package game

import (
	"fmt"
	"log"
)

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

type Action interface {
	Source() interface{}
	Controller() *Player
	Targets() *Targets
	Target() *Target // Shortcut for to select the first target

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

type PassPriority struct{ player *Player }

func (a *PassPriority) Source() interface{}       { return a.player }
func (a *PassPriority) Controller() *Player       { return a.player }
func (*PassPriority) Targets() *Targets           { return nil }
func (*PassPriority) Target() *Target             { return nil }
func (*PassPriority) NeedsActionCostChoice() bool { return false }
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 TargetSelection struct {
	player  *Player
	targets *Targets
}

func (sel *TargetSelection) Source() interface{}         { return sel.player }
func (sel *TargetSelection) Controller() *Player         { return sel.player }
func (sel *TargetSelection) Targets() *Targets           { return sel.targets }
func (sel *TargetSelection) Target() *Target             { return sel.targets.ts[0] }
func (*TargetSelection) NeedsActionCostChoice() bool     { return false }
func (sel *TargetSelection) CheckTargets(s *State) error { return sel.targets.CheckTargets(s) }
func (*TargetSelection) PayCosts(*State) bool            { return true }
func (*TargetSelection) resolve(*State)                  {}
func (*TargetSelection) String() string                  { return "target selection" }

func newTargetSelection(player *Player, targets *Targets) Action {
	return &TargetSelection{player, targets}
}

func newHandCardSelection(p *Player, min, max int) Action {
	a := &TargetSelection{player: p}
	targetDesc := TargetDesc{"hand card", fmt.Sprintf("%d-%d", min, max)}
	a.targets = newTargets(newTarget(p.gameState, targetDesc, a))
	return a
}

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

func (a *ActionBase) Source() interface{} { return a.source }
func (a *ActionBase) Controller() *Player {
	switch t := a.source.(type) {
	case *Player:
		return t
	case Permanent:
		return t.Controller()
	default:
		log.Panicf("Unhandled source type %v", t)
		return nil
	}

	return nil
}
func (a *ActionBase) resolve(s *State) { a.resolveFunc(s) }
func (a *ActionBase) PayCosts(s *State) bool {
	if a.costFunc != nil {
		return a.costFunc(s)
	}
	return true
}
func (a *ActionBase) Targets() *Targets { return a.targets }
func (a *ActionBase) Target() *Target   { return a.targets.ts[0] }
func (a *ActionBase) CheckTargets(s *State) error {
	if a.targets == nil {
		return nil
	}
	return a.targets.CheckTargets(s)
}

type TriggeredAction struct {
	ActionBase
	event Event
}

func newTriggeredAction(event Event, source Trigger, resolveFunc ActionResolveFunc,
	costFunc ActionCostFunc,
) *TriggeredAction {
	return &TriggeredAction{
		ActionBase: ActionBase{
			source:      source,
			Card:        source.Card(),
			resolveFunc: resolveFunc,
			costFunc:    costFunc,
		},
		event: event,
	}
}

func (a *TriggeredAction) String() string {
	return fmt.Sprintf("%v ! %v", a.event, a.source)
}

// Wrapper action to pass all triggered actions through the PlayerControl
type DeclareTriggeredActionsAction struct {
	actions []*TriggeredAction
}

func (sel *DeclareTriggeredActionsAction) Source() interface{}         { return nil }
func (sel *DeclareTriggeredActionsAction) Controller() *Player         { return nil }
func (sel *DeclareTriggeredActionsAction) Targets() *Targets           { return nil }
func (sel *DeclareTriggeredActionsAction) Target() *Target             { return nil }
func (*DeclareTriggeredActionsAction) NeedsActionCostChoice() bool     { return false }
func (sel *DeclareTriggeredActionsAction) CheckTargets(s *State) error { return nil }
func (*DeclareTriggeredActionsAction) PayCosts(*State) bool            { return true }
func (*DeclareTriggeredActionsAction) resolve(*State)                  {}
func (*DeclareTriggeredActionsAction) String() string                  { return "declared triggered actions" }

type PileDropAction struct {
	ActionBase
	pile []Permanent
}

func (a *PileDropAction) String() string {
	perm := a.source.(Permanent)
	controller := perm.Controller()
	if a.targets.RequireSelection() {
		return fmt.Sprintf("%s drop %v", controller.Name, perm.Tile().Position)
	}

