from __future__ import annotations

import uuid
from dataclasses import dataclass, field
from typing import Any

from shared.base_entity import BaseEntity
from shared.types import ChartType

from src.domain.entities.field_binding import FieldBinding
from src.domain.entities.style_config import StyleConfig


@dataclass
class ChartInstance(BaseEntity):
    """Aggregate root representing a configured chart."""

    dataset_id: uuid.UUID = field(default_factory=uuid.uuid4)
    chart_type: ChartType = ChartType.BAR
    bindings: list[FieldBinding] = field(default_factory=list)
    style: StyleConfig = field(default_factory=dict)
    filters: list[dict[str, Any]] = field(default_factory=list)
    sort_config: dict[str, Any] | None = None
    top_n: int | None = None

    # ------------------------------------------------------------------
    # Domain behaviour
    # ------------------------------------------------------------------

    def update_bindings(self, bindings: list[FieldBinding]) -> None:
        """Replace current bindings after validation."""
        errors = self.validate_bindings(bindings)
        if errors:
            raise ValueError("; ".join(errors))
        self.bindings = bindings
        self.touch()

    def update_style(self, style: StyleConfig) -> None:
        """Merge new style properties into current style."""
        self.style.update(style)
        self.touch()

    def validate_bindings(self, bindings: list[FieldBinding] | None = None) -> list[str]:
        """Return a list of validation error messages (empty means valid)."""
        from src.domain.services.binding_validation import validate_bindings as _validate

        target = bindings if bindings is not None else self.bindings
        return _validate(self.chart_type, target)