"""TypeSafe System One / OpenRouter Decisions protocol, not a chat endpoint.

Protocol shape informed by MIT-licensed jev-libero / embodied-jev; see THIRD_PARTY_NOTICES.
"""

import json
import math

from ..protocol import SCHEMA, VERSION, DecisionError, validate_jev
from .http import post, usage


def question(options, instruction):
    return {
        "type": "choice",
        "instructions": instruction,
        "criteria": {option: option for option in options},
    }


def answer(result, name, options):
    answers = result.get("answers")
    item = answers.get(name) if isinstance(answers, dict) else None
    if not isinstance(item, dict) or item.get("choice") not in options:
        raise DecisionError("jev_invalid_choice", 502)
    probabilities = item.get("probabilities", {})
    if (
        not isinstance(probabilities, dict)
        or probabilities.keys() - set(options)
        or any(
            type(p) not in (int, float) or not math.isfinite(p) or not 0 <= p <= 1
            for p in probabilities.values()
        )
    ):
        raise DecisionError("jev_invalid_probabilities", 502)
    # Keep official choice even when probabilities do not rank it highest.
    return item["choice"]


async def decide(session, conn, request):
    props = SCHEMA["$defs"]["JevDecision"]["properties"]
    options = {name: props[name]["enum"] for name in ("grasp", "diagnosis", "recovery")}
    options["choice"] = request["candidates"]
    prompts = {
        "choice": (
            "Choose an offered next skill if safe. Stop for hard safety faults. "
            "Only the local controller can determine success or permit actuation."
        ),
        "grasp": (
            "secure requires two finger forces >=0.2 N, verified lift and stable grasp evidence. "
            "empty means no held object. slipping means a previously secure grasp is being lost. "
            "Use uncertain if evidence is insufficient. An open gripper is not a secure grasp."
        ),
        "diagnosis": (
            "Report none when failure=none and there are no safety flags. "
            "An empty gripper before closing or after release is expected, not a fault. "
            "Otherwise diagnose empty, slipping, misaligned, unreachable, stalled or uncertain."
        ),
        "recovery": (
            "Continue with a safe next skill if failure=none; retry only recoverable alignment "
            "or empty grasp failures before transport; replan when retries are insufficient; "
            "stop for hard safety faults or unsafe uncertainty."
        ),
    }
    result = await post(
        session,
        conn,
        "",
        {
            "model": conn.model,
            **(
                {"provider": {"allow_fallbacks": False}}
                if conn.protocol == "openrouter-decisions"
                else {}
            ),
            "state": json.dumps(
                {"observation": request["observation"], "failure": request.get("failure", "none")},
                ensure_ascii=False,
            ),
            "questions": {
                name: question(values, prompts[name]) for name, values in options.items()
            },
        },
    )
    value = {
        "version": VERSION,
        **{name: answer(result, name, values) for name, values in options.items()},
    }
    return validate_jev(value, request["candidates"]), usage(result)