X-Git-Url: https://git.cworth.org/git?p=empires-server;a=blobdiff_plain;f=game.js;h=86a0e70b96f311dc2133898e679c1afa619406a7;hp=20cd2411e2275ff8aef51e1c35a3772931815b6b;hb=2690233f317b87e7336b0404ae711837e726d5cf;hpb=ea14cbbefb26afd558aff8329d92f1a7b9442bac

diff --git a/game.js b/game.js
index 20cd241..86a0e70 100644
--- a/game.js
+++ b/game.js
@@ -1,30 +1,222 @@
+const no_team = { name: "" };
+
+/* A single player can have multiple connections, (think, multiple
+ * browser windows with a common session cookie). */
+class Player {
+  constructor(id, session_id, name, connection) {
+    this.id = id;
+    this.session_id = session_id;
+    this.name = name;
+    this.connections = [connection];
+    this.team = no_team;
+  }
+
+  add_connection(connection) {
+    /* Don't add a duplicate connection if this player already has it. */
+    for (let c of this.connections) {
+      if (c === connection)
+        return;
+    }
+
+    this.connections.push(connection);
+  }
+
+  /* Returns the number of remaining connections after this one is removed. */
+  remove_connection(connection) {
+    this.connections.filter(c => c !== connection);
+    return this.connections.length;
+  }
+
+  /* Send a string to all connections for this player. */
+  send(data) {
+    this.connections.forEach(connection => connection.write(data));
+  }
+
+  info_json() {
+    return JSON.stringify({
+      id: this.id,
+      name: this.name,
+      team: this.team.name,
+      score: this.score
+    });
+  }
+}
+
 /* Base class providing common code for game engine implementations. */
 class Game {
-  constructor(name) {
-    this.name = name;
-    this.clients = [];
-    this.next_client_id = 1;
+  constructor(id) {
+    this.id = id;
+    this.players = [];
+    this.players_by_session = {};
+    this.next_player_id = 1;
+    this.teams = [];
+    this.state = {
+      team_to_play: no_team
+    };
+    this.first_move = true;
+
+    /* Send a comment to every connected client every 15 seconds. */
+    setInterval(() => {this.broadcast_string(":");}, 15000);
+  }
+
+  /* Suport for game meta-data.
+   *
+   * What we want here is an effectively static field that is
+   * accessible through either the class name (SomeGame.meta) or an
+   * instance (some_game.meta). To pull this off we do keep two copies
+   * of the data. But the game classes can just set SomeGame.meta once
+   * and then reference it either way.
+   */
+  static set meta(data) {
+    /* This allows class access (SomeGame.meta) via the get method below. */
+    this._meta = data;
+
+    /* While this allows access via an instance (some_game.meta). */
+    this.prototype.meta = data;
+  }
+
+  static get meta() {
+    return this._meta;
   }
 
-  add_client(response) {
-    const id = this.next_client_id;
-    this.clients.push({id: id,
-                       response: response});
-    this.next_client_id++;
+  /* Just performs some checks for whether a move is definitely not
+   * legal (such as not the player's turn). A child class is expected
+   * to override this (and call super.add_move early!) to implement
+   * the actual logic for a move. */
+  add_move(player, move) {
 
-    return id;
+    /* The checks here don't apply on the first move. */
+    if (! this.first_move) {
+
+      /* Discard any move asserting to be the first move if it's no
+       * longer the first move. This resolves the race condition if
+       * multiple players attempt to make the first move. */
+      if (move.assert_first_move) {
+        return { legal: false,
+                 message: "Your opponent beat you to the first move" };
+      }
+
+      /* Cannot move if you are not on a team. */
+      if (player.team === no_team)
+      {
+        return { legal: false,
+                 message: "You must be on a team to take a turn" };
+      }
+
+      /* Cannot move if it's not this player's team's turn. */
+      if (player.team !== this.state.team_to_play)
+      {
+        return { legal: false,
+                 message: "It's not your turn to move" };
+      }
+    }
+
+    return { legal: true };
   }
 
-  remove_client(id) {
-    this.clients = this.clients.filter(client => client.id !== id);
+  /* Assign team only if player is unassigned.
+   * Return true if assignment made, false otherwise. */
+  assign_player_to_team_perhaps(player, team)
+  {
+    if (player.team !== no_team)
+      return false;
+
+    player.team = team;
+    this.broadcast_event("player-update", player.info_json());
+
+    return true;
   }
 
