From 93b270c5f331e2561d6b421767cd178c49efb504 Mon Sep 17 00:00:00 2001
From: Michael Smith <m@michaelsmith.be>
Date: Sat, 13 Nov 2021 00:44:35 +0100
Subject: [PATCH] Fireball constants

---
 src/main.rs | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index 6654bd0..ae93c08 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -53,6 +53,8 @@ const LIGHTNING_DAMAGE: i32 = 40;
 const LIGHTNING_RANGE: i32 = 5;
 const CONFUSE_RANGE: i32 = 8;
 const CONFUSE_NUM_TURNS: i32 = 10;
+const FIREBALL_RADIUS: i32 = 3;
+const FIREBALL_DAMAGE: i32 = 12;
 
 struct Tcod {
   root: Root,
@@ -164,6 +166,11 @@ impl Object {
       }
     }
   }
+
+  // Return the distance to some coordinates
+  pub fn distance(&self, x: i32, y: i32) -> f32 {
+    (((x - self.x).pow(2) + (y - self.y).pow(2)) as f32).sqrt()
+  }
 }
 
 #[derive(Clone, Copy, Debug)]
@@ -918,6 +925,44 @@ fn cast_confuse(
   }
 }
 
+fn cast_fireball(
+  _inventory_id: usize,
+  tcod: &mut Tcod,
+  game: &mut Game,
+  objects: &mut [Object],
+) -> UseResult {
+  // Ask the player for a target tile to throw a fireball at
+  game.messages.add(
+    "Left-click a target tile for the fireball, or right-click to cancel.",
+    LIGHT_CYAN,
+  );
+  let (x, y) = match target_tile(tcod, game, objects, None) {
+    Some(tile_pos) => tile_pos,
+    None => return UseResult::Canceled,
+  };
+  game.messages.add(
+    format!(
+      "The fireball explodes, burning everything within {} tiles!",
+      FIREBALL_RADIUS
+    ),
+    ORANGE,
+  );
+
+  for obj in objects {
+    if obj.distance(x, y) <= FIREBALL_RADIUS as f32 && obj.fighter.is_some() {
+      game.messages.add(
+        format!(
+          "The {} gets burned for {} hit points.",
+          obj.name, FIREBALL_DAMAGE
+        ),
+        ORANGE,
+      );
+      obj.take_damage(FIREBALL_DAMAGE, game);
+    }
+  }
+  UseResult::UsedUp
+}
+
 // Find closest enemy, up to a maximum range, and in the player's FOV
 fn closest_monster(tcod: &Tcod, objects: &[Object], max_range: i32) -> Option<usize> {
   let mut closest_enemy = None;
@@ -942,6 +987,44 @@ fn closest_monster(tcod: &Tcod, objects: &[Object], max_range: i32) -> Option<us
   closest_enemy
 }
 
+// Return the position of a tile left-clicked in player's FOV (optionally in a
+// range), or (None, None) if right-clicked.
+fn target_tile(
+  tcod: &mut Tcod,
+  game: &mut Game,
+  objects: &[Object],
+  max_range: Option<f32>,
+) -> Option<(i32, i32)> {
+  use tcod::input::KeyCode::Escape;
+
+  loop {
+    // Render the screen. This erases the inventory and shows the names of
+    // objects under the mouse.
+    tcod.root.flush();
+    let event = input::check_for_event(input::KEY_PRESS | input::MOUSE).map(|e| e.1);
+    match event {
+      Some(Event::Mouse(m)) => tcod.mouse = m,
+      Some(Event::Key(k)) => tcod.key = k,
+      None => tcod.key = Default::default(),
+    }
+    render_all(tcod, game, objects, false);
+
+    let (x, y) = (tcod.mouse.cx as i32, tcod.mouse.cy as i32);
+
+    // Accept the target if the player clicked in FOV, and in case a range
+    // is specified, if it's in that range
+    let in_fov = (x < MAP_WIDTH) && (y < MAP_HEIGHT) && tcod.fov.is_in_fov(x, y);
+    let in_range = max_range.map_or(true, |range| objects[PLAYER].distance(x, y) <= range);
+    if tcod.mouse.lbutton_pressed && in_fov && in_range {
+      return Some((x, y));
+    }
+
+    if tcod.mouse.rbutton_pressed || tcod.key.code == Escape {
+      return None; // Cancel if the player right-clicked or pressed escape.
+    }
+  }
+}
+
 fn render_all(tcod: &mut Tcod, game: &mut Game, objects: &[Object], fov_recompute: bool) {
   if fov_recompute {
     let player = &objects[PLAYER];