package gui

import (
	"fmt"
	"strings"

	"github.com/jesseduffield/gocui"
	"github.com/jesseduffield/lazygit/pkg/commands"
)

// list panel functions

func (gui *Gui) getSelectedBranch() *commands.Branch {
	selectedLine := gui.State.Panels.Branches.SelectedLine
	if selectedLine == -1 {
		return nil
	}

	return gui.State.Branches[selectedLine]
}

// may want to standardise how these select methods work
func (gui *Gui) handleBranchSelect(g *gocui.Gui, v *gocui.View) error {
	if gui.popupPanelFocused() {
		return nil
	}

	gui.State.SplitMainPanel = false

	if _, err := gui.g.SetCurrentView(v.Name()); err != nil {
		return err
	}
	// This really shouldn't happen: there should always be a master branch
	if len(gui.State.Branches) == 0 {
		return gui.renderString(g, "main", gui.Tr.SLocalize("NoBranchesThisRepo"))
	}
	branch := gui.getSelectedBranch()
	if err := gui.focusPoint(0, gui.State.Panels.Branches.SelectedLine, len(gui.State.Branches), v); err != nil {
		return err
	}
	go func() {
		_ = gui.RenderSelectedBranchUpstreamDifferences()
	}()
	go func() {
		graph, err := gui.GitCommand.GetBranchGraph(branch.Name)
		if err != nil && strings.HasPrefix(graph, "fatal: ambiguous argument") {
			graph = gui.Tr.SLocalize("NoTrackingThisBranch")
		}
		_ = gui.renderString(g, "main", graph)
	}()
	return nil
}

func (gui *Gui) RenderSelectedBranchUpstreamDifferences() error {
	// here we tell the selected branch that it is selected.
	// this is necessary for showing stats on a branch that is selected, because
	// the displaystring function doesn't have access to gui state to tell if it's selected
	for i, branch := range gui.State.Branches {
		branch.Selected = i == gui.State.Panels.Branches.SelectedLine
	}

	branch := gui.getSelectedBranch()
	branch.Pushables, branch.Pullables = gui.GitCommand.GetBranchUpstreamDifferenceCount(branch.Name)
	return gui.renderListPanel(gui.getBranchesView(), gui.State.Branches)
}

// gui.refreshStatus is called at the end of this because that's when we can
// be sure there is a state.Branches array to pick the current branch from
func (gui *Gui) refreshBranches(g *gocui.Gui) error {
	g.Update(func(g *gocui.Gui) error {
		builder, err := commands.NewBranchListBuilder(gui.Log, gui.GitCommand)
		if err != nil {
			return err
		}
		gui.State.Branches = builder.Build()

		gui.refreshSelectedLine(&gui.State.Panels.Branches.SelectedLine, len(gui.State.Branches))
		if err := gui.RenderSelectedBranchUpstreamDifferences(); err != nil {
			return err
		}

		return gui.refreshStatus(g)
	})
	return nil
}

func (gui *Gui) handleBranchesNextLine(g *gocui.Gui, v *gocui.View) error {
	if gui.popupPanelFocused() {
		return nil
	}

	panelState := gui.State.Panels.Branches
	gui.changeSelectedLine(&panelState.SelectedLine, len(gui.State.Branches), false)

	if err := gui.resetOrigin(gui.getMainView()); err != nil {
		return err
	}
	return gui.handleBranchSelect(gui.g, v)
}

func (gui *Gui) handleBranchesPrevLine(g *gocui.Gui, v *gocui.View) error {
	if gui.popupPanelFocused() {
		return nil
	}

	panelState := gui.State.Panels.Branches
	gui.changeSelectedLine(&panelState.SelectedLine, len(gui.State.Branches), true)

	if err := gui.resetOrigin(gui.getMainView()); err != nil {
		return err
	}
	return gui.handleBranchSelect(gui.g, v)
}