-  /* Send a string to all clients */
+  /* This function is called after the child add_move has returned
+   * 'result' so that any generic processing can happen.
+   *
+   * In particular, we assign teams for a two-player game where a
+   * player assumed a team by making the first move. */
+  post_move(player, result)
+  {
+    if (this.first_move && result.legal) {
+      this.first_move = false;
+
+      this.assign_player_to_team_perhaps(player, this.teams[0]);
+
+      /* Yes, start at 1 to skip teams[0] which we just assigned. */
+      for (let i = 1; i < this.teams.length; i++) {
+        const other = this.players.find(p => (p !== player) && (p.team === no_team));
+        if (!other)
+          return;
+        this.assign_player_to_team_perhaps(other, this.teams[i]);
+      }
+    }
+  }
+
+  add_player(session, connection) {
+    /* First see if we already have a player object for this session. */
+    const existing = this.players_by_session[session.id];
+    if (existing) {
+      existing.add_connection(connection);
+      return existing;
+    }
+
+    /* No existing player. Add a new one. */
+    const id = this.next_player_id;
+    let nickname = session.nickname;
+    if (nickname === "")
+      nickname = "Guest";
+    const nickname_orig = nickname;
+
+    /* Ensure we don't have a name collision with a previous player. */
+    let unique_suffix = 1;
+    while (this.players.find(player => player.name === nickname))
+    {
+      nickname = `${nickname_orig}${unique_suffix.toString().padStart(2, '0')}`;
+      unique_suffix++;
+    }
+
+    const player = new Player(id, session.id, nickname, connection);
+
+    /* Broadcast before adding player to list (to avoid announcing the
+     * new player to itself). */
+    const player_data = JSON.stringify({ id: player.id, name: player.name });
+    this.broadcast_event("player-enter", player_data);
+
+    this.players.push(player);
+    this.players_by_session[session.id] = player;
+    this.next_player_id++;
+
+    /* After adding the player to the list, and if we are already past
+     * the first move, assign this player to the first team that
+     * doesn't already have a player assigned (if any). */
+    if (! this.first_move) {
+      const have_players = Array(this.teams.length).fill(false);
+      this.players.forEach(p => {
+        if (p.team.id !== undefined)
+          have_players[p.team.id] = true;
+      });
+      const first_empty = have_players.findIndex(i => i === false);
+      this.assign_player_to_team_perhaps(player, this.teams[first_empty]);
+    }
+
+    return player;
+  }
+
+  /* Drop a connection object from a player, and if it's the last one,
+   * then drop that player from the game's list of players. */
+  remove_player_connection(player, connection) {
+    const remaining = player.remove_connection(connection);
+    if (remaining === 0) {
+      const player_data = JSON.stringify({ id: player.id });
+      this.players.filter(p => p !== player);
+      delete this.players_by_session[player.session_id];
+      this.broadcast_event("player-exit", player_data);
+    }
+  }
+
+  /* Send a string to all players */
   broadcast_string(str) {
-    this.clients.forEach(client => client.response.write(str + '\n'));
+    this.players.forEach(player => player.send(str + '\n'));
   }
 
-  /* Send an event to all clients.
+  /* Send an event to all players.
    *
    * An event has both a declared type and a separate data block.
    * It also ends with two newlines (to mark the end of the event).
@@ -33,6 +225,10 @@ class Game {
     this.broadcast_string(`event: ${type}\ndata: ${data}\n`);
   }
 
+  broadcast_event_object(type, obj) {
+    this.broadcast_event(type, JSON.stringify(obj));
+  }
+
   handle_events(request, response) {
     /* These headers will keep the connection open so we can stream events. */
     const headers = {
@@ -42,13 +238,80 @@ class Game {
     };
     response.writeHead(200, headers);
 
-    /* Add this new client to our list of clients. */
-    const id = this.add_client(response);
+    /* Add this new player. */
+    const player = this.add_player(request.session, response);
 
     /* And queue up cleanup to be triggered on client close. */
     request.on('close', () => {
-      this.remove_client(id);
+      this.remove_player_connection(player, response);
     });
+
+    /* Give the client the game-info event. */
+    const game_info_json = JSON.stringify({
+      id: this.id,
+      url: `${request.protocol}://${request.hostname}/${this.id}`
+    });
+    response.write(`event: game-info\ndata: ${game_info_json}\n\n`);
+
+    /* And the player-info event. */
+    response.write(`event: player-info\ndata: ${player.info_json()}\n\n`);
+
+    /* As well as player-enter events for all existing players. */
+    this.players.filter(p => p !== player).forEach(p => {
+      response.write(`event: player-enter\ndata: ${p.info_json()}\n\n`);
+    });
+
+    /* Finally, if this game class has a "state" property, stream that
+     * current state to the client. */
+    if (this.state) {
+      const state_json = JSON.stringify(this.state);
+      response.write(`event: game-state\ndata: ${state_json}\n\n`);
+    }
+  }
+
+  handle_player(request, response) {
+    const player = this.players_by_session[request.session.id];
+    const name = request.body.name;
+    const team_name = request.body.team;
+    var updated = false;
+    if (! player) {
+      response.sendStatus(404);
+      return;
+    }
+
+    if (name && (player.name !== name)) {
+      player.name = name;
+
+      /* In addition to setting the name within this game's player
+       * object, also set the name in the session. */
+      request.session.nickname = name;
+      request.session.save();
+
+      updated = true;
+    }
+
+    if (team_name !== null && (player.team.name !== team_name))
+    {
+      if (team_name === "") {
+        player.team = no_team;
+        updated = true;
+      } else {
+        const index = this.teams.findIndex(t => t.name === team_name);
+        if (index >= 0) {
+          player.team = this.teams[index];
+          updated = true;
+        }
+      }
+    }
+
+    if (updated)
+      this.broadcast_event("player-update", player.info_json());
+
+    response.send("");
+  }
+
+  broadcast_move(move) {
+    this.broadcast_event("move", JSON.stringify(move));
   }
 
 }