package game

import (
	"fmt"
)

type (
	ActionCostFunc      func(*State) bool
	ActionResolveFunc   func(*State)
	ActionFuncPrototype func(Action) ActionResolveFunc
)

type Action interface {
	Source() interface{}
	Targets() *Targets

	CheckTargets(*State) error
	PayCosts(s *State) bool
	Resolve(s *State)
	String() string
}

type PassPriority struct{ source *Player }

func (a *PassPriority) Source() interface{}     { return a.source }
func (*PassPriority) Targets() *Targets         { return nil }
func (*PassPriority) CheckTargets(*State) error { return nil }
func (*PassPriority) PayCosts(*State) bool      { return true }
func (*PassPriority) Resolve(*State)            {}
func (*PassPriority) String() string            { return "pass" }
func NewPassPriority(p *Player) Action          { return &PassPriority{p} }

type HandCardSelection struct{ cards []*Card }

func (*HandCardSelection) Source() interface{}       { return nil }
func (*HandCardSelection) Targets() *Targets         { return nil }
func (*HandCardSelection) CheckTargets(*State) error { return nil }
func (*HandCardSelection) PayCosts(*State) bool      { return true }
func (*HandCardSelection) Resolve(*State)            {}
func (*HandCardSelection) String() string            { return "hand card selection" }
func NewHandCardSelection(cards []*Card) Action      { return &HandCardSelection{cards} }

type ActionBase struct {
	source      interface{}
	Card        *Card
	targets     *Targets
	resolveFunc ActionResolveFunc
	costFunc    ActionCostFunc
}

func (a *ActionBase) Source() interface{} {
	return a.source
}

func (a *ActionBase) Resolve(s *State) {
	a.resolveFunc(s)
}

func (a *ActionBase) PayCosts(s *State) bool {
	return a.costFunc(s)
}

func (a *ActionBase) Targets() *Targets {
	return a.targets
}

func (a *ActionBase) CheckTargets(s *State) error {
	return a.targets.CheckTargets(s)
}

type PlayAction struct {
	ActionBase
}

const permanentPlayActionTarget = "available spawn tile"

func NewPlayAction(p *Player, c *Card, args ...interface{}) *PlayAction {
	a := &PlayAction{ActionBase{
		source: p,
		Card:   c,
	}}

	if len(args) > 0 {
		if costFunc, ok := args[0].(ActionCostFunc); ok {
			a.costFunc = costFunc
		}
	}

	if a.costFunc == nil {
		a.costFunc = func(*State) bool {
			cost := c.PlayCosts()

			if p.Resource < cost {
				return false
			}
			p.Resource -= cost
			return true
		}
	}

	s := p.gameState
	if c.IsPermanent() {
		a.targets = newTargets(s, []string{permanentPlayActionTarget}, a)
	} else {
		a.targets = newTargets(s, []string{}, a)
	}

	p.Hand.RemoveCard(c)

	a.resolveFunc = func(s *State) {
		s.resolvePlay(p, c, a.targets)
	}

	return a
}

func (a *PlayAction) String() string {
	p := a.source.(*Player)
	if a.targets.RequireTargets() {
		return fmt.Sprintf(" %s play %s", p.Name, a.Card.Name)
	}

	return fmt.Sprintf("%s play %s@%v", p.Name, a.Card.Name, a.targets)
}

type MoveAction struct {
	ActionBase
}

const moveActionTargetDesc = "available tile"

func NewMoveAction(u *Unit) *MoveAction {
	a := &MoveAction{
		ActionBase{
			source: u,
			Card:   u.Card(),
		},
	}

	a.targets = newTargets(u.Controller().gameState, []string{moveActionTargetDesc}, a)

	a.resolveFunc = func(s *State) {
		tile := a.targets.sel[0].(*Tile)
		u.move(s, tile)
	}

	a.costFunc = func(*State) bool {
		if u.AvailMoveActions < 1 {
			return false
		}
		u.AvailMoveActions--
		return true
	}

	return a
}

func (a *MoveAction) String() string {
	u := a.source.(*Unit)
	if a.targets.RequireTargets() {
		return fmt.Sprintf("move %s", u.Movement.String())
	}

	t := a.targets.sel[0].(*Tile)
	return fmt.Sprintf("%v: %v -> %v", u.Controller().Name, u.Card().Name, t.Position)
}

type AttackAction struct {
	ActionBase
}

const attackActionTargetDesc = "attackable enemy permanent"

