# tools/geometry.py

from dataclasses import dataclass
import math


@dataclass
class Point:
    """Represents a 2D point in a Cartesian coordinate system."""

    x: float
    y: float


class Line:
    """Represents a finite line segment between two Points."""

    def __init__(self, p1: Point, p2: Point) -> None:
        self.p1 = p1
        self.p2 = p2

    def distance_to_point(self, point: Point) -> float:
        """
        Calculates the shortest distance from this line segment to a given point.
        Uses vector projection to find the closest point on the segment.
        """
        x1, y1 = self.p1.x, self.p1.y
        x2, y2 = self.p2.x, self.p2.y
        x3, y3 = point.x, point.y

        # If the line is actually just a single point
        if x1 == x2 and y1 == y2:
            return ((x1 - x3) ** 2 + (y1 - y3) ** 2) ** 0.5

        px, py = x2 - x1, y2 - y1
        norm = px * px + py * py

        # Calculate the projection scalar (u) of the point onto the line
        u = ((x3 - x1) * px + (y3 - y1) * py) / float(norm)

        # Clamp u to the [0, 1] range to ensure we stay on the line segment
        u = max(0.0, min(1.0, u))

        # Find the exact coordinates of the closest point on the segment
        closest_x = x1 + u * px
        closest_y = y1 + u * py

        # Return distance from the target point to the closest point
        dx, dy = closest_x - x3, closest_y - y3
        return (dx * dx + dy * dy) ** 0.5


class LineString:
    """Represents a path formed by a sequence of connected line segments."""

    def __init__(self, lines: list[list[float]]) -> None:
        if len(lines) < 2:
            raise ValueError("A LineString requires at least 2 coordinate pairs.")

        self.lineList: list[Line] = []
        for i in range(len(lines) - 1):
            p1 = Point(lines[i][0], lines[i][1])
            p2 = Point(lines[i + 1][0], lines[i + 1][1])
            self.lineList.append(Line(p1, p2))

    def distance_to(self, point: Point) -> float:
        """Calculates the minimum distance from the given point to the LineString."""
        # Cleanly check the distance to all segments and return the smallest one
        return min(line.distance_to_point(point) for line in self.lineList)

    def is_intersecting(self, point: Point) -> bool:
        """Checks if a given point lies exactly on the LineString (with tolerance)."""
        return math.isclose(self.distance_to(point), 0.0, abs_tol=1e-9)


class Polygon:
    """Represents a 2D shape enclosed by a series of connected points."""

    def __init__(self, points: list[list[float]]) -> None:
        self.listPoints: list[Point] = [Point(p[0], p[1]) for p in points]

    def contains(self, p: Point) -> bool:
        """
        Determines if a point is inside the Polygon using the Even-Odd rule.
        Includes an explicit check for points lying exactly on the boundary edges.
        """
        n = len(self.listPoints)
        if n < 3:
            return False

        inside = False
        j = n - 1
        for i in range(n):
            pi = self.listPoints[i]
            pj = self.listPoints[j]

            cross_product = (p.y - pi.y) * (pj.x - pi.x) - (p.x - pi.x) * (pj.y - pi.y)
            if math.isclose(cross_product, 0.0, abs_tol=1e-9):
                if min(pi.x, pj.x) <= p.x <= max(pi.x, pj.x) and min(
                    pi.y, pj.y
                ) <= p.y <= max(pi.y, pj.y):
                    return True

            if ((pi.y > p.y) != (pj.y > p.y)) and (
                p.x < (pj.x - pi.x) * (p.y - pi.y) / (pj.y - pi.y) + pi.x
            ):
                inside = not inside
            j = i

        return inside


class MultiPolygon:
    """Represents a collection of multiple separate Polygons."""

    def __init__(self, polygons: list) -> None:
        self.listPolygons: list[Polygon] = [Polygon(polygon[0]) for polygon in polygons]

    def contains(self, p: Point) -> bool:
        """Returns True if the point is inside ANY of the contained Polygons."""
        for polygon in self.listPolygons:
            if polygon.contains(p):
                return True
        return False


@dataclass
class Coordinate:
    """
    Custom type for the management of geographical coordinates.
    Provides utility to switch between lat/long and x/y point spaces.
    """

    lat: float
    long: float

    @property
    def tuple(self) -> tuple[float, float]:
        """Returns the coordinates as a (Latitude, Longitude) tuple."""
        return (self.lat, self.long)

    def to_Point(self, reversed: bool = False) -> Point:
        """
        Returns Coordinates mapped to a Cartesian Point.

        Args:
            reversed (bool): If True, switches orientation so x=long, y=lat.
                             Defaults to False (x=lat, y=long).
        """
        return Point(self.long, self.lat) if reversed else Point(self.lat, self.long)