import unittest
from pathlib import Path

from transformers.file_utils import cached_property
from transformers.testing_utils import require_torch
from transformers.tokenization_pegasus import PegasusTokenizer

from .test_tokenization_common import TokenizerTesterMixin


class PegasusTokenizationTest(TokenizerTesterMixin, unittest.TestCase):

    tokenizer_class = PegasusTokenizer

    def setUp(self):
        super().setUp()

        save_dir = Path(self.tmpdirname)
        spm_file = PegasusTokenizer.vocab_files_names["vocab_file"]
        if not (save_dir / spm_file).exists():
            tokenizer = self.pegasus_large_tokenizer
            tokenizer.save_pretrained(self.tmpdirname)

    @cached_property
    def pegasus_large_tokenizer(self):
        return PegasusTokenizer.from_pretrained("google/pegasus-large")

    @unittest.skip("add_tokens does not work yet")
    def test_swap_special_token(self):
        pass

    def get_tokenizer(self, **kwargs) -> PegasusTokenizer:
        if not kwargs:
            return self.pegasus_large_tokenizer
        else:
            return PegasusTokenizer.from_pretrained(self.tmpdirname, **kwargs)

    def get_input_output_texts(self, tokenizer):
        return ("This is a test", "This is a test")

    def test_pegasus_large_tokenizer_settings(self):
        tokenizer = self.pegasus_large_tokenizer
        # The tracebacks for the following asserts are **better** without messages or self.assertEqual
        assert tokenizer.vocab_size == 96103
        assert tokenizer.pad_token_id == 0
        assert tokenizer.eos_token_id == 1
        assert tokenizer.offset == 103
        assert tokenizer.unk_token_id == tokenizer.offset + 2 == 105
        assert tokenizer.unk_token == "<unk>"
        assert tokenizer.mask_token is None
        assert tokenizer.mask_token_id is None
        assert tokenizer.model_max_length == 1024
        raw_input_str = "To ensure a smooth flow of bank resolutions."
        desired_result = [413, 615, 114, 2291, 1971, 113, 1679, 10710, 107, 1]
        ids = tokenizer([raw_input_str], return_tensors=None).input_ids[0]
        self.assertListEqual(desired_result, ids)
        assert tokenizer.convert_ids_to_tokens([0, 1, 2]) == ["<pad>", "</s>", "unk_2"]

    @require_torch
    def test_pegasus_large_seq2seq_truncation(self):
        src_texts = ["This is going to be way too long" * 10000, "short example"]
        tgt_texts = ["not super long but more than 5 tokens", "tiny"]
        batch = self.pegasus_large_tokenizer.prepare_seq2seq_batch(src_texts, tgt_texts=tgt_texts, max_target_length=5)
        assert batch.input_ids.shape == (2, 1024)
        assert batch.attention_mask.shape == (2, 1024)
        assert "decoder_input_ids" in batch  # because tgt_texts was specified
        assert batch.decoder_input_ids.shape == (2, 5)
        assert batch.decoder_attention_mask.shape == (2, 5)
        assert len(batch) == 4  # no extra keys
