#include <algorithm>

#include "gen/llvm.h"

#include "mtype.h"
#include "aggregate.h"
#include "init.h"
#include "declaration.h"

#include "gen/irstate.h"
#include "gen/tollvm.h"
#include "gen/llvmhelpers.h"
#include "gen/arrays.h"
#include "gen/logger.h"
#include "gen/structs.h"
#include "gen/dvalue.h"

#include "ir/irstruct.h"

//////////////////////////////////////////////////////////////////////////////////////////
LLConstant* DtoConstStructInitializer(StructInitializer* si)
{
    Logger::println("DtoConstStructInitializer: %s", si->toChars());
    LOG_SCOPE;

    assert(si->ad);
    TypeStruct* ts = (TypeStruct*)si->ad->type;

    DtoResolveDsymbol(si->ad);

    const llvm::StructType* structtype = isaStruct(ts->ir.type->get());

    if (Logger::enabled())
        Logger::cout() << "llvm struct type: " << *structtype << '\n';

    assert(si->value.dim == si->vars.dim);

    std::vector<DUnionIdx> inits;
    for (int i = 0; i < si->value.dim; ++i)
    {
        Initializer* ini = (Initializer*)si->value.data[i];
        assert(ini);
        VarDeclaration* vd = (VarDeclaration*)si->vars.data[i];
        assert(vd);
        LLConstant* v = DtoConstInitializer(vd->type, ini);
        inits.push_back(DUnionIdx(vd->ir.irField->index, vd->ir.irField->indexOffset, v));
    }

    DtoConstInitStruct((StructDeclaration*)si->ad);
    return si->ad->ir.irStruct->dunion->getConst(inits);
}

//////////////////////////////////////////////////////////////////////////////////////////

LLValue* DtoIndexStruct(LLValue* src, StructDeclaration* sd, VarDeclaration* vd)
{
    Logger::println("indexing struct field %s:", vd->toPrettyChars());
    LOG_SCOPE;

    // vd must be a field
    IrField* field = vd->ir.irField;
    assert(field);

    unsigned idx = field->index;
    unsigned off = field->indexOffset;

    const LLType* st = getPtrToType(DtoType(sd->type));
    src = DtoBitCast(src, st);

    LLValue* val = DtoGEPi(src, 0,idx);
    val = DtoBitCast(val, getPtrToType(DtoType(vd->type)));

    if (off)
        val = DtoGEPi1(val, off);

    if (Logger::enabled())
        Logger::cout() << "value: " << *val << '\n';

    return val;
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoResolveStruct(StructDeclaration* sd)
{
    if (sd->ir.resolved) return;
    sd->ir.resolved = true;

    Logger::println("DtoResolveStruct(%s): %s", sd->toChars(), sd->loc.toChars());
    LOG_SCOPE;

    TypeStruct* ts = (TypeStruct*)sd->type->toBasetype();

    // this struct is a forward declaration
    // didn't even know had those ...
    if (sd->sizeok != 1)
    {
        sd->ir.irStruct = new IrStruct(ts);
        ts->ir.type = new llvm::PATypeHolder(llvm::OpaqueType::get());
        return;
    }

    bool ispacked = (ts->alignsize() == 1);

    IrStruct* irstruct = new IrStruct(ts);
    sd->ir.irStruct = irstruct;
    gIR->structs.push_back(irstruct);

    irstruct->packed = ispacked;

    // fields
    Array* arr = &sd->fields;
    for (int k=0; k < arr->dim; k++) {
        VarDeclaration* v = (VarDeclaration*)arr->data[k];
        v->toObjFile(0); // TODO: multiobj
    }

    bool thisModule = false;
    if (sd->getModule() == gIR->dmodule)
        thisModule = true;

    // methods
    arr = sd->members;
    for (int k=0; k < arr->dim; k++) {
        Dsymbol* s = (Dsymbol*)arr->data[k];
        if (FuncDeclaration* fd = s->isFuncDeclaration()) {
            if (thisModule || (fd->prot() != PROTprivate)) {
                fd->toObjFile(0); // TODO: multiobj
            }
        }
        else if (s->isAttribDeclaration()) {
            s->toObjFile(0); // TODO: multiobj
        }
        else {
            Logger::println("Ignoring dsymbol '%s' in this->members of kind '%s'", s->toPrettyChars(), s->kind());
        }
    }

