#ifndef AST_H
#define AST_H

#include "attachments.h"

#include <vector>
#include <stdlib.h>
#include <string>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <climits>
#include "utils.h"
#include <algorithm>

namespace llvm {
    class Value;
}

namespace xreate {

struct String_t {
};

struct Identifier_t {
};

struct Number_t {
};

struct Type_t {
};

template<typename A>
class Atom {
};

//DEBT hold for all atoms/identifiers Parser::Token data, like line:col position
template<> class 
Atom<Identifier_t> {
public:
    Atom(const std::wstring& value);
    Atom(std::string && name);
    const std::string& get() const;
    
private:
    std::string __value;
};

template<> 
class Atom<Number_t> {
public:
    Atom(wchar_t* value);
    Atom(int value);
    double get()const;
    
private:
    double __value;
};

template<> 
class Atom<String_t> {
public:
    Atom(const std::wstring& value);
    const std::string& get() const;

private:
    std::string __value;
};

enum class TypePrimitive {
    Invalid, Bool, I8, I32, Num, Int, Float, String
};

    enum class TypeOperator {
        NONE, CALL, CUSTOM, VARIANT, ARRAY, TUPLE, STRUCT, ACCESS, LINK
    };

    struct llvm_array_tag {
    };

    struct struct_tag {
    };
    const llvm_array_tag tag_array = llvm_array_tag();
    const struct_tag tag_struct = struct_tag();

    class TypeAnnotation {
    public:
        TypeAnnotation();
        TypeAnnotation(const Atom<Type_t>& typ);
        TypeAnnotation(TypePrimitive typ);
        TypeAnnotation(llvm_array_tag, TypeAnnotation typ, int size);

        TypeAnnotation(TypeOperator op, std::initializer_list<TypeAnnotation> operands);
        TypeAnnotation(TypeOperator op, std::vector<TypeAnnotation>&& operands);
        void addBindings(std::vector<Atom<Identifier_t>>&& params);
        void addFields(std::vector<Atom<Identifier_t>>&& listFields);
        bool operator<(const TypeAnnotation& t) const;
        //   TypeAnnotation (struct_tag, std::initializer_list<TypePrimitive>);

        bool isValid() const;

        TypeOperator __operator = TypeOperator::NONE;

        std::vector<TypeAnnotation> __operands;
        TypePrimitive __value;
        std::string __valueCustom;
        int conjuctionId = -1; //conjunction point id (relevant for recursive types)

        uint64_t __size = 0;
        std::vector<std::string> fields;
        std::vector<std::string> bindings;
    private:
    };

    enum class Operator {
        ADD, SUB, MUL, DIV,
        EQU, NE, NEG, LSS, 
        LSE, GTR, GTE, LIST, 
        LIST_RANGE, LIST_NAMED, 
        CALL, CALL_INTRINSIC, NONE, 
        IMPL/* implication */, MAP, 
        FOLD, FOLD_INF, LOOP_CONTEXT, 
        INDEX, IF, SWITCH, SWITCH_ADHOC, 
        CASE, CASE_DEFAULT, LOGIC_AND, 
        ADHOC, CONTEXT_RULE
    };

    class Function;
    class AST;
    class CodeScope;
    class MetaRuleAbstract;

    template<class Target>
    struct ManagedPtr {

        static ManagedPtr<Target> Invalid() {
            return ManagedPtr<Target>();
        }

        ManagedPtr() : __storage(0) {
        }

        ManagedPtr(unsigned int id, const std::vector<Target*>* storage)
        : __id(id), __storage(storage) {
        }

        Target&
        operator*() const {
            assert(isValid() && "Invalid Ptr");
            return *__storage->at(__id);
        }

        void operator=(const ManagedPtr<Target>& other) {
            __id = other.__id;
            __storage = other.__storage;
        }

        bool
        operator==(const ManagedPtr<Target>& other) {
            return isValid() && (__id == other.__id);
        }

        Target*
        operator->() const noexcept {
            assert(isValid() && "Invalid Ptr");
            return __storage->at(__id);
        }

        inline bool isValid() const {
            return (__storage) && (0 <= __id) && (__id < __storage->size());
        }

        inline operator bool() const {
            return isValid();
        }

        ManagedPtr<Target>& operator++() {
            ++__id;
            return *this;
        }

        inline unsigned int id() const {
            return __id;
        }

    private:
        unsigned int __id = 0;
        const std::vector<Target*> * __storage = 0;
    };

    typedef ManagedPtr<Function> ManagedFnPtr;
    typedef ManagedPtr<CodeScope> ManagedScpPtr;
    typedef ManagedPtr<MetaRuleAbstract> ManagedRulePtr;
    const ManagedScpPtr NO_SCOPE = ManagedScpPtr(UINT_MAX, 0);

    //To update ExpressionHints in case of any changes 
    struct Expression {
        friend class CodeScope;
        friend class ClaspLayer;
        friend class CFAPass;
        friend class ExpressionHints;

