Begin refactoring gui

This begins a big refactor of moving more code out of the Gui struct into contexts, controllers, and helpers. We also move some code into structs in the
gui package purely for the sake of better encapsulation

pkg/gui/context/commit_files_context.go

@@ -13,17 +13,16 @@ type CommitFilesContext struct {
 	*DynamicTitleBuilder
 }
 
-var _ types.IListContext = (*CommitFilesContext)(nil)
+var (
+	_ types.IListContext    = (*CommitFilesContext)(nil)
+	_ types.DiffableContext = (*CommitFilesContext)(nil)
+)
 
 func NewCommitFilesContext(
 	getModel func() []*models.CommitFile,
 	view *gocui.View,
 	getDisplayStrings func(startIdx int, length int) [][]string,
 
-	onFocus func(types.OnFocusOpts) error,
-	onRenderToMain func() error,
-	onFocusLost func(opts types.OnFocusLostOpts) error,
-
 	c *types.HelperCommon,
 ) *CommitFilesContext {
 	viewModel := filetree.NewCommitFileTreeViewModel(getModel, c.Log, c.UserConfig.Gui.ShowFileTree)
@@ -41,11 +40,7 @@ func NewCommitFilesContext(
 					Focusable:  true,
 					Transient:  true,
 				}),
-				ContextCallbackOpts{
-					OnFocus:        onFocus,
-					OnFocusLost:    onFocusLost,
-					OnRenderToMain: onRenderToMain,
-				}),
+				ContextCallbackOpts{}),
 			list:              viewModel,
 			getDisplayStrings: getDisplayStrings,
 			c:                 c,
@@ -61,3 +56,50 @@ func (self *CommitFilesContext) GetSelectedItemId() string {
 
 	return item.ID()
 }
+
+func (self *CommitFilesContext) GetDiffTerminals() []string {
+	return []string{self.GetRef().RefName()}
+}
+
+func (self *CommitFilesContext) renderToMain() error {
+	node := self.GetSelected()
+	if node == nil {
+		return nil
+	}
+
+	ref := self.GetRef()
+	to := ref.RefName()
+	from, reverse := self.c.Modes().Diffing.GetFromAndReverseArgsForDiff(ref.ParentRefName())
+
+	cmdObj := self.c.Git().WorkingTree.ShowFileDiffCmdObj(
+		from, to, reverse, node.GetPath(), false, self.c.State().GetIgnoreWhitespaceInDiffView(),
+	)
+	task := types.NewRunPtyTask(cmdObj.GetCmd())
+
+	pair := self.c.MainViewPairs().Normal
+	if node.File != nil {
+		pair = self.c.MainViewPairs().PatchBuilding
+	}
+
+	return self.c.RenderToMainViews(types.RefreshMainOpts{
+		Pair: pair,
+		Main: &types.ViewUpdateOpts{
+			Title: self.c.Tr.Patch,
+			Task:  task,
+		},
+		Secondary: secondaryPatchPanelUpdateOpts(self.c),
+	})
+}
+
+func secondaryPatchPanelUpdateOpts(c *types.HelperCommon) *types.ViewUpdateOpts {
+	if c.Git().Patch.PatchBuilder.Active() {
+		patch := c.Git().Patch.PatchBuilder.RenderAggregatedPatch(false)
+
+		return &types.ViewUpdateOpts{
+			Task:  types.NewRenderStringWithoutScrollTask(patch),
+			Title: c.Tr.CustomPatch,
+		}
+	}
+
+	return nil
+}