Add in choose action phase

src/lib.rs

@@ -258,6 +258,18 @@ impl Game {
         }
     }
 
+    pub fn action(&mut self, agents: &[&dyn Agent]) -> CoupResult<Phase> {
+        let move_ = agents[self.turn].choose_move(self);
+        if move_.action.is_targeted() && move_.target.is_none() {
+            Err("Targeted action with no target")
+        } else if move_.action.coin_cost() > self.players[self.turn].coins {
+            Err("Cannot afford action")
+        } else {
+            Ok(Phase::ActionChallenge(move_))
+        }
+        // TODO there're definately more cases, find and cover these
+    }
+
     pub fn action_challenge(&mut self, move_: Move, agents: &[&dyn Agent]) -> CoupResult<Phase> {
         match move_.action.challenger_mode() {
             ResMode::None => Ok(Phase::Block(move_)),
@@ -410,6 +422,8 @@ pub enum Phase {
 
 /// An interface to a game to make strategic decisions.
 pub trait Agent : fmt::Debug {
+    /// What move should the agent take?
+    fn choose_move(&self, game: &Game) -> Move;
     /// Should the agent challenge the action?
     fn should_action_challenge(&self, game: &Game, move_: Move) -> bool;
     /// Which [card](Card) the agent wishes to use to block the current action.

src/test.rs

@@ -3,6 +3,9 @@ use super::*;
 #[derive(Debug)]
 struct DummyAgent(Card, Option<Card>, bool);
 impl Agent for DummyAgent {
+    fn choose_move(&self, _game: &Game) -> Move {
+        unimplemented!();
+    }
     fn should_action_challenge(&self, _game: &Game, _move: Move) -> bool {
         self.2
     }