#include <cassert>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <iostream>
#include <cstdlib>
#include <set>
#include <vector>
#include <algorithm>
#include <tuple>

#include "../Utils/SgUtils.h"
#include "../CFGraph/CFGraph.h"
#include "CFGraph/IR.h"
#include "Distribution/Array.h"
#include "dvm.h"
#include "../Utils/errors.h"
#include "../GraphCall/graph_calls.h"
#include "../GraphCall/graph_calls_func.h"

#include "libSage++.h"
#include "projectParameters.h"

using namespace std;

template<typename Iterator>
static void processArgument(set<SAPFOR::Argument*>& worklist, SAPFOR::Argument* arg, Iterator instr, Iterator first_instr) {
    if (arg == NULL)
        return;
    if (arg->getType() == SAPFOR::CFG_ARG_TYPE::REG) 
        extract_vars_from_reg(worklist, arg, instr, first_instr);
    else if (arg->getType() == SAPFOR::CFG_ARG_TYPE::VAR && arg->getMemType() == SAPFOR::CFG_MEM_TYPE::LOCAL_)
    {
        std::cout << "worklist add: " << arg->getValue() << std::endl;           //DEBUG PRINT
        worklist.insert(arg);
    }
}

template<typename Iterator>
void extract_vars_from_reg(set<SAPFOR::Argument*>& worklist, SAPFOR::Argument* reg, Iterator instr, Iterator first_instr) {
    for (; instr >= first_instr; instr--) {
        if ((*instr)->getInstruction()->getResult() == reg) 
        {
            processArgument(worklist, (*instr)->getInstruction()->getArg1(), instr, first_instr);
            processArgument(worklist, (*instr)->getInstruction()->getArg2(), instr, first_instr);
            return;
        }
    }
}

static void lookup_for_vars(ResultSet& result_set,
                            set<SAPFOR::Argument*>& worklist,
                            SAPFOR::Instruction* instr,
                            SAPFOR::BasicBlock* bblock,
                            const std::map<FuncInfo*, std::vector<SAPFOR::BasicBlock*>>& fullIR)
{
    std::cout << "Lookup in bblock no." << bblock->getNumber() << std::endl;                //DEBUG PRINT
 
    auto first_instr = bblock->getInstructions().begin();
    auto cur_instr = std::find_if(first_instr, bblock->getInstructions().end(), [instr](SAPFOR::IR_Block* i) {
        return i->getInstruction() == instr;
    });

    for (; cur_instr >= bblock->getInstructions().begin(); cur_instr--)
    {
        auto instr = (*cur_instr)->getInstruction(); 
        auto result_arg = instr->getResult();
        auto arg1 = instr->getArg1();
        auto arg2 = instr->getArg2();

        if (worklist.count(result_arg))
        {
            processArgument(worklist, arg1, cur_instr, first_instr);
            processArgument(worklist, arg2, cur_instr, first_instr);
            std::cout << "worklist erase: " << result_arg->getValue() << std::endl;                 //DEBUG PRINT
            worklist.erase(result_arg);
        }
        if (instr->getOperation() == SAPFOR::CFG_OP::PARAM && worklist.count(arg1)) 
        {
            // skip to F_CALL
            auto f_call_instr = cur_instr;
            while ((*f_call_instr)->getInstruction()->getOperation() != SAPFOR::CFG_OP::F_CALL)
                f_call_instr++;

            if ((*f_call_instr)->getInstruction()->getArg1()->getValue() == "_READ") 
            {
                auto filename = (*f_call_instr)->getInstruction()->getOperator()->fileName();
                auto line = (*f_call_instr)->getInstruction()->getOperator()->lineNumber();
                __spf_print(1,"Please specify value of variable %s on line %d of file %s", arg1->getValue().c_str(), line, filename);
                result_set.insert(make_tuple(filename, line, arg1->getValue()));

                std::cout << "worklist erase: " << arg1->getValue() << std::endl;               //DEBUG PRINT
                worklist.erase(arg1);
            } else 
            {
                 //check if variable is modified in called function
            }
        }
    }


