package objects

import "image"
import "git.tebibyte.media/tomo/tomo"
import "git.tebibyte.media/tomo/tomo/event"

var _ tomo.ContentObject = new(Container)

// Container is an object that can contain other objects. It can be used as a
// primitive for building more complex layouts. It has two main variants: an
// outer container, and an inner container. The outer container has padding
// around its edges, whereas the inner container does not. It also has a
// "sunken" variation designed to hold a scrolled list of items.
//
// Tags:
//   - [outer] The container is the root of a window.
//   - [inner] The container is within another container, and is part of a
//     larger layout.
//   - [sunken] The container holds a visually grouped, usually scrolled, list
//     of items.
type Container struct {
	box tomo.ContainerBox
}

func newContainer (layout tomo.Layout, children ...tomo.Object) *Container {
	this := &Container {
		box: tomo.NewContainerBox(),
	}
	this.box.SetAttr(tomo.ALayout(layout))
	for _, child := range children {
		this.Add(child)
	}
	return this
}

// NewOuterContainer creates a new container that has padding around it, as well
// as a solid background color. It is meant to be used as a root container for a
// window, tab pane, etc.
func NewOuterContainer (layout tomo.Layout, children ...tomo.Object) *Container {
	this := newContainer(layout, children...)
	this.box.SetRole(tomo.R("objects", "Container"))
	this.box.SetTag("outer", true)
	return this
}

// NewSunkenContainer creates a new container with a sunken style and padding
// around it. It is meant to be used as a root container for a ScrollContainer.
func NewSunkenContainer (layout tomo.Layout, children ...tomo.Object) *Container {
	this := newContainer(layout, children...)
	this.box.SetRole(tomo.R("objects", "Container"))
	this.box.SetTag("sunken", true)
	return this
}

// NewInnerContainer creates a new container that has no padding around it.
func NewInnerContainer (layout tomo.Layout, children ...tomo.Object) *Container {
	this := newContainer(layout, children...)
	this.box.SetRole(tomo.R("objects", "Container"))
	this.box.SetTag("inner", true)
	return this
}

// GetBox returns the underlying box.
func (this *Container) GetBox () tomo.Box {
	return this.box
}

// ContentBounds returns the bounds of the inner content of the container
// relative to the container's InnerBounds.
func (this *Container) ContentBounds () image.Rectangle {
	return this.box.ContentBounds()
}

// ScrollTo shifts the origin of the container's content to the origin of the
// container's InnerBounds, offset by the given point.
func (this *Container) ScrollTo (position image.Point) {
	this.box.ScrollTo(position)
}

// OnContentBoundsChange specifies a function to be called when the container's
// ContentBounds or InnerBounds changes.
func (this *Container) OnContentBoundsChange (callback func ()) event.Cookie {
	return this.box.OnContentBoundsChange(callback)
}

// SetLayout sets the layout of the container.
func (this *Container) SetLayout (layout tomo.Layout) {
	this.box.SetAttr(tomo.ALayout(layout))
}

// SetAlign sets the X and Y alignment of the container.
func (this *Container) SetAlign (x, y tomo.Align) {
	this.box.SetAttr(tomo.AAlign(x, y))
}

// SetOverflow sets the X and Y overflow of the container.
func (this *Container) SetOverflow (x, y bool) {
	this.box.SetAttr(tomo.AOverflow(x, y))
}

// Add appends a child object. If the object is already a child of another
// object, it will be removed from that object first.
func (this *Container) Add (object tomo.Object) {
	this.box.Add(object)
}

// Remove removes a child object, if it is a child of this container.
func (this *Container) Remove (object tomo.Object) {
	this.box.Remove(object)
}

// Insert inserts a child object before a specified object. If the before object
// is nil or is not contained within this container, the inserted object is
// appended. If the inserted object is already a child of another object, it
// will be removed from that object first.
func (this *Container) Insert (child tomo.Object, before tomo.Object) {
	this.box.Insert(child, before)
}

// Clear removes all child objects.
func (this *Container) Clear () {
	this.box.Clear()
}

// Len returns hte amount of child objects.
func (this *Container) Len () int {
	return this.box.Len()
}

// At returns the child object at the specified index.
func (this *Container) At (index int) tomo.Object {
	return this.box.At(index)
}