from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from sqlalchemy import and_, desc, asc
from pydantic import BaseModel, Field
from typing import Optional
import uuid
from datetime import datetime

from ..database import get_db
from ..models import (
    User, Asset, AssetCategory, NovelChapter, KnowledgeDocument,
    KnowledgeBase,
    gen_uuid
)
from ..auth import get_current_user
from ..middleware.log_service import LogService

router = APIRouter()


class CreateAssetRequest(BaseModel):
    name: str = Field(min_length=1, max_length=200)
    category: Optional[str] = None
    description: Optional[str] = None
    file_type: Optional[str] = None
    content: Optional[str] = None


class UpdateAssetRequest(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None
    file_type: Optional[str] = None


class CreateChapterRequest(BaseModel):
    title: str = Field(min_length=1, max_length=500)
    content: Optional[str] = None
    sort_order: int = Field(default=0)


VALID_ASSET_CATEGORIES = ("file", "novel", "image", "video", "audio", "custom")


# ============================================================
# 静态路由 - 必须在动态路由之前定义
# ============================================================

@router.get("/storage-overview")
def get_storage_overview(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """获取用户资产存储概览，包含资产和知识库文档的总存储量"""
    # Asset表中的文件大小
    from sqlalchemy import func as sa_func
    asset_size = db.query(sa_func.sum(Asset.size)).filter(
        and_(
            Asset.user_id == current_user.id,
            Asset.status != "deleted",
        )
    ).scalar() or 0

    # 知识库文档的文件大小
    kb_doc_size = db.query(sa_func.sum(KnowledgeDocument.file_size)).join(
        KnowledgeBase, KnowledgeDocument.knowledge_base_id == KnowledgeBase.id
    ).filter(
        KnowledgeBase.user_id == current_user.id
    ).scalar() or 0

    total_storage = asset_size + kb_doc_size

    return {
        "code": 0,
        "data": {
            "asset_storage": asset_size,
            "knowledge_doc_storage": kb_doc_size,
            "total_storage": total_storage,
        },
        "message": "ok",
    }


@router.get("/categories")
def list_categories(
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    categories = (
        db.query(AssetCategory)
        .filter(AssetCategory.user_id == current_user.id)
        .order_by(asc(AssetCategory.name))
        .all()
    )

    result = []
    for c in categories:
        count = db.query(Asset).filter(
            and_(
                Asset.category == c.name,
                Asset.user_id == current_user.id,
                Asset.status != "deleted",
            )
        ).count()

        result.append({
            "id": c.id,
            "name": c.name,
            "type": c.type,
            "asset_count": count,
            "created_at": str(c.created_at) if c.created_at else None,
        })

    return {"code": 0, "data": result, "message": "ok"}


@router.get("/novels/{asset_id}/chapters")
def get_novel_chapters(
    asset_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    asset = db.query(Asset).filter(
        and_(Asset.id == asset_id, Asset.user_id == current_user.id)
    ).first()
    if not asset:
        raise HTTPException(status_code=404, detail="资产不存在")

    chapters = (
        db.query(NovelChapter)
        .filter(NovelChapter.asset_id == asset_id)
        .order_by(asc(NovelChapter.sort_order), asc(NovelChapter.created_at))
        .all()
    )

    result = []
    for ch in chapters:
        result.append({
            "id": ch.id,
            "asset_id": ch.asset_id,
            "title": ch.title,
            "sort_order": ch.sort_order,
            "word_count": ch.word_count or 0,
            "created_at": str(ch.created_at) if ch.created_at else None,
            "updated_at": str(ch.updated_at) if ch.updated_at else None,
        })

    return {"code": 0, "data": result, "message": "ok"}


@router.post("/novels/{asset_id}/chapters")
def add_novel_chapter(
    asset_id: str,
    req: CreateChapterRequest,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    asset = db.query(Asset).filter(
        and_(Asset.id == asset_id, Asset.user_id == current_user.id)
    ).first()
    if not asset:
        raise HTTPException(status_code=404, detail="资产不存在")

    chapter = NovelChapter(
        id=gen_uuid(),
        asset_id=asset_id,
        title=req.title,
        content=req.content,
        sort_order=req.sort_order,
        word_count=len(req.content or ""),
        created_at=datetime.now(),
        updated_at=datetime.now(),
    )
    db.add(chapter)

    LogService.log_operation(
        user_id=current_user.id, username=current_user.username, action="add_chapter",
        target="novel_chapter", target_id=chapter.id,
        detail=f"为资产 {asset.name} 添加章节 {chapter.title}",
    )

    db.commit()
    db.refresh(chapter)

    return {
        "code": 0,
        "data": {
            "id": chapter.id, "asset_id": chapter.asset_id, "title": chapter.title,
            "sort_order": chapter.sort_order, "word_count": chapter.word_count,
            "created_at": str(chapter.created_at),
        },
        "message": "章节添加成功",
    }


# ============================================================
# 动态路由 - {asset_id} 必须放在静态路由之后
# ============================================================

