/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
 *  
 *  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/register.h"
#include "kernel/celltypes.h"
#include "kernel/sigtools.h"
#include "kernel/log.h"
#include "kernel/satgen.h"
#include "frontends/verilog/verilog_frontend.h"
#include <stdlib.h>
#include <stdio.h>
#include <algorithm>

static void split(std::vector<std::string> &tokens, const std::string &text, char sep)
{
	size_t start = 0, end = 0;
	while ((end = text.find(sep, start)) != std::string::npos) {
		tokens.push_back(text.substr(start, end - start));
		start = end + 1;
	}
	tokens.push_back(text.substr(start));
}

bool parse_sigstr(RTLIL::SigSpec &sig, RTLIL::Module *module, std::string str)
{
	std::vector<std::string> tokens;
	split(tokens, str, ',');

	sig = RTLIL::SigSpec();
	for (auto &tok : tokens)
	{
		std::string netname = tok;
		std::string indices;

		if (netname.size() == 0)
			continue;

		if ('0' <= netname[0] && netname[0] <= '9') {
			AST::AstNode *ast = VERILOG_FRONTEND::const2ast(netname);
			if (ast == NULL)
				return false;
			sig.append(RTLIL::Const(ast->bits));
			delete ast;
			continue;
		}

		if (netname[0] != '$' && netname[0] != '\\')
			netname = "\\" + netname;

		if (module->wires.count(netname) == 0) {
			size_t indices_pos = netname.size()-1;
			if (indices_pos > 2 && netname[indices_pos] == ']')
			{
				indices_pos--;
				while (indices_pos > 0 && ('0' <= netname[indices_pos] && netname[indices_pos] <= '9')) indices_pos--;
				if (indices_pos > 0 && netname[indices_pos] == ':') {
					indices_pos--;
					while (indices_pos > 0 && ('0' <= netname[indices_pos] && netname[indices_pos] <= '9')) indices_pos--;
				}
				if (indices_pos > 0 && netname[indices_pos] == '[') {
					indices = netname.substr(indices_pos);
					netname = netname.substr(0, indices_pos);
				}
			}
		}

		if (module->wires.count(netname) == 0)
			return false;

		RTLIL::Wire *wire = module->wires.at(netname);
		if (!indices.empty()) {
			std::vector<std::string> index_tokens;
			split(index_tokens, indices.substr(1, indices.size()-2), ':');
			if (index_tokens.size() == 1)
				sig.append(RTLIL::SigSpec(wire, 1, atoi(index_tokens.at(0).c_str())));
			else {
				int a = atoi(index_tokens.at(0).c_str());
				int b = atoi(index_tokens.at(1).c_str());
				if (a > b) {
					int tmp = a;
					a = b, b = tmp;
				}
				sig.append(RTLIL::SigSpec(wire, b-a+1, a));
			}
		} else
			sig.append(wire);
	}

	return true;
}

struct SatSolvePass : public Pass {
	SatSolvePass() : Pass("sat_solve", "solve a SAT problem in the circuit") { }
	virtual void help()
	{
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
		log("\n");
		log("    sat_solve [options] [selection]\n");
		log("\n");
		log("This command solves a SAT problem defined over the currently selected circuit\n");
		log("and additional constraints passed as parameters.\n");
		log("\n");
		log("    -all\n");
		log("        show all solutions to the problem (this can grow exponentially, use\n");
		log("        -max <N> instead to get <N> solutions)\n");
		log("\n");
		log("    -max <N>\n");
		log("        like -all, but limit number of solutions to <N>\n");
		log("\n");
		log("    -set <signal> <value>\n");
		log("        set the specified signal to the specified value.\n");
		log("\n");
		log("    -show <signal>\n");
		log("        show the model for the specified signal. if no -show option is\n");
		log("        passed then a set of signals to be shown is automatically selected.\n");
		log("\n");
		log("The following options can be used to set up a sequential problem:\n");
		log("\n");
		log("    -seq <N>\n");
		log("        set up a sequential problem with <N> time steps. The steps will\n");
		log("        be numbered from 1 to N.\n");
		log("\n");
		log("    -set-at <N> <signal> <value>\n");
		log("    -unset-at <N> <signal>\n");
		log("        set or unset the specified signal to the specified value in the\n");
		log("        given timestep. this has priority over a -set for the same signal.\n");
		log("\n");
	}
	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
	{
		std::vector<std::pair<std::string, std::string>> sets;
		std::map<int, std::vector<std::pair<std::string, std::string>>> sets_at;
		std::map<int, std::vector<std::string>> unsets_at;
		std::vector<std::string> shows;
		int loopcount = 0, seq_len = 0;

		log_header("Executing SAT_SOLVE pass (solving SAT problems in the circuit).\n");

