from typing import Optional
import json
import csv
from io import StringIO
from datetime import datetime, timezone

from fastapi import APIRouter, Depends, HTTPException, Query, UploadFile, File
from pydantic import BaseModel, Field

from app.core.security import get_current_user
from app.core.config import get_settings

settings = get_settings()

router = APIRouter(prefix="/admin/knowledge", tags=["管理-知识库"])


# ============================================
# Schemas
# ============================================

class DrugCreate(BaseModel):
    drug_id: str
    name: str
    name_en: Optional[str] = None
    pinyin: Optional[str] = None
    category: Optional[str] = None
    subcategory: Optional[str] = None
    approval_number: Optional[str] = None
    sections: Optional[dict] = None
    source_version: Optional[str] = None
    source_volume: Optional[str] = None
    source_page: Optional[str] = None


class DrugUpdate(BaseModel):
    name: Optional[str] = None
    name_en: Optional[str] = None
    pinyin: Optional[str] = None
    category: Optional[str] = None
    subcategory: Optional[str] = None
    approval_number: Optional[str] = None
    sections: Optional[dict] = None
    source_version: Optional[str] = None
    source_volume: Optional[str] = None
    source_page: Optional[str] = None
    is_active: Optional[bool] = None


class KnowledgePointCreate(BaseModel):
    point_id: str
    subject: str
    chapter_id: str
    chapter_name: str
    title: str
    content: str
    difficulty: int = Field(default=1, ge=1, le=5)
    frequency: Optional[str] = None
    related_drugs: Optional[list] = None
    source: Optional[str] = None


class KnowledgePointUpdate(BaseModel):
    chapter_name: Optional[str] = None
    title: Optional[str] = None
    content: Optional[str] = None
    difficulty: Optional[int] = Field(default=None, ge=1, le=5)
    frequency: Optional[str] = None
    related_drugs: Optional[list] = None
    source: Optional[str] = None


class QuestionCreate(BaseModel):
    question_id: str
    question_type: str
    subject: str
    chapter_id: str
    difficulty: int = Field(default=1, ge=1, le=5)
    content: str
    options: list[str]
    answer: str
    explanation: str
    knowledge_point_ids: Optional[list[str]] = None
    source: Optional[str] = None
    frequency: Optional[str] = None


class QuestionUpdate(BaseModel):
    question_type: Optional[str] = None
    subject: Optional[str] = None
    chapter_id: Optional[str] = None
    difficulty: Optional[int] = Field(default=None, ge=1, le=5)
    content: Optional[str] = None
    options: Optional[list[str]] = None
    answer: Optional[str] = None
    explanation: Optional[str] = None
    knowledge_point_ids: Optional[list[str]] = None
    source: Optional[str] = None
    frequency: Optional[str] = None
    audited: Optional[bool] = None


class ReindexRequest(BaseModel):
    collection: str = Field(default="drug_entries", description="drug_entries / exam_knowledge")
    drug_ids: Optional[list[str]] = Field(default=None, description="指定药品ID，不填则全量重建")


class ImportRequest(BaseModel):
    type: str = Field(..., description="drug / knowledge_point / question")
    format: str = Field(default="json", description="json / csv")
    data: str = Field(..., description="JSON/CSV 内容字符串")


class BatchAuditRequest(BaseModel):
    question_ids: list[str]
    audited: bool = True


# ============================================
# 药品管理 CRUD
# ============================================

@router.get("/drugs")
async def list_drugs(
    keyword: Optional[str] = Query(None, description="药品名称搜索"),
    category: Optional[str] = Query(None, description="药品分类"),
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    user: dict = Depends(get_current_user),
):
    return {
        "items": [],
        "total": 0,
        "page": page,
        "page_size": page_size,
        "message": "数据入库后可用",
    }


@router.get("/drugs/{drug_id}")
async def get_drug(drug_id: str, user: dict = Depends(get_current_user)):
    return {"message": "数据入库后可用", "drug_id": drug_id}


@router.post("/drugs")
async def create_drug(
    drug: DrugCreate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已创建", "drug_id": drug.drug_id}


@router.put("/drugs/{drug_id}")
async def update_drug(
    drug_id: str,
    drug: DrugUpdate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已更新", "drug_id": drug_id}


@router.delete("/drugs/{drug_id}")
async def delete_drug(drug_id: str, user: dict = Depends(get_current_user)):
    return {"message": "已标记删除", "drug_id": drug_id}


@router.post("/drugs/import")
async def import_drugs(
    req: ImportRequest,
    user: dict = Depends(get_current_user),
):
    count = 0
    if req.format == "json":
        try:
            items = json.loads(req.data)
            count = len(items) if isinstance(items, list) else 0
        except json.JSONDecodeError as e:
            raise HTTPException(status_code=400, detail=f"JSON 解析失败: {str(e)}")
    elif req.format == "csv":
        try:
            reader = csv.DictReader(StringIO(req.data))
            count = sum(1 for _ in reader)
        except Exception as e:
            raise HTTPException(status_code=400, detail=f"CSV 解析失败: {str(e)}")

    return {
        "message": "导入任务已提交",
        "total": count,
        "success": 0,
        "failed": 0,
        "note": "Phase 2 实现异步批量写入 + 向量化",
    }


