#!/usr/bin/python3
# Copyright 2023 Weber Yann
#
# This file is part of rpnifs.
#
#        geneifs is free software: you can redistribute it and/or modify
#        it under the terms of the GNU General Public License as published by
#        the Free Software Foundation, either version 3 of the License, or
#        (at your option) any later version.
#
#        geneifs is distributed in the hope that it will be useful,
#        but WITHOUT ANY WARRANTY; without even the implied warranty of
#        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#        GNU General Public License for more details.
#
#        You should have received a copy of the GNU General Public License
#        along with geneifs.  If not, see <http://www.gnu.org/licenses/>.
#

import copy
import pickle
import sys

import unittest


try:
    import pyrpn
except (ImportError, NameError) as e:
    print("Error importing pyrpn. Try to run make.",
          file=sys.stderr)
    raise e


## TODO : move this function somewhere or implement it in C
def decode_state(state):
    """ Return a dict containing rpn state dump fields
    """
    res = dict()
    res['real_sz'] = len(state)
    res['total_sz'] = int.from_bytes(state[0:8], byteorder="little")
    res['argc'] =  int.from_bytes(state[8:16], byteorder="little")
    res['stack_sz_bytes'] = state[16:24]
    res['stack_sz'] = state[16]
    res['token_sz'] = int.from_bytes(state[24:32], byteorder="little", signed=True)
    res['stack'] = [int.from_bytes(state[i:i+8], byteorder="little")
                    for i in range(32, 32 + (8*res['stack_sz']),8)]
    res['tokens_off'] = 32 + (8*res['stack_sz'])
    res['tokens_real_sz'] = res['real_sz'] - res['tokens_off']
    res['tokens'] = [state[i:i+24]
                      for i in range(res['tokens_off'],
                                     res['tokens_off'] + (24*res['token_sz']),
                                     24)]
    return res



class TestRpnExprState(unittest.TestCase):
    """ Testing RPNExpr "state" related methods (__copy__, __get/setstate__)
    """

    def test_pickle_state(self):
        """ Testing pickling/unpickling """
        e = pyrpn.RPNExpr('0x42 + A0', 2)
        e2 = pickle.loads(pickle.dumps(e))
        ds_e = decode_state(e.__getstate__())
        ds_e2 = decode_state(e2.__getstate__())
        self.assertEqual(e.__getstate__(), e2.__getstate__(),
                         msg="EXPR: %r != %r (%r != %r)" % (e, e2, ds_e, ds_e2))
        for i in range(100):
            e = pyrpn.RPNExpr(pyrpn.random_expr(0), 2)
            e.mutate(n_mutations=15);

            e2 = pickle.loads(pickle.dumps(e))

            self.assertEqual(e.__getstate__(), e2.__getstate__(),
                             msg="EXPR#%d : %r != %r" % (i,e, e2))

            e3 = pickle.loads(pickle.dumps(e2))

            self.assertEqual(e.__getstate__(), e3.__getstate__(), msg=e)
            self.assertEqual(e2.__getstate__(), e3.__getstate__(), msg=e)



    def test_copy(self):
        """ Basic copy test based on pickling """
        e = pyrpn.RPNExpr('0x42 + A0', 2)
        e2 = copy.copy(e)
        ds_e = decode_state(e.__getstate__())
        ds_e2 = decode_state(e2.__getstate__())
        self.assertEqual(e.__getstate__(), e2.__getstate__(),
                         msg="EXPR: %r != %r (%r != %r)" % (e, e2, ds_e, ds_e2))
        for i in range(100):
            e = pyrpn.RPNExpr(pyrpn.random_expr(0), 2)

            e2 = copy.copy(e)

            self.assertEqual(e.__getstate__(), e2.__getstate__(),
                             msg="EXPR#%d : %r != %r" % (i,e, e2))

            e3 = pickle.loads(pickle.dumps(e2))

            self.assertEqual(e.__getstate__(), e3.__getstate__(), msg=e)
            self.assertEqual(e2.__getstate__(), e3.__getstate__(), msg=e)


if __name__ == '__main__':
    unittest.main()