import uuid

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.character import Character
from app.models.game import GameParticipant
from app.models.user import User

TOOL_SCHEMA = {
    "name": "upsert_character_sheet",
    "description": (
        "Create or update a player's character sheet as facts about them are confirmed or change during play "
        "(name, race, class, ability stats, abilities, backstory). Call this proactively as soon as details are "
        "settled — do not wait until the end of the session."
    ),
    "parameters": {
        "type": "object",
        "properties": {
            "player_name": {
                "type": "string",
                "description": "The real first name of the player this character belongs to, exactly as they introduced themselves.",
            },
            "character_id": {
                "type": "string",
                "description": "Omit when creating a new character. Provide the existing character's id when updating one.",
            },
            "name": {"type": "string"},
            "race": {"type": "string"},
            "char_class": {"type": "string"},
            "stats": {
                "type": "object",
                "description": "Ability scores, e.g. {\"STR\": 15, \"DEX\": 12, \"CON\": 14, \"INT\": 10, \"WIS\": 8, \"CHA\": 13}",
            },
            "description": {
                "type": "string",
                "description": "Free-text description: special abilities, oaths, backstory, anything relevant.",
            },
        },
        "required": ["player_name"],
    },
}


async def upsert(session: AsyncSession, game_id: uuid.UUID, tool_input: dict) -> dict:
    player_name = tool_input["player_name"]

    participant_row = (
        await session.execute(
            select(GameParticipant, User)
            .join(User, User.id == GameParticipant.user_id)
            .where(GameParticipant.game_id == game_id, User.name == player_name)
        )
    ).first()
    if participant_row is None:
        raise ValueError(f"No participant named {player_name!r} found in this game")

    participant, user = participant_row

    character_id = tool_input.get("character_id")
    character: Character | None = None
    if character_id:
        character = await session.get(Character, uuid.UUID(character_id))
        if character is None or character.owner_id != user.id:
            raise ValueError(f"Character {character_id!r} does not belong to {player_name!r}")
    elif participant.character_id is not None:
        # The player already has a character in this game (set by an earlier call in this
        # session) — reuse it instead of creating a duplicate when the model omits character_id.
        character = await session.get(Character, participant.character_id)

    if character is None:
        character = Character(owner_id=user.id, name=tool_input.get("name", "Unbenannt"), stats={})
        session.add(character)

    for field in ("name", "race", "char_class", "description"):
        if field in tool_input and tool_input[field] is not None:
            setattr(character, field, tool_input[field])
    if "stats" in tool_input and tool_input["stats"] is not None:
        character.stats = {**(character.stats or {}), **tool_input["stats"]}

    await session.flush()

    if participant.character_id != character.id:
        participant.character_id = character.id

    await session.commit()
    await session.refresh(character)

    return {"character_id": str(character.id), "name": character.name}