"""Anthropic Messages API transport.

Delegates to the existing adapter functions in agent/anthropic_adapter.py.
This transport owns format conversion and normalization — NOT client lifecycle.
"""

from typing import Any, Dict, List, Optional

from agent.transports.base import ProviderTransport
from agent.transports.types import NormalizedResponse


class AnthropicTransport(ProviderTransport):
    """Transport for api_mode='anthropic_messages'.

    Wraps the existing functions in anthropic_adapter.py behind the
    ProviderTransport ABC.  Each method delegates — no logic is duplicated.
    """

    @property
    def api_mode(self) -> str:
        return "anthropic_messages"

    def convert_messages(self, messages: List[Dict[str, Any]], **kwargs) -> Any:
        """Convert OpenAI messages to Anthropic (system, messages) tuple.

        kwargs:
            base_url: Optional[str] — affects thinking signature handling.
        """
        from agent.anthropic_adapter import convert_messages_to_anthropic

        base_url = kwargs.get("base_url")
        return convert_messages_to_anthropic(messages, base_url=base_url)

    def convert_tools(self, tools: List[Dict[str, Any]]) -> Any:
        """Convert OpenAI tool schemas to Anthropic input_schema format."""
        from agent.anthropic_adapter import convert_tools_to_anthropic

        return convert_tools_to_anthropic(tools)

    def build_kwargs(
        self,
        model: str,
        messages: List[Dict[str, Any]],
        tools: Optional[List[Dict[str, Any]]] = None,
        **params,
    ) -> Dict[str, Any]:
        """Build Anthropic messages.create() kwargs.

        Calls convert_messages and convert_tools internally.

        params (all optional):
            max_tokens: int
            reasoning_config: dict | None
            tool_choice: str | None
            is_oauth: bool
            preserve_dots: bool
            context_length: int | None
            base_url: str | None
            fast_mode: bool
        """
        from agent.anthropic_adapter import build_anthropic_kwargs

        return build_anthropic_kwargs(
            model=model,
            messages=messages,
            tools=tools,
            max_tokens=params.get("max_tokens", 16384),
            reasoning_config=params.get("reasoning_config"),
            tool_choice=params.get("tool_choice"),
            is_oauth=params.get("is_oauth", False),
            preserve_dots=params.get("preserve_dots", False),
            context_length=params.get("context_length"),
            base_url=params.get("base_url"),
            fast_mode=params.get("fast_mode", False),
        )

    def normalize_response(self, response: Any, **kwargs) -> NormalizedResponse:
        """Normalize Anthropic response to NormalizedResponse.

        kwargs:
            strip_tool_prefix: bool — strip 'mcp_mcp_' prefixes from tool names.
        """
        from agent.anthropic_adapter import normalize_anthropic_response_v2

        strip_tool_prefix = kwargs.get("strip_tool_prefix", False)
        return normalize_anthropic_response_v2(response, strip_tool_prefix=strip_tool_prefix)

    def validate_response(self, response: Any) -> bool:
        """Check Anthropic response structure is valid."""
        if response is None:
            return False
        content_blocks = getattr(response, "content", None)
        if not isinstance(content_blocks, list):
            return False
        if not content_blocks:
            return False
        return True

    def extract_cache_stats(self, response: Any) -> Optional[Dict[str, int]]:
        """Extract Anthropic cache_read and cache_creation token counts."""
        usage = getattr(response, "usage", None)
        if usage is None:
            return None
        cached = getattr(usage, "cache_read_input_tokens", 0) or 0
        written = getattr(usage, "cache_creation_input_tokens", 0) or 0
        if cached or written:
            return {"cached_tokens": cached, "creation_tokens": written}
        return None

    # Promote the adapter's canonical mapping to module level so it's shared
    _STOP_REASON_MAP = {
        "end_turn": "stop",
        "tool_use": "tool_calls",
        "max_tokens": "length",
        "stop_sequence": "stop",
        "refusal": "content_filter",
        "model_context_window_exceeded": "length",
    }

    def map_finish_reason(self, raw_reason: str) -> str:
        """Map Anthropic stop_reason to OpenAI finish_reason."""
        return self._STOP_REASON_MAP.get(raw_reason, "stop")


# Auto-register on import
from agent.transports import register_transport  # noqa: E402

register_transport("anthropic_messages", AnthropicTransport)