feat: add deleted_at field to workspace model (#7475)

* added impending_deletion workspace field

* gen docs

* update golden files

* added test

* PR comments

coderd/workspaces_internal_test.go

@@ -0,0 +1,82 @@
+package coderd
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/coderd/database"
+	"github.com/coder/coder/coderd/util/ptr"
+)
+
+func Test_calculateDeletingAt(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name      string
+		workspace database.Workspace
+		template  database.Template
+		expected  *time.Time
+	}{
+		{
+			name: "DeletingAt",
+			workspace: database.Workspace{
+				Deleted:    false,
+				LastUsedAt: time.Now().Add(time.Duration(-10) * time.Hour * 24), // 10 days ago
+			},
+			template: database.Template{
+				InactivityTTL: int64(9 * 24 * time.Hour), // 9 days
+			},
+			expected: ptr.Ref(time.Now().Add(time.Duration(-1) * time.Hour * 24)), // yesterday
+		},
+		{
+			name: "InactivityTTLUnset",
+			workspace: database.Workspace{
+				Deleted:    false,
+				LastUsedAt: time.Now().Add(time.Duration(-10) * time.Hour * 24),
+			},
+			template: database.Template{
+				InactivityTTL: 0,
+			},
+			expected: nil,
+		},
+		{
+			name: "DeletedWorkspace",
+			workspace: database.Workspace{
+				Deleted:    true,
+				LastUsedAt: time.Now().Add(time.Duration(-10) * time.Hour * 24),
+			},
+			template: database.Template{
+				InactivityTTL: int64(9 * 24 * time.Hour),
+			},
+			expected: nil,
+		},
+		{
+			name: "ActiveWorkspace",
+			workspace: database.Workspace{
+				Deleted:    true,
+				LastUsedAt: time.Now().Add(time.Duration(-5) * time.Hour), // 5 hours ago
+			},
+			template: database.Template{
+				InactivityTTL: int64(1 * 24 * time.Hour), // 1 day
+			},
+			expected: nil,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			found := calculateDeletingAt(tc.workspace, tc.template)
+			if tc.expected == nil {
+				require.Nil(t, found, "impending deletion should be nil")
+			} else {
+				require.NotNil(t, found)
+				require.WithinDuration(t, *tc.expected, *found, time.Second, "incorrect impending deletion")
+			}
+		})
+	}
+}