frontline

theater/frontline.py

@@ -1,44 +1,199 @@
 """Battlefield front lines."""
-from typing import Tuple
+from __future__ import annotations
+from dataclasses import dataclass
+
+import logging
+
+from itertools import tee
+from typing import Tuple, List, Union, Dict
 
 from dcs.mapping import Point
-from . import ControlPoint, MissionTarget
+
+from .controlpoint import ControlPoint, MissionTarget
+
+Numeric = Union[int, float]
 
 # TODO: Dedup by moving everything to using this class.
 FRONTLINE_MIN_CP_DISTANCE = 5000
 
 
-def compute_position(control_point_a: ControlPoint,
-                     control_point_b: ControlPoint) -> Point:
-    a = control_point_a.position
-    b = control_point_b.position
-    attack_heading = a.heading_between_point(b)
-    attack_distance = a.distance_to_point(b)
-    middle_point = a.point_from_heading(attack_heading, attack_distance / 2)
+def pairwise(iterable):
+    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+    a, b = tee(iterable)
+    next(b, None)
+    return zip(a, b)
 
-    strength_delta = float(control_point_a.base.strength -
-                           control_point_b.base.strength)
-    position = middle_point.point_from_heading(attack_heading,
-                                               strength_delta *
-                                               attack_distance / 2 -
-                                               FRONTLINE_MIN_CP_DISTANCE)
-    return position
+
+@dataclass
+class ComplexFrontLine:
+    """
+    Stores data necessary for building a multi-segment frontline.
+    "points" should be ordered from closest to farthest distance originating from start_cp.position
+    """
+
+    start_cp: ControlPoint
+    points: List[Point]
+    # control_points: List[ControlPoint]
+
+
+@dataclass
+class FrontLineSegment:
+    """
+    Describes a line segment of a FrontLine
+    """
+
+    point_a: Point
+    point_b: Point
+
+    @property
+    def attack_heading(self) -> Numeric:
+        return self.point_a.heading_between_point(self.point_b)
+
+    @property
+    def attack_distance(self) -> Numeric:
+        return self.point_a.distance_to_point(self.point_b)
 
 
 class FrontLine(MissionTarget):
     """Defines a front line location between two control points.
-
     Front lines are the area where ground combat happens.
+    Overwrites the entirety of MissionTarget __init__ method to allow for
+    dynamic position calculation.
     """
 
-    def __init__(self, control_point_a: ControlPoint,
-                 control_point_b: ControlPoint) -> None:
-        super().__init__(f"Front line {control_point_a}/{control_point_b}",
-                         compute_position(control_point_a, control_point_b))
+    def __init__(
+        self,
+        control_point_a: ControlPoint,
+        control_point_b: ControlPoint,
+        frontline_data: Dict[str, ComplexFrontLine],
+    ) -> None:
         self.control_point_a = control_point_a
         self.control_point_b = control_point_b
+        self.segments: List[FrontLineSegment] = []
+        self._build_segments(frontline_data)
+        self.name = f"Front line {control_point_a}/{control_point_b}"
+
+    @property
+    def position(self):
+        return self._calculate_position()
 
     @property
     def control_points(self) -> Tuple[ControlPoint, ControlPoint]:
         """Returns a tuple of the two control points."""
         return self.control_point_a, self.control_point_b
+
+    @property
+    def middle_point(self):
+        self.point_from_a(self.attack_distance / 2)
+
+    @property
+    def attack_distance(self):
+        return sum(i.attack_distance for i in self.segments)
+
+    @property
+    def attack_heading(self):
+        return self.active_segment.attack_heading
+
+    @property
+    def active_segment(self) -> FrontLineSegment:
+        """The FrontLine segment where there can be an active conflict"""
+        if self._position_distance <= self.segments[0].attack_distance:
+            return self.segments[0]
+
+        remaining_dist = self._position_distance
+        for segment in self.segments:
+            if remaining_dist <= segment.attack_distance:
+                return segment
+            else:
+                remaining_dist -= segment.attack_distance
+        logging.error(
+            "Frontline attack distance is greater than the sum of its segments"
+        )
+        return self.segments[0]
+
+    @property
+    def _position_distance(self) -> float:
+        """
+        The distance from point a where the conflict should occur
+        according to the current strength of each control point
+        """
+        total_strength = (
+            self.control_point_a.base.strength + self.control_point_b.base.strength
+        )
+        if total_strength == 0:
+            return self._adjust_for_min_dist(0)
+        strength_pct = self.control_point_a.base.strength / total_strength
+        return self._adjust_for_min_dist(strength_pct * self.attack_distance)
+
+    def _calculate_position(self) -> Point:
+        """
+        The position where the conflict should occur
+        according to the current strength of each control point.
+        """
+        return self.point_from_a(self._position_distance)
+
+    def _build_segments(self, frontline_data: Dict[str, ComplexFrontLine]) -> None:
+        control_point_ids = "|".join(
+            [str(self.control_point_a.id), str(self.control_point_b.id)]
+        )
+        reversed_cp_ids = "|".join(
+            [str(self.control_point_b.id), str(self.control_point_a.id)]
+        )
+        complex_frontlines = frontline_data
+        if (complex_frontlines) and (
+            (control_point_ids in complex_frontlines)
+            or (reversed_cp_ids in complex_frontlines)
+        ):
+            # The frontline segments must be stored in the correct order for the distance algorithms to work.
+            # The points in the frontline are ordered from the id before the | to the id after.
+            # First, check if control point id pair matches in order, and create segments if a match is found.
+            if control_point_ids in complex_frontlines:
+                point_pairs = pairwise(complex_frontlines[control_point_ids].points)
+                for i in point_pairs:
+                    self.segments.append(FrontLineSegment(i[0], i[1]))
+            # Check the reverse order and build in reverse if found.
+            elif reversed_cp_ids in complex_frontlines:
+                point_pairs = pairwise(
+                    reversed(complex_frontlines[reversed_cp_ids].points)
+                )
+                for i in point_pairs:
+                    self.segments.append(FrontLineSegment(i[0], i[1]))
+        # If no complex frontline has been configured, fall back to the old straight line method.
+        else:
+            self.segments.append(
+                FrontLineSegment(
+                    self.control_point_a.position, self.control_point_b.position
+                )
+            )
+
+    def _adjust_for_min_dist(self, distance: Numeric) -> Numeric:
+        """
+        Ensures the frontline conflict is never located within the minimum distance
+        constant of either end control point.
+        """
+        if (distance > self.attack_distance / 2) and (
+            distance + FRONTLINE_MIN_CP_DISTANCE > self.attack_distance
+        ):
+            distance = self.attack_distance - FRONTLINE_MIN_CP_DISTANCE
+        elif (distance < self.attack_distance / 2) and (
+            distance < FRONTLINE_MIN_CP_DISTANCE
+        ):
+            distance = FRONTLINE_MIN_CP_DISTANCE
+        return distance
+
+    def point_from_a(self, distance: Numeric) -> Point:
+        """
+        Returns a point {distance} away from control_point_a along the frontline segments.
+        """
+        if distance < self.segments[0].attack_distance:
+            return self.control_point_a.position.point_from_heading(
+                self.segments[0].attack_heading, distance
+            )
+        remaining_dist = distance
+        for segment in self.segments:
+            if remaining_dist < segment.attack_distance:
+                return self.control_point_a.position.point_from_heading(
+                    segment.attack_heading, remaining_dist
+                )
+            else:
+                remaining_dist -= segment.attack_distance