// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2018, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com

// This is an open source non-commercial project. Dear PVS-Studio, please check it.
// PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

#ifndef CHAISCRIPT_COMMON_HPP_
#define CHAISCRIPT_COMMON_HPP_

#include <algorithm>
#include <memory>
#include <sstream>
#include <stdexcept>
#include <string>
#include <vector>

#include "../chaiscript_defines.hpp"
#include "../dispatchkit/boxed_value.hpp"
#include "../dispatchkit/dispatchkit.hpp"
#include "../dispatchkit/proxy_functions.hpp"
#include "../dispatchkit/type_info.hpp"
#include <unordered_set>

namespace chaiscript {
  struct AST_Node;
} // namespace chaiscript

namespace chaiscript {
  struct Name_Validator {
    template<typename T>
    static bool is_reserved_word(const T &s) noexcept {
      const static std::unordered_set<std::uint32_t>
          words{utility::hash("def"), utility::hash("fun"), utility::hash("while"), utility::hash("for"), utility::hash("if"), utility::hash("else"), utility::hash("&&"), utility::hash("||"), utility::hash(","), utility::hash("auto"), utility::hash("return"), utility::hash("break"), utility::hash("true"), utility::hash("false"), utility::hash("class"), utility::hash("attr"), utility::hash("var"), utility::hash("global"), utility::hash("GLOBAL"), utility::hash("_"), utility::hash("__LINE__"), utility::hash("__FILE__"), utility::hash("__FUNC__"), utility::hash("__CLASS__")};

      return words.count(utility::hash(s)) == 1;
    }

    template<typename T>
    static bool valid_object_name(const T &name) noexcept {
      return name.find("::") == std::string::npos && !is_reserved_word(name);
    }

    template<typename T>
    static void validate_object_name(const T &name) {
      if (is_reserved_word(name)) {
        throw exception::reserved_word_error(std::string(name));
      }

      if (name.find("::") != std::string::npos) {
        throw exception::illegal_name_error(std::string(name));
      }
    }
  };

  /// Signature of module entry point that all binary loadable modules must implement.
  using Create_Module_Func = ModulePtr (*)();

  /// Types of AST nodes available to the parser and eval
  enum class AST_Node_Type {
    Id,
    Fun_Call,
    Unused_Return_Fun_Call,
    Arg_List,
    Equation,
    Var_Decl,
    Assign_Decl,
    Array_Call,
    Dot_Access,
    Lambda,
    Block,
    Scopeless_Block,
    Def,
    While,
    If,
    For,
    Ranged_For,
    Inline_Array,
    Inline_Map,
    Return,
    File,
    Prefix,
    Break,
    Continue,
    Map_Pair,
    Value_Range,
    Inline_Range,
    Try,
    Catch,
    Finally,
    Method,
    Attr_Decl,
    Logical_And,
    Logical_Or,
    Reference,
    Switch,
    Case,
    Default,
    Noop,
    Class,
    Binary,
    Arg,
    Global_Decl,
    Constant,
    Compiled
  };

  enum class Operator_Precedence {
    Ternary_Cond,
    Logical_Or,
    Logical_And,
    Bitwise_Or,
    Bitwise_Xor,
    Bitwise_And,
    Equality,
    Comparison,
    Shift,
    Addition,
    Multiplication,
    Prefix
  };

  namespace {
    /// Helper lookup to get the name of each node type
    constexpr const char *ast_node_type_to_string(AST_Node_Type ast_node_type) noexcept {
      constexpr const char *const ast_node_types[] = {"Id", "Fun_Call", "Unused_Return_Fun_Call", "Arg_List", "Equation", "Var_Decl", "Assign_Decl", "Array_Call", "Dot_Access", "Lambda", "Block", "Scopeless_Block", "Def", "While", "If", "For", "Ranged_For", "Inline_Array", "Inline_Map", "Return", "File", "Prefix", "Break", "Continue", "Map_Pair", "Value_Range", "Inline_Range", "Try", "Catch", "Finally", "Method", "Attr_Decl", "Logical_And", "Logical_Or", "Reference", "Switch", "Case", "Default", "Noop", "Class", "Binary", "Arg", "Global_Decl", "Constant", "Compiled"};

      return ast_node_types[static_cast<int>(ast_node_type)];
    }
  } // namespace

  /// \brief Convenience type for file positions
  struct File_Position {
    int line = 0;
    int column = 0;

    constexpr File_Position(int t_file_line, int t_file_column) noexcept
        : line(t_file_line)
        , column(t_file_column) {
    }

    constexpr File_Position() noexcept = default;
  };

  struct Parse_Location {
    Parse_Location(std::string t_fname = "", const int t_start_line = 0, const int t_start_col = 0, const int t_end_line = 0, const int t_end_col = 0)
        : start(t_start_line, t_start_col)
        , end(t_end_line, t_end_col)
        , filename(std::make_shared<std::string>(std::move(t_fname))) {
    }

