From c74f92cd80a537e3e27a583eda5bc4d35bee7e3d Mon Sep 17 00:00:00 2001
From: Michael Enion <caewok_2000@yahoo.com>
Date: Fri, 5 Apr 2024 12:23:33 -0700
Subject: [PATCH] Redo elevationAtLocation to handle force-to-ground

---
 scripts/Ruler.js             |  1 +
 scripts/settings.js          |  4 ++-
 scripts/terrain_elevation.js | 57 ++++++++++++++++++++++++++----------
 3 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/scripts/Ruler.js b/scripts/Ruler.js
index 45229b9..5828aee 100644
--- a/scripts/Ruler.js
+++ b/scripts/Ruler.js
@@ -544,6 +544,7 @@ function segmentGridHalfIntersection(gridCoords, a, b) {
  */
 function _onDragStart(wrapped, event) {
   Settings.FORCE_TO_GROUND = false;
+  this._userElevationIncrements = 0;
   this._unsnap = event.shiftKey || canvas.scene.grid.type === CONST.GRID_TYPES.GRIDLESS;
   return wrapped(event);
 }
diff --git a/scripts/settings.js b/scripts/settings.js
index d195953..e3ce0f1 100644
--- a/scripts/settings.js
+++ b/scripts/settings.js
@@ -288,8 +288,10 @@ export class Settings extends ModuleSettingsAbstract {
         { key: "KeyG" }
       ],
       onDown: _context => {
-        if ( !canvas.controls.ruler.active ) return;
+        const ruler = canvas.controls.ruler;
+        if ( !ruler.active ) return;
         this.FORCE_TO_GROUND = !this.FORCE_TO_GROUND;
+        ruler.measure(ruler.destination, { force: true });
         ui.notifications.info(`Ruler measure to ground ${this.FORCE_TO_GROUND ? "enabled" : "disabled"}.`);
       },
       precedence: CONST.KEYBINDING_PRECEDENCE.NORMAL
diff --git a/scripts/terrain_elevation.js b/scripts/terrain_elevation.js
index b753583..23cf674 100644
--- a/scripts/terrain_elevation.js
+++ b/scripts/terrain_elevation.js
@@ -42,7 +42,7 @@ elevationAtLocation -- all ruler types
 Used by ruler to get elevation at waypoints and at the end of the ruler.
 */
 
-import { MODULES_ACTIVE } from "./const.js";
+import { MODULES_ACTIVE, MOVEMENT_TYPES } from "./const.js";
 import { Settings } from "./settings.js";
 import { Point3d } from "./geometry/3d/Point3d.js";
 
@@ -114,23 +114,50 @@ export function elevationAtLocation(location, token) {
   token ??= this._getMovementToken();
   const isTokenRuler = Settings.get(Settings.KEYS.TOKEN_RULER.ENABLED)
     && ui.controls.activeControl === "token"
-    && ui.controls.activeTool === "select";
+    && ui.controls.activeTool === "select"
+    && token;
+
+  // 1. If forcing to ground, always use the terrain elevation.
+
+  /* If not forcing to ground:
+  2. No move token
+    --> Default: Use origin elevation
+    --> If hovering over a token, use that token's elevation
+  3. Move token, normal ruler
+    --> Default: Use move token elevation
+    --> If hovering over a token, use that token's elevation
+  4. Token ruler
+    --> Default: Use move token elevation
+    --> If token is walking, use terrain elevation
+  */
+  const terrainElevationFn = () => this.constructor.terrainElevationAtLocation(location, {
+    movementToken: token,
+    startingElevation: this.originElevation
+  });
 
-  // If at the token, use the token's elevation.
-  if ( token && location.almostEqual(token.center) ) return token.elevationE;
-
-  // If normal ruler and not prioritizing the token elevation, use elevation of other tokens at this point.
-  if ( !isTokenRuler ) {
-    const maxTokenE = retrieveVisibleTokens()
-      .filter(t => t.constrainedTokenBorder.contains(location.x, location.y))
-      .reduce((e, t) => Math.max(t.elevationE, e), Number.NEGATIVE_INFINITY);
-    if ( isFinite(maxTokenE) ) return maxTokenE;
+  // #1 Forcing to ground
+  if ( Settings.FORCE_TO_GROUND ) return terrainElevationFn();
+
+  // #4 token ruler
+  if ( isTokenRuler ) {
+    if ( token.movementType === MOVEMENT_TYPES.WALK ) return terrainElevationFn();
+    return token.elevationE;
   }
 
-  // Use the terrain at this point.
-  return this.constructor.terrainElevationAtLocation(location, {
-    movementToken: token,
-    startingElevation: this.originElevation });
+  // If at the token, use the token's elevation.
+  // if ( token && location.almostEqual(token.center) ) return token.elevationE;
+
+  // Check for other tokens at destination and use that elevation.
+  const maxTokenE = retrieveVisibleTokens()
+    .filter(t => t.constrainedTokenBorder.contains(location.x, location.y))
+    .reduce((e, t) => Math.max(t.elevationE, e), Number.NEGATIVE_INFINITY);
+  if ( isFinite(maxTokenE) ) return maxTokenE; // #2 or #3
+
+  // #3 move token
+  if ( token ) return token.elevationE;
+
+  // #2 no move token
+  return this.originElevation;
 }
 
 // ----- NOTE: HELPER FUNCTIONS ----- //