/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Claire Xenia Wolf <claire@yosyshq.com>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include "kernel/yosys.h"
#include "kernel/sigtools.h"
#include "libparse.h"
#include <string.h>
#include <errno.h>

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

struct cell_mapping {
	IdString cell_name;
	std::map<std::string, char> ports;
};
static std::map<RTLIL::IdString, cell_mapping> cell_mappings;

static void logmap(IdString dff)
{
	if (cell_mappings.count(dff) == 0) {
		log("    unmapped dff cell: %s\n", dff.c_str());
	} else {
		log("    %s %s (", cell_mappings[dff].cell_name.c_str(), dff.substr(1).c_str());
		bool first = true;
		for (auto &port : cell_mappings[dff].ports) {
			char arg[3] = { port.second, 0, 0 };
			if ('a' <= arg[0] && arg[0] <= 'z')
				arg[1] = arg[0] - ('a' - 'A'), arg[0] = '~';
			else
				arg[1] = arg[0], arg[0] = ' ';
			log("%s.%s(%s)", first ? "" : ", ", port.first.c_str(), arg);
			first = false;
		}
		log(");\n");
	}
}

static void logmap_all()
{
	logmap(ID($_DFF_N_));
	logmap(ID($_DFF_P_));

	logmap(ID($_DFF_NN0_));
	logmap(ID($_DFF_NN1_));
	logmap(ID($_DFF_NP0_));
	logmap(ID($_DFF_NP1_));
	logmap(ID($_DFF_PN0_));
	logmap(ID($_DFF_PN1_));
	logmap(ID($_DFF_PP0_));
	logmap(ID($_DFF_PP1_));

	logmap(ID($_DFFSR_NNN_));
	logmap(ID($_DFFSR_NNP_));
	logmap(ID($_DFFSR_NPN_));
	logmap(ID($_DFFSR_NPP_));
	logmap(ID($_DFFSR_PNN_));
	logmap(ID($_DFFSR_PNP_));
	logmap(ID($_DFFSR_PPN_));
	logmap(ID($_DFFSR_PPP_));
}

static bool parse_pin(LibertyAst *cell, LibertyAst *attr, std::string &pin_name, bool &pin_pol)
{
	if (cell == nullptr || attr == nullptr || attr->value.empty())
		return false;

	std::string value = attr->value;

	for (size_t pos = value.find_first_of("\" \t()"); pos != std::string::npos; pos = value.find_first_of("\" \t()"))
		value.erase(pos, 1);

	if (value[value.size()-1] == '\'') {
		pin_name = value.substr(0, value.size()-1);
		pin_pol = false;
	} else if (value[0] == '!') {
		pin_name = value.substr(1, value.size()-1);
		pin_pol = false;
	} else {
		pin_name = value;
		pin_pol = true;
	}

	for (auto child : cell->children)
		if (child->id == "pin" && child->args.size() == 1 && child->args[0] == pin_name)
			return true;

	/* If we end up here, the pin specified in the attribute does not exist, which is an error,
	   or, the attribute contains an expression which we do not yet support.
       For now, we'll simply produce a warning to let the user know something is up.
	*/
	if (pin_name.find_first_of("^*|&") == std::string::npos) {
		log_warning("Malformed liberty file - cannot find pin '%s' in cell '%s' - skipping.\n", pin_name.c_str(), cell->args[0].c_str());
	}
	else {
		log_warning("Found unsupported expression '%s' in pin attribute of cell '%s' - skipping.\n", pin_name.c_str(), cell->args[0].c_str());
	}

	return false;
}

static void find_cell(LibertyAst *ast, IdString cell_type, bool clkpol, bool has_reset, bool rstpol, bool rstval)
{
	LibertyAst *best_cell = nullptr;
	std::map<std::string, char> best_cell_ports;
	int best_cell_pins = 0;
	bool best_cell_noninv = false;
	double best_cell_area = 0;

	if (ast->id != "library")
		log_error("Format error in liberty file.\n");

	for (auto cell : ast->children)
	{
		if (cell->id != "cell" || cell->args.size() != 1)
			continue;

