package gui

import "github.com/jesseduffield/gocui"

type ListContext struct {
	ViewName              string
	ContextKey            string
	GetItemsLength        func() int
	GetSelectedLineIdxPtr func() *int
	OnFocus               func() error
	OnFocusLost           func() error
	OnItemSelect          func() error
	OnClickSelectedItem   func() error

	// OnFocus assumes that the content of the context has already been rendered to the view. OnRender is the function which actually renders the content to the view
	OnRender          func() error
	Gui               *Gui
	RendersToMainView bool
	Kind              int
}

func (lc *ListContext) GetKey() string {
	return lc.ContextKey
}

func (lc *ListContext) GetKind() int {
	return lc.Kind
}

func (lc *ListContext) GetViewName() string {
	return lc.ViewName
}

func (lc *ListContext) HandleFocusLost() error {
	if lc.OnFocusLost != nil {
		return lc.OnFocusLost()
	}

	return nil
}

func (lc *ListContext) HandleFocus() error {
	return lc.OnFocus()
}

func (lc *ListContext) HandleRender() error {
	return lc.OnRender()
}

func (lc *ListContext) handlePrevLine(g *gocui.Gui, v *gocui.View) error {
	return lc.handleLineChange(-1)
}

func (lc *ListContext) handleNextLine(g *gocui.Gui, v *gocui.View) error {
	return lc.handleLineChange(1)
}

func (lc *ListContext) handleLineChange(change int) error {
	if !lc.Gui.isPopupPanel(lc.ViewName) && lc.Gui.popupPanelFocused() {
		return nil
	}

	view, err := lc.Gui.g.View(lc.ViewName)
	if err != nil {
		return err
	}

	lc.Gui.changeSelectedLine(lc.GetSelectedLineIdxPtr(), lc.GetItemsLength(), change)
	view.FocusPoint(0, *lc.GetSelectedLineIdxPtr())

	if lc.RendersToMainView {
		if err := lc.Gui.resetOrigin(lc.Gui.getMainView()); err != nil {
			return err
		}
		if err := lc.Gui.resetOrigin(lc.Gui.getSecondaryView()); err != nil {
			return err
		}
	}

	if lc.OnItemSelect != nil {
		return lc.OnItemSelect()
	}
	return nil
}

func (lc *ListContext) handleNextPage(g *gocui.Gui, v *gocui.View) error {
	view, err := lc.Gui.g.View(lc.ViewName)
	if err != nil {
		return nil
	}
	_, height := view.Size()
	delta := height - 1
	if delta == 0 {
		delta = 1
	}
	return lc.handleLineChange(delta)
}

func (lc *ListContext) handleGotoTop(g *gocui.Gui, v *gocui.View) error {
	return lc.handleLineChange(-lc.GetItemsLength())
}

func (lc *ListContext) handleGotoBottom(g *gocui.Gui, v *gocui.View) error {
	return lc.handleLineChange(lc.GetItemsLength())
}

func (lc *ListContext) handlePrevPage(g *gocui.Gui, v *gocui.View) error {
	view, err := lc.Gui.g.View(lc.ViewName)
	if err != nil {
		return nil
	}
	_, height := view.Size()
	delta := height - 1
	if delta == 0 {
		delta = 1
	}
	return lc.handleLineChange(-delta)
}

func (lc *ListContext) handleClick(g *gocui.Gui, v *gocui.View) error {
	if !lc.Gui.isPopupPanel(lc.ViewName) && lc.Gui.popupPanelFocused() {
		return nil
	}

	selectedLineIdxPtr := lc.GetSelectedLineIdxPtr()
	prevSelectedLineIdx := *selectedLineIdxPtr
	newSelectedLineIdx := v.SelectedLineIdx()

