package imgui

import (
	"time"

	cimgui "github.com/AllenDang/cimgui-go/imgui"
)

// ImGui context & IO wrapper
type Context struct {
	ctx          *cimgui.Context
	io           *cimgui.IO
	lastDrawData *cimgui.DrawData
}

func New() *Context {
	ctx := cimgui.CreateContext()
	cimgui.SetCurrentContext(ctx)
	io := cimgui.CurrentIO()
	return &Context{ctx: ctx, io: io}
}

func (c *Context) Destroy() {
	cimgui.DestroyContext()
}

// Starts new ImGui frame
// dt - time since last frame
func (c *Context) BeginFrame(dt time.Duration, winW, winH int32) {
	c.io.SetDeltaTime(float32(dt.Seconds()))
	c.io.SetDisplaySize(cimgui.Vec2{X: float32(winW), Y: float32(winH)})
	cimgui.NewFrame()
}

// Ends the frame, renders
// and returns data for Vulkan
func (c *Context) EndFrame() *cimgui.DrawData {
	cimgui.EndFrame()
	cimgui.Render()
	c.lastDrawData = cimgui.CurrentDrawData()
	return cimgui.CurrentDrawData()
}

// expose io to input backend
func (c *Context) IO() *cimgui.IO { return c.io }

func (c *Context) LastDrawData() *cimgui.DrawData { return c.lastDrawData }