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#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from typing import Callable

import pytest
from datasets import Dataset, load_dataset
from transformers import AutoModelForCausalLM, AutoModelForSequenceClassification, AutoTokenizer

from trl.extras.dataset_formatting import get_formatting_func_from_dataset
from trl.models.utils import ChatMlSpecialTokens, clone_chat_template, setup_chat_format

from .testing_utils import TrlTestCase


@pytest.mark.filterwarnings("ignore::FutureWarning")
class TestDatasetFormatting(TrlTestCase):
    def setup_method(self):
        self.llama_tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-MistralForCausalLM-0.1")
        self.chatml_tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-Qwen2ForCausalLM-2.5")

    def test_get_formatting_func_from_dataset_with_chatml_messages(self):
        dataset = Dataset.from_dict(
            {
                "messages": [
                    [
                        {"role": "system", "content": "You are helpful"},
                        {"role": "user", "content": "Hello"},
                        {"role": "assistant", "content": "Hi, how can I help you?"},
                    ]
                ]
            }
        )

        # Llama tokenizer
        formatting_func = get_formatting_func_from_dataset(dataset, self.llama_tokenizer)
        assert isinstance(formatting_func, Callable)
        formatted_text = formatting_func(dataset[0])
        expected = "<s> [INST] You are helpful\n\nHello [/INST] Hi, how can I help you?</s>"
        assert formatted_text == expected
        formatted_text = formatting_func(dataset[0:1])
        assert formatted_text == [expected]

        # ChatML tokenizer
        formatting_func = get_formatting_func_from_dataset(dataset, self.chatml_tokenizer)
        formatted_text = formatting_func(dataset[0])
        expected = "<|im_start|>system\nYou are helpful<|im_end|>\n<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\nHi, how can I help you?<|im_end|>\n"
        assert formatted_text == expected
        formatted_text = formatting_func(dataset[0:1])
        assert formatted_text == [expected]

    def test_get_formatting_func_from_dataset_with_chatml_conversations(self):
        dataset = Dataset.from_dict(
            {
                "conversations": [
                    [
                        {"role": "system", "content": "You are helpful"},
                        {"role": "user", "content": "Hello"},
                        {"role": "assistant", "content": "Hi, how can I help you?"},
                    ]
                ]
            }
        )
        # Llama tokenizer
        formatting_func = get_formatting_func_from_dataset(dataset, self.llama_tokenizer)
        assert isinstance(formatting_func, Callable)
        formatted_text = formatting_func(dataset[0])
        expected = "<s> [INST] You are helpful\n\nHello [/INST] Hi, how can I help you?</s>"
        assert formatted_text == expected
        formatted_text = formatting_func(dataset[0:1])
        assert formatted_text == [expected]

        # ChatML tokenizer
        formatting_func = get_formatting_func_from_dataset(dataset, self.chatml_tokenizer)
        formatted_text = formatting_func(dataset[0])
        expected = "<|im_start|>system\nYou are helpful<|im_end|>\n<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\nHi, how can I help you?<|im_end|>\n"
        assert formatted_text == expected
        formatted_text = formatting_func(dataset[0:1])
        assert formatted_text == [expected]

    def test_get_formatting_func_from_dataset_with_instruction(self):
        dataset = Dataset.from_list(
            [{"prompt": "What is 2+2?", "completion": "4"}, {"prompt": "What is 3+3?", "completion": "6"}]
        )
        formatting_func = get_formatting_func_from_dataset(dataset, self.llama_tokenizer)
        assert formatting_func is not None
        assert isinstance(formatting_func, Callable)
        formatted_text = formatting_func(dataset[0])
        assert formatted_text == "<s> [INST] What is 2+2? [/INST] 4</s>"
        formatted_text = formatting_func(dataset[0:1])
        assert formatted_text == ["<s> [INST] What is 2+2? [/INST] 4</s>"]

    def test_get_formatting_func_from_dataset_from_hub(self):
        ds_1 = load_dataset("philschmid/trl-test-instruction", split="train")
        ds_2 = load_dataset("philschmid/dolly-15k-oai-style", split="train")
        for ds in [ds_1, ds_2]:
            formatting_func = get_formatting_func_from_dataset(ds, self.llama_tokenizer)
            assert formatting_func is not None
            assert isinstance(formatting_func, Callable)
        ds_3 = load_dataset("philschmid/guanaco-sharegpt-style", split="train")
        formatting_func = get_formatting_func_from_dataset(ds_3, self.llama_tokenizer)
        assert formatting_func is None

    def test_get_formatting_func_from_dataset_with_unknown_format(self):
        dataset = Dataset.from_dict({"text": "test"})
        formatting_func = get_formatting_func_from_dataset(dataset, self.llama_tokenizer)
        assert formatting_func is None


class TestSetupChatFormat(TrlTestCase):
    def setup_method(self):
        self.tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-Qwen2ForCausalLM-2.5")
        self.model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-Qwen2ForCausalLM-2.5")
        # remove built-in chat_template to simulate a model having no chat_template
        self.tokenizer.chat_template = None

    def test_setup_chat_format(self):
        modified_model, modified_tokenizer = setup_chat_format(
            self.model, self.tokenizer, format="chatml", resize_to_multiple_of=123
        )

