#include<vector>
#include<map>
#include<unordered_set>
#include<unordered_map>
#include<string>
#include <numeric>

#include "range_structures.h"
#include "region.h"

#include "../Utils/SgUtils.h"

using namespace std;

static bool isParentStmt(SgStatement* stmt, SgStatement* parent)
{
    for (; stmt; stmt = stmt->controlParent())
        if (stmt == parent)
            return true;

    return false;
}

/*returns head block and loop*/
pair<SAPFOR::BasicBlock*, unordered_set<SAPFOR::BasicBlock*>> GetBasicBlocksForLoop(const LoopGraph* loop, const vector<SAPFOR::BasicBlock*> blocks)
{
    unordered_set<SAPFOR::BasicBlock*> block_loop;
    SAPFOR::BasicBlock* head_block = nullptr;
    auto loop_operator = loop->loop->GetOriginal();
    for (const auto& block : blocks)
    {
        if (!block || (block->getInstructions().size() == 0))
            continue;

        SgStatement* first = block->getInstructions().front()->getInstruction()->getOperator();
        SgStatement* last = block->getInstructions().back()->getInstruction()->getOperator();
        if (isParentStmt(first, loop_operator) && isParentStmt(last, loop_operator))
        {
            block_loop.insert(block);

            if ((!head_block) && (first == loop_operator) && (last == loop_operator) &&
                (block->getInstructions().size() == 2) &&
                (block->getInstructions().back()->getInstruction()->getOperation() == SAPFOR::CFG_OP::JUMP_IF))
            {
                head_block = block;
            }

        }
    }
    return { head_block, block_loop };
}

static void BuildLoopIndex(map<string, LoopGraph*>& loopForIndex, LoopGraph* loop) {
    string index = loop->loopSymbol;
    loopForIndex[index] = loop;

    for (const auto& childLoop : loop->children)
        BuildLoopIndex(loopForIndex, childLoop);
}

static string FindIndexName(int pos, SAPFOR::BasicBlock* block, map<string, LoopGraph*>& loopForIndex) {
    unordered_set<SAPFOR::Argument*> args = { block->getInstructions()[pos]->getInstruction()->getArg1() };

    for (int i = pos - 1; i >= 0; i--) 
    {
        SAPFOR::Argument* res = block->getInstructions()[i]->getInstruction()->getResult();
        if (res && args.find(res) != args.end()) 
        {
            SAPFOR::Argument* arg1 = block->getInstructions()[i]->getInstruction()->getArg1();
            SAPFOR::Argument* arg2 = block->getInstructions()[i]->getInstruction()->getArg2();
            if (arg1) 
            {
                string name = arg1->getValue();
                int idx = name.find('%');
                if (idx != -1 && loopForIndex.find(name.substr(idx + 1)) != loopForIndex.end())
                    return name.substr(idx + 1);
                else
                    args.insert(arg1);
            }

            if (arg2)
            {
                string name = arg2->getValue();
                int idx = name.find('%');
                if (idx != -1 && loopForIndex.find(name.substr(idx + 1)) != loopForIndex.end())
                    return name.substr(idx + 1);
                else
                    args.insert(arg2);
            }
        }
    }
    return "";
}

static int GetDefUseArray(SAPFOR::BasicBlock* block, LoopGraph* loop, ArrayAccessingIndexes& def, ArrayAccessingIndexes& use) {
    auto instructions = block->getInstructions();
    map<string, LoopGraph*> loopForIndex;
    BuildLoopIndex(loopForIndex, loop);
    for (int i = 0; i < instructions.size(); i++)
    {
        auto instruction = instructions[i];
        if (!instruction->getInstruction()->getArg1())
            continue;

        auto operation = instruction->getInstruction()->getOperation();
        auto type = instruction->getInstruction()->getArg1()->getType();
        if ((operation == SAPFOR::CFG_OP::STORE || operation == SAPFOR::CFG_OP::LOAD) && type == SAPFOR::CFG_ARG_TYPE::ARRAY)
        {
            vector<SAPFOR::Argument*> index_vars;
            vector<int> refPos;
            string array_name;
            if (operation == SAPFOR::CFG_OP::STORE)
                array_name = instruction->getInstruction()->getArg1()->getValue();            
            else
                array_name = instruction->getInstruction()->getArg2()->getValue();

            int j = i - 1;
            while (j >= 0 && instructions[j]->getInstruction()->getOperation() == SAPFOR::CFG_OP::REF)
            {
                index_vars.push_back(instructions[j]->getInstruction()->getArg1());
                refPos.push_back(j);
                j--;
            }

