from __future__ import annotations

from pathlib import Path

from acp import ReadTextFileRequest, ReadTextFileResponse
import pytest

from vibe.acp.tools.builtins.read_file import AcpReadFileState, ReadFile
from vibe.core.tools.base import ToolError
from vibe.core.tools.builtins.read_file import (
    ReadFileArgs,
    ReadFileResult,
    ReadFileToolConfig,
)


class MockConnection:
    def __init__(
        self,
        file_content: str = "line 1\nline 2\nline 3",
        read_error: Exception | None = None,
    ) -> None:
        self._file_content = file_content
        self._read_error = read_error
        self._read_text_file_called = False
        self._session_update_called = False
        self._last_read_request: ReadTextFileRequest | None = None

    async def readTextFile(self, request: ReadTextFileRequest) -> ReadTextFileResponse:
        self._read_text_file_called = True
        self._last_read_request = request

        if self._read_error:
            raise self._read_error

        content = self._file_content
        if request.line is not None or request.limit is not None:
            lines = content.splitlines(keepends=True)
            start_line = (request.line or 1) - 1  # Convert to 0-indexed
            end_line = (
                start_line + request.limit if request.limit is not None else len(lines)
            )
            lines = lines[start_line:end_line]
            content = "".join(lines)

        return ReadTextFileResponse(content=content)

    async def sessionUpdate(self, notification) -> None:
        self._session_update_called = True


@pytest.fixture
def mock_connection() -> MockConnection:
    return MockConnection()


@pytest.fixture
def acp_read_file_tool(mock_connection: MockConnection, tmp_path: Path) -> ReadFile:
    config = ReadFileToolConfig(workdir=tmp_path)
    state = AcpReadFileState.model_construct(
        connection=mock_connection,  # type: ignore[arg-type]
        session_id="test_session_123",
        tool_call_id="test_tool_call_456",
    )
    return ReadFile(config=config, state=state)


class TestAcpReadFileBasic:
    def test_get_name(self) -> None:
        assert ReadFile.get_name() == "read_file"


class TestAcpReadFileExecution:
    @pytest.mark.asyncio
    async def test_run_success(
        self,
        acp_read_file_tool: ReadFile,
        mock_connection: MockConnection,
        tmp_path: Path,
    ) -> None:
        test_file = tmp_path / "test_file.txt"
        test_file.touch()
        args = ReadFileArgs(path=str(test_file))
        result = await acp_read_file_tool.run(args)

        assert isinstance(result, ReadFileResult)
        assert result.path == str(test_file)
        assert result.content == "line 1\nline 2\nline 3"
        assert result.lines_read == 3
        assert mock_connection._read_text_file_called
        assert mock_connection._session_update_called

        # Verify ReadTextFileRequest was created correctly
        request = mock_connection._last_read_request
        assert request is not None
        assert request.sessionId == "test_session_123"
        assert request.path == str(test_file)
        assert request.line is None  # offset=0 means no line specified
        assert request.limit is None

    @pytest.mark.asyncio
    async def test_run_with_offset(
        self, mock_connection: MockConnection, tmp_path: Path
    ) -> None:
        test_file = tmp_path / "test_file.txt"
        test_file.touch()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=mock_connection,  # type: ignore[arg-type]
                session_id="test_session",
                tool_call_id="test_call",
            ),
        )

        args = ReadFileArgs(path=str(test_file), offset=1)
        result = await tool.run(args)

        assert result.lines_read == 2
        assert result.content == "line 2\nline 3"

        request = mock_connection._last_read_request
        assert request is not None
        assert request.line == 2  # offset=1 means line 2 (1-indexed)

    @pytest.mark.asyncio
    async def test_run_with_limit(
        self, mock_connection: MockConnection, tmp_path: Path
    ) -> None:
        test_file = tmp_path / "test_file.txt"
        test_file.touch()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=mock_connection,  # type: ignore[arg-type]
                session_id="test_session",
                tool_call_id="test_call",
            ),
        )

        args = ReadFileArgs(path=str(test_file), limit=2)
        result = await tool.run(args)

        assert result.lines_read == 2
        assert result.content == "line 1\nline 2\n"

        request = mock_connection._last_read_request
        assert request is not None
        assert request.limit == 2

    @pytest.mark.asyncio
    async def test_run_with_offset_and_limit(
        self, mock_connection: MockConnection, tmp_path: Path
    ) -> None:
        test_file = tmp_path / "test_file.txt"
        test_file.touch()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=mock_connection,  # type: ignore[arg-type]
                session_id="test_session",
                tool_call_id="test_call",
            ),
        )

        args = ReadFileArgs(path=str(test_file), offset=1, limit=1)
        result = await tool.run(args)

        assert result.lines_read == 1
        assert result.content == "line 2\n"

        request = mock_connection._last_read_request
        assert request is not None
        assert request.line == 2
        assert request.limit == 1

    @pytest.mark.asyncio
    async def test_run_read_error(
        self, mock_connection: MockConnection, tmp_path: Path
    ) -> None:
        mock_connection._read_error = RuntimeError("File not found")
        test_file = tmp_path / "test.txt"
        test_file.touch()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=mock_connection,  # type: ignore[arg-type]
                session_id="test_session",
                tool_call_id="test_call",
            ),
        )

        args = ReadFileArgs(path=str(test_file))
        with pytest.raises(ToolError) as exc_info:
            await tool.run(args)

        assert str(exc_info.value) == f"Error reading {test_file}: File not found"

    @pytest.mark.asyncio
    async def test_run_without_connection(self, tmp_path: Path) -> None:
        test_file = tmp_path / "test.txt"
        test_file.touch()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=None, session_id="test_session", tool_call_id="test_call"
            ),
        )

        args = ReadFileArgs(path=str(test_file))
        with pytest.raises(ToolError) as exc_info:
            await tool.run(args)

        assert (
            str(exc_info.value)
            == "Connection not available in tool state. This tool can only be used within an ACP session."
        )

    @pytest.mark.asyncio
    async def test_run_without_session_id(self, tmp_path: Path) -> None:
        test_file = tmp_path / "test.txt"
        test_file.touch()
        mock_connection = MockConnection()
        tool = ReadFile(
            config=ReadFileToolConfig(workdir=tmp_path),
            state=AcpReadFileState.model_construct(
                connection=mock_connection,  # type: ignore[arg-type]
                session_id=None,
                tool_call_id="test_call",
            ),
        )

        args = ReadFileArgs(path=str(test_file))
        with pytest.raises(ToolError) as exc_info:
            await tool.run(args)

        assert (
            str(exc_info.value)
            == "Session ID not available in tool state. This tool can only be used within an ACP session."
        )