package game

import (
	"iter"
	"maps"
	"math"
	"slices"

	"github.com/google/uuid"
	e "github.com/iliadenisov/galaxy/internal/error"
	"github.com/iliadenisov/galaxy/internal/number"
)

type CargoType string

const (
	// CargoNone     CargoType = "-"
	CargoColonist CargoType = "COL" // Колонисты
	CargoMaterial CargoType = "MAT" // Сырьё
	CargoCapital  CargoType = "CAP" // Промышленность
)

func (ct CargoType) Ref() *CargoType {
	return &ct
}

type ShipGroup struct {
	Index   uint       `json:"index"`             // FIXME: use UUID for Group Index (ordered)
	OwnerID uuid.UUID  `json:"ownerId"`           // Race link
	TypeID  uuid.UUID  `json:"typeId"`            // ShipType link
	FleetID *uuid.UUID `json:"fleetId,omitempty"` // Fleet link
	Number  uint       `json:"number"`            // Number (quantity) ships of specific ShipType
	State   string     `json:"state"`             // TODO: kinda enum: In_Orbit, In_Space, Transfer_State, Upgrade

	CargoType *CargoType `json:"loadType,omitempty"`
	Load      float64    `json:"load"` // Cargo loaded - "Масса груза"

	Drive   float64 `json:"drive"`
	Weapons float64 `json:"weapons"`
	Shields float64 `json:"shields"`
	Cargo   float64 `json:"cargo"`

	// TODO: TEST: Destination, Origin, Range
	Destination uint     `json:"destination"`
	Origin      *uint    `json:"origin,omitempty"`
	Range       *float64 `json:"range,omitempty"`
}

func (sg ShipGroup) Equal(other ShipGroup) bool {
	return sg.OwnerID == other.OwnerID &&
		sg.TypeID == other.TypeID &&
		sg.FleetID == other.FleetID &&
		sg.Drive == other.Drive &&
		sg.Weapons == other.Weapons &&
		sg.Shields == other.Shields &&
		sg.Cargo == other.Cargo &&
		sg.CargoType == other.CargoType &&
		sg.Load == other.Load &&
		sg.State == other.State
}

// Грузоподъёмность
func (sg ShipGroup) CargoCapacity(st *ShipType) float64 {
	return sg.Cargo * (st.Cargo + (st.Cargo*st.Cargo)/20) * float64(sg.Number)
}

// Масса перевозимого груза -
// общее количество единиц груза, деленное на технологический уровень Грузоперевозок
func (sg ShipGroup) CarryingMass() float64 {
	return sg.Load / sg.Cargo
}

// Полная  масса -
// массу корабля самого по себе плюс масса перевозимого груза.
func (sg ShipGroup) FullMass(st *ShipType) float64 {
	return st.EmptyMass() + sg.CarryingMass()
}

// Эффективность двигателя -
// равна мощности Двигателей, умноженной на технологический уровень блока Двигателей
func (sg ShipGroup) DriveEffective(st *ShipType) float64 {
	return st.Drive * sg.Drive
}

// Корабли перемещаются за один ход на количество световых лет, равное
// эффективности двигателя, умноженной на 20 и деленной на "Полную массу" корабля.
func (sg ShipGroup) Speed(st *ShipType) float64 {
	return sg.DriveEffective(st) * 20 / sg.FullMass(st)
}

func (sg ShipGroup) UpgradeDriveCost(st *ShipType, drive float64) float64 {
	return (1 - sg.Drive/drive) * 10 * st.Drive
}

// TODO: test on other values
func (sg ShipGroup) UpgradeWeaponsCost(st *ShipType, weapons float64) float64 {
	return (1 - sg.Weapons/weapons) * 10 * st.WeaponsMass()
}

func (sg ShipGroup) UpgradeShieldsCost(st *ShipType, shields float64) float64 {
	return (1 - sg.Shields/shields) * 10 * st.Shields
}

func (sg ShipGroup) UpgradeCargoCost(st *ShipType, cargo float64) float64 {
	return (1 - sg.Cargo/cargo) * 10 * st.Cargo
}

