// Copyright 2017-2020 The Verible Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "verilog/analysis/checkers/void_cast_rule.h"

#include <set>
#include <string>

#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "common/analysis/lint_rule_status.h"
#include "common/analysis/matcher/bound_symbol_manager.h"
#include "common/analysis/matcher/core_matchers.h"
#include "common/analysis/matcher/matcher.h"
#include "common/text/concrete_syntax_leaf.h"
#include "common/text/concrete_syntax_tree.h"
#include "common/text/symbol.h"
#include "common/text/syntax_tree_context.h"
#include "common/text/token_info.h"
#include "common/text/tree_utils.h"
#include "verilog/CST/verilog_matchers.h"
#include "verilog/analysis/descriptions.h"
#include "verilog/analysis/lint_rule_registry.h"

namespace verilog {
namespace analysis {

using verible::LintRuleStatus;
using verible::LintViolation;
using verible::SyntaxTreeContext;
using verible::SyntaxTreeLeaf;
using verible::SyntaxTreeNode;
using verible::matcher::Matcher;

// Register VoidCastRule
VERILOG_REGISTER_LINT_RULE(VoidCastRule);

const LintRuleDescriptor& VoidCastRule::GetDescriptor() {
  static const LintRuleDescriptor d{
      .name = "void-cast",
      .topic = "void-casts",
      .desc =
          "Checks that void casts do not contain certain function/method "
          "calls. ",
  };
  return d;
}

const std::set<std::string>& VoidCastRule::ForbiddenFunctionsSet() {
  static const auto* forbidden_functions =
      new std::set<std::string>({"uvm_hdl_read"});
  return *forbidden_functions;
}

// Matches against top level function calls within void casts
// For example:
//   void'(foo());
// Here, the leaf representing "foo" will be bound to id
static const Matcher& FunctionMatcher() {
  static const Matcher matcher(NodekVoidcast(VoidcastHasExpression(
      ExpressionHasFunctionCall(FunctionCallHasId().Bind("id")))));
  return matcher;
}

// Matches against both calls to randomize and randomize methods within
// voidcasts.
// For example:
//   void'(obj.randomize(...));
// Here, the node representing "randomize(...)" will be bound to "id"
//
// For example:
//   void'(randomize(obj));
// Here, the node representing "randomize(obj)" will be bound to "id"
//
static const Matcher& RandomizeMatcher() {
  static const Matcher matcher(NodekVoidcast(VoidcastHasExpression(
      verible::matcher::AnyOf(ExpressionHasRandomizeCallExtension().Bind("id"),
                              ExpressionHasRandomizeFunction().Bind("id")))));
  return matcher;
}

void VoidCastRule::HandleSymbol(const verible::Symbol& symbol,
                                const SyntaxTreeContext& context) {
  // Check for forbidden function names
  verible::matcher::BoundSymbolManager manager;
  if (FunctionMatcher().Matches(symbol, &manager)) {
    if (const auto* function_id =
            manager.GetAs<verible::SyntaxTreeLeaf>("id")) {
      const auto& bfs = ForbiddenFunctionsSet();
      if (bfs.find(std::string(function_id->get().text())) != bfs.end()) {
        violations_.insert(LintViolation(function_id->get(),
                                         FormatReason(*function_id), context));
      }
    }
  }

  // Check for forbidden calls to randomize
  manager.Clear();
  if (RandomizeMatcher().Matches(symbol, &manager)) {
    if (const auto* randomize_node =
            manager.GetAs<verible::SyntaxTreeNode>("id")) {
      const auto* leaf_ptr = verible::GetLeftmostLeaf(*randomize_node);
      const verible::TokenInfo token = ABSL_DIE_IF_NULL(leaf_ptr)->get();
      violations_.insert(LintViolation(
          token, "randomize() is forbidden within void casts", context));
    }
  }
}

LintRuleStatus VoidCastRule::Report() const {
  return LintRuleStatus(violations_, GetDescriptor());
}

/* static */ std::string VoidCastRule::FormatReason(
    const verible::SyntaxTreeLeaf& leaf) {
  return std::string(leaf.get().text()) +
         " is an invalid call within this void cast";
}

}  // namespace analysis
}  // namespace verilog