"""RecipeTask and RecipeSubtask models."""
from typing import TYPE_CHECKING, Optional

from sqlalchemy import (
    DECIMAL, Enum, ForeignKey, Index, Integer, JSON, String, Text, UniqueConstraint,
)
from sqlalchemy.orm import Mapped, mapped_column, relationship

from src.backend.database import Base

if TYPE_CHECKING:
    from src.backend.models.orm.recipe import RecipeVersion


# What a task is, declared by whoever writes the recipe instead of guessed from its
# contents. The last two are not built yet; they are in the enum from the start
# because widening a MySQL enum later is an ALTER on a live table.
TASK_TYPES = ("note", "measure", "drawing", "xf_compare", "camera_measure")

# Types the operator screen treats as "there are quotes to take here".
MEASURING_TASK_TYPES = ("measure", "camera_measure")


class RecipeTask(Base):
    __tablename__ = "recipe_tasks"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    version_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("recipe_versions.id"), nullable=False
    )
    order_index: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    # Declared, not deduced. The old rule - "has subtasks, therefore a measurement" -
    # meant a measurement task whose quotes had not been entered yet behaved as a
    # note, so the system acted differently depending on how finished the recipe was.
    task_type: Mapped[str] = mapped_column(
        Enum(*TASK_TYPES, name="task_type_enum"),
        nullable=False,
        default="note",
        server_default="note",
        index=True,
    )
    title: Mapped[str] = mapped_column(String(255), nullable=False)
    directive: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    description: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    file_path: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)
    file_type: Mapped[Optional[str]] = mapped_column(
        Enum("image", "pdf", name="file_type_enum"), nullable=True
    )
    annotations_json: Mapped[Optional[dict]] = mapped_column(JSON, nullable=True)

    # Relationships
    version: Mapped["RecipeVersion"] = relationship(back_populates="tasks")
    subtasks: Mapped[list["RecipeSubtask"]] = relationship(
        back_populates="task", cascade="all, delete-orphan", lazy="selectin"
    )

    __table_args__ = (
        {"mysql_engine": "InnoDB", "mysql_charset": "utf8mb4"},
    )

    @property
    def recipe_id(self) -> int | None:
        """Shortcut: recipe_id via the version relationship."""
        if self.version:
            return self.version.recipe_id
        return None

    def __repr__(self) -> str:
        return f"<RecipeTask #{self.order_index} '{self.title}'>"


class RecipeSubtask(Base):
    __tablename__ = "recipe_subtasks"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    task_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("recipe_tasks.id", ondelete="CASCADE"), nullable=False
    )
    marker_number: Mapped[int] = mapped_column(Integer, nullable=False)
    description: Mapped[str] = mapped_column(String(500), nullable=False)
    measurement_type: Mapped[Optional[str]] = mapped_column(String(100), nullable=True)

    # Tolerance values
    nominal: Mapped[Optional[float]] = mapped_column(DECIMAL(12, 6), nullable=True)
    utl: Mapped[Optional[float]] = mapped_column(DECIMAL(12, 6), nullable=True)  # Upper Tolerance Limit
    uwl: Mapped[Optional[float]] = mapped_column(DECIMAL(12, 6), nullable=True)  # Upper Warning Limit
    lwl: Mapped[Optional[float]] = mapped_column(DECIMAL(12, 6), nullable=True)  # Lower Warning Limit
    ltl: Mapped[Optional[float]] = mapped_column(DECIMAL(12, 6), nullable=True)  # Lower Tolerance Limit

    unit: Mapped[str] = mapped_column(String(20), nullable=False, default="mm")
    image_path: Mapped[Optional[str]] = mapped_column(String(500), nullable=True)

    # Relationships
    task: Mapped["RecipeTask"] = relationship(back_populates="subtasks")

    __table_args__ = (
        UniqueConstraint("task_id", "marker_number", name="uq_task_marker"),
        Index("ix_subtask_task_id", "task_id"),
        {"mysql_engine": "InnoDB", "mysql_charset": "utf8mb4"},
    )

    def __repr__(self) -> str:
        return f"<RecipeSubtask #{self.marker_number} '{self.description}'>"