	s := fmt.Sprintf("%s drop [", controller.Name)
	pile := perm.Pile()
	for i, t := range a.targets.ts {
		s = fmt.Sprintf("%s %v@%v,", s, pile[i], t.sel[0])
	}
	return s[:len(s)-1] + " ]"
}

func (*PileDropAction) PayCosts(*State) bool { return true }

func newPileDropAction(perm Permanent, tile *Tile, pile []Permanent) *PileDropAction {
	a := &PileDropAction{
		ActionBase{
			source: perm,
		},
		pile,
	}

	a.resolveFunc = func(s *State) {
		for i, p := range pile {
			p.onDrop(p)
			p.setContainingPerm(nil)
			enterTileOrPile(p, a.targets.ts[i].sel[0].(*Tile))
		}

		perm.clearPile()
	}

	a.targets = newPileDropTargets(perm.Controller().gameState, a)
	return a
}

type PlayAction struct {
	ActionBase
}

var (
	permanentPlayActionTarget = TargetDesc{"available spawn tile", "1"}
	equipmentPlayActionTarget = TargetDesc{"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() {
		if c.Type == CardTypes.Equipment {
			a.targets = newTargets(newTarget(s, equipmentPlayActionTarget, a))
		} else {
			a.targets = newTargets(newTarget(s, permanentPlayActionTarget, a))
		}
	} else if targetDesc := c.Impl.playTargets(); targetDesc != INVALID_TARGET_DESC {
		a.targets = newTargets(newTarget(s, targetDesc, a))
	} else {
		a.targets = newTargets()
	}

	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.RequireSelection() {
		return fmt.Sprintf(" %s play %s", p.Name, a.Card.Name)
	}

	if a.Card.Type == CardTypes.Equipment && len(a.Target().sel) == 0 {
		return fmt.Sprintf("%s play %s@next unit", p.Name, a.Card.Name)
	}

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

type MoveAction struct {
	ActionBase
}

var moveActionTargetDesc = TargetDesc{"available tile", "1"}

func targetTile(t *Target) *Tile {
	if tile, ok := t.sel[0].(*Tile); ok {
		return tile
	}

	return t.sel[0].(*Unit).Tile()
}

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

	a.targets = newTargets(newTarget(u.Controller().gameState, moveActionTargetDesc, a))

	a.resolveFunc = func(s *State) {
		t := targetTile(a.Target())
		movePermanent(u, t)
	}

	a.costFunc = genMoveActionCost(u)

	return a
}

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

	t := targetTile(a.Target())
	return fmt.Sprintf("%v -> %v", u, t.Position)
}

func genBaseActionCost(u *Unit, attack, move int) ActionCostFunc {
	return func(*State) bool {
		if u.AvailAttackActions < attack || u.AvailMoveActions < move {
			return false
		}
		u.AvailAttackActions -= attack
		u.AvailMoveActions -= move
		return true
	}
}

func genAttackActionCost(u *Unit) ActionCostFunc {
	return genBaseActionCost(u, 1, 0)
}

func genMoveActionCost(u *Unit) ActionCostFunc {
	return genBaseActionCost(u, 0, 1)
}

func genFullActionCost(u *Unit) ActionCostFunc {
	return func(*State) bool {
		if u.AvailAttackActions < 1 || u.AvailMoveActions < 1 {
			return false
		}
		u.AvailAttackActions = 0
		u.AvailMoveActions = 0
		return true
	}
}

type EquipAction struct {
	ActionBase
	equipment *Equipment
}

func NewEquipAction(u *Unit, e *Equipment) *EquipAction {
	a := &EquipAction{
		ActionBase{
			source: u,
			Card:   u.Card(),
		},
		e,
	}

	a.resolveFunc = func(s *State) {
		u.equip(e)
	}

	return a
}

func (a *EquipAction) String() string {
	u := a.source.(*Unit)
	return fmt.Sprintf("%v equip %v", u, a.equipment)
}

type AttackAction struct {
	ActionBase
}

var attackActionTargetDesc = TargetDesc{"attackable enemy permanent", "1"}

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

	a.targets = newTargets(newTarget(u.Controller().gameState, attackActionTargetDesc, a))

