#include "cache.h"
#include "definitions.h"
#include "response.h"
#include "utils.h"
#include <bits/stdc++.h>
#include <iostream>
#include <iterator>

Cache::Cache(Storage *lower, int delay)
{
	this->data = new std::vector<std::array<signed int, LINE_SIZE>>;
	this->data->resize(L1_CACHE_LINES);
	this->delay = delay;
	this->is_waiting = false;
	this->lower = lower;
	this->meta.fill({-1, -1});
	this->requester = IDLE;
	this->wait_time = this->delay;
}

Cache::~Cache()
{
	delete this->lower;
	delete this->data;
}

Response Cache::write_word(Accessor accessor, signed int data, int address)
{
	return process(accessor, address, [&](int index, int offset) {
		this->data->at(index).at(offset) = data;
		this->meta[index].at(1) = 1;
	});
}

Response Cache::write_line(
	Accessor accessor, std::array<signed int, LINE_SIZE> data_line, int address)
{
	return process(accessor, address, [&](int index, int offset) {
		(void)offset;
		this->data->at(index) = data_line;
		this->meta[index].at(1) = 1;
	});
}

// TODO: tests for multi level cache
Response Cache::read_line(
	Accessor accessor,
	int address,
	std::array<signed int, LINE_SIZE> &data_line)
{
	return process(accessor, address, [&](int index, int offset) {
		(void)offset;
		data_line = this->data->at(index);
	});
}

Response Cache::read_word(Accessor accessor, int address, signed int &data)
{
	return process(accessor, address, [&](int index, int offset) {
		data = this->data->at(index).at(offset);
	});
}

Response Cache::process(
	Accessor accessor,
	int address,
	std::function<void(int index, int offset)> request_handler)
{
	Response r = this->is_access_cleared(accessor, address);
	if (r == OK) {
		int tag, index, offset;
		get_bit_fields(address, &tag, &index, &offset);
		request_handler(index, offset);
	}
	return r;
}

Response Cache::is_access_cleared(Accessor accessor, int address)
{
	Response r;
	r = WAIT;
	/* Do this first--then process the first cycle immediately. */
	if (this->requester == IDLE)
		this->requester = accessor;
	if (this->requester == accessor) {
		handle_miss(address);
		if (this->is_waiting)
			r = BLOCKED;
		else if (this->wait_time == 0) {
			this->requester = IDLE;
			this->wait_time = delay;
			r = OK;
		} else {
			--this->wait_time;
		}
	}
	return r;
}

void Cache::handle_miss(int expected)
{
	Response r, q;
	int tag, index, offset;
	std::array<signed int, LINE_SIZE> *actual;
	std::array<int, 2> *meta;

	get_bit_fields(expected, &tag, &index, &offset);
	r = OK;
	meta = &this->meta.at(index);
	actual = &this->data->at(index);

	if (meta->at(0) != tag) {
		r = WAIT;
		// address not in cache
		if (meta->at(1) >= 0) {
			// occupant is dirty
			// writing line to DRam in case of dirty cache eviction
			q = this->lower->write_line(
				L1CACHE, *actual,
				((index << LINE_SPEC) +
				 (meta->at(0) << (L1_CACHE_LINE_SPEC + LINE_SPEC))));
			if (q == OK) {
				meta->at(1) = -1;
			}
		} else {
			q = this->lower->read_line(L1CACHE, expected, *actual);
			if (q == OK) {
				meta->at(0) = tag;
			}
		}
	}

	this->is_waiting = (r == OK) ? false : true;
}

std::array<std::array<int, 2>, L1_CACHE_LINES> Cache::get_meta() const
{
	std::array<std::array<int, 2>, L1_CACHE_LINES> ret;
	std::copy(std::begin(this->meta), std::end(this->meta), std::begin(ret));
	return ret;
}

std::ostream &operator<<(std::ostream &os, const Cache &c)
{
	const auto default_flags = std::cout.flags();
	const auto default_fill = std::cout.fill();

	std::vector<std::array<signed int, LINE_SIZE>> data =
		c.view(0, L1_CACHE_LINES);
	std::array<std::array<int, 2>, L1_CACHE_LINES> meta = c.get_meta();

	os << " " << std::setfill(' ') << std::setw(L1_CACHE_LINE_SPEC + 2)
	   << "INDEX"
	   << " | " << std::setfill(' ') << std::setw((8 + 3) * 4 - 1) << "DATA"
	   << " | " << std::setfill(' ')
	   << std::setw(MEM_LINE_SPEC - L1_CACHE_LINE_SPEC + 2) << "TAG"
	   << " | D" << std::endl;
	for (int i = 0; i < L1_CACHE_LINES; ++i) {
		os << " 0b" << std::setw(L1_CACHE_LINE_SPEC)
		   << std::bitset<L1_CACHE_LINE_SPEC>(i) << " | ";
		for (int j = 0; j < LINE_SIZE; ++j) {
			os << "0x" << std::setfill('0') << std::setw(8) << std::hex
			   << data.at(i).at(j) << " ";
		}
		os << "| 0b" << std::setfill(' ');

		if (meta.at(i)[0] < 0)
			os << std::setfill('?')
			   << std::setw(MEM_LINE_SPEC - L1_CACHE_LINE_SPEC) << "";
		else
			os << std::bitset<MEM_LINE_SPEC - L1_CACHE_LINE_SPEC>(
				meta.at(i)[0]);

		os << " | " << (int)(meta.at(i)[0] >= 0) << std::endl;
	}

	std::cout.flags(default_flags);
	std::cout.fill(default_fill);
	return os;
}