	// we need to focus the view
	if err := lc.Gui.switchContext(lc); err != nil {
		return err
	}

	if newSelectedLineIdx > lc.GetItemsLength()-1 {
		return nil
	}

	*selectedLineIdxPtr = newSelectedLineIdx

	prevViewName := lc.Gui.currentViewName()
	if prevSelectedLineIdx == newSelectedLineIdx && prevViewName == lc.ViewName && lc.OnClickSelectedItem != nil {
		return lc.OnClickSelectedItem()
	}
	if lc.OnItemSelect != nil {
		return lc.OnItemSelect()
	}
	return nil
}

func (lc *ListContext) onSearchSelect(selectedLineIdx int) error {
	*lc.GetSelectedLineIdxPtr() = selectedLineIdx
	if lc.OnItemSelect != nil {
		return lc.OnItemSelect()
	}
	return nil
}

func (gui *Gui) menuListContext() *ListContext {
	return &ListContext{
		ViewName:              "menu",
		ContextKey:            "menu",
		GetItemsLength:        func() int { return gui.getMenuView().LinesHeight() },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Menu.SelectedLine },
		OnFocus:               gui.handleMenuSelect,
		OnItemSelect:          gui.handleMenuSelect,
		// rendering the menu happens on creation
		OnRender: func() error { return nil },
		// need to add a layer of indirection here because the callback changes during runtime
		OnClickSelectedItem: func() error { return gui.State.Panels.Menu.OnPress(gui.g, nil) },
		Gui:                 gui,
		RendersToMainView:   false,
		Kind:                PERSISTENT_POPUP,
	}
}

func (gui *Gui) filesListContext() *ListContext {
	return &ListContext{
		ViewName:              "files",
		ContextKey:            "files",
		GetItemsLength:        func() int { return len(gui.State.Files) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Files.SelectedLine },
		OnFocus:               gui.focusAndSelectFile,
		OnItemSelect:          gui.focusAndSelectFile,
		OnClickSelectedItem:   gui.handleFilePress,
		OnRender:              gui.renderFiles,
		Gui:                   gui,
		RendersToMainView:     false,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) branchesListContext() *ListContext {
	return &ListContext{
		ViewName:              "branches",
		ContextKey:            "local-branches",
		GetItemsLength:        func() int { return len(gui.State.Branches) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Branches.SelectedLine },
		OnFocus:               gui.handleBranchSelect,
		OnItemSelect:          gui.handleBranchSelect,
		OnRender:              gui.renderLocalBranchesContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) remotesListContext() *ListContext {
	return &ListContext{
		ViewName:              "branches",
		ContextKey:            "remotes",
		GetItemsLength:        func() int { return len(gui.State.Remotes) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Remotes.SelectedLine },
		OnFocus:               gui.handleRemoteSelect,
		OnItemSelect:          gui.handleRemoteSelect,
		OnClickSelectedItem:   gui.handleRemoteEnter,
		OnRender:              gui.renderRemotesContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) remoteBranchesListContext() *ListContext {
	return &ListContext{
		ViewName:              "branches",
		ContextKey:            "remote-branches",
		GetItemsLength:        func() int { return len(gui.State.RemoteBranches) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.RemoteBranches.SelectedLine },
		OnFocus:               gui.handleRemoteBranchSelect,
		OnItemSelect:          gui.handleRemoteBranchSelect,
		OnRender:              gui.renderRemoteBranchesContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) tagsListContext() *ListContext {
	return &ListContext{
		ViewName:              "branches",
		ContextKey:            "tags",
		GetItemsLength:        func() int { return len(gui.State.Tags) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Tags.SelectedLine },
		OnFocus:               gui.handleTagSelect,
		OnItemSelect:          gui.handleTagSelect,
		OnRender:              gui.renderTagsContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) branchCommitsListContext() *ListContext {
	return &ListContext{
		ViewName:              "commits",
		ContextKey:            "branch-commits",
		GetItemsLength:        func() int { return len(gui.State.Commits) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Commits.SelectedLine },
		OnFocus:               gui.handleCommitSelect,
		OnItemSelect:          gui.handleCommitSelect,
		OnClickSelectedItem:   gui.handleSwitchToCommitFilesPanel,
		OnRender:              gui.renderBranchCommitsContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) reflogCommitsListContext() *ListContext {
	return &ListContext{
		ViewName:              "commits",
		ContextKey:            "reflog-commits",
		GetItemsLength:        func() int { return len(gui.State.FilteredReflogCommits) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.ReflogCommits.SelectedLine },
		OnFocus:               gui.handleReflogCommitSelect,
		OnItemSelect:          gui.handleReflogCommitSelect,
		OnRender:              gui.renderReflogCommitsContext,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) stashListContext() *ListContext {
	return &ListContext{
		ViewName:              "stash",
		ContextKey:            "stash",
		GetItemsLength:        func() int { return len(gui.State.StashEntries) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.Stash.SelectedLine },
		OnFocus:               gui.handleStashEntrySelect,
		OnItemSelect:          gui.handleStashEntrySelect,
		OnRender:              gui.renderStash,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) commitFilesListContext() *ListContext {
	return &ListContext{
		ViewName:              "commitFiles",
		ContextKey:            "commitFiles",
		GetItemsLength:        func() int { return len(gui.State.CommitFiles) },
		GetSelectedLineIdxPtr: func() *int { return &gui.State.Panels.CommitFiles.SelectedLine },
		OnFocus:               gui.handleCommitFileSelect,
		OnItemSelect:          gui.handleCommitFileSelect,
		OnRender:              gui.renderCommitFiles,
		Gui:                   gui,
		RendersToMainView:     true,
		Kind:                  SIDE_CONTEXT,
	}
}