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++) {
			if (args[argidx] == "-all") {
				loopcount = -1;
				continue;
			}
			if (args[argidx] == "-max" && argidx+1 < args.size()) {
				loopcount = atoi(args[++argidx].c_str());
				continue;
			}
			if (args[argidx] == "-set" && argidx+2 < args.size()) {
				std::string lhs = args[++argidx].c_str();
				std::string rhs = args[++argidx].c_str();
				sets.push_back(std::pair<std::string, std::string>(lhs, rhs));
				continue;
			}
			if (args[argidx] == "-seq" && argidx+1 < args.size()) {
				seq_len = atoi(args[++argidx].c_str());
				continue;
			}
			if (args[argidx] == "-set-at" && argidx+3 < args.size()) {
				int timestep = atoi(args[++argidx].c_str());
				std::string lhs = args[++argidx].c_str();
				std::string rhs = args[++argidx].c_str();
				sets_at[timestep].push_back(std::pair<std::string, std::string>(lhs, rhs));
				continue;
			}
			if (args[argidx] == "-unset-at" && argidx+2 < args.size()) {
				int timestep = atoi(args[++argidx].c_str());
				std::string lhs = args[++argidx].c_str();
				unsets_at[timestep].push_back(lhs);
				continue;
			}
			if (args[argidx] == "-show" && argidx+1 < args.size()) {
				shows.push_back(args[++argidx]);
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		RTLIL::Module *module = NULL;
		for (auto &mod_it : design->modules)
			if (design->selected(mod_it.second)) {
				if (module)
					log_cmd_error("Only one module must be selected for the SAT_SOLVE pass! (selected: %s and %s)\n",
							RTLIL::id2cstr(module->name), RTLIL::id2cstr(mod_it.first));
				module = mod_it.second;
			}
		if (module == NULL)
			log_cmd_error("Can't perform SAT_SOLVE on an empty selection!\n");

		ezDefaultSAT ez;
		SigMap sigmap(module);
		SatGen satgen(&ez, design, &sigmap);

		// when no -show is passed, the set signals and other data is collected in
		// this variables, which is then used to generate the list of signals
		// on the  input cone on the set signals and used as show signals
		SigPool show_signal_pool;
		SigSet<RTLIL::Cell*> show_drivers;
		std::map<RTLIL::Cell*,RTLIL::SigSpec> show_driven;
		CellTypes ct(design);

		for (int timestep = -1; timestep <= seq_len; timestep++)
		{
			// set timestep=-1 for non-seq problems and timestep=1:N for seq problems
			if ((timestep == -1 && seq_len > 0) || timestep == 0)
				continue;

			if (timestep > 0)
				log ("\nSetting up time step %d:\n", timestep);
			else
				log ("\nSetting up SAT problem:\n");

			RTLIL::SigSpec big_lhs, big_rhs;

			for (auto &s : sets)
			{
				RTLIL::SigSpec lhs, rhs;

				if (!parse_sigstr(lhs, module, s.first))
					log_cmd_error("Failed to parse lhs set expression `%s'.\n", s.first.c_str());
				if (!parse_sigstr(rhs, module, s.second))
					log_cmd_error("Failed to parse rhs set expression `%s'.\n", s.second.c_str());
				show_signal_pool.add(sigmap(lhs));
				show_signal_pool.add(sigmap(rhs));

				if (lhs.width != rhs.width)
					log_cmd_error("Set expression with different lhs and rhs sizes: %s (%s, %d bits) vs. %s (%s, %d bits)\n",
						s.first.c_str(), log_signal(lhs), lhs.width, s.second.c_str(), log_signal(rhs), rhs.width);

				log("Import set-constraint: %s = %s\n", log_signal(lhs), log_signal(rhs));
				big_lhs.remove2(lhs, &big_rhs);
				big_lhs.append(lhs);
				big_rhs.append(rhs);
			}