// Мощность бомбардировки
// TODO: maybe rounding must be done only for display?
func (sg ShipGroup) BombingPower(st *ShipType) float64 {
	// return math.Sqrt(sg.Type.Weapons * sg.Weapons)
	result := (math.Sqrt(st.Weapons*sg.Weapons)/10. + 1.) *
		st.Weapons *
		sg.Weapons *
		float64(st.Armament) *
		float64(sg.Number)
	return number.Fixed3(result)
}

func (g *Game) JoinEqualGroups(raceName string) error {
	ri, err := g.raceIndex(raceName)
	if err != nil {
		return err
	}
	g.joinEqualGroupsInternal(ri)
	return nil
}

func (g *Game) BreakGroup(raceName string, groupIndex, quantity uint) error {
	ri, err := g.raceIndex(raceName)
	if err != nil {
		return err
	}
	return g.breakGroupInternal(ri, groupIndex, quantity)
}

func (g *Game) GiveawayGroup(raceName, raceAcceptor string, groupIndex, quantity uint) error {
	ri, err := g.raceIndex(raceName)
	if err != nil {
		return err
	}
	riAccept, err := g.raceIndex(raceAcceptor)
	if err != nil {
		return err
	}
	return g.giveawayGroupInternal(ri, riAccept, groupIndex, quantity)
}

func (g *Game) giveawayGroupInternal(ri, riAccept int, groupIndex, quantity uint) (err error) {
	if ri == riAccept {
		return e.NewInputSameRaceError(g.Race[riAccept].Name)
	}
	sgi := -1
	for i, sg := range g.listIndexShipGroups(ri) {
		if sgi < 0 && sg.Index == groupIndex {
			sgi = i
		}
	}
	if sgi < 0 {
		return e.NewEntityNotExistsError("group #%d", groupIndex)
	}
	if g.ShipGroups[sgi].Number < quantity {
		return e.NewBeakGroupNumberNotEnoughError("%d<%d", g.ShipGroups[sgi].Number, quantity)
	}

	var sti int
	if sti = slices.IndexFunc(g.Race[ri].ShipTypes, func(st ShipType) bool { return st.ID == g.ShipGroups[sgi].TypeID }); sti < 0 {
		// hard to test, need manual game data invalidation
		return e.NewGameStateError("not found: ShipType ID=%v", g.ShipGroups[sgi].TypeID)
	}

	var stAcc int
	if stAcc = slices.IndexFunc(g.Race[riAccept].ShipTypes, func(st ShipType) bool { return st.Name == g.Race[ri].ShipTypes[sti].Name }); stAcc >= 0 &&
		!g.Race[ri].ShipTypes[sti].Equal(g.Race[riAccept].ShipTypes[stAcc]) {
		return e.NewGiveawayGroupShipsTypeNotEqualError("race %w, ship type %w", g.Race[riAccept].Name, g.Race[riAccept].ShipTypes[stAcc].Name)
	}
	if stAcc < 0 {
		stAcc, err = g.createShipTypeInternal(riAccept,
			g.Race[ri].ShipTypes[sti].Name,
			g.Race[ri].ShipTypes[sti].Drive,
			g.Race[ri].ShipTypes[sti].Weapons,
			g.Race[ri].ShipTypes[sti].Shields,
			g.Race[ri].ShipTypes[sti].Cargo,
			int(g.Race[ri].ShipTypes[sti].Armament))
		if err != nil {
			return err
		}
	}

	var maxIndex uint
	for sg := range g.listShipGroups(riAccept) {
		if sg.Index > maxIndex {
			maxIndex = sg.Index
		}
	}

	g.ShipGroups = append(g.ShipGroups, ShipGroup{
		Index:   maxIndex + 1,
		OwnerID: g.Race[riAccept].ID,
		TypeID:  g.Race[riAccept].ShipTypes[stAcc].ID,
		Number:  uint(quantity),
		State:   g.ShipGroups[sgi].State,

		CargoType: g.ShipGroups[sgi].CargoType,
		Load:      g.ShipGroups[sgi].Load,

		Drive:   g.ShipGroups[sgi].Drive,
		Weapons: g.ShipGroups[sgi].Weapons,
		Shields: g.ShipGroups[sgi].Shields,
		Cargo:   g.ShipGroups[sgi].Cargo,

