import random
from dataclasses import dataclass
from typing import Optional

from ..factory import ProceduralDataset, register_dataset


@dataclass
class SimpleGeometryConfig:
    """
    Configuration for generating basic geometry (angle-finding) tasks.
    Produces a random convex polygon with N sides, random angles
    for the first (N-1) sides, and asks the solver to find the last angle.
    """

    min_sides: int = 3  # Minimum number of sides (e.g. triangle)
    max_sides: int = 6  # Maximum number of sides (e.g. hexagon)
    min_angle: int = 10  # Minimum angle (in degrees) for each of the first (N-1) angles
    max_angle: int = 170  # Maximum angle (in degrees) for each of the first (N-1) angles
    seed: Optional[int] = None  # Random seed
    size: int = 100  # Number of geometry tasks to generate

    def validate(self) -> None:
        """
        Validate configuration parameters.
        """
        assert self.min_sides >= 3, "min_sides must be at least 3 (triangle)."
        assert self.max_sides >= self.min_sides, "max_sides must be >= min_sides."
        assert 0 < self.min_angle < 180, "min_angle must be in (0, 180)."
        assert self.max_angle <= 179, "max_angle should be less than 180."
        assert self.max_angle >= self.min_angle, "max_angle must be >= min_angle."


class SimpleGeometryDataset(ProceduralDataset):
    """
    A dataset for simple polygon angle-finding tasks.
    We randomly choose the number of sides N within [min_sides, max_sides].
    We then generate (N-1) random angles (in degrees), ensuring their sum is
    strictly less than the total sum for an (N)-sided convex polygon (which is 180*(N-2)).
    The question asks for the missing angle; the answer is computed by subtracting the
    sum of known angles from 180*(N-2).
    """

    def __init__(self, config: SimpleGeometryConfig):
        self._prompt_templates = [
            (
                "Given a convex polygon with {n_sides} sides, its first {n_minus_1} interior angles "
                "are: {angle_list}. What is the measure of the remaining interior angle (in degrees)?"
            ),
            (
                "A convex polygon has {n_sides} sides. The measures of "
                "the first {n_minus_1} interior angles are: {angle_list}. "
                "Find the measure of the last interior angle."
            ),
            (
                "Consider a convex {n_sides}-gon whose first {n_minus_1} interior angles "
                "are: {angle_list}. Determine the measure of the remaining angle."
            ),
        ]
        super().__init__(config=config, seed=config.seed, size=config.size)

    def __getitem__(self, idx: int) -> dict:
        """
        Generate a single geometry angle-finding item.

        Returns:
            A dict with:
                - question: str
                - answer: str (the missing angle, as an integer or float in degrees)
                - metadata: dict (n_sides, angles, sum_of_known, missing_angle, etc.)
        """
        rng = random.Random(self.seed + idx)

        # Randomly pick the number of sides
        n_sides = rng.randint(self.config.min_sides, self.config.max_sides)

        # Total interior angle sum for a convex n_sides-gon
        total_sum = 180 * (n_sides - 2)

        # Generate (n_sides - 1) random angles, ensuring their sum < total_sum
        known_angles = self._generate_valid_angles(rng, n_sides, total_sum)

        # Missing angle
        missing_angle = total_sum - sum(known_angles)

        # Build the question string
        angle_list_str = ", ".join(f"{a:.1f}°" for a in known_angles)
        prompt = rng.choice(self._prompt_templates).format(
            n_sides=n_sides, n_minus_1=n_sides - 1, angle_list=angle_list_str
        )

        # Round the missing angle to one decimal place or integer if it is very close to an integer
        # so that the answer remains consistent and clean
        missing_angle_rounded = round(missing_angle, 1)
        if abs(missing_angle_rounded - round(missing_angle_rounded)) < 1e-6:
            # If it is effectively an integer, keep it as int
            missing_angle_rounded = int(missing_angle_rounded)

        answer_str = str(missing_angle_rounded)

        return {
            "question": prompt,
            "answer": answer_str,
            "metadata": {
                "n_sides": n_sides,
                "known_angles": known_angles,
                "sum_of_known_angles": sum(known_angles),
                "missing_angle_raw": missing_angle,
                "missing_angle_rounded": missing_angle_rounded,
                "total_interior_sum": total_sum,
            },
        }

    def _generate_valid_angles(self, rng: random.Random, n_sides: int, total_sum: int):
        """
        Generate (n_sides - 1) random angles in [min_angle, max_angle],
        ensuring the sum is strictly less than total_sum to keep a valid missing angle.
        We keep retrying until we find a valid set or reach a max attempt limit.
        """
        max_attempts = 100
        for _ in range(max_attempts):
            angles = []
            # We choose angles one by one
            for _ in range(n_sides - 1):
                angle = rng.randint(self.config.min_angle, self.config.max_angle)
                angles.append(float(angle))

            # Check if the sum is strictly less than total_sum
            if sum(angles) < total_sum:
                return angles

        # If we fail after max_attempts, raise an error
        raise ValueError(
            f"Could not generate valid angles for an {n_sides}-gon "
            f"with total sum {total_sum} within {max_attempts} attempts."
        )


# Register the dataset so it can be accessed similarly to the others
register_dataset("simple_geometry", SimpleGeometryDataset, SimpleGeometryConfig)