from datetime import datetime
from sqlalchemy import select
from sqlalchemy.orm import Session
from app.models import Item
from app.stages import is_valid_stage

DONE_STAGES = {"done", "logged_in_bookmark"}


def create_item(
    session: Session,
    *,
    modality: str,
    raw_content: str,
    captured_at: datetime,
    discord_message_id: str | None,
    sender_id: str | None = None,
    direction: str = "inbound",
) -> tuple[Item, bool]:
    if discord_message_id is not None:
        existing = session.scalar(
            select(Item).where(Item.discord_message_id == discord_message_id)
        )
        if existing is not None:
            return existing, False

    item = Item(
        modality=modality,
        raw_content=raw_content,
        captured_at=captured_at,
        discord_message_id=discord_message_id,
        sender_id=sender_id,
        direction=direction,
        stage="new",
    )
    session.add(item)
    session.commit()
    session.refresh(item)
    return item, True


def list_items(
    session: Session,
    *,
    stage: str | None = None,
    modality: str | None = None,
    include_done: bool = False,
) -> list[Item]:
    stmt = select(Item)
    if stage is not None:
        stmt = stmt.where(Item.stage == stage)
    if modality is not None:
        stmt = stmt.where(Item.modality == modality)
    if not include_done:
        stmt = stmt.where(Item.stage.not_in(DONE_STAGES))
    stmt = stmt.order_by(Item.captured_at.desc())
    return list(session.scalars(stmt))


def get_item(session: Session, item_id: int) -> Item | None:
    return session.get(Item, item_id)


def update_item(session: Session, item_id: int, **fields) -> Item | None:
    item = session.get(Item, item_id)
    if item is None:
        return None

    new_type = fields.get("type", item.type)
    new_stage = fields.get("stage", item.stage)
    new_direction = fields.get("direction", item.direction)
    if "stage" in fields and not is_valid_stage(new_type, new_stage, new_direction):
        raise ValueError(
            f"'{new_stage}' is not a valid stage for type '{new_type}' direction '{new_direction}'"
        )

    for key, value in fields.items():
        setattr(item, key, value)

    session.commit()
    session.refresh(item)
    return item