    Parse_Location(std::shared_ptr<std::string> t_fname,
                   const int t_start_line = 0,
                   const int t_start_col = 0,
                   const int t_end_line = 0,
                   const int t_end_col = 0)
        : start(t_start_line, t_start_col)
        , end(t_end_line, t_end_col)
        , filename(std::move(t_fname)) {
    }

    File_Position start;
    File_Position end;
    std::shared_ptr<std::string> filename;
  };

  /// \brief Typedef for pointers to AST_Node objects. Used in building of the AST_Node tree
  using AST_NodePtr = std::unique_ptr<AST_Node>;
  using AST_NodePtr_Const = std::unique_ptr<const AST_Node>;

  struct AST_Node_Trace;

  /// \brief Classes which may be thrown during error cases when ChaiScript is executing.
  namespace exception {
    /// \brief Thrown if an error occurs while attempting to load a binary module
    struct load_module_error : std::runtime_error {
      explicit load_module_error(const std::string &t_reason)
          : std::runtime_error(t_reason) {
      }

      load_module_error(const std::string &t_name, const std::vector<load_module_error> &t_errors)
          : std::runtime_error(format_error(t_name, t_errors)) {
      }

      load_module_error(const load_module_error &) = default;
      ~load_module_error() noexcept override = default;

      static std::string format_error(const std::string &t_name, const std::vector<load_module_error> &t_errors) {
        std::stringstream ss;
        ss << "Error loading module '" << t_name << "'\n"
           << "  The following locations were searched:\n";

        for (const auto &err : t_errors) {
          ss << "    " << err.what() << "\n";
        }

        return ss.str();
      }
    };

    /// Errors generated during parsing or evaluation
    struct eval_error : std::runtime_error {
      std::string reason;
      File_Position start_position;
      std::string filename;
      std::string detail;
      std::vector<AST_Node_Trace> call_stack;

      eval_error(const std::string &t_why,
                 const File_Position &t_where,
                 const std::string &t_fname,
                 const std::vector<Boxed_Value> &t_parameters,
                 const std::vector<chaiscript::Const_Proxy_Function> &t_functions,
                 bool t_dot_notation,
                 const chaiscript::detail::Dispatch_Engine &t_ss) noexcept
          : std::runtime_error(format(t_why, t_where, t_fname, t_parameters, t_dot_notation, t_ss))
          , reason(t_why)
          , start_position(t_where)
          , filename(t_fname)
          , detail(format_detail(t_functions, t_dot_notation, t_ss)) {
      }

      eval_error(const std::string &t_why,
                 const std::vector<Boxed_Value> &t_parameters,
                 const std::vector<chaiscript::Const_Proxy_Function> &t_functions,
                 bool t_dot_notation,
                 const chaiscript::detail::Dispatch_Engine &t_ss) noexcept
          : std::runtime_error(format(t_why, t_parameters, t_dot_notation, t_ss))
          , reason(t_why)
          , detail(format_detail(t_functions, t_dot_notation, t_ss)) {
      }

      eval_error(const std::string &t_why, const File_Position &t_where, const std::string &t_fname) noexcept
          : std::runtime_error(format(t_why, t_where, t_fname))
          , reason(t_why)
          , start_position(t_where)
          , filename(t_fname) {
      }

      explicit eval_error(const std::string &t_why) noexcept
          : std::runtime_error("Error: \"" + t_why + "\" ")
          , reason(t_why) {
      }

      eval_error(const eval_error &) = default;

      std::string pretty_print() const {
        std::ostringstream ss;

        ss << what();
        if (!call_stack.empty()) {
          ss << "during evaluation at (" << fname(call_stack[0]) << " " << startpos(call_stack[0]) << ")\n";
          ss << '\n'
             << detail << '\n';
          ss << "  " << fname(call_stack[0]) << " (" << startpos(call_stack[0]) << ") '" << pretty(call_stack[0]) << "'";
          for (size_t j = 1; j < call_stack.size(); ++j) {
            if (id(call_stack[j]) != chaiscript::AST_Node_Type::Block && id(call_stack[j]) != chaiscript::AST_Node_Type::File) {
              ss << '\n';
              ss << "  from " << fname(call_stack[j]) << " (" << startpos(call_stack[j]) << ") '" << pretty(call_stack[j]) << "'";
            }
          }
        }
        ss << '\n';
        return ss.str();
      }

