import math
from abc import ABC, abstractmethod
from f02_1_flight_lifecycle_manager import CameraParameters

class IGSDCalculator(ABC):
    @abstractmethod
    def compute_gsd(self, altitude: float, camera_params: CameraParameters) -> float: pass
    @abstractmethod
    def altitude_to_scale(self, altitude: float, focal_length: float) -> float: pass
    @abstractmethod
    def meters_per_pixel(self, lat: float, zoom: int) -> float: pass
    @abstractmethod
    def gsd_from_camera(self, altitude: float, focal_length: float, sensor_width: float, image_width: int) -> float: pass

class GSDCalculator(IGSDCalculator):
    """H02: Ground Sampling Distance computations for altitude and coordinate systems."""
    def compute_gsd(self, altitude: float, camera_params: CameraParameters) -> float:
        w = camera_params.resolution.get("width", 1920)
        return self.gsd_from_camera(altitude, camera_params.focal_length_mm, camera_params.sensor_width_mm, w)

    def altitude_to_scale(self, altitude: float, focal_length: float) -> float:
        if focal_length <= 0: return 1.0
        return altitude / focal_length

    def meters_per_pixel(self, lat: float, zoom: int) -> float:
        return 156543.03392 * math.cos(math.radians(lat)) / (2 ** zoom)

    def gsd_from_camera(self, altitude: float, focal_length: float, sensor_width: float, image_width: int) -> float:
        if focal_length <= 0 or image_width <= 0: return 0.0
        return (altitude * sensor_width) / (focal_length * image_width)