    /*for (int k=0; k < sd->members->dim; k++) {
        Dsymbol* dsym = (Dsymbol*)(sd->members->data[k]);
        dsym->toObjFile();
    }*/

    Logger::println("doing struct fields");

    const llvm::StructType* structtype = 0;
    std::vector<const LLType*> fieldtypes;

    if (irstruct->offsets.empty())
    {
        Logger::println("has no fields");
        fieldtypes.push_back(LLType::Int8Ty);
        structtype = llvm::StructType::get(fieldtypes, ispacked);
    }
    else
    {
        Logger::println("has fields");
        unsigned prevsize = (unsigned)-1;
        unsigned lastoffset = (unsigned)-1;
        const LLType* fieldtype = NULL;
        VarDeclaration* fieldinit = NULL;
        size_t fieldpad = 0;
        int idx = 0;
        for (IrStruct::OffsetMap::iterator i=irstruct->offsets.begin(); i!=irstruct->offsets.end(); ++i) {
            // first iteration
            if (lastoffset == (unsigned)-1) {
                lastoffset = i->first;
                assert(lastoffset == 0);
                fieldtype = i->second.type;
                fieldinit = i->second.var;
                prevsize = fieldinit->type->size();
                i->second.var->ir.irField->index = idx;
            }
            // colliding offset?
            else if (lastoffset == i->first) {
                size_t s = i->second.var->type->size();
                if (s > prevsize) {
                    fieldpad += s - prevsize;
                    prevsize = s;
                }
                sd->ir.irStruct->hasUnions = true;
                i->second.var->ir.irField->index = idx;
            }
            // intersecting offset?
            else if (i->first < (lastoffset + prevsize)) {
                size_t s = i->second.var->type->size();
                assert((i->first + s) <= (lastoffset + prevsize)); // this holds because all types are aligned to their size
                sd->ir.irStruct->hasUnions = true;
                i->second.var->ir.irField->index = idx;
                i->second.var->ir.irField->indexOffset = (i->first - lastoffset) / s;
            }
            // fresh offset
            else {
                // commit the field
                fieldtypes.push_back(fieldtype);
                irstruct->defaultFields.push_back(fieldinit);
                if (fieldpad) {
                    fieldtypes.push_back(llvm::ArrayType::get(LLType::Int8Ty, fieldpad));
                    irstruct->defaultFields.push_back(NULL);
                    idx++;
                }

                idx++;

                // start new
                lastoffset = i->first;
                fieldtype = i->second.type;
                fieldinit = i->second.var;
                prevsize = fieldinit->type->size();
                i->second.var->ir.irField->index = idx;
                fieldpad = 0;
            }
        }
        fieldtypes.push_back(fieldtype);
        irstruct->defaultFields.push_back(fieldinit);
        if (fieldpad) {
            fieldtypes.push_back(llvm::ArrayType::get(LLType::Int8Ty, fieldpad));
            irstruct->defaultFields.push_back(NULL);
        }

        Logger::println("creating struct type");
        structtype = llvm::StructType::get(fieldtypes, ispacked);
    }

    // refine abstract types for stuff like: struct S{S* next;}
    if (irstruct->recty != 0)
    {
        llvm::PATypeHolder& pa = irstruct->recty;
        llvm::cast<llvm::OpaqueType>(pa.get())->refineAbstractTypeTo(structtype);
        structtype = isaStruct(pa.get());
    }

    assert(ts->ir.type == 0);
    ts->ir.type = new llvm::PATypeHolder(structtype);

    if (sd->parent->isModule()) {
        gIR->module->addTypeName(sd->mangle(),structtype);
    }

    gIR->structs.pop_back();

    gIR->declareList.push_back(sd);
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoDeclareStruct(StructDeclaration* sd)
{
    if (sd->ir.declared) return;
    sd->ir.declared = true;

    Logger::println("DtoDeclareStruct(%s): %s", sd->toChars(), sd->loc.toChars());
    LOG_SCOPE;

