from fastapi import APIRouter, Depends, HTTPException, status
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select

from app.dependencies import get_db, get_current_user
from app.models.rule import RuleItem
from app.models.user import User

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


class RuleItemOut(BaseModel):
    id: int
    text: str
    order_index: int
    model_config = {"from_attributes": True}


class RuleItemCreate(BaseModel):
    text: str
    order_index: int = 0


class RuleItemUpdate(BaseModel):
    text: str | None = None
    order_index: int | None = None


class ReorderEntry(BaseModel):
    id: int
    order_index: int


@router.get("", response_model=list[RuleItemOut])
async def list_rules(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(RuleItem)
        .where(RuleItem.user_id == current_user.id)
        .order_by(RuleItem.order_index, RuleItem.id)
    )
    return result.scalars().all()


@router.post("", response_model=RuleItemOut, status_code=status.HTTP_201_CREATED)
async def create_rule(
    body: RuleItemCreate,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    item = RuleItem(user_id=current_user.id, text=body.text, order_index=body.order_index)
    db.add(item)
    await db.commit()
    await db.refresh(item)
    return item


@router.patch("/{item_id}", response_model=RuleItemOut)
async def update_rule(
    item_id: int,
    body: RuleItemUpdate,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(RuleItem).where(
            RuleItem.id == item_id,
            RuleItem.user_id == current_user.id,
        )
    )
    item = result.scalar_one_or_none()
    if not item:
        raise HTTPException(status_code=404, detail="Rule not found")
    if body.text is not None:
        item.text = body.text
    if body.order_index is not None:
        item.order_index = body.order_index
    await db.commit()
    await db.refresh(item)
    return item


@router.put("/reorder", status_code=status.HTTP_204_NO_CONTENT)
async def reorder_rules(
    body: list[ReorderEntry],
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    ids = [e.id for e in body]
    result = await db.execute(
        select(RuleItem).where(
            RuleItem.id.in_(ids),
            RuleItem.user_id == current_user.id,
        )
    )
    items = {item.id: item for item in result.scalars().all()}
    for entry in body:
        if entry.id in items:
            items[entry.id].order_index = entry.order_index
    await db.commit()


@router.delete("/{item_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_rule(
    item_id: int,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(RuleItem).where(
            RuleItem.id == item_id,
            RuleItem.user_id == current_user.id,
        )
    )
    item = result.scalar_one_or_none()
    if not item:
        raise HTTPException(status_code=404, detail="Rule not found")
    await db.delete(item)
    await db.commit()