// Copyright (c) 2020 Pantor. All rights reserved.

#ifndef INCLUDE_INJA_NODE_HPP_
#define INCLUDE_INJA_NODE_HPP_

#include <string>
#include <utility>

#include <nlohmann/json.hpp>

#include "function_storage.hpp"
#include "string_view.hpp"


namespace inja {

class NodeVisitor;
class BlockNode;
class TextNode;
class ExpressionNode;
class LiteralNode;
class JsonNode;
class FunctionNode;
class ExpressionListNode;
class StatementNode;
class ForStatementNode;
class ForArrayStatementNode;
class ForObjectStatementNode;
class IfStatementNode;
class IncludeStatementNode;
class SetStatementNode;


class NodeVisitor {
public:
  virtual void visit(const BlockNode& node) = 0;
  virtual void visit(const TextNode& node) = 0;
  virtual void visit(const ExpressionNode& node) = 0;
  virtual void visit(const LiteralNode& node) = 0;
  virtual void visit(const JsonNode& node) = 0;
  virtual void visit(const FunctionNode& node) = 0;
  virtual void visit(const ExpressionListNode& node) = 0;
  virtual void visit(const StatementNode& node) = 0;
  virtual void visit(const ForStatementNode& node) = 0;
  virtual void visit(const ForArrayStatementNode& node) = 0;
  virtual void visit(const ForObjectStatementNode& node) = 0;
  virtual void visit(const IfStatementNode& node) = 0;
  virtual void visit(const IncludeStatementNode& node) = 0;
  virtual void visit(const SetStatementNode& node) = 0;
};

/*!
 * \brief Base node class for the abstract syntax tree (AST).
 */
class AstNode {
public:
  virtual void accept(NodeVisitor& v) const = 0;

  size_t pos;

  AstNode(size_t pos) : pos(pos) { }
  virtual ~AstNode() { };
};


class BlockNode : public AstNode {
public:
  std::vector<std::shared_ptr<AstNode>> nodes;

  explicit BlockNode() : AstNode(0) {}

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class TextNode : public AstNode {
public:
  const size_t length;

  explicit TextNode(size_t pos, size_t length): AstNode(pos), length(length) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class ExpressionNode : public AstNode {
public:
  explicit ExpressionNode(size_t pos) : AstNode(pos) {}

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class LiteralNode : public ExpressionNode {
public:
  const nlohmann::json value;

  explicit LiteralNode(const nlohmann::json& value, size_t pos) : ExpressionNode(pos), value(value) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class JsonNode : public ExpressionNode {
public:
  const std::string name;
  const json::json_pointer ptr;

  static std::string convert_dot_to_json_ptr(nonstd::string_view ptr_name) {
    std::string result;
    do {
      nonstd::string_view part;
      std::tie(part, ptr_name) = string_view::split(ptr_name, '.');
      result.push_back('/');
      result.append(part.begin(), part.end());
    } while (!ptr_name.empty());
    return result;
  }

  explicit JsonNode(nonstd::string_view ptr_name, size_t pos) : ExpressionNode(pos), name(ptr_name), ptr(json::json_pointer(convert_dot_to_json_ptr(ptr_name))) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class FunctionNode : public ExpressionNode {
  using Op = FunctionStorage::Operation;

public:
  enum class Associativity {
    Left,
    Right,
  };

  unsigned int precedence;
  Associativity associativity;

