from pypy.interpreter.baseobjspace import ObjSpace, W_Root
from pypy.rpython.lltypesystem import rffi, lltype
from pypy.rpython.lltypesystem.rffi import llexternal, CCHARP, ExternalCompilationInfo, CStructPtr, INT
from pypy.rpython.lltypesystem.lltype import Signed, Ptr, Char, GcStruct
from pypy.rpython.lltypesystem.rstr import STR
from pypy.rpython.lltypesystem import lltype
from pypy.rpython.rtyper import RPythonTyper
from pypy.interpreter.baseobjspace import Wrappable
from pypy.interpreter.typedef import TypeDef
from pypy.interpreter.gateway import interp2app, ObjSpace, W_Root

import py, sys

datum = GcStruct('datum',('dptr',CCHARP), ('dsize', lltype.Signed))
err_func = lltype.Ptr(lltype.FuncType([], lltype.Void))

eci = ExternalCompilationInfo(includes=['gdbm.h'], libraries=['gdbm'])
gdbm_file = CStructPtr( 'GDBM_FILE', ('dummy', INT))

open_gdbm = rffi.llexternal('gdbm_open', [CCHARP, INT, INT, INT, err_func], gdbm_file, compilation_info=eci)
store_gdbm = rffi.llexternal('gdbm_store', [gdbm_file, CCHARP, CCHARP, INT], INT, compilation_info=eci)
fetch_gdbm = rffi.llexternal('gdbm_fetch', [gdbm_file, CCHARP], lltype.Ptr(datum), compilation_info=eci)
close_gdbm = rffi.llexternal('gdbm_close', [gdbm_file], INT, compilation_info = eci)

class GDBM(Wrappable):
    def __init__(self, space):
        self.space = space

    def gdbm_open(self, name, blocksize, read_write, mode):
        self.struct_gdbm = open_gdbm(name, blocksize, read_write, mode, 0) 

        if not struct_gdbm:
            return self.space.w_None
 
        return self.space.wrap(self.struct_gdbm)

    def gdbm_store(self, key, content, flag):
        res_gdbm = gdbm_store(self.struct_gdbm, key, content, flag)
        return self.space.wrap(res_gdbm)

    def gdbm_fetch(self, key):
        return self.space.wrap(fetch_gdbm(self.struct_gdbm, key))

    def gdbm_close(self):
        close_gdbm(self.struct_gdbm)

def GDBM_new(space, w_subtype, args):
    w_gdbm = space.allocate_instance(GDBM, w_subtype)
    
    gdbm = space.interp_w(GDBM, w_gdbm)
    GDBM.__init__(gdbm, space)
    return w_gdbm


GDBM.typedef = TypeDef(
     'GDBM',
     __new__  = interp2app(GDBM_new, unwrap_spec=[ObjSpace, W_Root, 'bufferstr']), 
     open     = interp2app(GDBM.gdbm_open, unwrap_spec=['self', str, int, int, int]),
     store    = interp2app(GDBM.gdbm_store, unwrap_spec=['self', str, str, int]),
     fetch    = interp2app(GDBM.gdbm_fetch, unwrap_spec=['self', str]),
     close    = interp2app(GDBM.gdbm_open, unwrap_spec=['self'])
)