# database/db_manager.py - 数据库 CRUD 操作封装
import os
from typing import List, Optional

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, Session

import config
from database.models import Base, Project, RawRequirement, FunctionalRequirement, CodeFile, ChangeHistory


class DBManager:
    """SQLite 数据库管理器，封装所有 CRUD 操作"""

    def __init__(self, db_path: str = None):
        db_path = db_path or config.DB_PATH
        os.makedirs(os.path.dirname(db_path), exist_ok=True)
        self.engine  = create_engine(f"sqlite:///{db_path}", echo=False)
        Base.metadata.create_all(self.engine)
        self._Session = sessionmaker(bind=self.engine)

    def _session(self) -> Session:
        return self._Session()

    # ══════════════════════════════════════════════════
    #  Project
    # ══════════════════════════════════════════════════

    def create_project(self, project: Project) -> int:
        with self._session() as s:
            s.add(project)
            s.commit()
            s.refresh(project)
            return project.id

    def get_project_by_name(self, name: str) -> Optional[Project]:
        with self._session() as s:
            return s.query(Project).filter_by(name=name).first()

    def get_project_by_id(self, project_id: int) -> Optional[Project]:
        with self._session() as s:
            return s.get(Project, project_id)

    def update_project(self, project: Project) -> None:
        with self._session() as s:
            s.merge(project)
            s.commit()

    def list_projects(self) -> List[Project]:
        with self._session() as s:
            return s.query(Project).order_by(Project.created_at.desc()).all()

    def delete_project(self, project_id: int) -> None:
        with self._session() as s:
            project = s.get(Project, project_id)
            if project:
                s.delete(project)
                s.commit()

    # ══════════════════════════════════════════════════
    #  RawRequirement
    # ══════════════════════════════════════════════════

    def create_raw_requirement(self, raw_req: RawRequirement) -> int:
        with self._session() as s:
            s.add(raw_req)
            s.commit()
            s.refresh(raw_req)
            return raw_req.id

    def get_raw_requirement(self, raw_req_id: int) -> Optional[RawRequirement]:
        with self._session() as s:
            return s.get(RawRequirement, raw_req_id)

    # ══════════════════════════════════════════════════
    #  FunctionalRequirement
    # ══════════════════════════════════════════════════

    def create_functional_requirement(self, req: FunctionalRequirement) -> int:
        with self._session() as s:
            s.add(req)
            s.commit()
            s.refresh(req)
            return req.id

    def get_functional_requirement(self, req_id: int) -> Optional[FunctionalRequirement]:
        with self._session() as s:
            return s.get(FunctionalRequirement, req_id)

    def list_functional_requirements(self, project_id: int) -> List[FunctionalRequirement]:
        with self._session() as s:
            return (
                s.query(FunctionalRequirement)
                .filter_by(project_id=project_id)
                .order_by(FunctionalRequirement.index_no)
                .all()
            )

    def update_functional_requirement(self, req: FunctionalRequirement) -> None:
        with self._session() as s:
            s.merge(req)
            s.commit()

    def delete_functional_requirement(self, req_id: int) -> None:
        with self._session() as s:
            obj = s.get(FunctionalRequirement, req_id)
            if obj:
                s.delete(obj)
                s.commit()

    # ══════════════════════════════════════════════════
    #  CodeFile
    # ══════════════════════════════════════════════════

    def upsert_code_file(self, code_file: CodeFile) -> int:
        with self._session() as s:
            existing = (
                s.query(CodeFile)
                .filter_by(func_req_id=code_file.func_req_id)
                .first()
            )
            if existing:
                existing.file_name    = code_file.file_name
                existing.file_path    = code_file.file_path
                existing.module       = code_file.module
                existing.language     = code_file.language
                existing.content      = code_file.content
                s.commit()
                return existing.id
            else:
                s.add(code_file)
                s.commit()
                s.refresh(code_file)
                return code_file.id

    def list_code_files(self, project_id: int) -> List[CodeFile]:
        with self._session() as s:
            return (
                s.query(CodeFile)
                .join(FunctionalRequirement)
                .filter(FunctionalRequirement.project_id == project_id)
                .all()
            )

    # ══════════════════════════════════════════════════
    #  ChangeHistory
    # ══════════════════════════════════════════════════

    def create_change_history(self, change: ChangeHistory) -> int:
        with self._session() as s:
            s.add(change)
            s.commit()
            s.refresh(change)
            return change.id

    def list_change_history(self, project_id: int) -> List[ChangeHistory]:
        with self._session() as s:
            return s.query(ChangeHistory).filter_by(project_id=project_id).order_by(ChangeHistory.change_time.desc()).all()