func NewAttackAction(u *Unit) *AttackAction {
	a := &AttackAction{ActionBase{
		source: u,
		Card:   u.Card(),
	}}

	a.targets = newTargets(u.Controller().gameState, []string{attackActionTargetDesc}, a)

	a.resolveFunc = func(s *State) {
		s.Fight(u, a.targets.sel[0].(Permanent))
	}

	a.costFunc = func(*State) bool {
		if u.AvailAttackActions < 1 {
			return false
		}
		u.AvailAttackActions--
		return true
	}

	return a
}

func (a *AttackAction) String() string {
	u := a.source.(*Unit)
	if a.targets.RequireTargets() {
		return fmt.Sprintf("attack %v", u.Attack)
	}

	target := a.targets.sel[0].(Permanent)
	return fmt.Sprintf("%v: %v x %v",
		u.Controller().Name, u.Card().Name, target.Tile().Position)
}

type FullAction struct {
	ActionBase
	desc string
}

func NewFullAction(u *Unit, proto ActionFuncPrototype, desc string) *FullAction {
	a := &FullAction{
		ActionBase{
			source: u,
			Card:   u.Card(),
		},

		desc,
	}

	a.resolveFunc = func(s *State) {
		rf := proto(a)
		rf(s)
	}

	a.costFunc = func(*State) bool {
		if u.AvailAttackActions < 1 && u.AvailMoveActions < 1 {
			return false
		}
		u.AvailAttackActions--
		u.AvailMoveActions--
		return true
	}
	return a
}

func (a *FullAction) String() string {
	u := a.source.(*Unit)
	if a.targets.RequireTargets() {
		return fmt.Sprintf("↻ %s", a.desc)
	}

	return fmt.Sprintf("%v: %s ↻@%v", u.Controller(), u.Card().Name, a.targets)
}

type FreeAction struct {
	ActionBase
	desc string
}

func NewFreeAction(p Permanent, resolveProto ActionFuncPrototype, costFunc ActionCostFunc,
	desc string,
) *FreeAction {
	a := &FreeAction{
		ActionBase{
			source:   p,
			Card:     p.Card(),
			costFunc: costFunc,
		},
		desc,
	}

	a.resolveFunc = func(s *State) {
		rf := resolveProto(a)
		rf(s)
	}

	return a
}

func (a *FreeAction) String() string {
	p := a.source.(Permanent)
	if a.targets.RequireTargets() {
		return fmt.Sprintf("free_action %s", a.desc)
	}

	return fmt.Sprintf("%v: %s free_action@%v", p.Controller(), p.Card().Name, a.targets)
}

type BuyAction struct {
	player *Player
	card   *Card
}

func (a *BuyAction) Source() interface{} {
	return a.player
}

func (a *BuyAction) Targets() *Targets {
	return newTargetsWithSel(a.player.gameState, []string{"store cards"}, a, []interface{}{a.card})
}

func (a *BuyAction) CheckTargets(s *State) error {
	return s.isValidBuy(a)
}

func (a *BuyAction) Resolve(s *State) {
	a.player.Store.MoveCard(a.card, a.player.DiscardPile)
}

func (a *BuyAction) PayCosts(*State) bool {
	if a.card.BuyCost < 0 || a.card.BuyCost > a.player.Resource {
		return false
	}

	a.player.Resource -= a.card.BuyCost
	return true
}

func (a *BuyAction) String() string { return fmt.Sprintf("%s buy %s", a.player.Name, a.card.Name) }

func NewBuyAction(p *Player, c *Card) *BuyAction {
	return &BuyAction{p, c}
}

type UpkeepAction struct {
	player *Player
	unit   *Unit
	pay    bool
}

func (a *UpkeepAction) Resolve(s *State) {
	if a.pay {
		a.player.Resource -= a.unit.Upkeep
	} else {
		s.DestroyPermanent(a.unit)
	}
}

func (a *UpkeepAction) PayCosts(*State) bool {
	if a.unit.Upkeep > a.player.Resource {
		return false
	}

	a.player.Resource -= a.unit.Upkeep
	return true
}

func (a *UpkeepAction) String() string {
	if a.pay {
		return fmt.Sprintf("%s keep %v", a.player.Name, a.unit.Tile().Position)
	}

	return fmt.Sprintf("%s disband %v", a.player.Name, a.unit.Tile().Position)
}

func NewUpkeepAction(p *Player, u *Unit, pay bool) *UpkeepAction {
	return &UpkeepAction{p, u, pay}
}