		LibertyAst *dn = cell->find("dont_use");
		if (dn != nullptr && dn->value == "true")
			continue;

		LibertyAst *ff = cell->find("ff");
		if (ff == nullptr)
			continue;

		std::string cell_clk_pin, cell_rst_pin, cell_next_pin;
		bool cell_clk_pol, cell_rst_pol, cell_next_pol;

		if (!parse_pin(cell, ff->find("clocked_on"), cell_clk_pin, cell_clk_pol) || cell_clk_pol != clkpol)
			continue;
		if (!parse_pin(cell, ff->find("next_state"), cell_next_pin, cell_next_pol))
			continue;
		if (has_reset && rstval == false) {
			if (!parse_pin(cell, ff->find("clear"), cell_rst_pin, cell_rst_pol) || cell_rst_pol != rstpol)
				continue;
		}
		if (has_reset && rstval == true) {
			if (!parse_pin(cell, ff->find("preset"), cell_rst_pin, cell_rst_pol) || cell_rst_pol != rstpol)
				continue;
		}

		std::map<std::string, char> this_cell_ports;
		this_cell_ports[cell_clk_pin] = 'C';
		if (has_reset)
			this_cell_ports[cell_rst_pin] = 'R';
		this_cell_ports[cell_next_pin] = 'D';

		double area = 0;
		LibertyAst *ar = cell->find("area");
		if (ar != nullptr && !ar->value.empty())
			area = atof(ar->value.c_str());

		int num_pins = 0;
		bool found_output = false;
		bool found_noninv_output = false;
		for (auto pin : cell->children)
		{
			if (pin->id != "pin" || pin->args.size() != 1)
				continue;

			LibertyAst *dir = pin->find("direction");
			if (dir == nullptr || dir->value == "internal")
				continue;
			num_pins++;

			if (dir->value == "input" && this_cell_ports.count(pin->args[0]) == 0)
				goto continue_cell_loop;

			LibertyAst *func = pin->find("function");
			if (dir->value == "output" && func != nullptr) {
				std::string value = func->value;
				for (size_t pos = value.find_first_of("\" \t"); pos != std::string::npos; pos = value.find_first_of("\" \t"))
					value.erase(pos, 1);
				if (value == ff->args[0]) {
					this_cell_ports[pin->args[0]] = cell_next_pol ? 'Q' : 'q';
					if (cell_next_pol)
						found_noninv_output = true;
					found_output = true;
				} else
				if (value == ff->args[1]) {
					this_cell_ports[pin->args[0]] = cell_next_pol ? 'q' : 'Q';
					if (!cell_next_pol)
						found_noninv_output = true;
					found_output = true;
				}
			}

			if (this_cell_ports.count(pin->args[0]) == 0)
				this_cell_ports[pin->args[0]] = 0;
		}

		if (!found_output || (best_cell != nullptr && (num_pins > best_cell_pins || (best_cell_noninv && !found_noninv_output))))
			continue;

		if (best_cell != nullptr && num_pins == best_cell_pins && area > best_cell_area)
			continue;

		best_cell = cell;
		best_cell_pins = num_pins;
		best_cell_area = area;
		best_cell_noninv = found_noninv_output;
		best_cell_ports.swap(this_cell_ports);
	continue_cell_loop:;
	}

	if (best_cell != nullptr) {
		log("  cell %s (%sinv, pins=%d, area=%.2f) is a direct match for cell type %s.\n",
				best_cell->args[0].c_str(), best_cell_noninv ? "non" : "", best_cell_pins, best_cell_area, cell_type.c_str());
		cell_mappings[cell_type].cell_name = RTLIL::escape_id(best_cell->args[0]);
		cell_mappings[cell_type].ports = best_cell_ports;
	}
}

static void find_cell_sr(LibertyAst *ast, IdString cell_type, bool clkpol, bool setpol, bool clrpol)
{
	LibertyAst *best_cell = nullptr;
	std::map<std::string, char> best_cell_ports;
	int best_cell_pins = 0;
	bool best_cell_noninv = false;
	double best_cell_area = 0;

	if (ast->id != "library")
		log_error("Format error in liberty file.\n");

	for (auto cell : ast->children)
	{
		if (cell->id != "cell" || cell->args.size() != 1)
			continue;