        Expression(const Operator &oprt, std::initializer_list<Expression> params);
        Expression(const Atom<Identifier_t>& ident);
        Expression(const Atom<Number_t>& number);
        Expression(const Atom<String_t>& a);
        
        Expression();

        void setOp(Operator oprt);
        void addArg(Expression&& arg);
        void addBindings(std::initializer_list<Atom<Identifier_t>> params);
        void bindType(TypeAnnotation t);

        template<class InputIt>
        void addBindings(InputIt paramsBegin, InputIt paramsEnd);
        void addTags(const std::list<Expression> tags) const;
        void addBlock(ManagedScpPtr scope);

        const std::vector<Expression>& getOperands() const;
        double getValueDouble() const;
        void setValueDouble(double value);
        const std::string& getValueString() const;
        void setValue(const Atom<Identifier_t>&& v);
        bool isValid() const;
        bool isDefined() const;
        

        bool operator==(const Expression& other) const;

        enum {
            INVALID, COMPOUND, IDENT, NUMBER, STRING, VARIANT, BINDING
        } __state = INVALID;
        
        Operator op;
        unsigned int id;
        std::vector<std::string> bindings;
        std::map<std::string, size_t> __indexBindings;
        std::vector<Expression> operands;
        TypeAnnotation type;

        mutable std::map<std::string, Expression> tags;
        std::list<CodeScope*> blocks;

    private:
        std::string __valueS;
        double __valueD;
        
        static unsigned int nextVacantId;
    };
    
    bool operator< (const Expression&, const Expression&);

    template<class InputIt>
    void Expression::addBindings(InputIt paramsBegin, InputIt paramsEnd) {
        size_t index = bindings.size();

        std::transform(paramsBegin, paramsEnd, std::inserter(bindings, bindings.end()),
                [&index, this] (const Atom<Identifier_t> atom) {
                    std::string key = atom.get();
                    this->__indexBindings[key] = index++;
                    return key;
                });
    }

    typedef std::list<Expression> ExpressionList;

    enum class TagModifier {
        NONE, ASSERT, REQUIRE
    };

    enum class DomainAnnotation {
        FUNCTION, VARIABLE
    };

    class RuleArguments : public std::vector<std::pair<std::string, DomainAnnotation>>
    {
        public:
        void add(const Atom<Identifier_t>& name, DomainAnnotation typ);
    };

    class RuleGuards : public std::vector<Expression> {
    public:
        void add(Expression&& e);
    };


    class ClaspLayer;
    class LLVMLayer;

    class MetaRuleAbstract {
    public:
        MetaRuleAbstract(RuleArguments&& args, RuleGuards&& guards);
        virtual ~MetaRuleAbstract();
        virtual void compile(ClaspLayer& layer) = 0;
    protected:
        RuleArguments __args;
        RuleGuards __guards;
    };

    class RuleWarning : public MetaRuleAbstract {
        friend class ClaspLayer;
    public:
        RuleWarning(RuleArguments&& args, RuleGuards&& guards, Expression&& condition, Atom<String_t>&& message);
        virtual void compile(ClaspLayer& layer);
        ~RuleWarning();

    private:
        std::string __message;
        Expression __condition;
    };

    typedef unsigned int VNameId;
    
    typedef int VariableVersion;
    const VariableVersion VERSION_NONE = -2;
    const VariableVersion VERSION_INIT = 0;
    
    template<>
    struct AttachmentsDict<VariableVersion>
    {
        typedef VariableVersion Data;
        static const unsigned int key = 6;
    };
    
    struct ScopedSymbol{
        VNameId id;
        VariableVersion version;
        
        static const ScopedSymbol RetSymbol;
    };
    
    struct Symbol {
        ScopedSymbol identifier;
        CodeScope * scope;
    };
    
    template<>
    struct AttachmentsDict<Symbol>
    {
        typedef Symbol Data;
        static const unsigned int key = 7;
    };
    
} 
namespace std
{
    template<>
    struct hash<xreate::ScopedSymbol>{
        std::size_t operator()(xreate::ScopedSymbol const& s) const;
    };

    template<>
    struct equal_to<xreate::ScopedSymbol>{
      bool operator()(const xreate::ScopedSymbol& __x, const xreate::ScopedSymbol& __y) const;
    };
}

namespace xreate {

    
    typedef std::pair<Expression, TagModifier> Tag;

    bool operator<(const ScopedSymbol& s1, const ScopedSymbol& s2);
    bool operator==(const ScopedSymbol& s1, const ScopedSymbol& s2);
    bool operator<(const Symbol& s1, const Symbol& s2);
    bool operator==(const Symbol& s1, const Symbol& s2);

class CodeScope {
    friend class Function;
    friend class PassManager;

public:
    CodeScope(CodeScope* parent = 0);
    void setBody(const Expression& body);
    Expression& getBody();
    void addDeclaration(Expression&& var, Expression&& body);
    void addBinding(Expression&& var, Expression&& argument);
    static const Expression& getDeclaration(const Symbol& symbol);
    const Expression& getDeclaration(const ScopedSymbol& symbol);

