"""Pydantic schemas for RecipeTask and RecipeSubtask operations."""
from typing import Any, Literal, Optional

from pydantic import BaseModel, ConfigDict, Field, model_validator

from src.backend.models.orm.task import TASK_TYPES

# Kept in step with the ORM enum so the two cannot drift apart.
TaskType = Literal[TASK_TYPES]


def validate_tolerance_order(
    ltl: Optional[float],
    lwl: Optional[float],
    nominal: Optional[float],
    uwl: Optional[float],
    utl: Optional[float],
) -> None:
    """ltl <= lwl <= nominal <= uwl <= utl, checked only across the values set.

    A one-sided tolerance - only utl, say - is not an error: what is wrong is
    limits that invert the sequence they do share, like utl landing below ltl.
    Shared by SubtaskCreate's own validator and by the router's partial-update
    check (SubtaskUpdate has no fixed set of fields to compare).
    """
    ordered = [
        ("ltl", ltl), ("lwl", lwl), ("nominal", nominal), ("uwl", uwl), ("utl", utl),
    ]
    present = [(name, value) for name, value in ordered if value is not None]
    for (prev_name, prev), (name, value) in zip(present, present[1:]):
        if prev > value:
            raise ValueError(
                f"Tolerance limits out of order: {prev_name}={prev} > {name}={value}"
            )


class SubtaskCreate(BaseModel):
    """Schema for creating a subtask."""
    marker_number: int = Field(..., ge=1)
    description: str = Field(..., min_length=1, max_length=500)
    measurement_type: Optional[str] = Field(None, max_length=100)
    nominal: Optional[float] = None
    utl: Optional[float] = None
    uwl: Optional[float] = None
    lwl: Optional[float] = None
    ltl: Optional[float] = None
    unit: str = Field("mm", max_length=20)
    image_path: Optional[str] = Field(None, max_length=500)
    vision_output: Optional[str] = None

    @model_validator(mode="after")
    def _check_tolerance_order(self) -> "SubtaskCreate":
        validate_tolerance_order(self.ltl, self.lwl, self.nominal, self.uwl, self.utl)
        return self


class SubtaskUpdate(BaseModel):
    """Schema for updating a subtask."""
    marker_number: Optional[int] = Field(None, ge=1)
    description: Optional[str] = Field(None, min_length=1, max_length=500)
    measurement_type: Optional[str] = Field(None, max_length=100)
    nominal: Optional[float] = None
    utl: Optional[float] = None
    uwl: Optional[float] = None
    lwl: Optional[float] = None
    ltl: Optional[float] = None
    unit: Optional[str] = Field(None, max_length=20)
    image_path: Optional[str] = Field(None, max_length=500)
    vision_output: Optional[str] = None


class SubtaskResponse(BaseModel):
    """Schema for subtask response."""
    model_config = ConfigDict(from_attributes=True)

    id: int
    task_id: int
    marker_number: int
    description: str
    measurement_type: Optional[str] = None
    nominal: Optional[float] = None
    utl: Optional[float] = None
    uwl: Optional[float] = None
    lwl: Optional[float] = None
    ltl: Optional[float] = None
    unit: str
    image_path: Optional[str] = None
    vision_output: Optional[str] = None


class TaskCreate(BaseModel):
    """Schema for creating a task."""
    title: str = Field(..., min_length=1, max_length=255)
    task_type: TaskType = "note"
    directive: Optional[str] = None
    description: Optional[str] = None
    file_path: Optional[str] = Field(None, max_length=500)
    file_type: Optional[str] = Field(None, pattern="^(image|pdf)$")
    annotations_json: Optional[dict[str, Any]] = None
    vision_json: Optional[dict] = None
    subtasks: list[SubtaskCreate] = []


class TaskUpdate(BaseModel):
    """Schema for updating a task."""
    title: Optional[str] = Field(None, min_length=1, max_length=255)
    task_type: Optional[TaskType] = None
    directive: Optional[str] = None
    description: Optional[str] = None
    file_path: Optional[str] = Field(None, max_length=500)
    file_type: Optional[str] = Field(None, pattern="^(image|pdf)$")
    annotations_json: Optional[dict[str, Any]] = None
    vision_json: Optional[dict] = None


class TaskResponse(BaseModel):
    """Schema for task response."""
    model_config = ConfigDict(from_attributes=True)

    id: int
    version_id: int
    recipe_id: Optional[int] = None
    order_index: int
    task_type: str
    title: str
    directive: Optional[str] = None
    description: Optional[str] = None
    file_path: Optional[str] = None
    file_type: Optional[str] = None
    annotations_json: Optional[dict[str, Any]] = None
    vision_json: Optional[dict] = None
    subtasks: list[SubtaskResponse] = []


class TaskReorderRequest(BaseModel):
    """Schema for reordering tasks."""
    task_ids: list[int] = Field(..., min_length=1)