		LibertyAst *dn = cell->find("dont_use");
		if (dn != nullptr && dn->value == "true")
			continue;

		LibertyAst *ff = cell->find("ff");
		if (ff == nullptr)
			continue;

		std::string cell_clk_pin, cell_set_pin, cell_clr_pin, cell_next_pin;
		bool cell_clk_pol, cell_set_pol, cell_clr_pol, cell_next_pol;

		if (!parse_pin(cell, ff->find("clocked_on"), cell_clk_pin, cell_clk_pol) || cell_clk_pol != clkpol)
			continue;
		if (!parse_pin(cell, ff->find("next_state"), cell_next_pin, cell_next_pol))
			continue;
		if (!parse_pin(cell, ff->find("preset"), cell_set_pin, cell_set_pol) || cell_set_pol != setpol)
			continue;
		if (!parse_pin(cell, ff->find("clear"), cell_clr_pin, cell_clr_pol) || cell_clr_pol != clrpol)
			continue;

		std::map<std::string, char> this_cell_ports;
		this_cell_ports[cell_clk_pin] = 'C';
		this_cell_ports[cell_set_pin] = 'S';
		this_cell_ports[cell_clr_pin] = 'R';
		this_cell_ports[cell_next_pin] = 'D';

		double area = 0;
		LibertyAst *ar = cell->find("area");
		if (ar != nullptr && !ar->value.empty())
			area = atof(ar->value.c_str());

		int num_pins = 0;
		bool found_output = false;
		bool found_noninv_output = false;
		for (auto pin : cell->children)
		{
			if (pin->id != "pin" || pin->args.size() != 1)
				continue;

			LibertyAst *dir = pin->find("direction");
			if (dir == nullptr || dir->value == "internal")
				continue;
			num_pins++;

			if (dir->value == "input" && this_cell_ports.count(pin->args[0]) == 0)
				goto continue_cell_loop;

			LibertyAst *func = pin->find("function");
			if (dir->value == "output" && func != nullptr) {
				std::string value = func->value;
				for (size_t pos = value.find_first_of("\" \t"); pos != std::string::npos; pos = value.find_first_of("\" \t"))
					value.erase(pos, 1);
				if (value == ff->args[0]) {
					this_cell_ports[pin->args[0]] = cell_next_pol ? 'Q' : 'q';
					if (cell_next_pol)
						found_noninv_output = true;
					found_output = true;
				} else
				if (value == ff->args[1]) {
					this_cell_ports[pin->args[0]] = cell_next_pol ? 'q' : 'Q';
					if (!cell_next_pol)
						found_noninv_output = true;
					found_output = true;
				}
			}

			if (this_cell_ports.count(pin->args[0]) == 0)
				this_cell_ports[pin->args[0]] = 0;
		}

		if (!found_output || (best_cell != nullptr && (num_pins > best_cell_pins || (best_cell_noninv && !found_noninv_output))))
			continue;

		if (best_cell != nullptr && num_pins == best_cell_pins && area > best_cell_area)
			continue;

		best_cell = cell;
		best_cell_pins = num_pins;
		best_cell_area = area;
		best_cell_noninv = found_noninv_output;
		best_cell_ports.swap(this_cell_ports);
	continue_cell_loop:;
	}

	if (best_cell != nullptr) {
		log("  cell %s (%sinv, pins=%d, area=%.2f) is a direct match for cell type %s.\n",
				best_cell->args[0].c_str(), best_cell_noninv ? "non" : "", best_cell_pins, best_cell_area, cell_type.c_str());
		cell_mappings[cell_type].cell_name = RTLIL::escape_id(best_cell->args[0]);
		cell_mappings[cell_type].ports = best_cell_ports;
	}
}

