"""Conversation service — 对话编排（列表、创建、结束、删除、消息、整理）。"""

import asyncio
import uuid
from datetime import datetime, timezone

from fastapi import HTTPException
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.cos_url_keys import (
    collect_cos_keys_from_conversation_history,
    collect_cos_keys_from_tts_url_list,
    extract_cos_object_key_if_owned,
)
from app.core.logging import get_logger
from app.core.redis import redis_service
from app.core.storage_purge import delete_object_storage_keys_best_effort
from app.features.conversation import repo
from app.features.conversation.models import Conversation, Segment
from app.features.conversation.session_history import (
    conversation_messages_to_redis_history,
)
from app.features.conversation.tts_delivery import apply_presigned_tts_urls_to_messages
from app.features.memory import repo as memory_repo
from app.features.quota.service import QuotaService
from app.ports.storage import ObjectStorage
from app.tasks.memoir_tasks import (
    dispatch_pending_memoir_phase2_for_user,
    process_memoir_phase1,
)

logger = get_logger(__name__)


def _datetime_to_timestamp_ms(value: datetime | None) -> int:
    if value is None:
        return int(datetime.now(timezone.utc).timestamp() * 1000)
    if value.tzinfo is None:
        value = value.replace(tzinfo=timezone.utc)
    return int(value.timestamp() * 1000)


def _message_timestamp_ms(msg: dict, fallback: datetime | None) -> int:
    raw_timestamp = msg.get("timestamp")
    if isinstance(raw_timestamp, (int, float)):
        return int(raw_timestamp)
    if isinstance(raw_timestamp, str):
        try:
            return int(
                datetime.fromisoformat(raw_timestamp.replace("Z", "+00:00")).timestamp()
                * 1000
            )
        except ValueError:
            pass
    return _datetime_to_timestamp_ms(fallback)


def _latest_message_time_ms(conversation: Conversation, history: list[dict]) -> int:
    last_at = getattr(conversation, "last_message_at", None)
    if last_at:
        return _datetime_to_timestamp_ms(last_at)
    if history:
        return _message_timestamp_ms(history[-1], conversation.started_at)
    return _datetime_to_timestamp_ms(conversation.started_at)


def _build_messages_from_history(
    conversation_id: str,
    history: list[dict],
    fallback_timestamp: datetime | None,
) -> list[dict]:
    messages: list[dict] = []
    seen_audio_sessions: set[str] = set()
    for idx, msg in enumerate(history):
        role = msg.get("role")
        message_type = msg.get("messageType", "text")
        voice_session_id = msg.get("voiceSessionId")
        if role == "human" and message_type == "audio" and voice_session_id:
            if voice_session_id in seen_audio_sessions:
                continue
            seen_audio_sessions.add(voice_session_id)
        item: dict = {
            "id": f"{conversation_id}_msg_{idx}",
            "conversationId": conversation_id,
            "content": msg.get("content", ""),
            "senderType": "user" if role == "human" else "assistant",
            "timestamp": _message_timestamp_ms(msg, fallback_timestamp),
            "messageType": message_type,
        }
        if voice_session_id and role == "human":
            item["voiceSessionId"] = voice_session_id
        ds = msg.get("durationSeconds")
        if isinstance(ds, (int, float)) and ds > 0:
            item["durationSeconds"] = int(ds)
        if role == "ai":
            tts = msg.get("ttsAudioUrls")
            if isinstance(tts, list) and tts:
                item["ttsAudioUrls"] = [x for x in tts if isinstance(x, str)]
        dm = msg.get("durableMessageId")
        if isinstance(dm, str) and dm:
            item["durableMessageId"] = dm
        messages.append(item)
    return messages


class ConversationService:
    def __init__(
        self,
        db: AsyncSession,
        quota_service: QuotaService,
        *,
        object_storage: ObjectStorage | None = None,
    ):
        self._db = db
        self._quota = quota_service
        self._object_storage = object_storage

