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/controllers/helpers/patch_building_helper.go

@@ -4,6 +4,7 @@ import (
 	"github.com/jesseduffield/lazygit/pkg/commands"
 	"github.com/jesseduffield/lazygit/pkg/commands/types/enums"
 	"github.com/jesseduffield/lazygit/pkg/gui/context"
+	"github.com/jesseduffield/lazygit/pkg/gui/patch_exploring"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
 )
 
@@ -60,3 +61,59 @@ func (self *PatchBuildingHelper) Reset() error {
 	// refreshing the current context so that the secondary panel is hidden if necessary.
 	return self.c.PostRefreshUpdate(self.c.CurrentContext())
 }
+
+func (self *PatchBuildingHelper) RefreshPatchBuildingPanel(opts types.OnFocusOpts) error {
+	selectedLineIdx := -1
+	if opts.ClickedWindowName == "main" {
+		selectedLineIdx = opts.ClickedViewLineIdx
+	}
+
+	if !self.git.Patch.PatchBuilder.Active() {
+		return self.Escape()
+	}
+
+	// get diff from commit file that's currently selected
+	path := self.contexts.CommitFiles.GetSelectedPath()
+	if path == "" {
+		return nil
+	}
+
+	ref := self.contexts.CommitFiles.CommitFileTreeViewModel.GetRef()
+	to := ref.RefName()
+	from, reverse := self.c.Modes().Diffing.GetFromAndReverseArgsForDiff(ref.ParentRefName())
+	diff, err := self.git.WorkingTree.ShowFileDiff(from, to, reverse, path, true, self.c.State().GetIgnoreWhitespaceInDiffView())
+	if err != nil {
+		return err
+	}
+
+	secondaryDiff := self.git.Patch.PatchBuilder.RenderPatchForFile(path, false, false)
+	if err != nil {
+		return err
+	}
+
+	context := self.contexts.CustomPatchBuilder
+
+	oldState := context.GetState()
+
+	state := patch_exploring.NewState(diff, selectedLineIdx, oldState, self.c.Log)
+	context.SetState(state)
+	if state == nil {
+		return self.Escape()
+	}
+
+	mainContent := context.GetContentToRender(true)
+
+	self.contexts.CustomPatchBuilder.FocusSelection()
+
+	return self.c.RenderToMainViews(types.RefreshMainOpts{
+		Pair: self.c.MainViewPairs().PatchBuilding,
+		Main: &types.ViewUpdateOpts{
+			Task:  types.NewRenderStringWithoutScrollTask(mainContent),
+			Title: self.c.Tr.Patch,
+		},
+		Secondary: &types.ViewUpdateOpts{
+			Task:  types.NewRenderStringWithoutScrollTask(secondaryDiff),
+			Title: self.c.Tr.CustomPatch,
+		},
+	})
+}