    const auto& RD = bblock->getRD_In();
    map<SAPFOR::BasicBlock*, SAPFOR::Instruction*> group_by_block;
    for (auto& arg : worklist) 
    {
        if (RD.count(arg))
        {
            if (RD.at(arg).size() == 0)
                __spf_print(1, "variable %s has no definition", arg->getValue().c_str());
            else if (RD.at(arg).size() > 1)
                __spf_print(1, "variable %s has multiple reaching definitions, further analysis is impossible", arg->getValue().c_str());
            else
            {
                for (const auto& instr_num : RD.at(arg))
                {
                    auto [instr, bblock] = getInstructionAndBlockByNumber(fullIR, instr_num);
                    if (group_by_block[bblock] == NULL || group_by_block[bblock]->getNumber() < instr_num) 
                        group_by_block[bblock] = instr;
                }
            }
        }
    }

    for (const auto& [bblock, instr] : group_by_block) 
    {
        lookup_for_vars(result_set, worklist, instr, bblock, fullIR);
    }
}

static void handle_single_allocate(ResultSet& result_set,
                                   SAPFOR::Instruction* instr,
                                   SAPFOR::BasicBlock* bblock,
                                   const std::map<FuncInfo*, std::vector<SAPFOR::BasicBlock*>>& fullIR)
{   
    auto first_instr = bblock->getInstructions().begin();
    auto cur_instr = std::find_if(first_instr, bblock->getInstructions().end(), [instr](SAPFOR::IR_Block* i) {
        return i->getInstruction() == instr;
    });
    auto alloc_instr = cur_instr;

    // skip to F_CALL _ALLOC n
    while ((*alloc_instr)->getInstruction()->getOperation() != SAPFOR::CFG_OP::F_CALL ||
           (*alloc_instr)->getInstruction()->getArg1()->getValue() != "_ALLOC") 
    {
        alloc_instr++;
    }

    auto arrays_num = stoi((*alloc_instr)->getInstruction()->getArg2()->getValue());
    std::cout << "arrays_num: " << arrays_num << std::endl;                 //DEBUG PRINT

    set<SAPFOR::Argument*> worklist;
    for (int i = 0; i < arrays_num; i++)
    {
        auto param_instr = --alloc_instr;
        auto param_reg = (*param_instr)->getInstruction()->getArg1();

        while ((*param_instr)->getInstruction()->getOperation() != SAPFOR::CFG_OP::LOAD ||
               (*param_instr)->getInstruction()->getResult() != param_reg)
        {
            param_instr--;
        }

        auto dimensions_num = stoi((*param_instr)->getInstruction()->getArg2()->getValue());
        
        for (int j = 0; j < dimensions_num; j++)
        {
            auto ref_instr = --param_instr;
            
            auto arg = (*ref_instr)->getInstruction()->getArg1();
            if (arg->getType() == SAPFOR::CFG_ARG_TYPE::REG)
            {
                extract_vars_from_reg(worklist, arg, ref_instr, first_instr);
            }
            else if (arg->getType() == SAPFOR::CFG_ARG_TYPE::VAR && arg->getMemType() == SAPFOR::CFG_MEM_TYPE::LOCAL_)
            {
                std::cout << "worklist add: " << arg->getValue() << std::endl;          //DEBUG PRINT
                worklist.insert(arg);
            }
        }
    }
    lookup_for_vars(result_set,worklist, instr, bblock, fullIR);
}

ResultSet
findParameters(const std::map<FuncInfo*, std::vector<SAPFOR::BasicBlock*>>& fullIR,
               const std::map<std::tuple<int, std::string, std::string>, std::pair<DIST::Array*, DIST::ArrayAccessInfo*>>& declaredArrays)
{
    ResultSet foundParameters;
    std::set<SgStatement*> alloc_statements;
    for (const auto& elem : declaredArrays) 
    {
        const auto& array = elem.second.first;
        assert(array->GetLocation().first == Distribution::arrayLocation::l_LOCAL); // v0.1

        SgSymbol* arraySymb = array->GetDeclSymbol()->GetOriginal();
        SgStatement* decl = declaratedInStmt(arraySymb);
        for (auto &stmt : getAttributes<SgStatement*, SgStatement*>(decl, set<int>{ ALLOCATE_STMT }))
        {
            alloc_statements.insert(stmt);
        }
    }
    
    for (const auto& alloc_statement : alloc_statements)
    {
        auto [instr, bblock] = getInstructionAndBlockByStatement(fullIR, alloc_statement);
        ResultSet result_set;
        handle_single_allocate(result_set, instr, bblock, fullIR);
    }
    return foundParameters;
}