    async def ensure_ws_connection(
        self, conversation_id: str, user_id: str
    ) -> tuple[Conversation | None, str]:
        """
        WebSocket：加载或创建对话。返回 (conversation, err)。
        err 为空表示成功；否则为 forbidden | deleted。
        """
        conv = await self._db.get(Conversation, conversation_id)
        if not conv:
            conv = Conversation(
                id=conversation_id,
                user_id=user_id,
                started_at=datetime.now(timezone.utc),
                status="active",
            )
            self._db.add(conv)
            await self._db.commit()
            await self._db.refresh(conv)
            return conv, ""
        if conv.user_id != user_id:
            return None, "forbidden"
        if conv.deleted_at is not None:
            return None, "deleted"
        return conv, ""

    async def create_user_segment(
        self,
        conversation: Conversation,
        user_id: str,
        text: str,
        *,
        audio_url: str | None = None,
        audio_duration_seconds: int | None = None,
    ) -> Segment:
        if conversation.user_id != user_id:
            raise ValueError("conversation ownership mismatch")
        segment = Segment(
            id=str(uuid.uuid4()),
            conversation_id=conversation.id,
            user_input_text=text,
            audio_url=audio_url,
            audio_duration_seconds=audio_duration_seconds,
            processed=False,
        )
        self._db.add(segment)
        conversation.last_message_at = datetime.now(timezone.utc)
        await self._db.commit()
        await self._db.refresh(segment)
        return segment

    async def _clear_history(self, conversation_id: str) -> None:
        try:
            await redis_service.clear_conversation_history(conversation_id)
        except Exception as e:
            logger.debug("清空会话历史失败: {}", e)

    async def ensure_redis_history_from_db(self, conversation_id: str) -> list[dict]:
        """
        供 WS 与 get_messages 使用：优先 Redis；若为空则用 DB conversation_messages 重建并写回。
        """
        try:
            history = await redis_service.get_conversation_history(conversation_id)
        except Exception as exc:
            logger.warning("conversation history cache read skipped: {}", exc)
            history = []
        if history:
            return history

        rows = await repo.get_conversation_messages(conversation_id, self._db)
        if rows:
            rebuilt = conversation_messages_to_redis_history(rows)
            try:
                await redis_service.set_conversation_history(conversation_id, rebuilt)
            except Exception as exc:
                logger.warning("conversation history cache write skipped: {}", exc)
            return rebuilt

        return []

    async def list_for_user(self, user_id: str) -> list[dict]:
        conversations = await repo.get_user_conversations(user_id, self._db)
        result = []
        for conv in conversations:
            history: list[dict] = []
            try:
                history = await self.ensure_redis_history_from_db(conv.id)
            except Exception:
                pass
            latest_message = history[-1].get("content", "")[:50] if history else None
            has_user_message = any((msg.get("role") == "human") for msg in history)
            result.append(
                {
                    "id": conv.id,
                    "title": (conv.summary or "")[:30] or "岁月知己",
                    "avatarUrl": None,
                    "latestMessagePreview": latest_message or conv.summary,
                    "latestMessageTime": _latest_message_time_ms(conv, history),
                    # 对话「初次创建」时间（ms），供客户端按日历日区分「打个招呼 / 继续对话」
                    "startedAt": _datetime_to_timestamp_ms(conv.started_at),
                    "unreadCount": 0,
                    "isDefaultAssistant": conv.summary is None,
                    "hasUserMessage": has_user_message,
                }
            )
        return result

    async def create(self, user_id: str) -> dict:
        conv = Conversation(
            id=str(uuid.uuid4()),
            user_id=user_id,
            started_at=datetime.now(timezone.utc),
            status="active",
        )
        repo.add_conversation(conv, self._db)
        await self._db.commit()
        await self._db.refresh(conv)
        return {
            "id": conv.id,
            "user_id": conv.user_id,
            "started_at": conv.started_at.isoformat(),
            "status": conv.status,
        }

    async def get_or_404(self, conversation_id: str, user_id: str) -> Conversation:
        conv = await repo.get_conversation(conversation_id, self._db)
        if not conv or conv.user_id != user_id or conv.deleted_at is not None:
            raise HTTPException(status_code=404, detail="Conversation not found")
        return conv

