"""大周天执行器：回顾→对照→提议→提交的最小实现（ADR-018/023）。

评估调用经模型网关（真实流）；提议产物为 persona_candidate（pending），
经既有审核机制确认后才影响道体——候选先于写入不变。
"""

from datetime import UTC, datetime
from typing import Any

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker

from app.gateway.adapters import AdapterRequest, GatewayError, stream_chat
from app.models import (
    AuditEvent,
    BigCycle,
    Character,
    CharacterVersion,
    Message,
    OutboxEvent,
    ProviderEndpoint,
)

EVALUATION_SYSTEM_PROMPT = (
    "你是角色演化评估器。根据近期对话、当前道体基线与内驱力，"
    "提出一至三条渐进式人格或关系演化建议。只输出建议正文，简洁分条。"
)


async def _select_endpoint(db: AsyncSession) -> ProviderEndpoint | None:
    return (
        await db.execute(
            select(ProviderEndpoint)
            .where(
                ProviderEndpoint.enabled.is_(True),
                ProviderEndpoint.logical_model_id == "default-chat",
            )
            .order_by(ProviderEndpoint.priority.asc())
            .limit(1)
        )
    ).scalar_one_or_none()


async def execute_big_cycle(
    factory: async_sessionmaker[AsyncSession],
    cycle_id: str,
    transport: Any | None = None,
) -> None:
    """四阶段：回顾（拉取消息）→ 对照（道体/内驱力）→ 提议（模型）→ 提交（候选落库）。"""
    async with factory() as db:
        cycle = await db.get(BigCycle, cycle_id)
        if cycle is None:
            return
        character = await db.get(Character, cycle.character_id)
        assert character is not None
        try:
            cycle.status = "running"
            await db.commit()

            # 阶段一：回顾——同域近期消息（对话暂未绑定角色维度，按个人域取窗口）
            from app.models import Conversation

            messages = list(
                (
                    await db.execute(
                        select(Message)
                        .where(
                            Message.conversation_id.in_(
                                select(Conversation.id).where(
                                    Conversation.personal_domain_id
                                    == character.personal_domain_id
                                )
                            ),
                            Message.role.in_(["user", "assistant"]),
                        )
                        .order_by(Message.created_at.desc())
                        .limit(20)
                    )
                ).scalars().all()
            )
            def _text_of(m: Any) -> str:
                joined = "".join(
                    str(b.get("text", "")) for b in m.content if isinstance(b, dict)
                )
                return joined[:120]

            recent = "\n".join(f"{m.role}: {_text_of(m)}" for m in reversed(messages))
            cycle.phase_memory = {**cycle.phase_memory, "recall": {"messages": len(messages)}}
            await db.commit()

            # 阶段二：对照——道体与内驱力快照
            cycle.phase_memory = {
                **cycle.phase_memory,
                "evaluate": {
                    "identity_baseline": character.identity_baseline,
                    "drives": character.drives,
                },
            }
            await db.commit()

            # 阶段三：提议——模型评估（真实流）
            endpoint = await _select_endpoint(db)
            if endpoint is None:
                cycle.status = "failed"
                cycle.completed_at = datetime.now(UTC)
                cycle.phase_memory = {**cycle.phase_memory, "error": "no_endpoint_available"}
                await db.commit()
                return
            prompt = [
                {"role": "system", "content": EVALUATION_SYSTEM_PROMPT},
                {
                    "role": "user",
                    "content": (
                        f"角色：{character.name}\n道体基线：{character.identity_baseline}\n"
                        f"内驱力：{character.drives}\n\n近期对话：\n{recent}\n\n"
                        "请提出演化建议。"
                    ),
                },
            ]
            parts: list[str] = []
            async for chunk in stream_chat(
                endpoint.base_url, endpoint.model_id, endpoint.api_key_env,
                AdapterRequest(messages=prompt, model=endpoint.model_id), transport=transport,
            ):
                if chunk.kind == "delta" and chunk.text:
                    parts.append(chunk.text)
            proposal = "".join(parts).strip()

            # 阶段四：提交——persona_candidate（pending，等待人工审核）
            version = CharacterVersion(
                character_id=character.id,
                kind="persona_candidate",
                status="pending",
                payload={"proposal": proposal, "cycle_id": cycle.id, "source": "big_cycle"},
            )
            db.add(version)
            await db.flush()
            cycle.produced_version_ids = [version.id]
            cycle.status = "completed"
            cycle.completed_at = datetime.now(UTC)
            db.add(
                AuditEvent(
                    actor_type="system", actor_id="big_cycle", action="big_cycle.completed",
                    aggregate_type="character", aggregate_id=character.id,
                    payload={"cycle_id": cycle.id, "version_id": version.id},
                )
            )
            db.add(
                OutboxEvent(
                    aggregate_type="character", aggregate_id=character.id,
                    event_type="character.persona_candidate_submitted",
                    payload={"cycle_id": cycle.id, "version_id": version.id},
                )
            )
            await db.commit()
        except GatewayError as exc:
            cycle.status = "failed"
            cycle.completed_at = datetime.now(UTC)
            cycle.phase_memory = {**cycle.phase_memory, "error": str(exc)[:300]}
            await db.commit()
        except Exception:
            await db.rollback()
            raise