func (gui *Gui) getListContexts() []*ListContext {
	return []*ListContext{
		gui.menuListContext(),
		gui.filesListContext(),
		gui.branchesListContext(),
		gui.remotesListContext(),
		gui.remoteBranchesListContext(),
		gui.tagsListContext(),
		gui.branchCommitsListContext(),
		gui.reflogCommitsListContext(),
		gui.stashListContext(),
		gui.commitFilesListContext(),
	}
}

func (gui *Gui) getListContextKeyBindings() []*Binding {
	bindings := make([]*Binding, 0)

	for _, listContext := range gui.getListContexts() {
		bindings = append(bindings, []*Binding{
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.prevItem-alt"), Modifier: gocui.ModNone, Handler: listContext.handlePrevLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.prevItem"), Modifier: gocui.ModNone, Handler: listContext.handlePrevLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gocui.MouseWheelUp, Modifier: gocui.ModNone, Handler: listContext.handlePrevLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.nextItem-alt"), Modifier: gocui.ModNone, Handler: listContext.handleNextLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.nextItem"), Modifier: gocui.ModNone, Handler: listContext.handleNextLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.prevPage"), Modifier: gocui.ModNone, Handler: listContext.handlePrevPage, Description: gui.Tr.SLocalize("prevPage")},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.nextPage"), Modifier: gocui.ModNone, Handler: listContext.handleNextPage, Description: gui.Tr.SLocalize("nextPage")},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gui.getKey("universal.gotoTop"), Modifier: gocui.ModNone, Handler: listContext.handleGotoTop, Description: gui.Tr.SLocalize("gotoTop")},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gocui.MouseWheelDown, Modifier: gocui.ModNone, Handler: listContext.handleNextLine},
			{ViewName: listContext.ViewName, Contexts: []string{listContext.ContextKey}, Key: gocui.MouseLeft, Modifier: gocui.ModNone, Handler: listContext.handleClick},
		}...)

		// the commits panel needs to lazyload things so it has a couple of its own handlers
		openSearchHandler := gui.handleOpenSearch
		gotoBottomHandler := listContext.handleGotoBottom
		if listContext.ViewName == "commits" {
			openSearchHandler = gui.handleOpenSearchForCommitsPanel
			gotoBottomHandler = gui.handleGotoBottomForCommitsPanel
		}

		bindings = append(bindings, []*Binding{
			{
				ViewName:    listContext.ViewName,
				Contexts:    []string{listContext.ContextKey},
				Key:         gui.getKey("universal.startSearch"),
				Handler:     openSearchHandler,
				Description: gui.Tr.SLocalize("startSearch"),
			},
			{
				ViewName:    listContext.ViewName,
				Contexts:    []string{listContext.ContextKey},
				Key:         gui.getKey("universal.gotoBottom"),
				Handler:     gotoBottomHandler,
				Description: gui.Tr.SLocalize("gotoBottom"),
			},
		}...)
	}

	return bindings
}