"""
章节相关 API 路由
"""
from typing import List, Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from database import get_async_db
from database.models import Chapter as ChapterModel
from database.models import User as UserModel
from middleware.auth import get_current_user
from agents.prompts.memory_prompts import CHAPTER_CATEGORIES, CHAPTER_ORDER, STAGE_TO_ORDER

router = APIRouter(prefix="/api/chapters", tags=["chapters"])


def _chapter_to_dict(ch: ChapterModel) -> dict:
    return {
        "id": ch.id,
        "title": ch.title,
        "content": ch.content,
        "order_index": ch.order_index,
        "status": ch.status,
        "category": ch.category,
        "images": ch.images or [],
        "updated_at": ch.updated_at.isoformat() if ch.updated_at else None,
        "is_new": ch.is_new,
        "source_segments": ch.source_segments or [],
    }


@router.get("", response_model=List[dict])
async def get_chapters(
    current_user: UserModel = Depends(get_current_user),
    is_new: Optional[bool] = Query(None, description="仅返回未读章节"),
    db: AsyncSession = Depends(get_async_db)
):
    """
    获取用户所有章节（需要认证，仅返回 active 章节）。
    始终返回全部 8 个预定义类别，没有内容的类别用占位符返回。
    """
    stmt = select(ChapterModel).where(
        ChapterModel.user_id == current_user.id,
        ChapterModel.is_active == True
    )
    if is_new is True:
        stmt = stmt.where(ChapterModel.is_new == True)
    stmt = stmt.order_by(ChapterModel.order_index)
    result = await db.execute(stmt)
    chapters = result.scalars().all()

    chapter_by_category: dict[str, ChapterModel] = {}
    for ch in chapters:
        if ch.category and ch.category not in chapter_by_category:
            chapter_by_category[ch.category] = ch

    all_chapters: List[dict] = []
    for category in CHAPTER_ORDER:
        ch = chapter_by_category.pop(category, None)
        if ch:
            all_chapters.append(_chapter_to_dict(ch))
        else:
            if is_new is True:
                continue
            all_chapters.append({
                "id": f"placeholder_{category}",
                "title": CHAPTER_CATEGORIES[category],
                "content": "",
                "order_index": STAGE_TO_ORDER.get(category, 999),
                "status": "empty",
                "category": category,
                "images": [],
                "updated_at": None,
                "is_new": False,
                "source_segments": [],
            })

    for ch in chapter_by_category.values():
        all_chapters.append(_chapter_to_dict(ch))

    return all_chapters


@router.get("/{chapter_id}", response_model=dict)
async def get_chapter(
    chapter_id: str,
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_async_db)
):
    """获取章节详情（需要认证，只能访问自己的章节）"""
    chapter = await db.get(ChapterModel, chapter_id)
    if not chapter:
        raise HTTPException(status_code=404, detail="Chapter not found")
    
    # 验证用户权限
    if chapter.user_id != current_user.id:
        raise HTTPException(status_code=403, detail="无权访问此章节")
    
    return {
        "id": chapter.id,
        "title": chapter.title,
        "content": chapter.content,
        "order_index": chapter.order_index,
        "status": chapter.status,
        "category": chapter.category,
        "images": chapter.images or [],
        "updated_at": chapter.updated_at.isoformat() if chapter.updated_at else None,
        "is_new": chapter.is_new,
        "source_segments": chapter.source_segments or [],
    }


@router.delete("/{chapter_id}")
async def disable_chapter(
    chapter_id: str,
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_async_db)
):
    """清除章节（将章节标记为 disabled，需要认证，只能操作自己的章节）"""
    chapter = await db.get(ChapterModel, chapter_id)
    if not chapter:
        raise HTTPException(status_code=404, detail="Chapter not found")
    
    # 验证用户权限
    if chapter.user_id != current_user.id:
        raise HTTPException(status_code=403, detail="无权操作此章节")
    
    # 将章节标记为 disabled（不物理删除）
    chapter.is_active = False
    await db.commit()
    
    return {"status": "ok", "message": "章节已清除"}


@router.post("/{chapter_id}/regenerate")
async def regenerate_chapter(
    chapter_id: str,
    current_user: UserModel = Depends(get_current_user),
    db: AsyncSession = Depends(get_async_db)
):
    """重新整理章节（需要认证，只能操作自己的章节）"""
    chapter = await db.get(ChapterModel, chapter_id)
    if not chapter:
        raise HTTPException(status_code=404, detail="Chapter not found")
    
    # 验证用户权限
    if chapter.user_id != current_user.id:
        raise HTTPException(status_code=403, detail="无权操作此章节")
    
    # TODO: 实现重新整理逻辑
    return {"status": "ok", "message": "Chapter regeneration triggered"}