// specific functions

func (gui *Gui) handleBranchPress(g *gocui.Gui, v *gocui.View) error {
	if gui.State.Panels.Branches.SelectedLine == -1 {
		return nil
	}
	if gui.State.Panels.Branches.SelectedLine == 0 {
		return gui.createErrorPanel(g, gui.Tr.SLocalize("AlreadyCheckedOutBranch"))
	}
	branch := gui.getSelectedBranch()
	return gui.handleCheckoutBranch(branch.Name)
}

func (gui *Gui) handleCreatePullRequestPress(g *gocui.Gui, v *gocui.View) error {
	pullRequest := commands.NewPullRequest(gui.GitCommand)

	branch := gui.getSelectedBranch()
	if err := pullRequest.Create(branch); err != nil {
		return gui.createErrorPanel(g, err.Error())
	}

	return nil
}

func (gui *Gui) handleGitFetch(g *gocui.Gui, v *gocui.View) error {
	if err := gui.createLoaderPanel(gui.g, v, gui.Tr.SLocalize("FetchWait")); err != nil {
		return err
	}
	go func() {
		unamePassOpend, err := gui.fetch(g, v, true)
		gui.HandleCredentialsPopup(g, unamePassOpend, err)
	}()
	return nil
}

func (gui *Gui) handleForceCheckout(g *gocui.Gui, v *gocui.View) error {
	branch := gui.getSelectedBranch()
	message := gui.Tr.SLocalize("SureForceCheckout")
	title := gui.Tr.SLocalize("ForceCheckoutBranch")
	return gui.createConfirmationPanel(g, v, title, message, func(g *gocui.Gui, v *gocui.View) error {
		if err := gui.GitCommand.Checkout(branch.Name, true); err != nil {
			gui.createErrorPanel(g, err.Error())
		}
		return gui.refreshSidePanels(g)
	}, nil)
}

func (gui *Gui) handleCheckoutBranch(branchName string) error {
	if err := gui.GitCommand.Checkout(branchName, false); err != nil {
		// note, this will only work for english-language git commands. If we force git to use english, and the error isn't this one, then the user will receive an english command they may not understand. I'm not sure what the best solution to this is. Running the command once in english and a second time in the native language is one option

		if strings.Contains(err.Error(), "Please commit your changes or stash them before you switch branch") {
			// offer to autostash changes
			return gui.createConfirmationPanel(gui.g, gui.getBranchesView(), gui.Tr.SLocalize("AutoStashTitle"), gui.Tr.SLocalize("AutoStashPrompt"), func(g *gocui.Gui, v *gocui.View) error {
				if err := gui.GitCommand.StashSave(gui.Tr.SLocalize("StashPrefix") + branchName); err != nil {
					return gui.createErrorPanel(g, err.Error())
				}
				if err := gui.GitCommand.Checkout(branchName, false); err != nil {
					return gui.createErrorPanel(g, err.Error())
				}

				// checkout successful so we select the new branch
				gui.State.Panels.Branches.SelectedLine = 0

				if err := gui.GitCommand.StashDo(0, "pop"); err != nil {
					if err := gui.refreshSidePanels(g); err != nil {
						return err
					}
					return gui.createErrorPanel(g, err.Error())
				}
				return gui.refreshSidePanels(g)
			}, nil)
		}

		if err := gui.createErrorPanel(gui.g, err.Error()); err != nil {
			return err
		}
	}

	gui.State.Panels.Branches.SelectedLine = 0
	return gui.refreshSidePanels(gui.g)
}

func (gui *Gui) handleCheckoutByName(g *gocui.Gui, v *gocui.View) error {
	gui.createPromptPanel(g, v, gui.Tr.SLocalize("BranchName")+":", func(g *gocui.Gui, v *gocui.View) error {
		return gui.handleCheckoutBranch(gui.trimmedContent(v))
	})
	return nil
}

func (gui *Gui) handleNewBranch(g *gocui.Gui, v *gocui.View) error {
	branch := gui.State.Branches[0]
	message := gui.Tr.TemplateLocalize(
		"NewBranchNameBranchOff",
		Teml{
			"branchName": branch.Name,
		},
	)
	gui.createPromptPanel(g, v, message, func(g *gocui.Gui, v *gocui.View) error {
		if err := gui.GitCommand.NewBranch(gui.trimmedContent(v)); err != nil {
			return gui.createErrorPanel(g, err.Error())
		}
		gui.refreshSidePanels(g)
		return gui.handleBranchSelect(g, v)
	})
	return nil
}

func (gui *Gui) handleDeleteBranch(g *gocui.Gui, v *gocui.View) error {
	return gui.deleteBranch(g, v, false)
}

func (gui *Gui) handleForceDeleteBranch(g *gocui.Gui, v *gocui.View) error {
	return gui.deleteBranch(g, v, true)
}