        _chatml = ChatMlSpecialTokens()
        # Check if special tokens are correctly set
        assert modified_tokenizer.eos_token == "<|im_end|>"
        assert modified_tokenizer.pad_token == "<|im_end|>"
        assert modified_tokenizer.bos_token == "<|im_start|>"
        assert modified_tokenizer.eos_token == _chatml.eos_token
        assert modified_tokenizer.pad_token == _chatml.pad_token
        assert modified_tokenizer.bos_token == _chatml.bos_token
        assert (modified_model.vocab_size % 123) == 0

    def test_example_with_setup_model(self):
        modified_model, modified_tokenizer = setup_chat_format(
            self.model,
            self.tokenizer,
        )
        messages = [
            {"role": "system", "content": "You are helpful"},
            {"role": "user", "content": "Hello"},
            {"role": "assistant", "content": "Hi, how can I help you?"},
        ]
        prompt = modified_tokenizer.apply_chat_template(messages, tokenize=False)

        assert (
            prompt
            == "<|im_start|>system\nYou are helpful<|im_end|>\n<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\nHi, how can I help you?<|im_end|>\n"
        )


class TestCloneChatTemplate(TrlTestCase):
    def test_clone(self):
        # This tokenizer doesn't have a chat_template by default
        tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        # This one has a chat_template by default
        source = "trl-internal-testing/tiny-Qwen3ForCausalLM"
        _, modified_tokenizer, _ = clone_chat_template(model, tokenizer, source)

        # Check if special tokens are correctly set
        assert modified_tokenizer.eos_token == "<|im_end|>"

    def test_clone_with_resize(self):
        # This tokenizer doesn't have a chat_template by default
        tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        # This one has a chat_template by default
        source = "trl-internal-testing/tiny-Qwen3ForCausalLM"
        modified_model, modified_tokenizer, _ = clone_chat_template(
            model, tokenizer, source, resize_to_multiple_of=123
        )

        # Check that the input embeddings have been resized to a multiple of 123
        assert (modified_model.vocab_size % 123) == 0
        # Check that the input embeddings size matches the tokenizer vocabulary size
        assert model.vocab_size == len(modified_tokenizer.vocab)

    def test_clone_with_resize_and_extra_tokens_already_in_vocab(self):
        # This tokenizer doesn't have a chat_template by default
        tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        # This one has a chat_template by default
        source = "trl-internal-testing/tiny-Qwen3ForCausalLM"
        # This will add <extra_id_0>, <extra_id_1>, ... to the tokenizer
        modified_model, modified_tokenizer, _ = clone_chat_template(
            model, tokenizer, source, resize_to_multiple_of=123
        )
        # Try if we can resize a tokenizer that already has extra these extra tokens
        modified_model, modified_tokenizer, _ = clone_chat_template(
            modified_model, modified_tokenizer, source, resize_to_multiple_of=124
        )

        # Check that the input embeddings have been resized to a multiple of 123
        assert (modified_model.vocab_size % 124) == 0
        # Check that the input embeddings size matches the tokenizer vocabulary size
        assert model.vocab_size == len(modified_tokenizer.vocab)

    def test_apply_new_chat_template(self):
        # This tokenizer doesn't have a chat_template by default
        tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        model = AutoModelForCausalLM.from_pretrained("trl-internal-testing/tiny-BloomForCausalLM")
        # This one has a chat_template by default
        source = "trl-internal-testing/tiny-Qwen3ForCausalLM"
        _, modified_tokenizer, _ = clone_chat_template(model, tokenizer, source)
        messages = [
            {"role": "system", "content": "You are helpful"},
            {"role": "user", "content": "Hello"},
            {"role": "assistant", "content": "Hi, how can I help you?"},
        ]
        prompt = modified_tokenizer.apply_chat_template(messages, tokenize=False)

        assert (
            prompt
            == "<|im_start|>system\nYou are helpful<|im_end|>\n<|im_start|>user\nHello<|im_end|>\n<|im_start|>assistant\n<think>\n\n</think>\n\nHi, how can I help you?<|im_end|>\n"
        )

    def test_clone_with_sequence_classification_model(self):
        # This tokenizer doesn't have a chat_template by default
        tokenizer = AutoTokenizer.from_pretrained("trl-internal-testing/tiny-GptNeoXForSequenceClassification")
        model = AutoModelForSequenceClassification.from_pretrained(
            "trl-internal-testing/tiny-GptNeoXForSequenceClassification"
        )
        # This one has a chat_template by default
        source = "trl-internal-testing/tiny-Qwen3ForCausalLM"
        _, modified_tokenizer, _ = clone_chat_template(model, tokenizer, source)

        # Check if special tokens are correctly set
        assert modified_tokenizer.eos_token == "<|im_end|>"