"""Conversation repository — Conversation, turn log, and Segment data access."""

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

from app.features.conversation.models import Conversation, ConversationMessage, Segment


async def get_conversation(
    conversation_id: str, db: AsyncSession
) -> Conversation | None:
    return await db.get(Conversation, conversation_id)


async def get_user_conversations(user_id: str, db: AsyncSession) -> list[Conversation]:
    stmt = (
        select(Conversation)
        .where(
            Conversation.user_id == user_id,
            Conversation.deleted_at.is_(None),
        )
        .order_by(
            func.coalesce(Conversation.last_message_at, Conversation.started_at).desc()
        )
    )
    result = await db.execute(stmt)
    return list(result.scalars().all())


def add_conversation(conv: Conversation, db: AsyncSession) -> None:
    db.add(conv)


def add_conversation_message(msg: ConversationMessage, db: AsyncSession) -> None:
    db.add(msg)


async def get_conversation_messages(
    conversation_id: str, db: AsyncSession
) -> list[ConversationMessage]:
    stmt = (
        select(ConversationMessage)
        .where(ConversationMessage.conversation_id == conversation_id)
        .order_by(ConversationMessage.created_at)
    )
    result = await db.execute(stmt)
    return list(result.scalars().all())


async def set_latest_ai_message_tts_audio_urls(
    conversation_id: str,
    db: AsyncSession,
    *,
    tts_audio_urls: list[str],
    segment_id: str | None = None,
) -> ConversationMessage | None:
    stmt = select(ConversationMessage).where(
        ConversationMessage.conversation_id == conversation_id,
        ConversationMessage.role == "ai",
    )
    if segment_id is not None:
        stmt = stmt.where(ConversationMessage.segment_id == segment_id)
    stmt = stmt.order_by(ConversationMessage.created_at.desc())
    result = await db.execute(stmt)
    row = result.scalars().first()
    if row is None:
        return None
    row.tts_audio_urls = list(tts_audio_urls)
    return row


async def get_segments_for_conversation(
    conversation_id: str, db: AsyncSession
) -> list[Segment]:
    stmt = (
        select(Segment)
        .where(Segment.conversation_id == conversation_id)
        .order_by(Segment.created_at)
    )
    result = await db.execute(stmt)
    return list(result.scalars().all())


async def get_segments_for_organize(
    conversation_id: str, db: AsyncSession
) -> list[Segment]:
    """兼容旧语义：优先返回 Phase1 未完成的片段；若无则返回本会话全部片段。"""
    pending = await get_segments_pending_phase1(conversation_id, db)
    if pending:
        return pending
    return await get_segments_for_conversation(conversation_id, db)


async def get_segments_pending_phase1(
    conversation_id: str, db: AsyncSession
) -> list[Segment]:
    """尚未跑 Phase1 分类的 segments（topic_category 为空且未标记 narrated）。"""
    stmt = (
        select(Segment)
        .where(
            Segment.conversation_id == conversation_id,
            Segment.topic_category.is_(None),
            Segment.narrated.is_(False),
            Segment.processed.is_(False),
        )
        .order_by(Segment.created_at)
    )
    result = await db.execute(stmt)
    return list(result.scalars().all())


async def conversation_has_pending_phase2(
    conversation_id: str, db: AsyncSession
) -> bool:
    """Phase1 已完成但叙事未消费的片段（本会话范围内）。"""
    stmt = select(func.count(Segment.id)).where(
        Segment.conversation_id == conversation_id,
        Segment.topic_category.isnot(None),
        Segment.narrated.is_(False),
        Segment.skip_narrative.is_(False),
    )
    result = await db.execute(stmt)
    return int(result.scalar() or 0) > 0


async def count_segments_for_user(user_id: str, db: AsyncSession) -> int:
    stmt = (
        select(func.count(Segment.id))
        .select_from(Segment)
        .join(Conversation, Segment.conversation_id == Conversation.id)
        .where(
            Conversation.user_id == user_id,
            Conversation.deleted_at.is_(None),
        )
    )
    result = await db.execute(stmt)
    return result.scalar() or 0