            /*to choose correct dimension*/
            int n = index_vars.size();
            vector<ArrayDimension> accessPoint(n);

            auto* ref = isSgArrayRefExp(instruction->getInstruction()->getExpression());
            vector<pair<int, int>> coefsForDims;
            for (int i = 0; ref && i < ref->numberOfSubscripts(); ++i)
            {
                const vector<int*>& coefs = getAttributes<SgExpression*, int*>(ref->subscript(i), set<int>{ INT_VAL });
                if (coefs.size() == 1)
                {
                    const pair<int, int> coef(coefs[0][0], coefs[0][1]);
                    coefsForDims.push_back(coef);
                }

            }

            while (!index_vars.empty())
            {
                auto var = index_vars.back();
                int currentVarPos = refPos.back();
                pair currentCoefs = coefsForDims.back();
                ArrayDimension current_dim;
                if (var->getType() == SAPFOR::CFG_ARG_TYPE::CONST)
                    current_dim = { stoul(var->getValue()), 1, 1 };
                else
                {
                    string name, full_name = var->getValue();
                    int pos = full_name.find('%');
                    LoopGraph* currentLoop;
                    if (pos != -1) 
                    {
                        name = full_name.substr(pos + 1);
                        if (loopForIndex.find(name) != loopForIndex.end())
                            currentLoop = loopForIndex[name];                        
                        else
                            return -1;
                    }
                    else 
                    {
                        name = FindIndexName(currentVarPos, block, loopForIndex);
                        if (name == "")
                            return -1;

                        if (loopForIndex.find(name) != loopForIndex.end())
                            currentLoop = loopForIndex[name];                        
                        else
                            return -1;
                    }

                    uint64_t start = currentLoop->startVal * currentCoefs.first + currentCoefs.second;
                    uint64_t step = currentCoefs.first;
                    current_dim = { start, step, (uint64_t)currentLoop->calculatedCountOfIters };
                }

                accessPoint[n - index_vars.size()] = current_dim;
                index_vars.pop_back();
                refPos.pop_back();
                coefsForDims.pop_back();
            }

            if (operation == SAPFOR::CFG_OP::STORE)            
                def[array_name].Insert(accessPoint);
            else
                use[array_name].Insert(accessPoint);
        }
    }
    return 0;

}

static void SetConnections(unordered_map<SAPFOR::BasicBlock*, Region*>& bbToRegion, const unordered_set<SAPFOR::BasicBlock*>& blockSet)
{
    for (SAPFOR::BasicBlock* block : blockSet)
    {
        for (SAPFOR::BasicBlock* nextBlock : block->getNext())
            if (bbToRegion.find(nextBlock) != bbToRegion.end())
                bbToRegion[block]->addNextRegion(bbToRegion[nextBlock]);
         
        for (SAPFOR::BasicBlock* prevBlock : block->getPrev())
            if (bbToRegion.find(prevBlock) != bbToRegion.end())
                bbToRegion[block]->addPrevRegion(bbToRegion[prevBlock]);
    }
}

static Region* CreateSubRegion(LoopGraph* loop, const vector<SAPFOR::BasicBlock*>& Blocks, const unordered_map<SAPFOR::BasicBlock*, Region*>& bbToRegion)
{
    Region* region = new Region;
    auto [header, blockSet] = GetBasicBlocksForLoop(loop, Blocks);
    if (bbToRegion.find(header) != bbToRegion.end())
        region->setHeader(bbToRegion.at(header));    
    else
        return NULL;
    
    for (SAPFOR::BasicBlock* block : blockSet)
        if (bbToRegion.find(block) != bbToRegion.end())
            region->addBasickBlocks(bbToRegion.at(block));

    for (LoopGraph* childLoop : loop->children)
        region->addSubRegions(CreateSubRegion(childLoop, Blocks, bbToRegion));

    cout << header << endl;
    return region;
}

Region::Region(LoopGraph* loop, const vector<SAPFOR::BasicBlock*>& Blocks)
{
    auto [header, blockSet] = GetBasicBlocksForLoop(loop, Blocks);
    unordered_map<SAPFOR::BasicBlock*, Region*> bbToRegion;
    for (auto poiner : blockSet)
    {
        bbToRegion[poiner] = new Region(*poiner);
        this->basickBlocks.insert(bbToRegion[poiner]);
        GetDefUseArray(poiner, loop, bbToRegion[poiner]->array_def, bbToRegion[poiner]->array_use);

    }
    this->header = bbToRegion[header];
    SetConnections(bbToRegion, blockSet);
    //create subRegions
    for (LoopGraph* childLoop : loop->children)
        subRegions.insert(CreateSubRegion(childLoop, Blocks, bbToRegion));
}