							// Overflow detection
							val = -1;
						}

						return true;
					}

					return false;
				}).second;

				if (!ok)
				{
					return;
				}

				u32 spu_base_pc = 0;

				if (mode == as_fake_spu_inst)
				{
					// Check if we can extend the limits of SPU decoder so it can use the previous 64k block
					// For SPU instruction patterns
					spu_base_pc = (addr >= 0x10000 && (m_ptr != vm::g_sudo_addr || vm::check_addr(addr - 0x10000, 0))) ? 0x10000 : 0;

					// Set base for SPU decoder
					spu_dis.change_ptr(static_cast<const u8*>(m_ptr) + addr - spu_base_pc);
				}

				for (u32 i = 0; i < 0x10000; i += 4)
				{
					if (mode == as_fake_spu_inst ? spu_dis.disasm(spu_base_pc + i) : disasm->disasm(addr + i))
					{
						auto& last = mode == as_fake_spu_inst ? spu_dis.last_opcode : disasm->last_opcode;

						if (case_insensitive)
						{
							std::transform(last.begin(), last.end(), last.begin(), ::tolower);
						}

						if (last.find(wstr) != umax)
						{
							gui_log.success("Found instruction at 0x%08x: '%s'", addr + i, last);
							found++;
						}
					}
				}
			}

			return;
		}

		u32 local_found = 0;

		u32 addr = 0;
		bool ok = false;

		const u64 addr_limit = (m_size >= block_size ? m_size - block_size : 0);

		while (true)
		{
			if (!(addr % block_size))
			{
				std::tie(addr, ok) = avail_addr.fetch_op([&](u32& val)
				{
					if (val <= addr_limit)
					{
						// Iterate in 32MB blocks
						val += block_size;

						if (!val) val = -1; // Overflow detection

						return true;
					}

					return false;
				});
			}

			if (!ok)
			{
				break;
			}

			if (![&]()
			{
				if (m_ptr != vm::g_sudo_addr)
				{
					// Always valid
					return true;
				}

				// Skip unmapped memory
				for (const u32 end = utils::align(addr + 1, block_size) - 0x1000; !vm::check_addr(addr, 0); addr += 0x1000)
				{
					if (addr == end)
					{
						return false;
					}
				}

				return true;
			}())
			{
				if (addr == 0u - 0x1000)
				{
					break;
				}

				// The entire block is unmapped
				addr += 0x1000;
				continue;
			}

			const u64 end_mem = std::min<u64>(utils::align<u64>(addr + 1, block_size), m_size);

			u64 addr_max = m_ptr == vm::g_sudo_addr ? addr : end_mem;

			// Determine allocation size quickly
			while (addr_max < end_mem && vm::check_addr(static_cast<u32>(addr_max), vm::page_1m_size))
			{
				addr_max += 0x100000;
			}

			while (addr_max < end_mem && vm::check_addr(static_cast<u32>(addr_max), vm::page_64k_size))
			{
				addr_max += 0x10000;
			}

			while (addr_max < end_mem && vm::check_addr(static_cast<u32>(addr_max), 0))
			{
				addr_max += 0x1000;
			}

			auto get_ptr = [&](u32 address)
			{
				return static_cast<const char*>(m_ptr) + address;
			};

			std::string_view section{get_ptr(addr), addr_max - addr};

			usz first_char = 0;

			auto log_occurance = [&](std::string_view& test_sv, bool always_log_str)
			{
				// Cut out a view which may or may not be suffixed by a single null character
				// This view is a peek at the full string which resides in PS3 memory 
				test_sv = test_sv.substr(0, std::max<usz>(wstr.size(), 100));
				const usz null_pos = test_sv.find_first_of("\n\0"sv, wstr.size());
				test_sv = test_sv.substr(0, null_pos);

				const usz start = test_sv.data() - get_ptr(0);

				if (!always_log_str && test_sv.size() == wstr.size())
				{
					// Shorthand logging for identical strings
					gui_log.success("Found at 0x%08x", start);
				}
				else if (null_pos != umax)
				{
					gui_log.success("Found at 0x%08x: '%s'", start, test_sv);
				}
				else
				{
					gui_log.success("Found at 0x%08x: '%s'..", start, test_sv);
				}
			};

			if (case_insensitive)
			{
				while (first_char = section.find_first_of(insensitive_search, first_char), first_char != umax)
				{
					const u32 start = addr + first_char;

					std::string_view test_sv{get_ptr(start), addr_max - start};

					// Do not use allocating functions such as fmt::to_lower
					if (test_sv.size() >= wstr.size() && std::all_of(wstr.begin(), wstr.end(), [&](const char& c) { return c == ::tolower(test_sv[&c - wstr.data()]); }))
					{
						// Force full logging if any character differs in case
						log_occurance(test_sv, !test_sv.starts_with(wstr));
						local_found++;
					}

					// Allow overlapping strings
					first_char++;
				}
			}
			else
			{
				while (first_char = section.find_first_of(wstr[0], first_char), first_char != umax)
				{
					const u32 start = addr + first_char;

					std::string_view test_sv{get_ptr(start), addr_max - start};

					if (test_sv.starts_with(wstr))
					{
						if (mode == as_string)
						{
							log_occurance(test_sv, false);
						}
						else
						{
							gui_log.success("Found at 0x%08x", start);
						}

						local_found++;
					}

					first_char++;
				}
			}

			// Check if at last page
			if (addr_max >= m_size - 0x1000)
			{
				break;
			}

			addr = addr_max;
		}

		found += local_found;
	});

	workers.join();

	return found;
}