import httpx
from core_domain import ToolBindingDetailContract
from core_shared import JSONValue


class ToolServiceClientError(Exception):
    pass


class ToolServiceClient:
    def __init__(self, base_url: str, timeout_seconds: float = 10.0) -> None:
        self.base_url = base_url.rstrip("/")
        self.timeout_seconds = timeout_seconds

    def get_tool_binding_detail(
        self,
        *,
        binding_id: str) -> ToolBindingDetailContract:
        try:
            with httpx.Client(timeout=self.timeout_seconds) as client:
                response = client.get(f"{self.base_url}/tools/bindings/{binding_id}")
                response.raise_for_status()
                return ToolBindingDetailContract.model_validate(response.json())
        except httpx.HTTPError as exc:
            raise ToolServiceClientError(f"tool-service lookup failed: {exc}") from exc

    def invoke_http_tool(
        self,
        *,
        detail: ToolBindingDetailContract,
        input_json: dict[str, JSONValue],
        config_json: dict[str, JSONValue]) -> tuple[str | None, dict[str, JSONValue]]:
        invoke_config_json = detail.connection.invoke_config_json or {}
        binding_config_json = detail.binding.config_json or {}

        url = _read_string(config_json, "url") or _read_string(invoke_config_json, "url")
        base_url = (
            _read_string(config_json, "base_url")
            or _read_string(binding_config_json, "base_url")
            or _read_string(invoke_config_json, "base_url")
        )
        path = _read_string(config_json, "path") or _read_string(invoke_config_json, "path")
        resolved_url = _resolve_url(url=url, base_url=base_url, path=path)
        if resolved_url is None:
            raise ToolServiceClientError("http tool requires url or base_url/path")

        method = (_read_string(invoke_config_json, "method") or "GET").upper()
        headers = _merge_string_maps(
            _read_dict(invoke_config_json, "headers"),
            _read_dict(binding_config_json, "headers"),
            _read_dict(config_json, "headers"))
        params = _merge_string_maps(
            _read_dict(invoke_config_json, "query"),
            _read_dict(config_json, "query"))
        body_json = _merge_json_dicts(
            _read_dict(invoke_config_json, "body"),
            _read_dict(config_json, "body"))
        if not body_json and method not in {"GET", "HEAD"}:
            body_json = input_json

        try:
            with httpx.Client(timeout=self.timeout_seconds) as client:
                response = client.request(
                    method=method,
                    url=resolved_url,
                    headers=headers,
                    params=params,
                    json=None if method in {"GET", "HEAD"} else body_json)
                response.raise_for_status()
        except httpx.HTTPError as exc:
            raise ToolServiceClientError(f"http tool invocation failed: {exc}") from exc

        response_json = _try_parse_json_response(response)
        response_text = None if response_json is not None else response.text
        return response_text, {
            "tool_binding_id": detail.binding.id,
            "tool_code": detail.tool_definition.code,
            "tool_connection_id": detail.connection.id,
            "tool_name": detail.tool_definition.name,
            "request_url": resolved_url,
            "request_method": method,
            "response_status_code": response.status_code,
            "response_json": response_json,
        }


def _read_string(payload: dict[str, JSONValue], key: str) -> str | None:
    value = payload.get(key)
    if isinstance(value, str) and value:
        return value
    return None


def _read_dict(payload: dict[str, JSONValue], key: str) -> dict[str, JSONValue]:
    value = payload.get(key)
    if isinstance(value, dict):
        return {str(item_key): item_value for item_key, item_value in value.items()}
    return {}


def _merge_json_dicts(*items: dict[str, JSONValue]) -> dict[str, JSONValue]:
    merged: dict[str, JSONValue] = {}
    for item in items:
        merged.update(item)
    return merged


def _merge_string_maps(*items: dict[str, JSONValue]) -> dict[str, str]:
    merged: dict[str, str] = {}
    for item in items:
        for key, value in item.items():
            if isinstance(value, (str, int, float, bool)):
                merged[key] = str(value)
    return merged


def _resolve_url(*, url: str | None, base_url: str | None, path: str | None) -> str | None:
    if url is not None:
        return url
    if base_url is None or path is None:
        return None
    return f"{base_url.rstrip('/')}/{path.lstrip('/')}"


def _try_parse_json_response(response: httpx.Response) -> JSONValue | None:
    content_type = response.headers.get("content-type", "")
    if "json" not in content_type.lower():
        return None
    try:
        value = response.json()
    except ValueError:
        return None
    if isinstance(value, (dict, list, str, int, float, bool)) or value is None:
        return value
    return None