import pytest
from mcp.types import ImageContent, TextContent
from pydantic import BaseModel

from fastmcp import Image
from fastmcp.tools.tool import Tool


class TestToolFromFunction:
    def test_basic_function(self):
        """Test registering and running a basic function."""

        def add(a: int, b: int) -> int:
            """Add two numbers."""
            return a + b

        tool = Tool.from_function(add)

        assert tool.name == "add"
        assert tool.description == "Add two numbers."
        assert tool.parameters["properties"]["a"]["type"] == "integer"
        assert tool.parameters["properties"]["b"]["type"] == "integer"

    async def test_async_function(self):
        """Test registering and running an async function."""

        async def fetch_data(url: str) -> str:
            """Fetch data from URL."""
            return f"Data from {url}"

        tool = Tool.from_function(fetch_data)

        assert tool.name == "fetch_data"
        assert tool.description == "Fetch data from URL."
        assert tool.parameters["properties"]["url"]["type"] == "string"

    def test_pydantic_model_function(self):
        """Test registering a function that takes a Pydantic model."""

        class UserInput(BaseModel):
            name: str
            age: int

        def create_user(user: UserInput, flag: bool) -> dict:
            """Create a new user."""
            return {"id": 1, **user.model_dump()}

        tool = Tool.from_function(create_user)

        assert tool.name == "create_user"
        assert tool.description == "Create a new user."
        assert "name" in tool.parameters["$defs"]["UserInput"]["properties"]
        assert "age" in tool.parameters["$defs"]["UserInput"]["properties"]
        assert "flag" in tool.parameters["properties"]

    async def test_tool_with_image_return(self):
        def image_tool(data: bytes) -> Image:
            return Image(data=data)

        tool = Tool.from_function(image_tool)

        result = await tool.run({"data": "test.png"})
        assert tool.parameters["properties"]["data"]["type"] == "string"
        assert isinstance(result[0], ImageContent)

    def test_non_callable_fn(self):
        with pytest.raises(TypeError, match="not a callable object"):
            Tool.from_function(1)  # type: ignore

    def test_lambda(self):
        tool = Tool.from_function(lambda x: x, name="my_tool")
        assert tool.name == "my_tool"

    def test_lambda_with_no_name(self):
        with pytest.raises(
            ValueError, match="You must provide a name for lambda functions"
        ):
            Tool.from_function(lambda x: x)

    def test_private_arguments(self):
        def add(_a: int, _b: int) -> int:
            """Add two numbers."""
            return _a + _b

        tool = Tool.from_function(add)
        assert tool.parameters["properties"]["_a"]["type"] == "integer"
        assert tool.parameters["properties"]["_b"]["type"] == "integer"

    def test_tool_with_varargs_not_allowed(self):
        def func(a: int, b: int, *args: int) -> int:
            """Add two numbers."""
            return a + b

        with pytest.raises(
            ValueError, match=r"Functions with \*args are not supported as tools"
        ):
            Tool.from_function(func)

    def test_tool_with_varkwargs_not_allowed(self):
        def func(a: int, b: int, **kwargs: int) -> int:
            """Add two numbers."""
            return a + b

        with pytest.raises(
            ValueError, match=r"Functions with \*\*kwargs are not supported as tools"
        ):
            Tool.from_function(func)

    async def test_instance_method(self):
        class MyClass:
            def add(self, x: int, y: int) -> int:
                """Add two numbers."""
                return x + y

        obj = MyClass()

        tool = Tool.from_function(obj.add)
        assert tool.name == "add"
        assert tool.description == "Add two numbers."
        assert "self" not in tool.parameters["properties"]

    async def test_instance_method_with_varargs_not_allowed(self):
        class MyClass:
            def add(self, x: int, y: int, *args: int) -> int:
                """Add two numbers."""
                return x + y

        obj = MyClass()

        with pytest.raises(
            ValueError, match=r"Functions with \*args are not supported as tools"
        ):
            Tool.from_function(obj.add)

    async def test_instance_method_with_varkwargs_not_allowed(self):
        class MyClass:
            def add(self, x: int, y: int, **kwargs: int) -> int:
                """Add two numbers."""
                return x + y

        obj = MyClass()

        with pytest.raises(
            ValueError, match=r"Functions with \*\*kwargs are not supported as tools"
        ):
            Tool.from_function(obj.add)

    async def test_classmethod(self):
        class MyClass:
            x: int = 10


class TestToolJsonParsing:
    """Tests for Tool's JSON pre-parsing functionality."""

