#ifndef ABSTRACTPASS_H
#define ABSTRACTPASS_H
#include "ast.h"
#include "passmanager.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 std::move(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:        
        Output processSymbol(const Symbol& symbol, PassContext context, std::string hintSymbol=""){
            if (__visitedSymbols.isCached(symbol))
                return __visitedSymbols.getCachedValue(symbol);

            
            const Expression& declaration = CodeScope::findDeclaration(symbol);
            if (declaration.isDefined()){
                PassContext context2 = context.updateScope(symbol.scope);
                
                Output&& result = process(declaration, context2, ident);
                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;
            }
        }
        
    private:

    template<>
    void
    AbstractPass<void>::processSymbol(const Symbol& symbol, PassContext context);
    
}
#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));