From 7b6452c695e408ecebfca1c9d810baf6eca03620 Mon Sep 17 00:00:00 2001
From: Eugene Blikh <bigbes@gmail.com>
Date: Tue, 28 Apr 2026 04:21:30 +0300
Subject: [PATCH] combat: NewEnemyShip layout

PH2 of combat task: enemy ship layout.

- ship.go: NewEnemyShip() returns same 5 rooms as NewPlayerShip
  with each GridX shifted +24 tiles. Pure data; no Ebitengine (IV1).
- ship_test.go: 2 tests covering room count and per-room shift
  (GridX +24, all other fields preserved).

Refs: docs/tasks/combat.md PH2
---
 ship.go      | 13 +++++++++++++
 ship_test.go | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 ship_test.go

diff --git a/ship.go b/ship.go
index 4b78b4986b3971fcb408351bf0983bd227c5011d..35d5338bc84c73a75093c7992128141bfdf3cb24 100644
--- a/ship.go
+++ b/ship.go
@@ -31,6 +31,19 @@ type Ship struct {
 	Rooms []Room
 }
 
+// NewEnemyShip returns a 5-room layout that mirrors NewPlayerShip but with
+// every room shifted +24 tiles along the X axis so the enemy ship sits on
+// the right half of the virtual screen.
+func NewEnemyShip() Ship {
+	player := NewPlayerShip()
+	rooms := make([]Room, len(player.Rooms))
+	for i, r := range player.Rooms {
+		r.GridX += 24
+		rooms[i] = r
+	}
+	return Ship{Rooms: rooms}
+}
+
 // NewPlayerShip returns a hard-coded 5-room placeholder layout:
 // Pilot front-left, Weapons mid-upper, Shields mid-center,
 // MedBay mid-lower, Engines rear-right.
diff --git a/ship_test.go b/ship_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..72bb4f35aa58dc904a889831d515806e76db6078
--- /dev/null
+++ b/ship_test.go
@@ -0,0 +1,48 @@
+package main
+
+import "testing"
+
+// TestNewEnemyShip_roomCount verifies that NewEnemyShip returns exactly 5 rooms.
+func TestNewEnemyShip_roomCount(t *testing.T) {
+	enemy := NewEnemyShip()
+	if len(enemy.Rooms) != 5 {
+		t.Fatalf("expected 5 rooms, got %d", len(enemy.Rooms))
+	}
+}
+
+// TestNewEnemyShip_shifted verifies that each enemy room has GridX shifted by +24
+// relative to the corresponding player room, while GridY/GridW/GridH/Role/Name
+// are unchanged.
+func TestNewEnemyShip_shifted(t *testing.T) {
+	player := NewPlayerShip()
+	enemy := NewEnemyShip()
+
+	if len(enemy.Rooms) != len(player.Rooms) {
+		t.Fatalf("room count mismatch: enemy %d, player %d", len(enemy.Rooms), len(player.Rooms))
+	}
+
+	for i := range player.Rooms {
+		p := player.Rooms[i]
+		e := enemy.Rooms[i]
+
+		wantGridX := p.GridX + 24
+		if e.GridX != wantGridX {
+			t.Errorf("rooms[%d] GridX = %d, want %d (player %d + 24)", i, e.GridX, wantGridX, p.GridX)
+		}
+		if e.GridY != p.GridY {
+			t.Errorf("rooms[%d] GridY = %d, want %d", i, e.GridY, p.GridY)
+		}
+		if e.GridW != p.GridW {
+			t.Errorf("rooms[%d] GridW = %d, want %d", i, e.GridW, p.GridW)
+		}
+		if e.GridH != p.GridH {
+			t.Errorf("rooms[%d] GridH = %d, want %d", i, e.GridH, p.GridH)
+		}
+		if e.Role != p.Role {
+			t.Errorf("rooms[%d] Role = %v, want %v", i, e.Role, p.Role)
+		}
+		if e.Name != p.Name {
+			t.Errorf("rooms[%d] Name = %q, want %q", i, e.Name, p.Name)
+		}
+	}
+}