    ~CodeScope();

    std::vector<std::string> __bindings;
    std::map<std::string, VNameId> __identifiers;

    //TODO move __definitions to SymbolsAttachments data
    //NOTE: definition of return type has zero(0) variable index
    std::unordered_map<ScopedSymbol, Expression> __declarations;
    std::vector<Expression> tags;
    std::vector<Expression> contextRules;

private:
    VNameId __vCounter = 1;
    CodeScope* __parent;

    ScopedSymbol registerIdentifier(const Expression& identifier);

public:
    bool recognizeIdentifier(const Expression& identifier) const;
    ScopedSymbol getSymbol(const std::string& alias);
};

class Function {
    friend class Expression;
    friend class CodeScope;
    friend class AST;

public:
    Function(const Atom<Identifier_t>& name);

    void addBinding(Atom <Identifier_t>&& name, Expression&& argument);
    void addTag(Expression&& tag, const TagModifier mod);

    const std::string& getName() const;
    const std::map<std::string, Expression>& getTags() const;
    CodeScope* getEntryScope() const;
    CodeScope* __entry;
    std::string __name;
    bool isPrefunction = false; //SECTIONTAG adhoc Function::isPrefunction flag

    Expression guardContext;
private:

    std::map<std::string, Expression> __tags;
};


class ExternData;

struct ExternEntry {
    std::string package;
    std::vector<std::string> headers;
};

typedef Expanded<TypeAnnotation> ExpandedType;

enum ASTInterface {
    CFA, DFA, Extern, Adhoc
};

struct FunctionSpecialization {
    std::string guard;
    size_t id;
};

struct FunctionSpecializationQuery {
    std::unordered_set<std::string> context;
};

template<>
struct AttachmentsId<Expression>{
    static unsigned int getId(const Expression& expression){
        return expression.id;
    }
};

template<>
struct AttachmentsId<Symbol>{
    static unsigned int getId(const Symbol& s){
        return s.scope->__declarations.at(s.identifier).id;
    }
};

template<>
struct AttachmentsId<ManagedFnPtr>{
    static unsigned int getId(const ManagedFnPtr& f){
        const Symbol symbolFunction{ScopedSymbol::RetSymbol, f->getEntryScope()};
        
        return AttachmentsId<Symbol>::getId(symbolFunction);
    }
};

class AST {
public:
    AST();

    //TASK extern and DFA interfaces move into addInterfaceData
    /**
     *  DFA Interface
     */
    void addDFAData(Expression&& data);

    /**
     * Extern Interface
     */
    void addExternData(ExternData&& data);

    void addInterfaceData(const ASTInterface& interface, Expression&& data);
    void add(Function* f);

    void add(MetaRuleAbstract* r);
    ManagedScpPtr add(CodeScope* scope);

    std::string getModuleName();
    ManagedPtr<Function> findFunction(const std::string& name);

    typedef std::multimap<std::string, unsigned int> FUNCTIONS_REGISTRY;
    std::list<ManagedFnPtr> getAllFunctions() const;
    std::list<ManagedFnPtr> getFunctionVariants(const std::string& name) const;


    template<class Target>
    ManagedPtr<Target> begin();

    std::vector<ExternEntry> __externdata;
    std::list<Expression> __dfadata; //TODO move to more appropriate place
    std::list<std::string> __rawImports; //TODO move to more appropriate place
    std::multimap<ASTInterface, Expression> __interfacesData; //TODO CFA data here.

private:
    std::vector<MetaRuleAbstract*> __rules;
    std::vector<Function*> __functions;
    std::vector<CodeScope*> __scopes;

    FUNCTIONS_REGISTRY __indexFunctions;


    // ***** TYPES SECTION *****
public:
    std::map<std::string, TypeAnnotation> __indexTypeAliases;
    ExpandedType expandType(const TypeAnnotation &t) const;
    ExpandedType findType(const std::string& name);
    void add(TypeAnnotation t, Atom<Identifier_t> alias);

    //TODO revisit enums/variants, move to codescope
    bool recognizeVariantIdentifier(Expression& identifier);


private:
    std::map<std::string, std::pair<TypeAnnotation, int>> __dictVariants;
    ExpandedType expandType(const TypeAnnotation &t, std::map<std::string, TypeAnnotation> scope,
            const std::vector<TypeAnnotation> &args = std::vector<TypeAnnotation>()) const;

    // ***** SYMBOL RECOGNITION *****
public:
    std::set<std::pair<CodeScope*, Expression>> binUnrecognizedIdentifiers;

public:
    void postponeIdentifier(CodeScope* scope, const Expression& id);
    void recognizePostponedIdentifiers();
};

template<>
ManagedPtr<Function>
AST::begin<Function>();

template<>
ManagedPtr<CodeScope>
AST::begin<CodeScope>();

template<>
ManagedPtr<MetaRuleAbstract>
AST::begin<MetaRuleAbstract>();

}
#endif // AST_H