#ifndef ABSTRACTPASS_H
#define ABSTRACTPASS_H
#include "ast.h"
#include "xreatemanager.h"

#include<iostream>
namespace xreate
{
    struct PassContext
    {
        CodeScope* scope = 0;
        ManagedFnPtr function;
        ManagedRulePtr rule;
        std::string varDecl;

        PassContext()
        {}

        PassContext updateScope(CodeScope* scopeNew) {
            PassContext context2{*this};
            context2.scope = scopeNew;
            return context2;
        }

        ~PassContext(){}
    };

    class AbstractPassBase {
    public:
        AbstractPassBase(PassManager* manager);
        virtual void run()=0;
        virtual void finish();

        PassManager* man;
    };

    template<class Output>
    Output defaultValue();
    
    template<>
    void defaultValue<void>();

    template<class Output>
    class SymbolCache: private std::map<Symbol, Output>{
        public:
            bool isCached(const Symbol& symbol){
                return this->count(symbol);
            }

            Output setCachedValue(const Symbol& symbol, Output&& value){
                (*this)[symbol] = value;
                return value;
            }

            Output getCachedValue(const  Symbol& symbol){
                assert(this->count(symbol));
                return this->at(symbol);
            }
    };

    template<>
    class SymbolCache<void>: private std::set<Symbol>{
        public:
        bool isCached(const Symbol& symbol){
            bool result = this->count(symbol) > 0;
            return result;
        }
        void setCachedValue(const Symbol& symbol){
            this->insert(symbol);
        }

        void getCachedValue(const  Symbol& symbol){
        }
    };

template<class Output>
class AbstractPass: public AbstractPassBase    {

    SymbolCache<Output> __visitedSymbols;

protected:        
    virtual Output processSymbol(const Symbol& symbol, PassContext context, const std::string& hintSymbol=""){
        if (__visitedSymbols.isCached(symbol))
            return __visitedSymbols.getCachedValue(symbol);


        const Expression& declaration = CodeScope::getDeclaration(symbol);
        if (declaration.isDefined()){
            PassContext context2 = context.updateScope(symbol.scope);

            Output&& result = process(declaration, context2, hintSymbol);
            return __visitedSymbols.setCachedValue(symbol, std::move(result));
        }

        return defaultValue<Output>();
    }

    Output processExpressionCall(const Expression& expression, PassContext context){
        const std::string &calleeName = expression.getValueString();
        std::list<ManagedFnPtr> callees = man->root->getFunctionVariants(calleeName);
        if (callees.size() == 1 && callees.front()){
            return processFnCall(callees.front(), context);

        } else {
            for (const ManagedFnPtr& callee: callees){
                processFnCallUncertain(callee, context);
            }

            return defaultValue<Output>();
        }
    }

    SymbolCache<Output>& getSymbolCache(){
        return __visitedSymbols;
    }



public:
    AbstractPass(PassManager* manager)
        : AbstractPassBase(manager){}

    virtual Output processFnCall(ManagedFnPtr function, PassContext context){
        return defaultValue<Output>();
    }

    virtual void processFnCallUncertain(ManagedFnPtr function, PassContext context)
    {}

    virtual void process(ManagedRulePtr rule)
    {}

    virtual Output process(ManagedFnPtr function)
    {
        PassContext context;
        context.function = function;

        return process(function->getEntryScope(), context);
    }    

    virtual Output process(CodeScope* scope, PassContext context, const std::string& hintBlockDecl=""){
        context.scope = scope;

        return processSymbol(Symbol{ScopedSymbol::RetSymbol, scope}, context);
    }

    virtual Output process(const Expression& expression, PassContext context, const std::string& varDecl=""){
        if (expression.__state == Expression::IDENT){
            assert(context.scope);
            return processSymbol(Attachments::get<Symbol>(expression), context, expression.getValueString());
        }

        assert(false);
        return defaultValue<Output>();
    }

    void run() {
        ManagedRulePtr rule = man->root->begin<MetaRuleAbstract>();
        while (rule.isValid()) {
            process(rule);
            ++rule;
        }

        ManagedFnPtr f = man->root->begin<Function>();
        while (f.isValid()) {
            process(f);
            ++f;
        }
    }

};

template<>
void
AbstractPass<void>::processSymbol(const Symbol& symbol, PassContext context, const std::string& hintSymbol);

template<>
void
AbstractPass<void>::process(const Expression& expression, PassContext context, const std::string& hintSymbol);

}    
#endif

//PROCESS FUNCTION:
//    const Symbol& symbolFunction{0, function->getEntryScope()};
//
//    if (__visitedSymbols.isCached(symbolFunction))
//        return __visitedSymbols.getCachedValue(symbolFunction);
//
//    PassContext context;
//    context.function = function;
//
//    Output&& result = process(function->getEntryScope(), context);
//    return __visitedSymbols.setCachedValue(symbolFunction, std::move(result));