static void dfflibmap(RTLIL::Design *design, RTLIL::Module *module)
{
	log("Mapping DFF cells in module `%s':\n", module->name.c_str());

	dict<SigBit, pool<Cell*>> notmap;
	SigMap sigmap(module);

	std::vector<RTLIL::Cell*> cell_list;
	for (auto cell : module->cells()) {
		if (design->selected(module, cell) && cell_mappings.count(cell->type) > 0)
			cell_list.push_back(cell);
		if (cell->type == ID($_NOT_))
			notmap[sigmap(cell->getPort(ID::A))].insert(cell);
	}

	std::map<std::string, int> stats;
	for (auto cell : cell_list)
	{
		auto cell_type = cell->type;
		auto cell_name = cell->name;
		auto cell_connections = cell->connections();
		std::string src = cell->get_src_attribute();

		module->remove(cell);

		cell_mapping &cm = cell_mappings[cell_type];
		RTLIL::Cell *new_cell = module->addCell(cell_name, cm.cell_name);

		new_cell->set_src_attribute(src);

		bool has_q = false, has_qn = false;
		for (auto &port : cm.ports) {
			if (port.second == 'Q') has_q = true;
			if (port.second == 'q') has_qn = true;
		}

		for (auto &port : cm.ports) {
			RTLIL::SigSpec sig;
			if ('A' <= port.second && port.second <= 'Z') {
				sig = cell_connections[std::string("\\") + port.second];
			} else
			if (port.second == 'q') {
				RTLIL::SigSpec old_sig = cell_connections[std::string("\\") + char(port.second - ('a' - 'A'))];
				sig = module->addWire(NEW_ID, GetSize(old_sig));
				if (has_q && has_qn) {
					for (auto &it : notmap[sigmap(old_sig)]) {
						module->connect(it->getPort(ID::Y), sig);
						it->setPort(ID::Y, module->addWire(NEW_ID, GetSize(old_sig)));
					}
				} else {
					module->addNotGate(NEW_ID, sig, old_sig);
				}
			} else
			if ('a' <= port.second && port.second <= 'z') {
				sig = cell_connections[std::string("\\") + char(port.second - ('a' - 'A'))];
				sig = module->NotGate(NEW_ID, sig);
			} else
			if (port.second == '0' || port.second == '1') {
				sig = RTLIL::SigSpec(port.second == '0' ? 0 : 1, 1);
			} else
			if (port.second == 0) {
				sig = module->addWire(NEW_ID);
			} else
				log_abort();
			new_cell->setPort("\\" + port.first, sig);
		}

		stats[stringf("  mapped %%d %s cells to %s cells.\n", cell_type.c_str(), new_cell->type.c_str())]++;
	}

	for (auto &stat: stats)
		log(stat.first.c_str(), stat.second);
}

struct DfflibmapPass : public Pass {
	DfflibmapPass() : Pass("dfflibmap", "technology mapping of flip-flops") { }
	void help() override
	{
		log("\n");
		log("    dfflibmap [-prepare] [-map-only] [-info] -liberty <file> [selection]\n");
		log("\n");
		log("Map internal flip-flop cells to the flip-flop cells in the technology\n");
		log("library specified in the given liberty file.\n");
		log("\n");
		log("This pass may add inverters as needed. Therefore it is recommended to\n");
		log("first run this pass and then map the logic paths to the target technology.\n");
		log("\n");
		log("When called with -prepare, this command will convert the internal FF cells\n");
		log("to the internal cell types that best match the cells found in the given\n");
		log("liberty file, but won't actually map them to the target cells.\n");
		log("\n");
		log("When called with -map-only, this command will only map internal cell\n");
		log("types that are already of exactly the right type to match the target\n");
		log("cells, leaving remaining internal cells untouched.\n");
		log("\n");
		log("When called with -info, this command will only print the target cell\n");
		log("list, along with their associated internal cell types, and the arguments");
		log("that would be passed to the dfflegalize pass.  The design will not be\n");
		log("changed.\n");
		log("\n");
	}
	void execute(std::vector<std::string> args, RTLIL::Design *design) override
	{
		log_header(design, "Executing DFFLIBMAP pass (mapping DFF cells to sequential cells from liberty file).\n");
		log_push();

		std::string liberty_file;
		bool prepare_mode = false;
		bool map_only_mode = false;
		bool info_mode = false;