    async def get_one(self, conversation_id: str, user_id: str) -> dict:
        conv = await self.get_or_404(conversation_id, user_id)
        return {
            "id": conv.id,
            "user_id": conv.user_id,
            "started_at": conv.started_at.isoformat(),
            "ended_at": conv.ended_at.isoformat() if conv.ended_at else None,
            "duration_seconds": conv.duration_seconds,
            "summary": conv.summary,
            "status": conv.status,
            "current_topic": conv.current_topic,
            "conversation_stage": conv.conversation_stage,
        }

    async def end(self, conversation_id: str, user_id: str) -> dict:
        conv = await self.get_or_404(conversation_id, user_id)
        conv.status = "ended"
        conv.ended_at = datetime.now(timezone.utc)
        if conv.started_at:
            conv.duration_seconds = int(
                (conv.ended_at - conv.started_at).total_seconds()
            )
        await self._db.commit()
        return {
            "id": conv.id,
            "status": conv.status,
            "ended_at": conv.ended_at.isoformat(),
            "duration_seconds": conv.duration_seconds,
        }

    async def delete(self, conversation_id: str, user_id: str) -> None:
        conv = await self.get_or_404(conversation_id, user_id)
        cos_keys: set[str] = set(
            await memory_repo.list_storage_keys_for_conversation(
                self._db, conversation_id
            )
        )
        try:
            hist = await redis_service.get_conversation_history(conversation_id)
            cos_keys |= collect_cos_keys_from_conversation_history(hist)
        except Exception:
            pass
        segments = await repo.get_segments_for_conversation(conversation_id, self._db)
        for seg in segments:
            k = extract_cos_object_key_if_owned(seg.audio_url)
            if k:
                cos_keys.add(k)
            raw_tts = getattr(seg, "tts_audio_urls", None)
            if isinstance(raw_tts, list):
                cos_keys |= collect_cos_keys_from_tts_url_list(
                    [str(x) for x in raw_tts if isinstance(x, str)]
                )

        await self._clear_history(conversation_id)
        conv.deleted_at = datetime.now(timezone.utc)
        await self._db.commit()

        delete_object_storage_keys_best_effort(
            self._object_storage,
            sorted(cos_keys),
            log_prefix=f"conversation_soft_delete id={conversation_id}",
        )

    async def get_messages(self, conversation_id: str, user_id: str) -> list[dict]:
        conv = await self.get_or_404(conversation_id, user_id)
        try:
            history = await self.ensure_redis_history_from_db(conversation_id)
            messages = _build_messages_from_history(
                conversation_id=conversation_id,
                history=history,
                fallback_timestamp=conv.started_at,
            )
            apply_presigned_tts_urls_to_messages(messages, self._object_storage)
            return messages
        except Exception:
            return []

    async def organize(
        self, conversation_id: str, user_id: str, subscription_type: str
    ) -> dict:
        conv = await self.get_or_404(conversation_id, user_id)
        pending_p1 = await repo.get_segments_pending_phase1(conversation_id, self._db)
        has_p2 = await repo.conversation_has_pending_phase2(conversation_id, self._db)
        if not pending_p1 and not has_p2:
            raise HTTPException(status_code=400, detail="该对话没有可整理的内容")
        can_submit, quota_message = await self._quota.check_can_submit_organize(
            user_id, subscription_type
        )
        if not can_submit:
            raise HTTPException(status_code=403, detail=quota_message)
        if pending_p1:
            segment_ids = [s.id for s in pending_p1]
            process_memoir_phase1.delay(conv.user_id, segment_ids)
            logger.info(
                "手动触发 Phase1: conversation_id={}, segments={}",
                conversation_id,
                len(segment_ids),
            )
        await asyncio.to_thread(dispatch_pending_memoir_phase2_for_user, conv.user_id)
        return {
            "message": "对话整理任务已提交",
            "conversation_id": conversation_id,
            "segments_count": len(pending_p1),
        }