api/detection.py

"""Request detection utilities for API optimizations.

Detects quota checks, title generation, prefix detection, suggestion mode,
and filepath extraction requests to enable fast-path responses.
"""

from providers.common.text import extract_text_from_content

from .models.anthropic import MessagesRequest


def is_quota_check_request(request_data: MessagesRequest) -> bool:
    """Check if this is a quota probe request.

    Quota checks are typically simple requests with max_tokens=1
    and a single message containing the word "quota".
    """
    if (
        request_data.max_tokens == 1
        and len(request_data.messages) == 1
        and request_data.messages[0].role == "user"
    ):
        text = extract_text_from_content(request_data.messages[0].content)
        if "quota" in text.lower():
            return True
    return False


def is_title_generation_request(request_data: MessagesRequest) -> bool:
    """Check if this is a conversation title generation request.

    Title generation requests are detected by a system prompt containing
    title extraction instructions, no tools, and a single user message.
    """
    if not request_data.system or request_data.tools:
        return False
    system_text = extract_text_from_content(request_data.system).lower()
    return "new conversation topic" in system_text and "title" in system_text


def is_prefix_detection_request(request_data: MessagesRequest) -> tuple[bool, str]:
    """Check if this is a fast prefix detection request.

    Prefix detection requests contain a policy_spec block and
    a Command: section for extracting shell command prefixes.

    Returns:
        Tuple of (is_prefix_request, command_string)
    """
    if len(request_data.messages) != 1 or request_data.messages[0].role != "user":
        return False, ""

    content = extract_text_from_content(request_data.messages[0].content)

    if "<policy_spec>" in content and "Command:" in content:
        try:
            cmd_start = content.rfind("Command:") + len("Command:")
            return True, content[cmd_start:].strip()
        except Exception:
            pass

    return False, ""


def is_suggestion_mode_request(request_data: MessagesRequest) -> bool:
    """Check if this is a suggestion mode request.

    Suggestion mode requests contain "[SUGGESTION MODE:" in the user's message,
    used for auto-suggesting what the user might type next.
    """
    for msg in request_data.messages:
        if msg.role == "user":
            text = extract_text_from_content(msg.content)
            if "[SUGGESTION MODE:" in text:
                return True
    return False


def is_filepath_extraction_request(
    request_data: MessagesRequest,
) -> tuple[bool, str, str]:
    """Check if this is a filepath extraction request.

    Filepath extraction requests have a single user message with
    "Command:" and "Output:" sections, asking to extract file paths
    from command output.

    Returns:
        Tuple of (is_filepath_request, command, output)
    """
    if len(request_data.messages) != 1 or request_data.messages[0].role != "user":
        return False, "", ""
    if request_data.tools:
        return False, "", ""

    content = extract_text_from_content(request_data.messages[0].content)

    if "Command:" not in content or "Output:" not in content:
        return False, "", ""

    # Match if user content OR system block indicates filepath extraction
    user_has_filepaths = (
        "filepaths" in content.lower() or "<filepaths>" in content.lower()
    )
    system_text = (
        extract_text_from_content(request_data.system) if request_data.system else ""
    )
    system_has_extract = (
        "extract any file paths" in system_text.lower()
        or "file paths that this command" in system_text.lower()
    )
    if not user_has_filepaths and not system_has_extract:
        return False, "", ""

    try:
        cmd_start = content.find("Command:") + len("Command:")
        output_marker = content.find("Output:", cmd_start)
        if output_marker == -1:
            return False, "", ""

        command = content[cmd_start:output_marker].strip()
        output = content[output_marker + len("Output:") :].strip()

        for marker in ["<", "\n\n"]:
            if marker in output:
                output = output.split(marker)[0].strip()

        return True, command, output
    except Exception:
        return False, "", ""