"""Deterministic model for isolated acceptance; never calls a provider or platform."""

import asyncio
import json
from contextlib import asynccontextmanager
from uuid import uuid4

from pydantic_ai.messages import ToolReturnPart, UserPromptPart
from pydantic_ai.models.function import DeltaToolCall, FunctionModel


async def fake_stream(messages, info):
    latest = max(
        (i for i, m in enumerate(messages) if any(isinstance(p, UserPromptPart) for p in m.parts)), default=0
    )
    text = " ".join(
        str(p.content) for m in messages[latest:] for p in m.parts if isinstance(p, UserPromptPart)
    )
    returns = [p for m in messages[latest:] for p in m.parts if isinstance(p, ToolReturnPart)]
    if returns and "LOOP" not in text:
        if returns[-1].tool_name == "capability_probe":
            yield str(returns[-1].content)
        else:
            yield "操作结果已返回。"
            yield "请查看下方业务记录与数据来源。"
        return
    if any(t.name == "capability_probe" for t in info.function_tools):
        name, args = "capability_probe", {}
    elif "READY" in text:
        yield "REA"
        yield "DY"
        return
    elif "SLOW" in text:
        yield "正在查询"
        await asyncio.sleep(2)
        yield "，查询完成。"
        return
    elif "批量" in text:
        name, args = "bulk_update_research", {"alpha_ids": ["a0000", "a0001"], "add_tags": ["AI"]}
    elif "修改" in text or "update" in text:
        alpha_id = "TEST0001" if "TEST0001" in text else "a0000"
        name, args = "update_research", {"alpha_id": alpha_id, "changes": {"note": "AI 测试研究记录"}}
    elif "同步" in text:
        name, args = "create_sync_job", {"kind": "full_sync"}
    elif "PnL" in text:
        name, args = "get_alpha_pnl", {"alpha_id": "TEST0001" if "TEST" in text else "a0000"}
    else:
        name, args = "search_alphas", {"filters": {"turnover_max": 0.15, "limit": 5}}
    yield {0: DeltaToolCall(name=name, json_args=json.dumps(args), tool_call_id=uuid4().hex)}


@asynccontextmanager
async def fake_model(config, settings):
    yield FunctionModel(stream_function=fake_stream, model_name="test-model")