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

	a.costFunc = genAttackActionCost(u)

	return a
}

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

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

type ArtifactSwitchAction struct {
	ActionBase
	Artifact Permanent
}

func newArtifactSwitchAction(u *Unit, artifact Permanent) *ArtifactSwitchAction {
	a := &ArtifactSwitchAction{
		ActionBase{
			source: u,
			Card:   u.Card(),
		},
		artifact,
	}

	a.resolveFunc = func(s *State) {
		s.switchPermanents(a.Source().(*Unit), a.Artifact)
	}

	a.costFunc = genMoveActionCost(u)

	return a
}

func (a *ArtifactSwitchAction) String() string {
	return fmt.Sprintf("%v <-> %v", a.Source().(*Unit), a.Artifact)
}

type ArtifactMoveAction struct {
	ActionBase
	Artifact Permanent
}

func newArtifactMoveAction(u *Unit, artifact Permanent) *ArtifactMoveAction {
	a := &ArtifactMoveAction{
		ActionBase{
			source: u,
			Card:   u.Card(),
		},
		artifact,
	}

	a.targets = newArtifactMoveTargets(u.Controller().gameState, a)

	a.resolveFunc = func(s *State) {
		tile := targetTile(a.Targets().ts[0])
		movePermanent(u, tile)

		tile = targetTile(a.Targets().ts[1])
		movePermanent(artifact, tile)
	}

	a.costFunc = genFullActionCost(u)

	return a
}

func (a *ArtifactMoveAction) String() string {
	if !a.Targets().HasSelections() {
		return fmt.Sprintf("%v move %v", a.Source().(*Unit), a.Artifact)
	}

	t1 := targetTile(a.Targets().ts[0])
	t2 := targetTile(a.Targets().ts[1])
	return fmt.Sprintf("%v,%v -> %v,%v", a.Source().(*Unit), a.Artifact, t1, t2)
}

type FullAction struct {
	ActionBase
	desc string
	tag  string
}

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

		desc: desc,
	}

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

	a.costFunc = genFullActionCost(u)
	return a
}

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

	return fmt.Sprintf("%v↻@%v", u, 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.RequireSelection() {
		return fmt.Sprintf("free_action %s", a.desc)
	}

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

var buyActionTargetDesc = TargetDesc{"store card", "?"}

type BuyAction struct{ TargetSelection }

func (a *BuyAction) card() *Card {
	return a.Target().sel[0].(*Card)
}

func (a *BuyAction) CheckTargets(s *State) error {
	err := a.targets.CheckTargets(s)
	if err != nil {
		return err
	}
	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 {
	cost := a.card().BuyCost
	if cost < 0 || cost > a.player.Resource {
		return false
	}

	a.player.Resource -= cost
	return true
}

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

	return fmt.Sprintf("%s buy %s", a.player.Name, a.card().Name)
}

func newBuyAction(p *Player) *BuyAction {
	a := &BuyAction{TargetSelection{player: p}}
	a.targets = newTargets(newTarget(p.gameState, buyActionTargetDesc, a))
	return a
}

var upkeepActionTargetDesc = TargetDesc{"unit you controll", "*"}

type UpkeepAction struct {
	TargetSelection
}

func (a *UpkeepAction) PayCosts(*State) bool {
	costs := 0
	for _, t := range a.Target().sel {
		u := t.(*Unit)
		costs += u.UpkeepCost()
	}

	if a.player.Resource < costs {
		return false
	}

	a.player.Resource -= costs
	return true
}

func (a *UpkeepAction) resolve(*State) {
	p := a.player
	s := p.gameState
	for _, i := range a.Target().sel {
		u := i.(*Unit)
		s.destroyPermanent(u)
	}

	// Keep and pay for the rest
	for _, u := range s.Units {
		if u.Controller() != p {
			continue
		}

		p.Resource -= u.upkeep
		u.onUpkeep()
	}
}

func (a *UpkeepAction) String() string {
	return fmt.Sprintf("upkeep disbanding: %v", a.Target().sel)
}

func newUpkeepAction(p *Player) *UpkeepAction {
	a := &UpkeepAction{TargetSelection{player: p}}
	a.targets = newTargets(newTarget(p.gameState, upkeepActionTargetDesc, a))

	return a
}

func (a *ActionBase) NeedsActionCostChoice() bool {
	return a.costFunc == nil
}

func UseMoveAction(a Action) {
	switch a := a.(type) {
	case *EquipAction:
		a.costFunc = genMoveActionCost(a.Source().(*Unit))
	}
}

func UseAttackAction(a Action) {
	switch a := a.(type) {
	case *EquipAction:
		a.costFunc = genAttackActionCost(a.Source().(*Unit))
	}
}