"""Persistent selection preferences scoped to a library and its stable item ID."""

from pigway_frame_flow.errors import ErrorCode as E
from pigway_frame_flow.errors import FlowError


def ensure_compatible(starred, excluded):
    if starred and excluded:
        raise FlowError(
            E.CONFLICT,
            "Starred photos cannot be excluded; clear the existing mark first",
            409,
        )


def flags(db, source_id, item_id):
    row = db.one(
        "SELECT starred,excluded FROM photo_preferences WHERE source_id=? AND item_id=?",
        (source_id, item_id),
    )
    return {key: bool(row and row[key]) for key in ("starred", "excluded")}


def set_flags(db, source_id, item_id, *, starred=None, excluded=None):
    with db.transaction() as connection:
        current = flags(db, source_id, item_id)
        if source_id == "@assets":
            meta = db.one(
                "SELECT starred FROM asset_metadata WHERE asset_id=?", (item_id,)
            )
            current["starred"] = bool(meta and meta["starred"])
        ensure_compatible(
            current["starred"] if starred is None else starred,
            current["excluded"] if excluded is None else excluded,
        )
        connection.execute(
            "INSERT INTO photo_preferences(source_id,item_id,starred,excluded) VALUES(?,?,?,?) ON CONFLICT(source_id,item_id) DO UPDATE SET starred=coalesce(?,starred),excluded=coalesce(?,excluded)",
            (
                source_id,
                item_id,
                int(starred or False),
                int(excluded or False),
                None if starred is None else int(starred),
                None if excluded is None else int(excluded),
            ),
        )
    return flags(db, source_id, item_id)


def annotate(db, source_id, items):
    preferences = {
        row["item_id"]: row
        for row in db.all(
            "SELECT item_id,starred,excluded FROM photo_preferences WHERE source_id=?",
            (source_id,),
        )
    }
    return [
        {
            **item,
            **{
                key: bool(preferences.get(item["id"], {}).get(key))
                for key in ("starred", "excluded")
            },
        }
        for item in items
    ]


def eligible(db, source_id, items):
    excluded = {
        row["item_id"]
        for row in db.all(
            "SELECT item_id FROM photo_preferences WHERE source_id=? AND excluded=1",
            (source_id,),
        )
    }
    return [item for item in items if item["id"] not in excluded]