    TypeStruct* ts = (TypeStruct*)sd->type->toBasetype();

    std::string initname("_D");
    initname.append(sd->mangle());
    initname.append("6__initZ");

    llvm::GlobalValue::LinkageTypes _linkage = DtoExternalLinkage(sd);
    llvm::GlobalVariable* initvar = new llvm::GlobalVariable(ts->ir.type->get(), true, _linkage, NULL, initname, gIR->module);
    sd->ir.irStruct->init = initvar;

    gIR->constInitList.push_back(sd);
    if (DtoIsTemplateInstance(sd) || sd->getModule() == gIR->dmodule)
        gIR->defineList.push_back(sd);
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoConstInitStruct(StructDeclaration* sd)
{
    if (sd->ir.initialized) return;
    sd->ir.initialized = true;

    Logger::println("DtoConstInitStruct(%s): %s", sd->toChars(), sd->loc.toChars());
    LOG_SCOPE;

    IrStruct* irstruct = sd->ir.irStruct;
    gIR->structs.push_back(irstruct);

    // make sure each offset knows its default initializer
    for (IrStruct::OffsetMap::iterator i=irstruct->offsets.begin(); i!=irstruct->offsets.end(); ++i)
    {
        IrStruct::Offset* so = &i->second;
        LLConstant* finit = DtoConstFieldInitializer(so->var->type, so->var->init);
        so->init = finit;
        so->var->ir.irField->constInit = finit;
    }

    const llvm::StructType* structtype = isaStruct(sd->type->ir.type->get());

    // go through the field inits and build the default initializer
    std::vector<LLConstant*> fieldinits_ll;
    size_t nfi = irstruct->defaultFields.size();
    for (size_t i=0; i<nfi; ++i) {
        LLConstant* c;
        if (irstruct->defaultFields[i] != NULL) {
            c = irstruct->defaultFields[i]->ir.irField->constInit;
            assert(c);
        }
        else {
            const llvm::ArrayType* arrty = isaArray(structtype->getElementType(i));
            std::vector<LLConstant*> vals(arrty->getNumElements(), llvm::ConstantInt::get(LLType::Int8Ty, 0, false));
            c = llvm::ConstantArray::get(arrty, vals);
        }
        fieldinits_ll.push_back(c);
    }

    // generate the union mapper
    sd->ir.irStruct->dunion = new DUnion(); // uses gIR->topstruct()

    // always generate the constant initalizer
    if (!sd->zeroInit) {
        Logger::println("Not zero initialized");
    #if 0
        //assert(tk == gIR->gIR->topstruct()().size());
        #ifndef LLVMD_NO_LOGGER
        Logger::cout() << "struct type: " << *structtype << '\n';
        for (size_t k=0; k<fieldinits_ll.size(); ++k) {
            Logger::cout() << "Type:" << '\n';
            Logger::cout() << *fieldinits_ll[k]->getType() << '\n';
            Logger::cout() << "Value:" << '\n';
            Logger::cout() << *fieldinits_ll[k] << '\n';
        }
        Logger::cout() << "Initializer printed" << '\n';
        #endif
    #endif
        sd->ir.irStruct->constInit = llvm::ConstantStruct::get(structtype,fieldinits_ll);
    }
    else {
        Logger::println("Zero initialized");
        sd->ir.irStruct->constInit = llvm::ConstantAggregateZero::get(structtype);
    }

    gIR->structs.pop_back();

    // emit typeinfo
    if (sd->getModule() == gIR->dmodule && sd->llvmInternal != LLVMno_typeinfo)
        DtoTypeInfoOf(sd->type, false);
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoDefineStruct(StructDeclaration* sd)
{
    if (sd->ir.defined) return;
    sd->ir.defined = true;

    Logger::println("DtoDefineStruct(%s): %s", sd->toChars(), sd->loc.toChars());
    LOG_SCOPE;

    assert(sd->type->ty == Tstruct);
    TypeStruct* ts = (TypeStruct*)sd->type;
    sd->ir.irStruct->init->setInitializer(sd->ir.irStruct->constInit);

    sd->ir.DModule = gIR->dmodule;
}

//////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////   D STRUCT UTILITIES     ////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////

LLValue* DtoStructEquals(TOK op, DValue* lhs, DValue* rhs)
{
    Type* t = lhs->getType()->toBasetype();
    assert(t->ty == Tstruct);

    // set predicate
    llvm::ICmpInst::Predicate cmpop;
    if (op == TOKequal || op == TOKidentity)
        cmpop = llvm::ICmpInst::ICMP_EQ;
    else
        cmpop = llvm::ICmpInst::ICMP_NE;

