package client

import (
	"image"
	"sync"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/layout"
	"github.com/iliadenisov/galaxy/client/world"
)

type Editor interface {
	BuildUI(fyne.Window)
}

type editor struct {
	world       *world.World
	drawer      *world.GGDrawer
	raster      *canvas.Raster
	canvasScale float32

	canvas *interactiveRaster
	win    fyne.Window

	// Coalescer for latest-wins refresh scheduling.
	co *RasterCoalescer[world.RenderParams]

	pan *PanController

	// Protected render params state. Stored as value to avoid aliasing issues.
	mu sync.RWMutex
	wp *world.RenderParams

	// Last viewport size we indexed the world for.
	lastViewportW int
	lastViewportH int

	// Optional: you can keep the last expanded canvas size to avoid reallocations.
	lastCanvasW int
	lastCanvasH int

	// Reusable viewport buffer to avoid per-frame allocations.
	viewportImg *image.RGBA
	viewportW   int
	viewportH   int
}

func (e *editor) CanvasScale() float32 { return e.canvasScale }

func (e *editor) ForceFullRedraw() {
	e.world.ForceFullRedrawNext()
}

func (e *editor) buildUI() fyne.CanvasObject {
	return e.canvas
}

// здесь определяю, изменились ли границы raster, если да - обновляю размеры viewport, margin и корректирую zoom
func (e *editor) updateSizes() {
	canvas := fyne.CurrentApp().Driver().CanvasForObject(e.raster)
	if canvas == nil {
		return
	}

	size := e.raster.Size()
	e.canvasScale = canvas.Scale()

	width := int(size.Width * e.canvasScale)
	height := int(size.Height * e.canvasScale)

	if width > 0 && height > 0 && (width != e.wp.ViewportWidthPx || height != e.wp.ViewportHeightPx) {
		e.wp.ViewportWidthPx = width
		e.wp.ViewportHeightPx = height
		e.wp.MarginXPx = e.wp.ViewportWidthPx / 4
		e.wp.MarginYPx = e.wp.ViewportHeightPx / 4

		e.wp.CameraZoom = e.world.CorrectCameraZoom(e.wp.CameraZoom, e.wp.ViewportWidthPx, e.wp.ViewportHeightPx)
		e.world.IndexOnViewportChange(e.wp.ViewportWidthPx, e.wp.ViewportHeightPx, e.wp.CameraZoom)

		e.co.Request(*e.wp)
	}
}

func (e *editor) onDragged(ev *fyne.DragEvent) {
	e.pan.Dragged(ev)
}

func (e *editor) onDradEnd() {
	e.pan.DragEnd()
}

func (e *editor) wheelZoom(stepDelta int) {}

func (e *editor) InitImage() {
	s := fyne.NewSize(292, 292)
	e.canvas.SetMinSize(s)
	e.updateSizes()
}

func (e *editor) onMapLayout(s fyne.Size) {
	e.updateSizes()
}

func (e *editor) BuildUI(w fyne.Window) {
	e.win = w
	content := container.New(layout.NewStackLayout(), e.buildUI())
	w.CenterOnScreen()
	w.SetContent(content)
}

func NewEditor() *editor {
	w := world.NewWorld(300, 300)
	testWorldInit(w)
	e := &editor{
		world: w,
		wp: &world.RenderParams{
			CameraZoom:     1.0,
			CameraXWorldFp: 300 * world.SCALE,
			CameraYWorldFp: 300 * world.SCALE,
			// Viewport sizes and margins will be filled from draw(w,h).
		},
		canvasScale: 1.0,
	}

	// Create a drawer with some initial context; real size will be adjusted on first draw.
	e.drawer = &world.GGDrawer{DC: nil}

	// Create raster; its draw callback delegates to coalescer.
	e.raster = canvas.NewRaster(func(wPx, hPx int) image.Image {
		return e.draw(wPx, hPx)
	})

	e.canvas = newInteractiveRaster(e, e.raster, e.onMapLayout, e.onDragged, e.onDradEnd)
	e.pan = NewPanController(e)

	// Wire coalescer: it schedules raster.Refresh() on UI thread and renders once per draw call.
	exec := FyneExecutor{}
	e.co = NewRasterCoalescer(
		exec,
		e.raster, // Refresher
		func(wPx, hPx int, p world.RenderParams) image.Image {
			// This runs on UI thread (inside draw). It must return an image.
			return e.renderRasterImage(wPx, hPx, p)
		},
	)

	// Kick initial draw.
	e.RequestRefresh()

	e.InitImage()
	return e
}

func testWorldInit(w *world.World) {
	if _, err := w.AddCircle(150, 150, 50); err != nil {
		panic(err)
	}

	if _, err := w.AddCircle(150, 299, 30); err != nil {
		panic(err)
	}
	if _, err := w.AddCircle(299, 150, 30); err != nil {
		panic(err)
	}

	if _, err := w.AddLine(100, 20, 200, 30); err != nil {
		panic(err)
	}

	if _, err := w.AddLine(50, 50, 250, 100); err != nil {
		panic(err)
	}

	if _, err := w.AddPoint(10, 10); err != nil {
		panic(err)
	}

	if _, err := w.AddPoint(25, 255); err != nil {
		panic(err)
	}
}