# Copyright (c) 2026 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from abc import abstractmethod
from typing import Any, Optional

import httpx

from ..base import Inference
from ..errors import InferenceError
from ..types import InferenceRequest, InferenceResult
from .async_http_client import AsyncHTTPClient
from .input_adapters import HTTPInputAdapter, InputAdapter
from .param_mapping import convert_params_to_camel
from ...providers import InferenceProvider


class HTTPInferenceBase(Inference):
    def __init__(
        self,
        base_url: str,
        http_timeout: int = 600,
        api_key: Optional[str] = None,
        provider: InferenceProvider | str = InferenceProvider.SELF_HOSTED,
    ):
        self._base_url = base_url
        self._http_timeout = http_timeout
        self._api_key = api_key
        self._input_adapter = HTTPInputAdapter(provider)
        self._client: Optional[AsyncHTTPClient] = None

    @property
    def input_adapter(self) -> InputAdapter:
        return self._input_adapter

    async def start(self) -> None:
        headers = {}
        if self._api_key:
            headers["Authorization"] = f"Bearer {self._api_key}"
        self._client = AsyncHTTPClient(self._base_url, self._http_timeout, headers)
        await self._client.start()

    async def stop(self) -> None:
        if self._client:
            await self._client.stop()
            self._client = None

    async def predict(self, request: InferenceRequest) -> InferenceResult:
        if not self._client:
            raise RuntimeError("Inference not started")

        payload = self._prepare_payload(
            request.input_data,
            request.file_type,
            **request.runtime_params,
        )

        endpoint = self._get_endpoint()
        provider = self._input_adapter.provider.value
        try:
            response = await self._client.post(endpoint, payload)
            return self._parse_result(response)
        except httpx.ReadTimeout as e:
            raise InferenceError(
                f"HTTP read timeout after {self._http_timeout}s "
                f"({provider}/{endpoint}): {e}"
            ) from e
        except httpx.HTTPStatusError as e:
            raise InferenceError(
                f"HTTP {e.response.status_code} ({provider}/{endpoint}): {e}"
            ) from e
        except httpx.HTTPError as e:
            raise InferenceError(f"HTTP error ({provider}/{endpoint}): {e}") from e
        except Exception as e:
            raise InferenceError(
                f"HTTP request failed ({provider}/{endpoint}): {e}"
            ) from e

    def _prepare_payload(
        self, input_data: str, file_type: Optional[str], **params
    ) -> dict[str, Any]:
        http_adapter = self._input_adapter
        payload: dict[str, Any] = {
            "file": http_adapter.prepare_http_file_field(input_data)
        }
        if file_type == "image":
            payload["fileType"] = 1
        elif file_type == "pdf":
            payload["fileType"] = 0

        payload.update(convert_params_to_camel({**params, "visualize": False}))
        return payload

    @abstractmethod
    def _get_endpoint(self) -> str:
        pass

    @abstractmethod
    def _get_params(self) -> tuple[set[str], dict[str, Any]]:
        pass

    @abstractmethod
    def _parse_result(self, response: dict[str, Any]) -> InferenceResult:
        pass

    def get_valid_params(self) -> set[str]:
        valid_params, _ = self._get_params()
        return valid_params

    def get_default_params(self) -> dict[str, Any]:
        _, defaults = self._get_params()
        return defaults