package elements

import (
	"fluids/fluid"
	"image/color"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/vector"
)

const (
	FS10PixelWidth  = 200
	FS10PixelHeight = 100
	FS10FluidWidth  = 3.0 //meters
	FS10FluidHeight = 1.0 //meters
	FS10Resolution  = 20  //need to workshop this
)

type FluidSim10 struct {
	MappedEntityBase
	fluid        *fluid.Fluid
	angle        float64
	particlebuff *ebiten.Image
}

func NewFluidSim10() *FluidSim10 {
	fsim := &FluidSim10{
		fluid:        fluid.NewFluid(fluid.FieldVector{X: FS10FluidWidth, Y: FS10FluidHeight}, FS10FluidHeight/FS10Resolution),
		particlebuff: ebiten.NewImage(1, 1),
	}
	fsim.Initialize()
	return fsim
}

func (f *FluidSim10) Initialize() {
	f.Sprite = ebiten.NewImage(FS10PixelWidth, FS10PixelHeight)
	f.particlebuff.Fill(color.White)
	f.fluid.Initialize()
}

func (f *FluidSim10) SetAngle(angle float64) {
	f.angle = angle
	f.fluid.SetAngle(float32(angle))
}

func (f *FluidSim10) GetAngle() float64 {
	return f.angle
}

func (f *FluidSim10) Draw() {
	f.Sprite.Clear()

	vector.StrokeRect(f.Sprite, 0, 0, FS10PixelWidth, FS10PixelHeight, 2, color.White, true)

	for i := range f.fluid.Particles {
		//for each particle, compute its relative position based on its
		//position within the fluid field
		p := &f.fluid.Particles[i]
		percentx := p.Position.X / f.fluid.Field.Dimensions.X
		percenty := p.Position.Y / f.fluid.Field.Dimensions.Y
		ox := float64(percentx * FS10PixelWidth)
		oy := float64(percenty * FS10PixelHeight)

		op := &ebiten.DrawImageOptions{}
		op.GeoM.Translate(ox, oy)
		f.Sprite.DrawImage(f.particlebuff, op)
	}
}

func (f *FluidSim10) Update() {

	if f.paused {
		return
	}

	f.fluid.Step()
}