    // call memcmp
    size_t sz = getABITypeSize(DtoType(t));
    LLValue* val = DtoMemCmp(lhs->getRVal(), rhs->getRVal(), DtoConstSize_t(sz));
    return gIR->ir->CreateICmp(cmpop, val, LLConstantInt::get(val->getType(), 0, false), "tmp");
}

//////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////   D UNION HELPER CLASS   ////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////

DUnion::DUnion()
{
    DUnionField* f = NULL;
    IrStruct* topstruct = gIR->topstruct();
    bool unions = false;
    for (IrStruct::OffsetMap::iterator i=topstruct->offsets.begin(); i!=topstruct->offsets.end(); ++i)
    {
        unsigned o = i->first;
        IrStruct::Offset* so = &i->second;
        const LLType* ft = so->init->getType();
        size_t sz = getABITypeSize(ft);
        if (f == NULL) { // new field
            fields.push_back(DUnionField());
            f = &fields.back();
            f->size = sz;
            f->offset = o;
            f->init = so->init;
            f->initsize = sz; 
            f->types.push_back(ft);
        }
        else if (o == f->offset) { // same offset
            if (sz > f->size)
                f->size = sz;
            f->types.push_back(ft);
            unions = true;
        }
        else if (o < f->offset+f->size) {
            assert((o+sz) <= (f->offset+f->size));
            unions = true;
        }
        else {
            fields.push_back(DUnionField());
            f = &fields.back();
            f->size = sz;
            f->offset = o;
            f->init = so->init;
            f->initsize = sz;
            f->types.push_back(ft);
        }
    }

    ispacked = topstruct->packed;

    /*{
        LOG_SCOPE;
        Logger::println("******** DUnion BEGIN");
        size_t n = fields.size();
        for (size_t i=0; i<n; ++i) {
            Logger::cout()<<"field #"<<i<<" offset: "<<fields[i].offset<<" size: "<<fields[i].size<<'('<<fields[i].initsize<<")\n";
            LOG_SCOPE;
            size_t nt = fields[i].types.size();
            for (size_t j=0; j<nt; ++j) {
                Logger::cout()<<*fields[i].types[j]<<'\n';
            }
        }
        Logger::println("******** DUnion END");
    }*/
}

static void push_nulls(size_t nbytes, std::vector<LLConstant*>& out)
{
    assert(nbytes > 0);
    std::vector<LLConstant*> i(nbytes, llvm::ConstantInt::get(LLType::Int8Ty, 0, false));
    out.push_back(llvm::ConstantArray::get(llvm::ArrayType::get(LLType::Int8Ty, nbytes), i));
}

LLConstant* DUnion::getConst(std::vector<DUnionIdx>& in)
{
    std::sort(in.begin(), in.end());
    std::vector<LLConstant*> out;

    size_t nin = in.size();
    size_t nfields = fields.size();

    size_t fi = 0;
    size_t last = 0;
    size_t ii = 0;
    size_t os = 0;

    for(;;)
    {
        if (fi == nfields) break;

        bool nextSame = (ii+1 < nin) && (in[ii+1].idx == fi);

        if (ii < nin && fi == in[ii].idx)
        {
            size_t s = getABITypeSize(in[ii].c->getType());
            if (in[ii].idx == last)
            {
                size_t nos = in[ii].idxos * s;
                if (nos && nos-os) {
                    assert(nos >= os);
                    push_nulls(nos-os, out);
                }
                os = nos + s;
            }
            else
            {
                os = s;
            }
            out.push_back(in[ii].c);
            ii++;
            if (!nextSame)
            {
                if (os < fields[fi].size)
                    push_nulls(fields[fi].size - os, out);
                os = 0;
                last = fi++;
            }
            continue;
        }

        // default initialize if necessary
        if (ii == nin || fi < in[ii].idx)
        {
            DUnionField& f = fields[fi];
            out.push_back(f.init);
            if (f.initsize < f.size)
                push_nulls(f.size - f.initsize, out);
            last = fi++;
            os = 0;
            continue;
        }
    }

    std::vector<const LLType*> tys;
    size_t nout = out.size();
    for (size_t i=0; i<nout; ++i)
        tys.push_back(out[i]->getType());

    const llvm::StructType* st = llvm::StructType::get(tys, ispacked);
    return llvm::ConstantStruct::get(st, out);
}