"""电子书：管理员上传/替换 PDF·EPUB，登录用户在线阅读并记录进度。"""
from __future__ import annotations

from fastapi import APIRouter, Depends, File, HTTPException, UploadFile
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session

from database import get_db
from dependencies import get_current_user, require_permission
from models import EbookProgress, Textbook, User
from schemas import EbookProgressIn, EbookProgressOut
from services import ebooks as store


# 上传 / 删除 / 取文件挂在教材下，进度单独成组
router = APIRouter(prefix="/textbooks", tags=["ebooks"])
progress_router = APIRouter(prefix="/ebooks", tags=["ebooks"])


def _load(db: Session, textbook_id: int) -> Textbook:
    textbook = db.get(Textbook, textbook_id)
    if textbook is None:
        raise HTTPException(status_code=404, detail="教材不存在")
    return textbook


def _require_file(textbook: Textbook) -> None:
    if not textbook.ebook_file:
        raise HTTPException(status_code=404, detail="该书还没有上传电子书")


@router.post("/{textbook_id}/ebook")
async def upload_ebook(
    textbook_id: int,
    file: UploadFile = File(...),
    db: Session = Depends(get_db),
    _: User = Depends(require_permission("catalog:manage")),
):
    textbook = _load(db, textbook_id)
    await store.store_upload(db, textbook, file)
    return {
        "id": textbook.id,
        "ebook_format": textbook.ebook_format,
        "ebook_name": textbook.ebook_name,
        "ebook_size": textbook.ebook_size,
        "ebook_pages": textbook.ebook_pages,
    }


@router.delete("/{textbook_id}/ebook")
def delete_ebook(
    textbook_id: int,
    db: Session = Depends(get_db),
    _: User = Depends(require_permission("catalog:manage")),
):
    textbook = _load(db, textbook_id)
    _require_file(textbook)
    store.clear_ebook(db, textbook)
    return {"deleted": textbook_id}


@router.get("/{textbook_id}/ebook/file/{filename}")
def ebook_file(
    textbook_id: int,
    filename: str,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_user),
):
    """阅读器取原始文件。FileResponse 自带 Range/206 支持，PDF 可分段加载。"""
    textbook = _load(db, textbook_id)
    _require_file(textbook)
    if filename != textbook.ebook_file:
        raise HTTPException(status_code=404, detail="电子书文件不存在")
    path = store.resolve_path(textbook.id, filename)
    return FileResponse(
        path,
        media_type=store.media_type(textbook.ebook_format),
        filename=textbook.ebook_name or path.name,
        content_disposition_type="inline",
    )


@progress_router.get("/progress", response_model=list[EbookProgressOut])
def list_progress(
    db: Session = Depends(get_db),
    user: User = Depends(get_current_user),
):
    rows = (
        db.query(EbookProgress)
        .filter(EbookProgress.user_id == user.id)
        .all()
    )
    return [
        EbookProgressOut(
            textbook_id=row.textbook_id,
            locator=row.locator,
            page=row.page,
            total=row.total,
            position=row.position,
            updated_at=row.updated_at,
        )
        for row in rows
    ]


@progress_router.put("/{textbook_id}/progress", response_model=EbookProgressOut)
def save_progress(
    textbook_id: int,
    payload: EbookProgressIn,
    db: Session = Depends(get_db),
    user: User = Depends(get_current_user),
):
    textbook = _load(db, textbook_id)
    _require_file(textbook)
    row = (
        db.query(EbookProgress)
        .filter(
            EbookProgress.user_id == user.id,
            EbookProgress.textbook_id == textbook_id,
        )
        .first()
    )
    if row is None:
        row = EbookProgress(user_id=user.id, textbook_id=textbook_id)
        db.add(row)
    row.locator = payload.locator[:512]
    row.page = max(0, payload.page)
    row.total = max(0, payload.total)
    row.position = min(1.0, max(0.0, payload.position))
    # 阅读器拿到的才是真实篇幅（PDF 页数 / EPUB 章节数），回填给管理端展示
    if row.total > 0 and textbook.ebook_pages != row.total:
        textbook.ebook_pages = row.total
    db.commit()
    return EbookProgressOut(
        textbook_id=textbook_id,
        locator=row.locator,
        page=row.page,
        total=row.total,
        position=row.position,
        updated_at=row.updated_at,
    )