func (gui *Gui) deleteBranch(g *gocui.Gui, v *gocui.View, force bool) error {
	selectedBranch := gui.getSelectedBranch()
	if selectedBranch == nil {
		return nil
	}
	checkedOutBranch := gui.State.Branches[0]
	if checkedOutBranch.Name == selectedBranch.Name {
		return gui.createErrorPanel(g, gui.Tr.SLocalize("CantDeleteCheckOutBranch"))
	}
	return gui.deleteNamedBranch(g, v, selectedBranch, force)
}

func (gui *Gui) deleteNamedBranch(g *gocui.Gui, v *gocui.View, selectedBranch *commands.Branch, force bool) error {
	title := gui.Tr.SLocalize("DeleteBranch")
	var messageID string
	if force {
		messageID = "ForceDeleteBranchMessage"
	} else {
		messageID = "DeleteBranchMessage"
	}
	message := gui.Tr.TemplateLocalize(
		messageID,
		Teml{
			"selectedBranchName": selectedBranch.Name,
		},
	)
	return gui.createConfirmationPanel(g, v, title, message, func(g *gocui.Gui, v *gocui.View) error {
		if err := gui.GitCommand.DeleteBranch(selectedBranch.Name, force); err != nil {
			errMessage := err.Error()
			if !force && strings.Contains(errMessage, "is not fully merged") {
				return gui.deleteNamedBranch(g, v, selectedBranch, true)
			}
			return gui.createErrorPanel(g, errMessage)
		}
		return gui.refreshSidePanels(g)
	}, nil)
}

func (gui *Gui) handleMerge(g *gocui.Gui, v *gocui.View) error {
	checkedOutBranch := gui.State.Branches[0].Name
	selectedBranch := gui.getSelectedBranch().Name
	if checkedOutBranch == selectedBranch {
		return gui.createErrorPanel(g, gui.Tr.SLocalize("CantMergeBranchIntoItself"))
	}
	prompt := gui.Tr.TemplateLocalize(
		"ConfirmMerge",
		Teml{
			"checkedOutBranch": checkedOutBranch,
			"selectedBranch":   selectedBranch,
		},
	)
	return gui.createConfirmationPanel(g, v, gui.Tr.SLocalize("MergingTitle"), prompt,
		func(g *gocui.Gui, v *gocui.View) error {

			err := gui.GitCommand.Merge(selectedBranch)
			return gui.handleGenericMergeCommandResult(err)
		}, nil)
}

func (gui *Gui) handleRebase(g *gocui.Gui, v *gocui.View) error {
	checkedOutBranch := gui.State.Branches[0].Name
	selectedBranch := gui.getSelectedBranch().Name
	if selectedBranch == checkedOutBranch {
		return gui.createErrorPanel(g, gui.Tr.SLocalize("CantRebaseOntoSelf"))
	}
	prompt := gui.Tr.TemplateLocalize(
		"ConfirmRebase",
		Teml{
			"checkedOutBranch": checkedOutBranch,
			"selectedBranch":   selectedBranch,
		},
	)
	return gui.createConfirmationPanel(g, v, gui.Tr.SLocalize("RebasingTitle"), prompt,
		func(g *gocui.Gui, v *gocui.View) error {

			err := gui.GitCommand.RebaseBranch(selectedBranch)
			return gui.handleGenericMergeCommandResult(err)
		}, nil)
}

func (gui *Gui) handleFastForward(g *gocui.Gui, v *gocui.View) error {
	branch := gui.getSelectedBranch()
	if branch == nil {
		return nil
	}
	if branch.Pushables == "" {
		return nil
	}
	if branch.Pushables == "?" {
		return gui.createErrorPanel(gui.g, gui.Tr.SLocalize("FwdNoUpstream"))
	}
	if branch.Pushables != "0" {
		return gui.createErrorPanel(gui.g, gui.Tr.SLocalize("FwdCommitsToPush"))
	}
	upstream := "origin" // hardcoding for now
	message := gui.Tr.TemplateLocalize(
		"Fetching",
		Teml{
			"from": fmt.Sprintf("%s/%s", upstream, branch.Name),
			"to":   branch.Name,
		},
	)
	go func() {
		_ = gui.createLoaderPanel(gui.g, v, message)
		if err := gui.GitCommand.FastForward(branch.Name); err != nil {
			_ = gui.createErrorPanel(gui.g, err.Error())
		} else {
			_ = gui.closeConfirmationPrompt(gui.g)
			_ = gui.RenderSelectedBranchUpstreamDifferences()
		}
	}()
	return nil
}