@router.get("/")
def list_assets(
    category: Optional[str] = Query(None),
    search: Optional[str] = Query(None),
    page: int = Query(default=1, ge=1),
    page_size: int = Query(default=20, ge=1, le=100),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    query = db.query(Asset).filter(
        and_(
            Asset.user_id == current_user.id,
            Asset.status != "deleted",
        )
    )

    if category:
        query = query.filter(Asset.category == category)
    if search:
        query = query.filter(Asset.name.ilike(f"%{search}%"))

    total = query.count()
    assets = (
        query.order_by(desc(Asset.updated_at))
        .offset((page - 1) * page_size)
        .limit(page_size)
        .all()
    )

    result = []
    for a in assets:
        result.append({
            "id": a.id,
            "name": a.name,
            "category": a.category,
            "file_type": a.file_type,
            "size": a.size or 0,
            "description": a.description,
            "url": a.url or "",
            "content": a.content or "",
            "status": a.status,
            "created_at": str(a.created_at) if a.created_at else None,
            "updated_at": str(a.updated_at) if a.updated_at else None,
        })

    return {
        "code": 0,
        "data": {"total": total, "page": page, "page_size": page_size, "items": result},
        "message": "ok",
    }


@router.post("/")
def create_asset(
    req: CreateAssetRequest,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    cat = req.category if req.category in VALID_ASSET_CATEGORIES else "file"
    asset = Asset(
        id=gen_uuid(),
        user_id=current_user.id,
        name=req.name,
        category=cat,
        description=req.description or (req.content[:100] if req.content else None),
        file_type=req.file_type or "unknown",
        size=len(req.content.encode('utf-8')) if req.content else 0,
        content=req.content,
        status="active",
        created_at=datetime.now(),
        updated_at=datetime.now(),
    )
    db.add(asset)
    db.commit()
    db.refresh(asset)

    LogService.log_operation(
        user_id=current_user.id, username=current_user.username, action="create",
        target="asset", target_id=asset.id,
        detail=f"创建资产 {asset.name}",
    )

    return {
        "code": 0,
        "data": {
            "id": asset.id, "name": asset.name, "category": asset.category,
            "description": asset.description, "status": asset.status,
            "created_at": str(asset.created_at),
        },
        "message": "创建成功",
    }


@router.get("/{asset_id}")
def get_asset(
    asset_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    asset = db.query(Asset).filter(
        and_(Asset.id == asset_id, Asset.user_id == current_user.id)
    ).first()
    if not asset:
        raise HTTPException(status_code=404, detail="资产不存在")

    return {
        "code": 0,
        "data": {
            "id": asset.id, "name": asset.name, "category": asset.category,
            "description": asset.description, "file_type": asset.file_type,
            "size": asset.size or 0,
            "url": asset.url or "",
            "content": asset.content or "",
            "status": asset.status,
            "created_at": str(asset.created_at), "updated_at": str(asset.updated_at),
        },
        "message": "ok",
    }


@router.put("/{asset_id}")
def update_asset(
    asset_id: str,
    req: UpdateAssetRequest,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    asset = db.query(Asset).filter(
        and_(Asset.id == asset_id, Asset.user_id == current_user.id)
    ).first()
    if not asset:
        raise HTTPException(status_code=404, detail="资产不存在")

    if req.name is not None:
        asset.name = req.name
    if req.description is not None:
        asset.description = req.description
    if req.file_type is not None:
        asset.file_type = req.file_type
    asset.updated_at = datetime.now()

    LogService.log_operation(
        user_id=current_user.id, username=current_user.username, action="update",
        target="asset", target_id=asset.id,
        detail=f"更新资产 {asset.name}",
    )

    db.commit()
    db.refresh(asset)

    return {"code": 0, "data": {
        "id": asset.id, "name": asset.name, "status": asset.status,
        "updated_at": str(asset.updated_at),
    }, "message": "更新成功"}


@router.delete("/{asset_id}")
def delete_asset(
    asset_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    asset = db.query(Asset).filter(
        and_(Asset.id == asset_id, Asset.user_id == current_user.id)
    ).first()
    if not asset:
        raise HTTPException(status_code=404, detail="资产不存在")

    # 软删除
    asset.status = "deleted"
    asset.updated_at = datetime.now()

    # 若资产由知识库文档同步而来，双向删除对应的知识库文档
    if asset.knowledge_doc_id:
        try:
            kb_doc = db.query(KnowledgeDocument).filter(KnowledgeDocument.id == asset.knowledge_doc_id).first()
            if kb_doc:
                kb = db.query(KnowledgeBase).filter(KnowledgeBase.id == kb_doc.knowledge_base_id).first()
                if kb:
                    kb.document_count = max(0, (kb.document_count or 0) - 1)
                    kb.updated_at = datetime.now()
                db.delete(kb_doc)
        except Exception:
            pass

    LogService.log_operation(
        user_id=current_user.id, username=current_user.username, action="delete",
        target="asset", target_id=asset.id,
        detail=f"删除资产 {asset.name}",
    )

    db.commit()

    return {"code": 0, "message": "资产已删除"}