"""Bounded, non-redirecting HTTP. No SDK retries or environment credential discovery."""

import asyncio
import math

import aiohttp

from ..protocol import DecisionError, loads


async def post(session, connection, path, payload):
    try:
        async with session.post(
            connection.base_url + path,
            json=payload,
            headers={"Authorization": "Bearer " + connection.key},
            allow_redirects=False,
            timeout=aiohttp.ClientTimeout(total=45),
        ) as response:
            if response.status != 200:
                raise DecisionError(f"upstream_http_{response.status}", 502)
            # read(n) may return a partial chunk: accumulate with an explicit byte bound.
            data = bytearray()
            async for chunk in response.content.iter_chunked(16384):
                data.extend(chunk)
                if len(data) > 262144:
                    raise DecisionError("upstream_response_too_large", 502)
            try:
                result = loads(data.decode("utf-8"))
            except UnicodeError as exc:
                raise DecisionError("invalid_upstream_encoding", 502) from exc
            if not isinstance(result, dict):
                raise DecisionError("invalid_upstream_response", 502)
            return result
    except TimeoutError as exc:
        raise DecisionError("upstream_timeout", 504) from exc
    except (aiohttp.ClientError, OSError) as exc:
        raise DecisionError("upstream_transport_error", 502) from exc
    except asyncio.CancelledError:
        raise


def usage(result):
    """Only real numeric counters, no inferred price, upstream strings or raw body."""
    raw = result.get("usage", {})
    if not isinstance(raw, dict):
        return {}
    return {
        k: v
        for k, v in raw.items()
        if k
        in (
            "input_tokens",
            "output_tokens",
            "total_tokens",
            "prompt_tokens",
            "completion_tokens",
            "cost",
        )
        and type(v) in (int, float)
        and math.isfinite(v)
        and 0 <= v <= 1e9
    }