package controllers

import (
	"github.com/jesseduffield/gocui"
	"github.com/jesseduffield/lazygit/pkg/gui/types"
)

type ListControllerFactory struct {
	c *types.HelperCommon
}

func NewListControllerFactory(c *types.HelperCommon) *ListControllerFactory {
	return &ListControllerFactory{
		c: c,
	}
}

func (self *ListControllerFactory) Create(context types.IListContext) *ListController {
	return &ListController{
		baseController: baseController{},
		c:              self.c,
		context:        context,
	}
}

type ListController struct {
	baseController
	c *types.HelperCommon

	context types.IListContext
}

func (self *ListController) Context() types.Context {
	return self.context
}

func (self *ListController) HandlePrevLine() error {
	return self.handleLineChange(-1)
}

func (self *ListController) HandleNextLine() error {
	return self.handleLineChange(1)
}

func (self *ListController) HandleScrollLeft() error {
	return self.scrollHorizontal(self.context.GetViewTrait().ScrollLeft)
}

func (self *ListController) HandleScrollRight() error {
	return self.scrollHorizontal(self.context.GetViewTrait().ScrollRight)
}

func (self *ListController) HandleScrollUp() error {
	scrollHeight := self.c.UserConfig.Gui.ScrollHeight
	self.context.GetViewTrait().ScrollUp(scrollHeight)

	// we only need to do a line change if our line has been pushed out of the viewport, because
	// at the moment much logic depends on the selected line always being visible
	if !self.isSelectedLineInViewPort() {
		return self.handleLineChange(-scrollHeight)
	}

	return nil
}

func (self *ListController) HandleScrollDown() error {
	scrollHeight := self.c.UserConfig.Gui.ScrollHeight
	self.context.GetViewTrait().ScrollDown(scrollHeight)

	if !self.isSelectedLineInViewPort() {
		return self.handleLineChange(scrollHeight)
	}

	return nil
}

func (self *ListController) isSelectedLineInViewPort() bool {
	selectedLineIdx := self.context.GetList().GetSelectedLineIdx()
	startIdx, length := self.context.GetViewTrait().ViewPortYBounds()
	return selectedLineIdx >= startIdx && selectedLineIdx < startIdx+length
}

func (self *ListController) scrollHorizontal(scrollFunc func()) error {
	scrollFunc()

	return self.context.HandleFocus(types.OnFocusOpts{})
}

func (self *ListController) handleLineChange(change int) error {
	before := self.context.GetList().GetSelectedLineIdx()
	self.context.GetList().MoveSelectedLine(change)
	after := self.context.GetList().GetSelectedLineIdx()

	if err := self.pushContextIfNotFocused(); err != nil {
		return err
	}

	// doing this check so that if we're holding the up key at the start of the list
	// we're not constantly re-rendering the main view.
	if before != after {
		return self.context.HandleFocus(types.OnFocusOpts{})
	}

	return nil
}

func (self *ListController) HandlePrevPage() error {
	return self.handleLineChange(-self.context.GetViewTrait().PageDelta())
}

func (self *ListController) HandleNextPage() error {
	return self.handleLineChange(self.context.GetViewTrait().PageDelta())
}

func (self *ListController) HandleGotoTop() error {
	return self.handleLineChange(-self.context.GetList().Len())
}

func (self *ListController) HandleGotoBottom() error {
	return self.handleLineChange(self.context.GetList().Len())
}

func (self *ListController) HandleClick(opts gocui.ViewMouseBindingOpts) error {
	prevSelectedLineIdx := self.context.GetList().GetSelectedLineIdx()
	newSelectedLineIdx := opts.Y
	alreadyFocused := self.isFocused()

	if err := self.pushContextIfNotFocused(); err != nil {
		return err
	}

	if newSelectedLineIdx > self.context.GetList().Len()-1 {
		return nil
	}

	self.context.GetList().SetSelectedLineIdx(newSelectedLineIdx)

	if prevSelectedLineIdx == newSelectedLineIdx && alreadyFocused && self.context.GetOnClick() != nil {
		return self.context.GetOnClick()()
	}
	return self.context.HandleFocus(types.OnFocusOpts{})
}

func (self *ListController) pushContextIfNotFocused() error {
	if !self.isFocused() {
		if err := self.c.PushContext(self.context); err != nil {
			return err
		}
	}

	return nil
}

func (self *ListController) isFocused() bool {
	return self.c.CurrentContext().GetKey() == self.context.GetKey()
}

func (self *ListController) GetKeybindings(opts types.KeybindingsOpts) []*types.Binding {
	return []*types.Binding{
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.PrevItemAlt), Handler: self.HandlePrevLine},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.PrevItem), Handler: self.HandlePrevLine},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.NextItemAlt), Handler: self.HandleNextLine},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.NextItem), Handler: self.HandleNextLine},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.PrevPage), Handler: self.HandlePrevPage, Description: self.c.Tr.LcPrevPage},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.NextPage), Handler: self.HandleNextPage, Description: self.c.Tr.LcNextPage},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.GotoTop), Handler: self.HandleGotoTop, Description: self.c.Tr.LcGotoTop},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.ScrollLeft), Handler: self.HandleScrollLeft},
		{Tag: "navigation", Key: opts.GetKey(opts.Config.Universal.ScrollRight), Handler: self.HandleScrollRight},
		{
			Key:         opts.GetKey(opts.Config.Universal.StartSearch),
			Handler:     func() error { self.c.OpenSearch(); return nil },
			Description: self.c.Tr.LcStartSearch,
			Tag:         "navigation",
		},
		{
			Key:         opts.GetKey(opts.Config.Universal.GotoBottom),
			Description: self.c.Tr.LcGotoBottom,
			Handler:     self.HandleGotoBottom,
			Tag:         "navigation",
		},
	}
}

func (self *ListController) GetMouseKeybindings(opts types.KeybindingsOpts) []*gocui.ViewMouseBinding {
	return []*gocui.ViewMouseBinding{
		{
			ViewName: self.context.GetViewName(),
			Key:      gocui.MouseWheelUp,
			Handler:  func(gocui.ViewMouseBindingOpts) error { return self.HandleScrollUp() },
		},
		{
			ViewName: self.context.GetViewName(),
			Key:      gocui.MouseLeft,
			Handler:  func(opts gocui.ViewMouseBindingOpts) error { return self.HandleClick(opts) },
		},
		{
			ViewName: self.context.GetViewName(),
			Key:      gocui.MouseWheelDown,
			Handler:  func(gocui.ViewMouseBindingOpts) error { return self.HandleScrollDown() },
		},
	}
}