"""电子书种子：把 res/ 下已有的三本书挂到教材上。

幂等：只补不覆盖，管理员在后台重新上传的文件不会被种子冲掉。
"""
from __future__ import annotations

from pathlib import Path

from sqlalchemy.orm import Session

from database import REPO_ROOT
from models import Textbook
from services import ebooks as store

RES_ROOT = REPO_ROOT / "res"

# res/ 里的文件名带书目后缀，展示时用干净的名称
PRINCETON = {
    "name": "普林斯顿微积分读本(修订版)",
    "author": "阿德里安·班纳 (Adrian Banner)",
    "publisher": "人民邮电出版社",
    "grade": "高中至大学先修",
    "description": "面向微积分入门的系统辅导书，覆盖极限、导数、积分与级数，"
    "按考点组织，适合自学与考前查漏补缺。",
    "resource": "普林斯顿微积分读本(修订版)",
    "display": "普林斯顿微积分读本(修订版).epub",
}

# 已有教材 → res/ 中的 PDF（按教材名前缀匹配）
PDF_LINKS = [
    ("函数和图像", "函数和图像", "函数和图像（盖尔范德中学生数学思维丛书）.pdf"),
    ("三角函数", "三角函数", "三角函数（盖尔范德中学生数学思维丛书）.pdf"),
]


def _find_resource(prefix: str, suffix: str) -> Path | None:
    """res/ 下的文件名带作者与来源后缀，只按标题前缀匹配。"""
    if not RES_ROOT.is_dir():
        return None
    for path in sorted(RES_ROOT.iterdir()):
        if (
            path.is_file()
            and path.suffix.lower() == suffix
            and path.name.startswith(prefix)
        ):
            return path
    return None


def ensure_ebooks(db: Session) -> None:
    created = False
    textbook = (
        db.query(Textbook).filter(Textbook.name == PRINCETON["name"]).first()
    )
    if textbook is None:
        position = (
            db.query(Textbook).count()
        )
        textbook = Textbook(
            name=PRINCETON["name"],
            author=PRINCETON["author"],
            publisher=PRINCETON["publisher"],
            grade=PRINCETON["grade"],
            description=PRINCETON["description"],
            position=position,
        )
        db.add(textbook)
        db.commit()
        created = True
    if created:
        epub = _find_resource(PRINCETON["resource"], ".epub")
        if epub is not None and not textbook.ebook_file:
            store.attach_local_file(
                db, textbook, epub, display_name=PRINCETON["display"]
            )

    for name_prefix, file_prefix, display in PDF_LINKS:
        textbook = (
            db.query(Textbook)
            .filter(Textbook.name.startswith(name_prefix))
            .first()
        )
        if textbook is None or textbook.ebook_file:
            continue
        pdf = _find_resource(file_prefix, ".pdf")
        if pdf is None:
            continue
        store.attach_local_file(db, textbook, pdf, display_name=display)