		Destination: g.ShipGroups[sgi].Destination,
		Origin:      g.ShipGroups[sgi].Origin,
		Range:       g.ShipGroups[sgi].Range,
	})

	if quantity == 0 || quantity == g.ShipGroups[sgi].Number {
		g.ShipGroups = append(g.ShipGroups[:sgi], g.ShipGroups[sgi+1:]...)
	} else {
		g.ShipGroups[sgi].Number -= quantity
	}

	return nil
}

func (g *Game) breakGroupInternal(ri int, groupIndex, quantity uint) error {
	sgi := -1
	var maxIndex uint
	for i, sg := range g.listIndexShipGroups(ri) {
		if sgi < 0 && sg.Index == groupIndex {
			sgi = i
		}
		if sg.Index > maxIndex {
			maxIndex = sg.Index
		}
	}
	if sgi < 0 {
		return e.NewEntityNotExistsError("group #%d", groupIndex)
	}

	if g.ShipGroups[sgi].State != "In_Orbit" || g.ShipGroups[sgi].Origin != nil || g.ShipGroups[sgi].Range != nil {
		return e.NewShipsBusyError()
	}

	if g.ShipGroups[sgi].Number < quantity {
		return e.NewBeakGroupNumberNotEnoughError("%d<%d", g.ShipGroups[sgi].Number, quantity)
	}

	if quantity == 0 || quantity == g.ShipGroups[sgi].Number {
		g.ShipGroups[sgi].FleetID = nil
	} else {
		newGroup := g.ShipGroups[sgi]
		newGroup.Number = quantity
		g.ShipGroups[sgi].Number -= quantity
		newGroup.Index = maxIndex + 1
		newGroup.FleetID = nil
		g.ShipGroups = append(g.ShipGroups, newGroup)
	}

	return nil
}

func (g *Game) joinEqualGroupsInternal(ri int) {
	shipGroups := slices.Collect(maps.Values(maps.Collect(g.listIndexShipGroups(ri))))
	origin := len(shipGroups)
	if origin < 2 {
		return
	}
	for i := 0; i < len(shipGroups)-1; i++ {
		for j := len(shipGroups) - 1; j > i; j-- {
			if shipGroups[i].Equal(shipGroups[j]) {
				shipGroups[i].Index = maxUint(shipGroups[i].Index, shipGroups[j].Index)
				shipGroups[i].Number += shipGroups[j].Number
				shipGroups = append(shipGroups[:j], shipGroups[j+1:]...)
			}
		}
	}
	if len(shipGroups) == origin {
		return
	}
	g.ShipGroups = slices.DeleteFunc(g.ShipGroups, func(v ShipGroup) bool { return v.OwnerID == g.Race[ri].ID })
	g.ShipGroups = append(g.ShipGroups, shipGroups...)
}

func (g *Game) createShips(ri int, shipTypeName string, planetNumber int, quantity int) error {
	st := slices.IndexFunc(g.Race[ri].ShipTypes, func(st ShipType) bool { return st.Name == shipTypeName })
	if st < 0 {
		return e.NewEntityNotExistsError("ship type %w", shipTypeName)
	}
	pl := slices.IndexFunc(g.Map.Planet, func(p Planet) bool { return p.Number == uint(planetNumber) })
	if pl < 0 {
		return e.NewEntityNotExistsError("planet #%d", planetNumber)
	}
	if g.Map.Planet[pl].Owner != g.Race[ri].ID {
		return e.NewEntityNotOwnedError("planet %#d", planetNumber)
	}

	var maxIndex uint
	for _, sg := range g.listIndexShipGroups(ri) {
		if sg.Index > maxIndex {
			maxIndex = sg.Index
		}
	}
	g.ShipGroups = append(g.ShipGroups, ShipGroup{
		Index:       maxIndex + 1,
		OwnerID:     g.Race[ri].ID,
		TypeID:      g.Race[ri].ShipTypes[st].ID,
		Destination: g.Map.Planet[pl].Number,
		Number:      uint(quantity),
		State:       "In_Orbit",
		Drive:       g.Race[ri].Drive,
		Weapons:     g.Race[ri].Weapons,
		Shields:     g.Race[ri].Shields,
		Cargo:       g.Race[ri].Cargo,
	})
	return nil
}

func (g Game) listShipGroups(ri int) iter.Seq[ShipGroup] {
	return func(yield func(ShipGroup) bool) {
		for _, sg := range g.listIndexShipGroups(ri) {
			if !yield(sg) {
				return
			}
		}
	}
}

func (g Game) listIndexShipGroups(ri int) iter.Seq2[int, ShipGroup] {
	return func(yield func(int, ShipGroup) bool) {
		for i := range g.ShipGroups {
			if g.ShipGroups[i].OwnerID == g.Race[ri].ID {
				if !yield(i, g.ShipGroups[i]) {
					return
				}
			}
		}
	}
}

func maxUint(a, b uint) uint {
	if b > a {
		return b
	}
	return a
}