    async def test_json_string_arguments(self):
        """Test that JSON string arguments are parsed and validated correctly"""

        def simple_func(x: int, y: list[str]) -> str:
            return f"{x}-{','.join(y)}"

        # Create a tool to use its JSON pre-parsing logic
        tool = Tool.from_function(simple_func)

        # Prepare arguments where some are JSON strings
        json_args = {
            "x": 1,
            "y": '["a", "b", "c"]',  # JSON string
        }

        # Run the tool which will do JSON parsing
        result = await tool.run(json_args)
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert result[0].text == "1-a,b,c"

    async def test_str_vs_list_str(self):
        """Test handling of string vs list[str] type annotations."""

        def func_with_str_types(str_or_list: str | list[str]) -> str | list[str]:
            return str_or_list

        tool = Tool.from_function(func_with_str_types)

        # Test regular string input (should remain a string)
        result = await tool.run({"str_or_list": "hello"})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert result[0].text == "hello"

        # Test JSON string input (should be parsed as a string)
        result = await tool.run({"str_or_list": '"hello"'})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert result[0].text == "hello"

        # Test JSON list input (should be parsed as a list)
        result = await tool.run({"str_or_list": '["hello", "world"]'})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)

        # The exact formatting might vary, so we just check that it contains the key elements
        text_without_whitespace = result[0].text.replace(" ", "").replace("\n", "")
        assert "hello" in text_without_whitespace
        assert "world" in text_without_whitespace
        assert "[" in text_without_whitespace
        assert "]" in text_without_whitespace

    async def test_keep_str_as_str(self):
        """Test that string arguments are kept as strings when they're not valid JSON"""

        def func_with_str_types(string: str) -> str:
            return string

        tool = Tool.from_function(func_with_str_types)

        # Invalid JSON should remain a string
        invalid_json = "{'nice to meet you': 'hello', 'goodbye': 5}"
        result = await tool.run({"string": invalid_json})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert result[0].text == invalid_json

    async def test_keep_str_union_as_str(self):
        """Test that string arguments are kept as strings when parsing would create an invalid value"""

        def func_with_str_types(
            string: str | dict[int, str] | None,
        ) -> str | dict[int, str] | None:
            return string

        tool = Tool.from_function(func_with_str_types)

        # Invalid JSON for the union type should remain a string
        invalid_json = "{'nice to meet you': 'hello', 'goodbye': 5}"
        result = await tool.run({"string": invalid_json})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert result[0].text == invalid_json

    async def test_complex_type_validation(self):
        """Test that parsed JSON is validated against complex types"""

        class SomeModel(BaseModel):
            x: int
            y: dict[int, str]

        def func_with_complex_type(data: SomeModel) -> SomeModel:
            return data

        tool = Tool.from_function(func_with_complex_type)

        # Valid JSON for the model
        valid_json = '{"x": 1, "y": {"1": "hello"}}'
        result = await tool.run({"data": valid_json})
        assert len(result) == 1
        assert isinstance(result[0], TextContent)
        assert '"x": 1' in result[0].text
        assert '"y": {' in result[0].text
        assert '"1": "hello"' in result[0].text

        # Invalid JSON for the model (y has string keys, not int keys)
        # Should throw a validation error
        invalid_json = '{"x": 1, "y": {"invalid": "hello"}}'
        with pytest.raises(Exception):
            await tool.run({"data": invalid_json})