			for (auto &s : sets_at[timestep])
			{
				RTLIL::SigSpec lhs, rhs;

				if (!parse_sigstr(lhs, module, s.first))
					log_cmd_error("Failed to parse lhs set expression `%s'.\n", s.first.c_str());
				if (!parse_sigstr(rhs, module, s.second))
					log_cmd_error("Failed to parse rhs set expression `%s'.\n", s.second.c_str());
				show_signal_pool.add(sigmap(lhs));
				show_signal_pool.add(sigmap(rhs));

				if (lhs.width != rhs.width)
					log_cmd_error("Set expression with different lhs and rhs sizes: %s (%s, %d bits) vs. %s (%s, %d bits)\n",
						s.first.c_str(), log_signal(lhs), lhs.width, s.second.c_str(), log_signal(rhs), rhs.width);

				log("Import set-constraint for timestep: %s = %s\n", log_signal(lhs), log_signal(rhs));
				big_lhs.remove2(lhs, &big_rhs);
				big_lhs.append(lhs);
				big_rhs.append(rhs);
			}

			for (auto &s : unsets_at[timestep])
			{
				RTLIL::SigSpec lhs;

				if (!parse_sigstr(lhs, module, s))
					log_cmd_error("Failed to parse lhs set expression `%s'.\n", s.c_str());
				show_signal_pool.add(sigmap(lhs));

				log("Import unset-constraint for timestep: %s\n", log_signal(lhs));
				big_lhs.remove2(lhs, &big_rhs);
			}

			log("Final constraint equation: %s = %s\n", log_signal(big_lhs), log_signal(big_rhs));

			std::vector<int> lhs_vec = satgen.importSigSpec(big_lhs, timestep);
			std::vector<int> rhs_vec = satgen.importSigSpec(big_rhs, timestep);
			ez.assume(ez.vec_eq(lhs_vec, rhs_vec));

			int import_cell_counter = 0;
			for (auto &c : module->cells)
				if (design->selected(module, c.second) && ct.cell_known(c.second->type)) {
					// log("Import cell: %s\n", RTLIL::id2cstr(c.first));
					if (satgen.importCell(c.second, timestep)) {
						for (auto &p : c.second->connections)
							if (ct.cell_output(c.second->type, p.first))
								show_drivers.insert(sigmap(p.second), c.second);
							else
								show_driven[c.second].append(sigmap(p.second));
						import_cell_counter++;
					} else
						log("Warning: failed to import cell %s (type %s) to SAT database.\n", RTLIL::id2cstr(c.first), RTLIL::id2cstr(c.second->type));
			}
			log("Imported %d cells to SAT database.\n", import_cell_counter);
		}

		struct ModelBlockInfo {
			int timestep, offset, width;
			std::string description;
			bool operator < (const ModelBlockInfo &other) const {
				if (timestep != other.timestep)
					return timestep < other.timestep;
				if (description != other.description)
					return description < other.description;
				if (offset != other.offset)
					return offset < other.offset;
				if (width != other.width)
					return width < other.width;
				return false;
			}
		};

		std::vector<int> modelExpressions;
		std::vector<bool> modelValues;
		std::set<ModelBlockInfo> modelInfo;

		// Add "normal" show signals for every timestep

		RTLIL::SigSpec modelSig;

		if (shows.size() == 0) {
			SigPool handled_signals, final_signals;
			for (auto &s : show_driven)
				s.second.sort_and_unify();
			while (show_signal_pool.size() > 0) {
				RTLIL::SigSpec sig = show_signal_pool.export_one();
				show_signal_pool.del(sig);
				handled_signals.add(sig);
				std::set<RTLIL::Cell*> drivers = show_drivers.find(sig);
				if (drivers.size() == 0) {
					final_signals.add(sig);
				} else {
					for (auto &d : drivers)
					for (auto &p : d->connections)
						show_signal_pool.add(handled_signals.remove(p.second));
				}
			}
			modelSig = final_signals.export_all();
		} else {
			for (auto &s : shows) {
				RTLIL::SigSpec sig;
				if (!parse_sigstr(sig, module, s))
					log_cmd_error("Failed to parse show expression `%s'.\n", s.c_str());
				log("Import show expression: %s\n", log_signal(sig));
				modelSig.append(sig);
			}
		}

