/**
 *   Copyright 2016, Quickstep Research Group, Computer Sciences Department,
 *     University of Wisconsin—Madison.
 *
 *   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 "utility/PlanVisualizer.hpp"

#include <cstddef>
#include <memory>
#include <sstream>
#include <string>
#include <unordered_map>
#include <vector>

#include "catalog/CatalogRelation.hpp"

#include "query_optimizer/cost_model/StarSchemaSimpleCostModel.hpp"
#include "query_optimizer/expressions/AttributeReference.hpp"
#include "query_optimizer/physical/HashJoin.hpp"
#include "query_optimizer/physical/Physical.hpp"
#include "query_optimizer/physical/PhysicalType.hpp"
#include "query_optimizer/physical/TableReference.hpp"
#include "query_optimizer/physical/TopLevelPlan.hpp"
#include "utility/StringUtil.hpp"

#include "glog/logging.h"

namespace quickstep {

namespace E = ::quickstep::optimizer::expressions;
namespace P = ::quickstep::optimizer::physical;
namespace C = ::quickstep::optimizer::cost;

std::string PlanVisualizer::visualize(const P::PhysicalPtr &input) {
  DCHECK(input->getPhysicalType() == P::PhysicalType::kTopLevelPlan);
  cost_model_.reset(
      new C::StarSchemaSimpleCostModel(
          std::static_pointer_cast<const P::TopLevelPlan>(input)->shared_subplans()));

  color_map_["TableReference"] = "skyblue";
  color_map_["Selection"] = "#90EE90";
  color_map_["HashJoin"] = "red";
  color_map_["HashLeftOuterJoin"] = "orange";
  color_map_["HashLeftSemiJoin"] = "orange";
  color_map_["HashLeftAntiJoin"] = "orange";

  visit(input);

  // Format output graph
  std::ostringstream graph_oss;
  graph_oss << "digraph g {\n";
  graph_oss << "  rankdir=BT\n";
  graph_oss << "  node [penwidth=2]\n";
  graph_oss << "  edge [fontsize=16 fontcolor=gray penwidth=2]\n\n";

  // Format nodes
  for (const NodeInfo &node_info : nodes_) {
    graph_oss << "  " << node_info.id << " [";
    if (!node_info.labels.empty()) {
      graph_oss << "label=\""
                << EscapeSpecialChars(JoinToString(node_info.labels, "&#10;"))
                << "\"";
    }
    if (!node_info.color.empty()) {
      graph_oss << " style=filled fillcolor=\"" << node_info.color << "\"";
    }
    graph_oss << "]\n";
  }
  graph_oss << "\n";

  // Format edges
  for (const EdgeInfo &edge_info : edges_) {
    graph_oss << "  " << edge_info.src_node_id << " -> "
              << edge_info.dst_node_id << " [";
    if (!edge_info.labels.empty()) {
      graph_oss << "label=\""
                << EscapeSpecialChars(JoinToString(edge_info.labels, "&#10;"))
                << "\"";
    }
    graph_oss << "]\n";
  }

  graph_oss << "}\n";

  return graph_oss.str();
}

void PlanVisualizer::visit(const P::PhysicalPtr &input) {
  int node_id = ++id_counter_;
  node_id_map_.emplace(input, node_id);

  for (const auto &child : input->children()) {
    visit(child);

    int child_id = node_id_map_[child];

    edges_.emplace_back(EdgeInfo());
    EdgeInfo &edge_info = edges_.back();
    edge_info.src_node_id = child_id;
    edge_info.dst_node_id = node_id;

    // Print output attributes except for TableReference -- there are just too many
    // attributes out of TableReference.
    if (child->getPhysicalType() != P::PhysicalType::kTableReference) {
      for (const auto &attr : child->getOutputAttributes()) {
        edge_info.labels.emplace_back(attr->attribute_alias());
      }
    }
  }

  nodes_.emplace_back(NodeInfo());
  NodeInfo &node_info = nodes_.back();
  node_info.id = node_id;
  if (color_map_.find(input->getName()) != color_map_.end()) {
    node_info.color = color_map_[input->getName()];
  }

  switch (input->getPhysicalType()) {
    case P::PhysicalType::kTableReference: {
      const P::TableReferencePtr table_reference =
        std::static_pointer_cast<const P::TableReference>(input);
      node_info.labels.emplace_back(table_reference->relation()->getName());
      break;
    }
    case P::PhysicalType::kHashJoin: {
      const P::HashJoinPtr hash_join =
        std::static_pointer_cast<const P::HashJoin>(input);
      node_info.labels.emplace_back(input->getName());

      const auto &left_attributes = hash_join->left_join_attributes();
      const auto &right_attributes = hash_join->right_join_attributes();
      for (std::size_t i = 0; i < left_attributes.size(); ++i) {
        node_info.labels.emplace_back(
            left_attributes[i]->attribute_alias() + " = " + right_attributes[i]->attribute_alias());
      }
      break;
    }
    default: {
      node_info.labels.emplace_back(input->getName());
      break;
    }
  }
  node_info.labels.emplace_back(
      "est. # = " + std::to_string(cost_model_->estimateCardinality(input)));
  node_info.labels.emplace_back(
      "est. Selectivity = " + std::to_string(cost_model_->estimateSelectivity(input)));
}

}  // namespace quickstep