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++)
		{
			std::string arg = args[argidx];
			if (arg == "-liberty" && argidx+1 < args.size()) {
				liberty_file = args[++argidx];
				rewrite_filename(liberty_file);
				continue;
			}
			if (arg == "-prepare") {
				prepare_mode = true;
				continue;
			}
			if (arg == "-map-only") {
				map_only_mode = true;
				continue;
			}
			if (arg == "-info") {
				info_mode = true;
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		int modes = 0;
		if (prepare_mode)
			modes++;
		if (map_only_mode)
			modes++;
		if (info_mode)
			modes++;
		if (modes > 1)
			log_cmd_error("Only one of -prepare, -map-only, or -info options should be given!\n");

		if (liberty_file.empty())
			log_cmd_error("Missing `-liberty liberty_file' option!\n");

		std::ifstream f;
		f.open(liberty_file.c_str());
		if (f.fail())
			log_cmd_error("Can't open liberty file `%s': %s\n", liberty_file.c_str(), strerror(errno));
		LibertyParser libparser(f);
		f.close();

		find_cell(libparser.ast, ID($_DFF_N_), false, false, false, false);
		find_cell(libparser.ast, ID($_DFF_P_), true, false, false, false);

		find_cell(libparser.ast, ID($_DFF_NN0_), false, true, false, false);
		find_cell(libparser.ast, ID($_DFF_NN1_), false, true, false, true);
		find_cell(libparser.ast, ID($_DFF_NP0_), false, true, true, false);
		find_cell(libparser.ast, ID($_DFF_NP1_), false, true, true, true);
		find_cell(libparser.ast, ID($_DFF_PN0_), true, true, false, false);
		find_cell(libparser.ast, ID($_DFF_PN1_), true, true, false, true);
		find_cell(libparser.ast, ID($_DFF_PP0_), true, true, true, false);
		find_cell(libparser.ast, ID($_DFF_PP1_), true, true, true, true);

		find_cell_sr(libparser.ast, ID($_DFFSR_NNN_), false, false, false);
		find_cell_sr(libparser.ast, ID($_DFFSR_NNP_), false, false, true);
		find_cell_sr(libparser.ast, ID($_DFFSR_NPN_), false, true, false);
		find_cell_sr(libparser.ast, ID($_DFFSR_NPP_), false, true, true);
		find_cell_sr(libparser.ast, ID($_DFFSR_PNN_), true, false, false);
		find_cell_sr(libparser.ast, ID($_DFFSR_PNP_), true, false, true);
		find_cell_sr(libparser.ast, ID($_DFFSR_PPN_), true, true, false);
		find_cell_sr(libparser.ast, ID($_DFFSR_PPP_), true, true, true);

		log("  final dff cell mappings:\n");
		logmap_all();

		if (!map_only_mode) {
			std::string dfflegalize_cmd = "dfflegalize";
			for (auto it : cell_mappings)
				dfflegalize_cmd += stringf(" -cell %s 01", it.first.c_str());
			dfflegalize_cmd += " t:$_DFF* t:$_SDFF*";
			if (info_mode) {
				log("dfflegalize command line: %s\n", dfflegalize_cmd.c_str());
			} else {
				Pass::call(design, dfflegalize_cmd);
			}
		}

		if (!prepare_mode && !info_mode) {
			for (auto module : design->selected_modules())
				if (!module->get_blackbox_attribute())
					dfflibmap(design, module);
		}

		log_pop();
		cell_mappings.clear();
	}
} DfflibmapPass;

PRIVATE_NAMESPACE_END