      ~eval_error() noexcept override = default;

    private:
      template<typename T>
      static AST_Node_Type id(const T &t) noexcept {
        return t.identifier;
      }

      template<typename T>
      static std::string pretty(const T &t) {
        return t.pretty_print();
      }

      template<typename T>
      static const std::string &fname(const T &t) noexcept {
        return t.filename();
      }

      template<typename T>
      static std::string startpos(const T &t) {
        std::ostringstream oss;
        oss << t.start().line << ", " << t.start().column;
        return oss.str();
      }

      static std::string format_why(const std::string &t_why) { return "Error: \"" + t_why + "\""; }

      static std::string format_types(const Const_Proxy_Function &t_func, bool t_dot_notation, const chaiscript::detail::Dispatch_Engine &t_ss) {
        assert(t_func);
        int arity = t_func->get_arity();
        std::vector<Type_Info> types = t_func->get_param_types();

        std::string retval;
        if (arity == -1) {
          retval = "(...)";
          if (t_dot_notation) {
            retval = "(Object)." + retval;
          }
        } else if (types.size() <= 1) {
          retval = "()";
        } else {
          std::stringstream ss;
          ss << "(";

          std::string paramstr;

          for (size_t index = 1; index != types.size(); ++index) {
            paramstr += (types[index].is_const() ? "const " : "");
            paramstr += t_ss.get_type_name(types[index]);

            if (index == 1 && t_dot_notation) {
              paramstr += ").(";
              if (types.size() == 2) {
                paramstr += ", ";
              }
            } else {
              paramstr += ", ";
            }
          }

          ss << paramstr.substr(0, paramstr.size() - 2);

          ss << ")";
          retval = ss.str();
        }

        std::shared_ptr<const dispatch::Dynamic_Proxy_Function> dynfun
            = std::dynamic_pointer_cast<const dispatch::Dynamic_Proxy_Function>(t_func);

        if (dynfun && dynfun->has_parse_tree()) {
          Proxy_Function f = dynfun->get_guard();

          if (f) {
            auto dynfunguard = std::dynamic_pointer_cast<const dispatch::Dynamic_Proxy_Function>(f);
            if (dynfunguard && dynfunguard->has_parse_tree()) {
              retval += " : " + format_guard(dynfunguard->get_parse_tree());
            }
          }

          retval += "\n          Defined at " + format_location(dynfun->get_parse_tree());
        }

        return retval;
      }

      template<typename T>
      static std::string format_guard(const T &t) {
        return t.pretty_print();
      }

      template<typename T>
      static std::string format_location(const T &t) {
        std::ostringstream oss;
        oss << "(" << t.filename() << " " << t.start().line << ", " << t.start().column << ")";
        return oss.str();
      }

      static std::string format_detail(const std::vector<chaiscript::Const_Proxy_Function> &t_functions,
                                       bool t_dot_notation,
                                       const chaiscript::detail::Dispatch_Engine &t_ss) {
        std::stringstream ss;
        if (t_functions.size() == 1) {
          assert(t_functions[0]);
          ss << "  Expected: " << format_types(t_functions[0], t_dot_notation, t_ss) << '\n';
        } else {
          ss << "  " << t_functions.size() << " overloads available:\n";

          for (const auto &t_function : t_functions) {
            ss << "      " << format_types((t_function), t_dot_notation, t_ss) << '\n';
          }
        }

        return ss.str();
      }

      static std::string
      format_parameters(const std::vector<Boxed_Value> &t_parameters, bool t_dot_notation, const chaiscript::detail::Dispatch_Engine &t_ss) {
        std::stringstream ss;
        ss << "(";

        if (!t_parameters.empty()) {
          std::string paramstr;

          for (auto itr = t_parameters.begin(); itr != t_parameters.end(); ++itr) {
            paramstr += (itr->is_const() ? "const " : "");
            paramstr += t_ss.type_name(*itr);

            if (itr == t_parameters.begin() && t_dot_notation) {
              paramstr += ").(";
              if (t_parameters.size() == 1) {
                paramstr += ", ";
              }
            } else {
              paramstr += ", ";
            }
          }

          ss << paramstr.substr(0, paramstr.size() - 2);
        }
        ss << ")";

