#define NEED_newRV_noinc
#define NEED_sv_2pv_flags
#include "xshelper.h"

typedef struct {
    bool finished;
    bool incremented;
} unpack_user;

#include "msgpack/unpack_define.h"

#define msgpack_unpack_struct(name) \
    struct template ## name

#define msgpack_unpack_func(ret, name) \
    STATIC_INLINE ret template ## name

#define msgpack_unpack_callback(name) \
    template_callback ## name

#define msgpack_unpack_object SV*

#define msgpack_unpack_user unpack_user

/* ---------------------------------------------------------------------- */
/* utility functions                                                      */

STATIC_INLINE SV *
get_bool (const char* const name) {
    dTHX;
    return newSVsv(get_sv( name, GV_ADD ));
}

/* ---------------------------------------------------------------------- */
struct template_context;
typedef struct template_context msgpack_unpack_t;

static void template_init(msgpack_unpack_t* u);

static SV* template_data(msgpack_unpack_t* u);

static int template_execute(msgpack_unpack_t* u PERL_UNUSED_DECL,
    const char* data, size_t len, size_t* off);

STATIC_INLINE SV* template_callback_root(unpack_user* u PERL_UNUSED_DECL)
{
    return NULL;
}

#if IVSIZE == 4

STATIC_INLINE int template_callback_UV(unpack_user* u PERL_UNUSED_DECL, UV const d, SV** o)
{
    dTHX;
    *o = newSVuv(d);
    return 0;
}

STATIC_INLINE int template_callback_uint64(unpack_user* u PERL_UNUSED_DECL, uint64_t const d, SV** o)
{
    dTHX;
    *o = newSVnv((NV)d);
    return 0;
}

STATIC_INLINE int template_callback_IV(unpack_user* u PERL_UNUSED_DECL, IV const d, SV** o)
{
    dTHX;
    *o = newSViv(d);
    return 0;
}

STATIC_INLINE int template_callback_int64(unpack_user* u PERL_UNUSED_DECL, int64_t const d, SV** o)
{
    dTHX;
    *o = newSVnv((NV)d);
    return 0;
}

#else /* IVSIZE == 8 */


STATIC_INLINE int template_callback_UV(unpack_user* u PERL_UNUSED_DECL, UV const d, SV** o)
{
    dTHX;
    *o = newSVuv(d);
    return 0;
}

#define template_callback_uint64 template_callback_UV

STATIC_INLINE int template_callback_IV(unpack_user* u PERL_UNUSED_DECL, IV const d, SV** o)
{
    dTHX;
    *o = newSViv(d);
    return 0;
}

#define template_callback_uint64 template_callback_IV

#endif /* IVSIZE */

#define template_callback_uint8  template_callback_UV
#define template_callback_uint16 template_callback_UV
#define template_callback_uint32 template_callback_UV

#define template_callback_int8  template_callback_IV
#define template_callback_int16 template_callback_IV
#define template_callback_int32 template_callback_IV

#define template_callback_float template_callback_double

STATIC_INLINE int template_callback_double(unpack_user* u PERL_UNUSED_DECL, double d, SV** o)
{
    dTHX;
    *o = newSVnv(d);
    return 0;
}

/* &PL_sv_undef is not so good. see http://gist.github.com/387743 */
STATIC_INLINE int template_callback_nil(unpack_user* u PERL_UNUSED_DECL, SV** o)
{
    dTHX;
    *o = newSV(0);
    return 0;
}

STATIC_INLINE int template_callback_true(unpack_user* u PERL_UNUSED_DECL, SV** o)
{
    dTHX;
    *o = get_bool("Data::MessagePack::true");
    return 0;
}

STATIC_INLINE int template_callback_false(unpack_user* u PERL_UNUSED_DECL, SV** o)
{
    dTHX;
    *o = get_bool("Data::MessagePack::false");
    return 0;
}

STATIC_INLINE int template_callback_array(unpack_user* u PERL_UNUSED_DECL, unsigned int n, SV** o)
{
    dTHX;
    AV* const a = newAV();
    *o = newRV_noinc((SV*)a);
    av_extend(a, n + 1);
    return 0;
}

STATIC_INLINE int template_callback_array_item(unpack_user* u PERL_UNUSED_DECL, SV** c, SV* o)
{
    dTHX;
    AV* const a = (AV*)SvRV(*c);
    assert(SvTYPE(a) == SVt_PVAV);
    (void)av_store(a, AvFILLp(a) + 1, o); // the same as av_push(a, o)
    return 0;
}

STATIC_INLINE int template_callback_map(unpack_user* u PERL_UNUSED_DECL, unsigned int n, SV** o)
{
    dTHX;
    HV* const h = newHV();
    hv_ksplit(h, n);
    *o = newRV_noinc((SV*)h);
    return 0;
}

STATIC_INLINE int template_callback_map_item(unpack_user* u PERL_UNUSED_DECL, SV** c, SV* k, SV* v)
{
    dTHX;
    HV* const h = (HV*)SvRV(*c);
    assert(SvTYPE(h) == SVt_PVHV);
    (void)hv_store_ent(h, k, v, 0);
    SvREFCNT_dec(k);
    return 0;
}

STATIC_INLINE int template_callback_raw(unpack_user* u PERL_UNUSED_DECL, const char* b PERL_UNUSED_DECL, const char* p, unsigned int l, SV** o)
{
    dTHX;
    /*  newSVpvn_flags(p, l, SVs_TEMP) returns an undef if l == 0 */
    *o = ((l==0) ? newSVpvs("") : newSVpvn(p, l));
    return 0;
}

