openquell/systems/player_system.go

package systems

import (
	"log/slog"
	. "openquell/components"
	. "openquell/config"
	"openquell/grid"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/inpututil"
	"github.com/mlange-42/arche/ecs"
	"github.com/mlange-42/arche/generic"
)

type PlayerSystem struct {
	World         *ecs.World
	Selector      *generic.Filter4[Position, Velocity, Player, Renderable]
	GridContainer *grid.GridContainer
}

func NewPlayerSystem(world *ecs.World, gridcontainer *grid.GridContainer) System {
	system := &PlayerSystem{
		Selector:      generic.NewFilter4[Position, Velocity, Player, Renderable](),
		GridContainer: gridcontainer,
		World:         world,
	}

	return system
}

func (system PlayerSystem) Update() error {
	// first check if we need to switch player
	switchable := false
	query := system.Selector.Query(system.World)
	count := query.Count()

	for query.Next() {
		_, _, player, _ := query.Get()
		if !player.IsPrimary {
			switchable = true
		}
	}

	if switchable {
		query := system.Selector.Query(system.World)
		for query.Next() {
			_, _, player, render := query.Get()

			if count == 1 && !player.IsPrimary {
				// there's only one player left, make it the primary one
				player.IsPrimary = true
				render.Image = player.SwitchSprite()
			} else {
				// many players, switch when requested
				if inpututil.IsKeyJustPressed(ebiten.KeyTab) {
					slog.Debug("switch players")
					if player.IsPrimary {
						player.IsPrimary = false
						render.Image = player.SwitchSprite()
					} else {
						player.IsPrimary = true
						render.Image = player.SwitchSprite()
					}
				}
			}
		}
	}

	// check player movements etc
	query = system.Selector.Query(system.World)
	for query.Next() {
		playerposition, velocity, player, _ := query.Get()

		if !player.IsPrimary {
			continue
		}

		if !velocity.Moving() {
			switch {
			case ebiten.IsKeyPressed(ebiten.KeyRight):
				velocity.Change(East)
			case ebiten.IsKeyPressed(ebiten.KeyLeft):
				velocity.Change(West)
			case ebiten.IsKeyPressed(ebiten.KeyDown):
				velocity.Change(South)
			case ebiten.IsKeyPressed(ebiten.KeyUp):
				velocity.Change(North)
			case ebiten.IsKeyPressed(ebiten.Key1):
				velocity.Speed = 1
			case ebiten.IsKeyPressed(ebiten.Key2):
				velocity.Speed = 2
			case ebiten.IsKeyPressed(ebiten.Key3):
				velocity.Speed = 3
			case ebiten.IsKeyPressed(ebiten.Key4):
				velocity.Speed = 4
			case ebiten.IsKeyPressed(ebiten.Key5):
				velocity.Speed = 5
			case ebiten.IsKeyPressed(ebiten.Key6):
				velocity.Speed = 6
			case ebiten.IsKeyPressed(ebiten.Key7):
				velocity.Speed = 7
			case ebiten.IsKeyPressed(ebiten.Key8):
				velocity.Speed = 8
			case ebiten.IsKeyPressed(ebiten.Key9):
				velocity.Speed = 9
				// other keys: <tab>: switch player, etc
			}
		}

		if velocity.Moving() {
			ok, newpos := system.GridContainer.Grid.BumpEdge(playerposition, velocity)
			if ok {
				//slog.Debug("falling off the edge", "newpos", newpos)
				playerposition.Set(newpos)
			} else {
				ok, tilepos := system.GridContainer.Grid.GetSolidNeighborPosition(playerposition, velocity, true)
				if ok {
					slog.Debug("HaveSolidNeighbor", "ok", ok, "tilepos",
						tilepos.Point(), "playerpos", playerposition)
					intersects, newpos := tilepos.Intersects(playerposition, velocity)
					if intersects {
						// slog.Debug("collision detected", "tile",
						// 	tilepos, "player", playerposition, "new", newpos)

						playerposition.Set(newpos)
						velocity.Change(Stop)
					}
				}
			}
		}
	}

	query = system.Selector.Query(system.World)
	for query.Next() {
		// move player after obstacle or collectible updates
		playerposition, velocity, _, _ := query.Get()
		playerposition.Move(velocity)
	}

	return nil
}

func (system *PlayerSystem) Draw(screen *ebiten.Image) {
	// write the movable tiles
	op := &ebiten.DrawImageOptions{}
	query := system.Selector.Query(system.World)

	for query.Next() {
		pos, _, _, sprite := query.Get()

		op.GeoM.Reset()
		op.GeoM.Translate(float64(pos.X), float64(pos.Y))

		screen.DrawImage(sprite.Image, op)
	}
}