        return ss.str();
      }

      static std::string format_filename(const std::string &t_fname) {
        std::stringstream ss;

        if (t_fname != "__EVAL__") {
          ss << "in '" << t_fname << "' ";
        } else {
          ss << "during evaluation ";
        }

        return ss.str();
      }

      static std::string format_location(const File_Position &t_where) {
        std::stringstream ss;
        ss << "at (" << t_where.line << ", " << t_where.column << ")";
        return ss.str();
      }

      static std::string format(const std::string &t_why,
                                const File_Position &t_where,
                                const std::string &t_fname,
                                const std::vector<Boxed_Value> &t_parameters,
                                bool t_dot_notation,
                                const chaiscript::detail::Dispatch_Engine &t_ss) {
        std::stringstream ss;

        ss << format_why(t_why);
        ss << " ";

        ss << "With parameters: " << format_parameters(t_parameters, t_dot_notation, t_ss);
        ss << " ";

        ss << format_filename(t_fname);
        ss << " ";

        ss << format_location(t_where);

        return ss.str();
      }

      static std::string format(const std::string &t_why,
                                const std::vector<Boxed_Value> &t_parameters,
                                bool t_dot_notation,
                                const chaiscript::detail::Dispatch_Engine &t_ss) {
        std::stringstream ss;

        ss << format_why(t_why);
        ss << " ";

        ss << "With parameters: " << format_parameters(t_parameters, t_dot_notation, t_ss);
        ss << " ";

        return ss.str();
      }

      static std::string format(const std::string &t_why, const File_Position &t_where, const std::string &t_fname) {
        std::stringstream ss;

        ss << format_why(t_why);
        ss << " ";

        ss << format_filename(t_fname);
        ss << " ";

        ss << format_location(t_where);

        return ss.str();
      }
    };

    /// Errors generated when loading a file
    struct file_not_found_error : std::runtime_error {
      explicit file_not_found_error(const std::string &t_filename)
          : std::runtime_error("File Not Found: " + t_filename)
          , filename(t_filename) {
      }

      file_not_found_error(const file_not_found_error &) = default;
      ~file_not_found_error() noexcept override = default;

      std::string filename;
    };

  } // namespace exception

  /// \brief Struct that doubles as both a parser ast_node and an AST node.
  struct AST_Node {
  public:
    const AST_Node_Type identifier;
    const std::string text;
    Parse_Location location;

    const std::string &filename() const noexcept { return *location.filename; }

    const File_Position &start() const noexcept { return location.start; }

    const File_Position &end() const noexcept { return location.end; }

    std::string pretty_print() const {
      std::ostringstream oss;

      oss << text;

      for (auto &elem : get_children()) {
        oss << elem.get().pretty_print() << ' ';
      }

      return oss.str();
    }

    virtual std::vector<std::reference_wrapper<AST_Node>> get_children() const = 0;
    virtual Boxed_Value eval(const chaiscript::detail::Dispatch_State &t_e) const = 0;

    /// Prints the contents of an AST node, including its children, recursively
    std::string to_string(const std::string &t_prepend = "") const {
      std::ostringstream oss;

      oss << t_prepend << "(" << ast_node_type_to_string(this->identifier) << ") " << this->text << " : " << this->location.start.line
          << ", " << this->location.start.column << '\n';

      for (auto &elem : get_children()) {
        oss << elem.get().to_string(t_prepend + "  ");
      }
      return oss.str();
    }

    static bool get_bool_condition(const Boxed_Value &t_bv, const chaiscript::detail::Dispatch_State &t_ss) {
      try {
        return t_ss->boxed_cast<bool>(t_bv);
      } catch (const exception::bad_boxed_cast &) {
        throw exception::eval_error("Condition not boolean");
      }
    }

    virtual ~AST_Node() noexcept = default;
    AST_Node(AST_Node &&) = default;
    AST_Node &operator=(AST_Node &&) = delete;
    AST_Node(const AST_Node &) = delete;
    AST_Node &operator=(const AST_Node &) = delete;

  protected:
    AST_Node(std::string t_ast_node_text, AST_Node_Type t_id, Parse_Location t_loc)
        : identifier(t_id)
        , text(std::move(t_ast_node_text))
        , location(std::move(t_loc)) {
    }
  };

  struct AST_Node_Trace {
    const AST_Node_Type identifier;
    const std::string text;
    Parse_Location location;

    const std::string &filename() const noexcept { return *location.filename; }

    const File_Position &start() const noexcept { return location.start; }

    const File_Position &end() const noexcept { return location.end; }

    std::string pretty_print() const {
      std::ostringstream oss;

      oss << text;

      for (const auto &elem : children) {
        oss << elem.pretty_print() << ' ';
      }

      return oss.str();
    }

    std::vector<AST_Node_Trace> get_children(const AST_Node &node) {
      const auto node_children = node.get_children();
      return std::vector<AST_Node_Trace>(node_children.begin(), node_children.end());
    }

