"""Demo point cloud generation (mirrors generateDemoPoints in mainwindow.cpp)."""

from __future__ import annotations

import math
import random
from typing import Any


def generate_demo_points(surface_type: str, count: int = 350) -> list[list[float]]:
    points: list[list[float]] = []
    rng = random.Random()

    for _ in range(count):
        if surface_type == "Дно реки + труба":
            if rng.random() < 0.35:
                angle = rng.random() * 2.0 * math.pi
                y = rng.random() * 2.6 - 1.3
                pipe_radius = 0.22
                jitter = rng.random() * 0.02 - 0.01
                radial = pipe_radius + jitter
                x = 0.0 + radial * math.cos(angle)
                z = -0.62 + radial * math.sin(angle)
            else:
                x = rng.random() * 4.0 - 2.0
                y = rng.random() * 3.0 - 1.5
                waviness = 0.11 * math.cos(2.2 * y)
                channel = 0.08 * x * x
                noise = rng.random() * 0.04 - 0.02
                z = -0.45 + channel + waviness + noise
        elif surface_type == "Тор":
            u = rng.random() * 2.0 * math.pi
            v = rng.random() * 2.0 * math.pi
            major_r = 1.0
            minor_r = 0.35
            jitter = rng.random() * 0.02 - 0.01
            radial = minor_r + jitter
            x = (major_r + radial * math.cos(v)) * math.cos(u)
            y = (major_r + radial * math.cos(v)) * math.sin(u)
            z = radial * math.sin(v)
        elif surface_type == "Волна":
            x = rng.random() * 2.4 - 1.2
            y = rng.random() * 2.4 - 1.2
            noise = rng.random() * 0.03 - 0.015
            z = 0.35 * math.sin(2.5 * x) * math.cos(2.5 * y) + noise
        else:
            u = rng.random() * 2.0 - 1.0
            theta = rng.random() * 2.0 * math.pi
            r = 1.0 + rng.random() * 0.08 - 0.04
            s = math.sqrt(max(0.0, 1.0 - u * u))
            x = r * s * math.cos(theta)
            y = r * s * math.sin(theta)
            z = r * u
        points.append([x, y, z])
    return points


DEMO_SURFACE_TYPES = ["Сфера", "Тор", "Волна", "Дно реки + труба"]


def demo_payload(surface_type: str, count: int = 350) -> dict[str, Any]:
    if surface_type not in DEMO_SURFACE_TYPES:
        surface_type = "Сфера"
    points = generate_demo_points(surface_type, count)
    return {
        "surfaceType": surface_type,
        "pointCount": len(points),
        "points": points,
        "sourceLabel": f"demo: {surface_type}",
    }