  Op operation;

  std::string name;
  int number_args; // Should also be negative -> -1 for unknown number
  std::vector<std::shared_ptr<ExpressionNode>> arguments;
  CallbackFunction callback;

  explicit FunctionNode(nonstd::string_view name, size_t pos) : ExpressionNode(pos), precedence(8), associativity(Associativity::Left), operation(Op::Callback), name(name), number_args(1) { }
  explicit FunctionNode(Op operation, size_t pos) : ExpressionNode(pos), operation(operation), number_args(1) {
    switch (operation) {
      case Op::Not: {
        number_args = 1;
        precedence = 4;
        associativity = Associativity::Left;
      } break;
      case Op::And: {
        number_args = 2;
        precedence = 1;
        associativity = Associativity::Left;
      } break;
      case Op::Or: {
        number_args = 2;
        precedence = 1;
        associativity = Associativity::Left;
      } break;
      case Op::In: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::Equal: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::NotEqual: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::Greater: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::GreaterEqual: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::Less: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::LessEqual: {
        number_args = 2;
        precedence = 2;
        associativity = Associativity::Left;
      } break;
      case Op::Add: {
        number_args = 2;
        precedence = 3;
        associativity = Associativity::Left;
      } break;
      case Op::Subtract: {
        number_args = 2;
        precedence = 3;
        associativity = Associativity::Left;
      } break;
      case Op::Multiplication: {
        number_args = 2;
        precedence = 4;
        associativity = Associativity::Left;
      } break;
      case Op::Division: {
        number_args = 2;
        precedence = 4;
        associativity = Associativity::Left;
      } break;
      case Op::Power: {
        number_args = 2;
        precedence = 5;
        associativity = Associativity::Right;
      } break;
      case Op::Modulo: {
        number_args = 2;
        precedence = 4;
        associativity = Associativity::Left;
      } break;
      case Op::AtId: {
        number_args = 2;
        precedence = 8;
        associativity = Associativity::Left;
      } break;
      default: {
        precedence = 1;
        associativity = Associativity::Left;
      }
    }
  }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class ExpressionListNode : public AstNode {
public:
  std::shared_ptr<ExpressionNode> root;

  explicit ExpressionListNode() : AstNode(0) { }
  explicit ExpressionListNode(size_t pos) : AstNode(pos) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class StatementNode : public AstNode {
public:
  StatementNode(size_t pos) : AstNode(pos) { }

  virtual void accept(NodeVisitor& v) const = 0;
};

class ForStatementNode : public StatementNode {
public:
  ExpressionListNode condition;
  BlockNode body;
  BlockNode *const parent;

  ForStatementNode(BlockNode *const parent, size_t pos) : StatementNode(pos), parent(parent) { }

  virtual void accept(NodeVisitor& v) const = 0;
};

class ForArrayStatementNode : public ForStatementNode {
public:
  const std::string value;

  explicit ForArrayStatementNode(const std::string& value, BlockNode *const parent, size_t pos) : ForStatementNode(parent, pos), value(value) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class ForObjectStatementNode : public ForStatementNode {
public:
  const std::string key;
  const std::string value;

  explicit ForObjectStatementNode(const std::string& key, const std::string& value, BlockNode *const parent, size_t pos) : ForStatementNode(parent, pos), key(key), value(value) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class IfStatementNode : public StatementNode {
public:
  ExpressionListNode condition;
  BlockNode true_statement;
  BlockNode false_statement;
  BlockNode *const parent;

  const bool is_nested;
  bool has_false_statement {false};

  explicit IfStatementNode(BlockNode *const parent, size_t pos) : StatementNode(pos), parent(parent), is_nested(false) { }
  explicit IfStatementNode(bool is_nested, BlockNode *const parent, size_t pos) : StatementNode(pos), parent(parent), is_nested(is_nested) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  }
};

class IncludeStatementNode : public StatementNode {
public:
  const std::string file;

  explicit IncludeStatementNode(const std::string& file, size_t pos) : StatementNode(pos), file(file) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  };
};

class SetStatementNode : public StatementNode {
public:
  const std::string key;
  ExpressionListNode expression;

  explicit SetStatementNode(const std::string& key, size_t pos) : StatementNode(pos), key(key) { }

  void accept(NodeVisitor& v) const {
    v.visit(*this);
  };
};

} // namespace inja

#endif // INCLUDE_INJA_NODE_HPP_