    AST_Node_Trace(const AST_Node &node)
        : identifier(node.identifier)
        , text(node.text)
        , location(node.location)
        , children(get_children(node)) {
    }

    std::vector<AST_Node_Trace> children;
  };

  namespace parser {
    class ChaiScript_Parser_Base {
    public:
      virtual AST_NodePtr parse(const std::string &t_input, const std::string &t_fname) = 0;
      virtual void debug_print(const AST_Node &t, std::string prepend = "") const = 0;
      virtual void *get_tracer_ptr() = 0;
      virtual ~ChaiScript_Parser_Base() = default;
      ChaiScript_Parser_Base() = default;
      ChaiScript_Parser_Base(ChaiScript_Parser_Base &&) = default;
      ChaiScript_Parser_Base &operator=(ChaiScript_Parser_Base &&) = delete;
      ChaiScript_Parser_Base &operator=(const ChaiScript_Parser_Base &&) = delete;

      template<typename T>
      T &get_tracer() noexcept {
        // to do type check this somehow?
        return *static_cast<T *>(get_tracer_ptr());
      }

    protected:
      ChaiScript_Parser_Base(const ChaiScript_Parser_Base &) = default;
    };
  } // namespace parser

  namespace eval {
    namespace detail {
      /// Special type for returned values
      struct Return_Value {
        Boxed_Value retval;
      };

      /// Special type indicating a call to 'break'
      struct Break_Loop {
      };

      /// Special type indicating a call to 'continue'
      struct Continue_Loop {
      };

      /// Creates a new scope then pops it on destruction
      struct Scope_Push_Pop {
        Scope_Push_Pop(Scope_Push_Pop &&) = default;
        Scope_Push_Pop &operator=(Scope_Push_Pop &&) = delete;
        Scope_Push_Pop(const Scope_Push_Pop &) = delete;
        Scope_Push_Pop &operator=(const Scope_Push_Pop &) = delete;

        explicit Scope_Push_Pop(const chaiscript::detail::Dispatch_State &t_ds)
            : m_ds(t_ds) {
          m_ds->new_scope(m_ds.stack_holder());
        }

        ~Scope_Push_Pop() { m_ds->pop_scope(m_ds.stack_holder()); }

      private:
        const chaiscript::detail::Dispatch_State &m_ds;
      };

      /// Creates a new function call and pops it on destruction
      struct Function_Push_Pop {
        Function_Push_Pop(Function_Push_Pop &&) = default;
        Function_Push_Pop &operator=(Function_Push_Pop &&) = delete;
        Function_Push_Pop(const Function_Push_Pop &) = delete;
        Function_Push_Pop &operator=(const Function_Push_Pop &) = delete;

        explicit Function_Push_Pop(const chaiscript::detail::Dispatch_State &t_ds)
            : m_ds(t_ds) {
          m_ds->new_function_call(m_ds.stack_holder(), m_ds.conversion_saves());
        }

        ~Function_Push_Pop() { m_ds->pop_function_call(m_ds.stack_holder(), m_ds.conversion_saves()); }

        void save_params(const Function_Params &t_params) { m_ds->save_function_params(t_params); }

      private:
        const chaiscript::detail::Dispatch_State &m_ds;
      };

      /// Creates a new scope then pops it on destruction
      struct Stack_Push_Pop {
        Stack_Push_Pop(Stack_Push_Pop &&) = default;
        Stack_Push_Pop &operator=(Stack_Push_Pop &&) = delete;
        Stack_Push_Pop(const Stack_Push_Pop &) = delete;
        Stack_Push_Pop &operator=(const Stack_Push_Pop &) = delete;

        explicit Stack_Push_Pop(const chaiscript::detail::Dispatch_State &t_ds)
            : m_ds(t_ds) {
          m_ds->new_stack(m_ds.stack_holder());
        }

        ~Stack_Push_Pop() { m_ds->pop_stack(m_ds.stack_holder()); }

      private:
        const chaiscript::detail::Dispatch_State &m_ds;
      };
    } // namespace detail
  } // namespace eval
} // namespace chaiscript

#endif /* _CHAISCRIPT_COMMON_HPP */