package game

import (
	"fmt"
	"slices"

	e "github.com/iliadenisov/galaxy/internal/error"
	"github.com/iliadenisov/galaxy/internal/util"
)

func (g *Game) SendFleet(raceName, fleetName string, planetNumber uint) error {
	ri, err := g.raceIndex(raceName)
	if err != nil {
		return err
	}
	fi := g.fleetIndex(ri, fleetName)
	if fi < 0 {
		return e.NewEntityNotExistsError("fleet %q", fleetName)
	}
	return g.sendFleetInternal(ri, fi, planetNumber)
}

func (g *Game) sendFleetInternal(ri, fi int, planetNumber uint) error {
	state, sourcePlanet, _ := FleetState(g, g.Fleets[fi].ID)
	if StateInOrbit != state && StateLaunched != state {
		return e.NewShipsBusyError()
	}

	p1, ok := PlanetByNum(g, *sourcePlanet)
	if !ok {
		return e.NewGameStateError("source planet #%d does not exists", sourcePlanet)
	}
	p2, ok := PlanetByNum(g, planetNumber)
	if !ok {
		return e.NewEntityNotExistsError("destination planet #%d", planetNumber)
	}
	rangeToDestination := util.ShortDistance(g.Map.Width, g.Map.Height, p1.X, p1.Y, p2.X, p2.Y)
	if rangeToDestination > g.Race[ri].FlightDistance() {
		return e.NewSendUnreachableDestinationError("range=%.03f", rangeToDestination)
	}

	for sg := range FleetGroups(g, ri, fi) {
		st, ok := ShipClass(g, ri, sg.TypeID)
		if !ok {
			return e.NewGameStateError("not found: ShipType ID=%v", sg.TypeID)
		}
		if st.DriveBlockMass() == 0 {
			return e.NewSendShipHasNoDrivesError("Class=%s", st.Name)
		}
	}

	if *sourcePlanet == planetNumber {
		UnsendFleet(g, ri, fi)
		return nil
	}

	LaunchFleet(g, ri, fi, planetNumber)

	return nil
}

func LaunchFleet(g *Game, ri, fi int, destination uint) {
	for sg := range FleetGroups(g, ri, fi) {
		sgi := slices.IndexFunc(g.ShipGroups, func(s ShipGroup) bool { return sg.Index == s.Index })
		if sgi < 0 {
			panic(fmt.Sprintf("LauncgFleet: cannot find ship group index=%d", sg.Index))
		}
		g.ShipGroups[sgi] = LaunchShips(sg, destination)
	}
}

func UnsendFleet(g *Game, ri, fi int) {
	for sg := range FleetGroups(g, ri, fi) {
		sgi := slices.IndexFunc(g.ShipGroups, func(s ShipGroup) bool { return sg.Index == s.Index })
		if sgi < 0 {
			panic(fmt.Sprintf("UnsendFleet: cannot find ship group index=%d", sg.Index))
		}
		g.ShipGroups[sgi] = UnsendShips(sg)
	}
}