"""Unit tests for srt/parser/code_completion_parser.py"""

import unittest
from unittest.mock import patch

from sglang.srt.entrypoints.openai.protocol import CompletionRequest
from sglang.srt.parser.code_completion_parser import (
    CompletionTemplate,
    FimPosition,
    completion_template_exists,
    completion_templates,
    generate_completion_prompt,
    generate_completion_prompt_from_request,
    is_completion_template_defined,
    register_completion_template,
    set_completion_template,
)
from sglang.test.ci.ci_register import register_cpu_ci
from sglang.test.test_utils import CustomTestCase

register_cpu_ci(est_time=5, suite="stage-a-cpu-only")


class TestFimPosition(CustomTestCase):
    def test_middle_and_end_are_distinct(self):
        """Test that MIDDLE and END are different enum values."""
        self.assertNotEqual(FimPosition.MIDDLE, FimPosition.END)


class TestCompletionTemplate(CustomTestCase):
    def test_dataclass_fields(self):
        """Test creating a CompletionTemplate with all fields."""
        t = CompletionTemplate(
            name="test",
            fim_begin_token="<begin>",
            fim_middle_token="<middle>",
            fim_end_token="<end>",
            fim_position=FimPosition.MIDDLE,
        )
        self.assertEqual(t.name, "test")
        self.assertEqual(t.fim_begin_token, "<begin>")
        self.assertEqual(t.fim_position, FimPosition.MIDDLE)


class TestRegisterCompletionTemplate(CustomTestCase):
    def test_builtin_templates_registered(self):
        """Test that deepseek_coder, star_coder, qwen_coder are pre-registered."""
        self.assertTrue(completion_template_exists("deepseek_coder"))
        self.assertTrue(completion_template_exists("star_coder"))
        self.assertTrue(completion_template_exists("qwen_coder"))

    def test_unregistered_template_not_found(self):
        """Test that a non-existent template returns False."""
        self.assertFalse(completion_template_exists("nonexistent_template"))

    def test_register_new_template(self):
        """Test registering a new template."""
        t = CompletionTemplate(
            name="_test_new_template",
            fim_begin_token="<b>",
            fim_middle_token="<m>",
            fim_end_token="<e>",
            fim_position=FimPosition.END,
        )
        register_completion_template(t)
        self.assertTrue(completion_template_exists("_test_new_template"))
        # Cleanup
        del completion_templates["_test_new_template"]

    def test_register_duplicate_raises(self):
        """Test that registering a duplicate name without override raises."""
        with self.assertRaises(AssertionError):
            register_completion_template(
                CompletionTemplate(
                    name="deepseek_coder",
                    fim_begin_token="x",
                    fim_middle_token="y",
                    fim_end_token="z",
                    fim_position=FimPosition.MIDDLE,
                )
            )

    def test_register_duplicate_with_override(self):
        """Test that override=True allows re-registration."""
        original = completion_templates["deepseek_coder"]
        try:
            register_completion_template(
                CompletionTemplate(
                    name="deepseek_coder",
                    fim_begin_token="<new>",
                    fim_middle_token="<new_m>",
                    fim_end_token="<new_e>",
                    fim_position=FimPosition.END,
                ),
                override=True,
            )
            self.assertEqual(
                completion_templates["deepseek_coder"].fim_begin_token, "<new>"
            )
        finally:
            # Restore original
            completion_templates["deepseek_coder"] = original


class TestGenerateCompletionPrompt(CustomTestCase):
    def test_deepseek_coder_middle_position(self):
        """Test FIM prompt with MIDDLE position (deepseek_coder style)."""
        result = generate_completion_prompt(
            "prefix_code", "suffix_code", "deepseek_coder"
        )
        t = completion_templates["deepseek_coder"]
        expected = f"{t.fim_begin_token}prefix_code{t.fim_middle_token}suffix_code{t.fim_end_token}"
        self.assertEqual(result, expected)

    def test_star_coder_end_position(self):
        """Test FIM prompt with END position (star_coder style)."""
        result = generate_completion_prompt("prefix_code", "suffix_code", "star_coder")
        t = completion_templates["star_coder"]
        expected = f"{t.fim_begin_token}prefix_code{t.fim_end_token}suffix_code{t.fim_middle_token}"
        self.assertEqual(result, expected)

    def test_qwen_coder_end_position(self):
        """Test FIM prompt with END position (qwen_coder style)."""
        result = generate_completion_prompt("prefix", "suffix", "qwen_coder")
        t = completion_templates["qwen_coder"]
        expected = (
            f"{t.fim_begin_token}prefix{t.fim_end_token}suffix{t.fim_middle_token}"
        )
        self.assertEqual(result, expected)

    def test_empty_prompt_and_suffix(self):
        """Test FIM prompt generation with empty strings."""
        result = generate_completion_prompt("", "", "deepseek_coder")
        t = completion_templates["deepseek_coder"]
        expected = f"{t.fim_begin_token}{t.fim_middle_token}{t.fim_end_token}"
        self.assertEqual(result, expected)


class TestGenerateCompletionPromptFromRequest(CustomTestCase):
    def test_empty_suffix_returns_prompt_directly(self):
        """Test that empty suffix bypasses FIM formatting."""
        request = CompletionRequest(prompt="just code", suffix="")
        result = generate_completion_prompt_from_request(request)
        self.assertEqual(result, "just code")

    def test_nonempty_suffix_uses_fim_template(self):
        """Test that non-empty suffix triggers FIM formatting."""
        with patch(
            "sglang.srt.parser.code_completion_parser.completion_template_name",
            "deepseek_coder",
        ):
            request = CompletionRequest(prompt="prefix", suffix="suffix")
            result = generate_completion_prompt_from_request(request)
            t = completion_templates["deepseek_coder"]
            expected = (
                f"{t.fim_begin_token}prefix{t.fim_middle_token}suffix{t.fim_end_token}"
            )
            self.assertEqual(result, expected)


class TestSetCompletionTemplate(CustomTestCase):
    def test_set_only_once(self):
        """Test that set_completion_template only sets the name once."""
        import sglang.srt.parser.code_completion_parser as module

        with patch.object(module, "completion_template_name", None):
            set_completion_template("star_coder")
            self.assertEqual(module.completion_template_name, "star_coder")
            # Second call should be ignored
            set_completion_template("qwen_coder")
            self.assertEqual(module.completion_template_name, "star_coder")

    def test_is_completion_template_defined(self):
        """Test the defined check before and after setting."""
        import sglang.srt.parser.code_completion_parser as module

        old_name = module.completion_template_name
        try:
            module.completion_template_name = None
            self.assertFalse(is_completion_template_defined())
            set_completion_template("deepseek_coder")
            self.assertTrue(is_completion_template_defined())
        finally:
            module.completion_template_name = old_name


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