package helpers

import (
	"fmt"

	"github.com/jesseduffield/lazygit/pkg/gui/context"
	"github.com/jesseduffield/lazygit/pkg/gui/filetree"
	"github.com/jesseduffield/lazygit/pkg/gui/types"
)

type CommitFilesHelper struct {
	c *HelperCommon

	patchBuildingHelper *PatchBuildingHelper
}

func NewCommitFilesHelper(c *HelperCommon, patchBuildingHelper *PatchBuildingHelper) *CommitFilesHelper {
	return &CommitFilesHelper{
		c:                   c,
		patchBuildingHelper: patchBuildingHelper,
	}
}

// focusedMainViewSnapshot records the focused main view to return to when
// escaping the patch builder, for the case where we're entering it straight from
// there; it's nil for the normal flow that goes through the commit files panel.
// See types.FocusedMainViewSnapshot.
func (self *CommitFilesHelper) EnterCommitFile(node *filetree.CommitFileNode, focusedMainViewSnapshot *types.FocusedMainViewSnapshot, opts types.OnFocusOpts) error {
	if node.File == nil {
		self.handleToggleCommitFileDirCollapsed(node)
		return nil
	}

	if self.c.UserConfig().Git.DiffContextSize == 0 {
		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextToStage,
			self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView)
	}

	from, to, reverse := self.CurrentFromToReverseForPatchBuilding()
	mustDiscardPatch := self.c.Git().Patch.PatchBuilder.Active() && self.c.Git().Patch.PatchBuilder.NewPatchRequired(from, to, reverse)
	return self.c.ConfirmIf(mustDiscardPatch, types.ConfirmOpts{
		Title:  self.c.Tr.DiscardPatch,
		Prompt: self.c.Tr.DiscardPatchConfirm,
		HandleConfirm: func() error {
			if mustDiscardPatch {
				self.c.Git().Patch.PatchBuilder.Reset()
			}

			if !self.c.Git().Patch.PatchBuilder.Active() {
				if err := self.StartPatchBuilder(); err != nil {
					return err
				}
			}

			// Set on every entry (so it can't leak from a previous main-view
			// entry into a subsequent normal one), right as we push the patch
			// builder.
			self.c.Contexts().CustomPatchBuilder.SetFocusedMainViewSnapshot(focusedMainViewSnapshot)

			self.c.Context().Push(self.c.Contexts().CustomPatchBuilder, opts)
			self.patchBuildingHelper.ShowHunkStagingHint()

			return nil
		},
	})
}

func (self *CommitFilesHelper) context() *context.CommitFilesContext {
	return self.c.Contexts().CommitFiles
}

func (self *CommitFilesHelper) handleToggleCommitFileDirCollapsed(node *filetree.CommitFileNode) {
	self.context().CommitFileTreeViewModel.ToggleCollapsed(node.GetInternalPath())

	self.c.PostRefreshUpdate(self.context())
}

func (self *CommitFilesHelper) StartPatchBuilder() error {
	commitFilesContext := self.context()

	canRebase := commitFilesContext.GetCanRebase()
	from, to, reverse := self.CurrentFromToReverseForPatchBuilding()

	self.c.Git().Patch.PatchBuilder.Start(from, to, reverse, canRebase)
	return nil
}

func (self *CommitFilesHelper) CurrentFromToReverseForPatchBuilding() (string, string, bool) {
	commitFilesContext := self.context()

	from, to := commitFilesContext.GetFromAndToForDiff()
	from, reverse := self.c.Modes().Diffing.GetFromAndReverseArgsForDiff(from)
	return from, to, reverse
}