		modelSig.sort_and_unify();
		// log("Model signals: %s\n", log_signal(modelSig));

		for (auto &c : modelSig.chunks)
			if (c.wire != NULL) {
				ModelBlockInfo info;
				RTLIL::SigSpec chunksig = c;
				info.width = chunksig.width;
				info.description = log_signal(chunksig);

				for (int timestep = -1; timestep <= seq_len; timestep++) {
					if ((timestep == -1 && seq_len > 0) || timestep == 0)
						continue;
					std::vector<int> vec = satgen.importSigSpec(chunksig, timestep);
					info.timestep = timestep;
					info.offset = modelExpressions.size();
					modelExpressions.insert(modelExpressions.end(), vec.begin(), vec.end());
					modelInfo.insert(info);
				}
			}

		// Add zero step signals as collected by satgen

		modelSig = satgen.initial_signals.export_all();
		for (auto &c : modelSig.chunks)
			if (c.wire != NULL) {
				ModelBlockInfo info;
				RTLIL::SigSpec chunksig = c;
				info.timestep = 0;
				info.offset = modelExpressions.size();
				info.width = chunksig.width;
				info.description = log_signal(chunksig);
				std::vector<int> vec = satgen.importSigSpec(chunksig, 1);
				modelExpressions.insert(modelExpressions.end(), vec.begin(), vec.end());
				modelInfo.insert(info);
			}

#if 0
		// print CNF for debugging
		ez.printDIMACS(stdout, true);
#endif

rerun_solver:
		log("\nSolving problem with %d variables and %d clauses..\n", ez.numCnfVariables(), ez.numCnfClauses());
		if (ez.solve(modelExpressions, modelValues))
		{
			log("SAT solving finished - model found:\n");
			log("\n");

			int maxModelName = 10;
			int maxModelWidth = 10;

			for (auto &info : modelInfo) {
				maxModelName = std::max(maxModelName, int(info.description.size()));
				maxModelWidth = std::max(maxModelWidth, info.width);
			}

			int last_timestep = -2;
			for (auto &info : modelInfo)
			{
				RTLIL::Const value;
				for (int i = 0; i < info.width; i++)
					value.bits.push_back(modelValues.at(info.offset+i) ? RTLIL::State::S1 : RTLIL::State::S0);

				if (info.timestep != last_timestep) {
					const char *hline = "---------------------------------------------------------------------------------------------------"
							    "---------------------------------------------------------------------------------------------------"
							    "---------------------------------------------------------------------------------------------------";
					if (last_timestep == -2) {
						log(seq_len > 0 ? "  Time " : "  ");
						log("%-*s %10s %10s %*s\n", maxModelName+10, "Signal Name", "Dec", "Hex", maxModelWidth+5, "Bin");
					}
					log(seq_len > 0 ? "  ---- " : "  ");
					log("%*.*s %10.10s %10.10s %*.*s\n", maxModelName+10, maxModelName+10,
							hline, hline, hline, maxModelWidth+5, maxModelWidth+5, hline);
					last_timestep = info.timestep;
				}

				if (seq_len > 0) {
					if (info.timestep > 0)
						log("  %4d ", info.timestep);
					else
						log("  init ");
				} else
					log("  ");

				if (info.width <= 32)
					log("%-*s %10d %10x %*s\n", maxModelName+10, info.description.c_str(), value.as_int(), value.as_int(), maxModelWidth+5, value.as_string().c_str());
				else
					log("%-*s %10s %10s %*s\n", maxModelName+10, info.description.c_str(), "--", "--", maxModelWidth+5, value.as_string().c_str());
			}

			if (last_timestep == -2)
				log("  no model variables selected for display.\n");

			if (loopcount != 0) {
				std::vector<int> clause;
				for (size_t i = 0; i < modelExpressions.size(); i++)
					clause.push_back(modelValues.at(i) ? ez.NOT(modelExpressions.at(i)) : modelExpressions.at(i));
				ez.assume(ez.expression(ezSAT::OpOr, clause));
				loopcount--;
				goto rerun_solver;
			}
		}
		else
			log("SAT solving finished - no model found.\n");
	}
} SatSolvePass;