@router.post("/drugs/reindex")
async def reindex_drugs(
    req: ReindexRequest,
    user: dict = Depends(get_current_user),
):
    return {
        "message": "重建索引任务已提交",
        "collection": req.collection,
        "drug_ids": req.drug_ids,
        "status": "pending",
        "note": "Phase 2 实现：重新 chunk → 向量化 → 写入 Milvus",
    }


# ============================================
# 知识点管理 CRUD
# ============================================

@router.get("/knowledge-points")
async def list_knowledge_points(
    subject: Optional[str] = Query(None),
    chapter_id: Optional[str] = Query(None),
    difficulty: Optional[int] = Query(None, ge=1, le=5),
    frequency: Optional[str] = Query(None),
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    user: dict = Depends(get_current_user),
):
    return {
        "items": [],
        "total": 0,
        "page": page,
        "page_size": page_size,
    }


@router.get("/knowledge-points/{point_id}")
async def get_knowledge_point(point_id: str, user: dict = Depends(get_current_user)):
    return {"message": "数据入库后可用", "point_id": point_id}


@router.post("/knowledge-points")
async def create_knowledge_point(
    kp: KnowledgePointCreate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已创建", "point_id": kp.point_id}


@router.put("/knowledge-points/{point_id}")
async def update_knowledge_point(
    point_id: str,
    kp: KnowledgePointUpdate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已更新", "point_id": point_id}


@router.delete("/knowledge-points/{point_id}")
async def delete_knowledge_point(point_id: str, user: dict = Depends(get_current_user)):
    return {"message": "已删除", "point_id": point_id}


@router.post("/knowledge-points/import")
async def import_knowledge_points(
    req: ImportRequest,
    user: dict = Depends(get_current_user),
):
    count = 0
    try:
        items = json.loads(req.data)
        count = len(items) if isinstance(items, list) else 0
    except json.JSONDecodeError as e:
        raise HTTPException(status_code=400, detail=f"JSON 解析失败: {str(e)}")

    return {
        "message": "导入任务已提交",
        "total": count,
        "success": 0,
        "failed": 0,
    }


# ============================================
# 题库管理 CRUD
# ============================================

@router.get("/questions")
async def list_questions(
    subject: Optional[str] = Query(None),
    chapter_id: Optional[str] = Query(None),
    question_type: Optional[str] = Query(None),
    difficulty: Optional[int] = Query(None, ge=1, le=5),
    audited: Optional[bool] = Query(None),
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    user: dict = Depends(get_current_user),
):
    return {
        "items": [],
        "total": 0,
        "page": page,
        "page_size": page_size,
    }


@router.get("/questions/{question_id}")
async def get_question(question_id: str, user: dict = Depends(get_current_user)):
    return {"message": "数据入库后可用", "question_id": question_id}


@router.post("/questions")
async def create_question(
    q: QuestionCreate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已创建", "question_id": q.question_id}


@router.put("/questions/{question_id}")
async def update_question(
    question_id: str,
    q: QuestionUpdate,
    user: dict = Depends(get_current_user),
):
    return {"message": "已更新", "question_id": question_id}


@router.delete("/questions/{question_id}")
async def delete_question(question_id: str, user: dict = Depends(get_current_user)):
    return {"message": "已删除", "question_id": question_id}


@router.post("/questions/batch-audit")
async def batch_audit_questions(
    req: BatchAuditRequest,
    user: dict = Depends(get_current_user),
):
    return {
        "message": "批量审核完成",
        "question_ids": req.question_ids,
        "audited": req.audited,
    }


@router.post("/questions/import")
async def import_questions(
    req: ImportRequest,
    user: dict = Depends(get_current_user),
):
    count = 0
    try:
        items = json.loads(req.data)
        count = len(items) if isinstance(items, list) else 0
    except json.JSONDecodeError as e:
        raise HTTPException(status_code=400, detail=f"JSON 解析失败: {str(e)}")

    return {
        "message": "导入任务已提交",
        "total": count,
        "success": 0,
        "failed": 0,
    }


@router.post("/questions/generate")
async def ai_generate_questions(
    point_id: str = Query(..., description="知识点ID"),
    count: int = Query(10, ge=1, le=50),
    question_type: str = Query("A", description="A/B/X"),
    user: dict = Depends(get_current_user),
):
    return {
        "message": "AI 出题任务已提交",
        "point_id": point_id,
        "count": count,
        "question_type": question_type,
        "status": "pending",
        "note": "Phase 2 实现：LLM 根据知识点生成题目",
    }


# ============================================
# 知识库状态与统计
# ============================================

@router.get("/stats")
async def knowledge_stats(user: dict = Depends(get_current_user)):
    return {
        "drugs": {"total": 0, "active": 0, "with_chunks": 0},
        "knowledge_points": {"total": 0, "by_subject": {}},
        "questions": {"total": 0, "audited": 0, "pending": 0},
        "vector_index": {
            "status": "empty",
            "collection": settings.milvus_collection,
            "last_reindex": None,
        },
        "last_data_update": None,
    }