"""数据库服务 - PostgreSQL"""

from sqlalchemy import create_engine, Column, String, Integer, DateTime, Enum, Text
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session
from datetime import datetime
from typing import Optional, List
import enum
from app.core.config import settings
from app.utils.logger import logger


# 数据库连接
DATABASE_URL = f"postgresql://{settings.postgres_user}:{settings.postgres_password}@{settings.postgres_host}:{settings.postgres_port}/{settings.postgres_db}"

engine = create_engine(DATABASE_URL, echo=False, pool_pre_ping=True)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


class DocStatus(str, enum.Enum):
    """文档处理状态"""
    uploaded = "uploaded"       # 已上传
    parsing = "parsing"         # 解析中
    parsed = "parsed"           # 已解析
    embedding = "embedding"     # 向量化中
    indexed = "indexed"         # 已索引
    failed = "failed"           # 处理失败


class Document(Base):
    """文档表"""
    __tablename__ = "documents"

    id = Column(String(64), primary_key=True)
    filename = Column(String(255), nullable=False)
    original_name = Column(String(255), nullable=False)
    minio_path = Column(String(512), nullable=False)  # MinIO 存储路径
    size = Column(Integer, default=0)
    status = Column(String(32), default=DocStatus.uploaded.value)
    chunks = Column(Integer, default=0)
    vectors = Column(Integer, default=0)
    error_message = Column(Text, nullable=True)
    created_at = Column(DateTime, default=datetime.now)
    updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)

    def to_dict(self):
        return {
            "id": self.id,
            "name": self.original_name,
            "chunks": self.chunks,
            "status": self.status,
            "created_at": self.created_at.isoformat() if self.created_at else None,
        }


class ParseTask(Base):
    """解析任务表"""
    __tablename__ = "parse_tasks"

    id = Column(String(64), primary_key=True)
    doc_id = Column(String(64), nullable=False)
    status = Column(String(32), default="pending")
    progress = Column(Integer, default=0)
    message = Column(Text, nullable=True)
    created_at = Column(DateTime, default=datetime.now)
    started_at = Column(DateTime, nullable=True)
    completed_at = Column(DateTime, nullable=True)


def init_db():
    """初始化数据库表"""
    try:
        Base.metadata.create_all(bind=engine)
        logger.info("Database tables created successfully")
    except Exception as e:
        logger.error(f"Database initialization failed: {e}")


def get_db() -> Session:
    """获取数据库会话"""
    db = SessionLocal()
    try:
        return db
    finally:
        # 注意：调用者需要负责关闭会话
        pass


class DatabaseService:
    """数据库服务"""

    def __init__(self):
        self.engine = engine
        self.SessionLocal = SessionLocal

    def create_document(
        self,
        doc_id: str,
        filename: str,
        original_name: str,
        minio_path: str,
        size: int,
    ) -> Document:
        """创建文档记录"""
        db = self.SessionLocal()
        try:
            doc = Document(
                id=doc_id,
                filename=filename,
                original_name=original_name,
                minio_path=minio_path,
                size=size,
                status=DocStatus.uploaded.value,
            )
            db.add(doc)
            db.commit()
            db.refresh(doc)
            return doc
        finally:
            db.close()

    def get_document(self, doc_id: str) -> Optional[Document]:
        """获取文档"""
        db = self.SessionLocal()
        try:
            return db.query(Document).filter(Document.id == doc_id).first()
        finally:
            db.close()

    def update_document_status(
        self,
        doc_id: str,
        status: str,
        chunks: int = None,
        vectors: int = None,
        error_message: str = None,
    ) -> Optional[Document]:
        """更新文档状态"""
        db = self.SessionLocal()
        try:
            doc = db.query(Document).filter(Document.id == doc_id).first()
            if doc:
                doc.status = status
                doc.updated_at = datetime.now()
                if chunks is not None:
                    doc.chunks = chunks
                if vectors is not None:
                    doc.vectors = vectors
                if error_message:
                    doc.error_message = error_message
                db.commit()
                db.refresh(doc)
            return doc
        finally:
            db.close()

    def list_documents(self) -> List[Document]:
        """列出所有文档"""
        db = self.SessionLocal()
        try:
            return db.query(Document).order_by(Document.created_at.desc()).all()
        finally:
            db.close()

    def delete_document(self, doc_id: str) -> bool:
        """删除文档"""
        db = self.SessionLocal()
        try:
            doc = db.query(Document).filter(Document.id == doc_id).first()
            if doc:
                db.delete(doc)
                db.commit()
                return True
            return False
        finally:
            db.close()

    def create_parse_task(self, task_id: str, doc_id: str) -> ParseTask:
        """创建解析任务"""
        db = self.SessionLocal()
        try:
            task = ParseTask(id=task_id, doc_id=doc_id)
            db.add(task)
            db.commit()
            db.refresh(task)
            return task
        finally:
            db.close()

    def get_parse_task(self, task_id: str) -> Optional[ParseTask]:
        """获取解析任务"""
        db = self.SessionLocal()
        try:
            return db.query(ParseTask).filter(ParseTask.id == task_id).first()
        finally:
            db.close()

    def update_parse_task(
        self,
        task_id: str,
        status: str,
        progress: int = None,
        message: str = None,
    ) -> Optional[ParseTask]:
        """更新解析任务状态"""
        db = self.SessionLocal()
        try:
            task = db.query(ParseTask).filter(ParseTask.id == task_id).first()
            if task:
                task.status = status
                if progress is not None:
                    task.progress = progress
                if message:
                    task.message = message
                if status == "running":
                    task.started_at = datetime.now()
                elif status in ("completed", "failed"):
                    task.completed_at = datetime.now()
                db.commit()
                db.refresh(task)
            return task
        finally:
            db.close()


# 单例
db_service = DatabaseService()