from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.deps import require_role
from app.db.database import get_db
from app.db.models import User
from app.schemas.timeline import TimelineCreate, TimelineUpdate, TimelineOut
from app.schemas.common import PageResponse
from app.services.timeline_service import (
    create_timeline,
    update_timeline,
    delete_timeline,
    get_timeline_by_id,
    list_timelines,
    add_images_to_timeline,
)
from app.services.cos_service import upload_image

router = APIRouter(prefix="/api/timeline", tags=["timeline"])


@router.get("/", response_model=PageResponse[TimelineOut])
async def get_timelines(
    page: int = 1,
    page_size: int = 20,
    class_id: int | None = None,
    user: User = Depends(require_role("super_admin", "class_admin", "student")),
    db: AsyncSession = Depends(get_db),
):
    effective_class_id = class_id if user.role == "super_admin" and class_id else user.class_id
    if effective_class_id is None:
        return PageResponse(items=[], total=0, page=page, page_size=page_size, total_pages=0)

    posts, total = await list_timelines(db, effective_class_id, page, page_size)
    total_pages = (total + page_size - 1) // page_size

    items = []
    for p in posts:
        items.append(
            TimelineOut(
                id=p.id,
                class_id=p.class_id,
                author_id=p.author_id,
                author_name=p.author.name if p.author else "Unknown",
                title=p.title,
                content=p.content,
                image_urls=p.get_image_urls_list(),
                created_at=p.created_at,
                updated_at=p.updated_at,
            )
        )

    return PageResponse(
        items=items, total=total, page=page, page_size=page_size, total_pages=total_pages
    )


@router.post("/", response_model=TimelineOut)
async def create_new_timeline(
    data: TimelineCreate,
    class_id: int | None = None,
    user: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    effective_class_id = class_id if user.role == "super_admin" and class_id else user.class_id
    if effective_class_id is None:
        raise HTTPException(status_code=400, detail="You are not assigned to a class")

    post = await create_timeline(db, effective_class_id, user.id, data)
    return TimelineOut(
        id=post.id,
        class_id=post.class_id,
        author_id=post.author_id,
        author_name=user.name,
        title=post.title,
        content=post.content,
        image_urls=[],
        created_at=post.created_at,
        updated_at=post.updated_at,
    )


@router.post("/{post_id}/images")
async def upload_timeline_images(
    post_id: int,
    files: list[UploadFile] = File(...),
    user: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    post = await get_timeline_by_id(db, post_id)
    if post is None:
        raise HTTPException(status_code=404, detail="Timeline post not found")

    # Verify post belongs to user's class (super_admin can access any)
    if user.role != "super_admin" and post.class_id != user.class_id:
        raise HTTPException(status_code=403, detail="Access denied")

    urls = []
    for f in files:
        contents = await f.read()
        if len(contents) > 10 * 1024 * 1024:  # 10MB limit
            raise HTTPException(
                status_code=400, detail=f"File {f.filename} too large (max 10MB)"
            )
        if f.content_type not in {"image/jpeg", "image/png", "image/gif", "image/webp"}:
            raise HTTPException(
                status_code=400, detail=f"File {f.filename} has invalid type"
            )
        url = upload_image(
            f"timeline/{post_id}", f.filename or "image.jpg", contents, f.content_type
        )
        urls.append(url)

    await add_images_to_timeline(db, post, urls)
    return {"image_urls": urls}


@router.put("/{post_id}", response_model=TimelineOut)
async def update_existing_timeline(
    post_id: int,
    data: TimelineUpdate,
    user: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    post = await get_timeline_by_id(db, post_id)
    if post is None:
        raise HTTPException(status_code=404, detail="Timeline post not found")
    if user.role != "super_admin" and post.class_id != user.class_id:
        raise HTTPException(status_code=403, detail="Access denied")

    updated = await update_timeline(db, post, data)
    return TimelineOut(
        id=updated.id,
        class_id=updated.class_id,
        author_id=updated.author_id,
        author_name=user.name,
        title=updated.title,
        content=updated.content,
        image_urls=updated.get_image_urls_list(),
        created_at=updated.created_at,
        updated_at=updated.updated_at,
    )


@router.delete("/{post_id}")
async def delete_existing_timeline(
    post_id: int,
    user: User = Depends(require_role("super_admin", "class_admin")),
    db: AsyncSession = Depends(get_db),
):
    post = await get_timeline_by_id(db, post_id)
    if post is None:
        raise HTTPException(status_code=404, detail="Timeline post not found")
    if user.role != "super_admin" and post.class_id != user.class_id:
        raise HTTPException(status_code=403, detail="Access denied")

    await delete_timeline(db, post)
    return {"message": "Timeline post deleted"}