#include "msgpack/unpack_template.h"

#define UNPACKER(from, name)                                              \
    msgpack_unpack_t *name;                                               \
    if(!(SvROK(from) && SvIOK(SvRV(from)))) {                             \
        Perl_croak(aTHX_ "Invalid unpacker instance for " #name);         \
    }                                                                     \
    name = INT2PTR(msgpack_unpack_t*, SvIVX(SvRV((from))));               \
    if(name == NULL) {                                                    \
        Perl_croak(aTHX_ "NULL found for " # name " when shouldn't be."); \
    }

XS(xs_unpack) {
    dXSARGS;
    SV* const data = ST(1);
    size_t limit;

    if (items == 2) {
        limit = sv_len(data);
    }
    else if(items == 3) {
        limit = SvUVx(ST(2));
    }
    else {
        Perl_croak(aTHX_ "Usage: Data::MessagePack->unpack('data' [, $limit])");
    }

    STRLEN dlen;
    const char* const dptr = SvPV_const(data, dlen);

    msgpack_unpack_t mp;
    template_init(&mp);

    unpack_user const u = {false, false};
    mp.user = u;

    size_t from = 0;
    int const ret = template_execute(&mp, dptr, (size_t)dlen, &from);
    SV* const obj = template_data(&mp);
    sv_2mortal(obj);

    if(ret < 0) {
        Perl_croak(aTHX_ "Data::MessagePack->unpack: parse error");
    } else if(ret == 0) {
        Perl_croak(aTHX_ "Data::MessagePack->unpack: insufficient bytes");
    } else {
        if(from < dlen) {
            Perl_croak(aTHX_ "Data::MessagePack->unpack: extra bytes");
        }
    }

    ST(0) = obj;
    XSRETURN(1);
}

/* ------------------------------ stream -- */
/* http://twitter.com/frsyuki/status/13249304748 */

STATIC_INLINE void _reset(SV* const self) {
    dTHX;
	unpack_user const u = {false, false};

	UNPACKER(self, mp);
	template_init(mp);
	mp->user = u;
}

XS(xs_unpacker_new) {
    dXSARGS;
    if (items != 1) {
        Perl_croak(aTHX_ "Usage: Data::MessagePack::Unpacker->new()");
    }

    SV* const self = sv_newmortal();
    msgpack_unpack_t *mp;

    Newxz(mp, 1, msgpack_unpack_t);

    sv_setref_pv(self, "Data::MessagePack::Unpacker", mp);
    _reset(self);

    ST(0) = self;
    XSRETURN(1);
}

STATIC_INLINE SV*
_execute_impl(SV* const self, SV* const data, UV const offset, UV const limit) {
    dTHX;

    if(offset >= limit) {
        Perl_croak(aTHX_ "offset (%"UVuf") is bigger than data buffer size (%"UVuf")",
            offset, limit);
    }

    UNPACKER(self, mp);

    size_t from = offset;
    const char* const dptr = SvPV_nolen_const(data);

    int const ret = template_execute(mp, dptr, limit, &from);

    if(ret < 0) {
        Perl_croak(aTHX_ "Data::MessagePack::Unpacker: parse error while executing");
    } else {
        mp->user.finished = (ret > 0) ? true : false;
        return sv_2mortal(newSVuv(from));
    }
}

XS(xs_unpacker_execute) {
    dXSARGS;
    SV* const self = ST(0);
    SV* const data = ST(1);
    UV offset;

    if (items == 2) {
        offset = 0;
    }
    else if (items == 3) {
        offset = SvUVx(ST(2));
    }
    else {
        Perl_croak(aTHX_ "Usage: $unpacker->execute(data, offset = 0)");
    }

    UNPACKER(self, mp);

    ST(0) = _execute_impl(self, data, offset, sv_len(data));
    XSRETURN(1);
}

XS(xs_unpacker_execute_limit) {
    dXSARGS;
    if (items != 4) {
        Perl_croak(aTHX_ "Usage: $unpacker->execute_limit(data, offset, limit)");
    }

    SV* const self   = ST(0);
    SV* const data   = ST(1);
    UV  const offset = SvUVx(ST(2));
    UV  const limit  = SvUVx(ST(3));

    ST(0) = _execute_impl(self, data, offset, limit);
    XSRETURN(1);
}

XS(xs_unpacker_is_finished) {
    dXSARGS;
    if (items != 1) {
        Perl_croak(aTHX_ "Usage: $unpacker->is_finished()");
    }

    UNPACKER(ST(0), mp);
    ST(0) = boolSV(mp->user.finished);
    XSRETURN(1);
}

XS(xs_unpacker_data) {
    dXSARGS;
    if (items != 1) {
        Perl_croak(aTHX_ "Usage: $unpacker->data()");
    }

    UNPACKER(ST(0), mp);
    ST(0) = template_data(mp);
    XSRETURN(1);
}

XS(xs_unpacker_reset) {
    dXSARGS;
    if (items != 1) {
        Perl_croak(aTHX_ "Usage: $unpacker->reset()");
    }

    UNPACKER(ST(0), mp);

    SV* const data = template_data(mp);
    sv_2mortal(data);
    _reset(ST(0));

    XSRETURN(0);
}

XS(xs_unpacker_destroy) {
    dXSARGS;
    if (items != 1) {
        Perl_croak(aTHX_ "Usage: $unpacker->DESTROY()");
    }

    UNPACKER(ST(0), mp);

    SV* const data = template_data(mp);
    sv_2mortal(data);
    Safefree(mp);

    XSRETURN(0);
}