CardSimEngine/cardsim/player.go

454 lines
16 KiB
Go

package cardsim
import (
"errors"
"fmt"
"math/rand"
"time"
)
var (
ErrUncooperativeCards = errors.New("a milion cards refused to join the hand")
ErrInvalidCard = errors.New("invalid card specified")
ErrInvalidChoice = errors.New("invalid choice specified")
ErrNotUrgent = errors.New("action not urgent when urgent card is available")
ErrNoActions = errors.New("no actions remaining")
WarningStalemate = errors.New("no actions can be taken")
)
// Player stores all gameplay state for one player at a specific point in time.
// Game-specific data is stored in Stats.
//
// Player is a generic type -- see https://go.dev/blog/intro-generics for more
// information on how these work. Think of "Player" as a "type of type" --
// when you create one, you tell it what kind of data it needs to keep for
// the simulation itself, and each Player that works with a different kind of
// data is a different kind of Player and the compiler will help you with that.
// This is the same idea as "slice of something" or "map from something to
// something" -- different kinds of Players are different from each other and
// "know" what type of data they use, so the compiler can tell you if you're
// using the wrong type.
//
// Generic types have to use a placeholder to represent the type (or types --
// consider maps, which have both keys and values) that will be more specific
// when the type is actually used. They're called "type parameters", like
// function parameters, because they're the same kind of idea. A function puts
// its parameters into variables so you can write a function that works with
// whatever data it gets; a generic type takes type parameters and represents
// them with type placeholders so you can write a *type* that works with
// whatever specific other types it gets.
//
// Just like function parameters have a type that says what kind of data the
// function works with, type parameters have a "type constraint" that says what
// kind of types the generic type works with. Go already has a familiar way
// to express the idea of "what a type has to do": `interface`. In Go, type
// constraints are just interfaces.
//
// But wait, why use generics at all? Can't we just use an interface in the
// normal way instead of doing this thing? Well, yes, we could, but then the
// compiler doesn't know that the "real types" for things matching these
// interfaces all have to actually be the same type. The compiler will stop
// you from putting an `Orange` into a `[]Apple`, but it wouldn't stop you from
// putting a `Fruit` into a `[]Fruit` because, well, of course it wouldn't,
// they're the same type.
//
// Different simulation games made with `cardsim` are different. Rules made for
// simulating the economy of a kobold colony and mine wouldn't work at all with
// data for a simulation about three flocks of otter-gryphons having a
// territory conflict over a river full of fish. By using generics, the compiler
// can recognize functions and data and types intended for different simulation
// games and prevent you from using the wrong one, when it wouldn't be able to
// if all this stuff was written for "some simulation game, don't care what".
//
// Generic interfaces (like `Card[C]`, `Rule[C]`, `InfoPanel[C]`, and more)
// don't mean you have to write generics of your own. It's exactly the opposite!
// Because the interface has this extra type in it, you only need to implement
// the specific kind of interface that works with your game. There's more detail
// on this in the comment on `Rule[C]`.
type Player[C StatsCollection] struct {
// Stats stores simulation-specific state.
Stats C
// Name stores the player's name.
Name string
// Rand is a source of randomness that other components can use.
Rand *rand.Rand
Deck *Deck[C]
Hand []Card[C]
TurnNumber int
State GameState
// HandLimit is number of cards to draw to at the start of each turn.
// If the player has more cards than this already, none will be drawn,
// but the player will keep them all.
//
// If this is 0 or less and the player has no cards in hand, no permanent
// actions available, and must take an action, the game ends in stalemate.
HandLimit int
// ActionsPerTurn is what ActionsRemaining resets to at the start of each
// turn. If this is 0 or less at the start of a turn, the game ends in
// stalemate. Activating a card or permanent action spends an action, but
// the card or action itself can counter this by changing the player's
// ActionsRemaining by giving the action back -- or force the turn to
// progress immediately to simulation by setting it to 0.
ActionsPerTurn int
ActionsRemaining int
// PermanentActions are an "extra hand" of cards that are not discarded when
// used. An Urgent PermanentAction does not block non-urgent actions and
// cards in hand from being used, but it can be used even when an urgent
// card is in the hand.
PermanentActions []Card[C]
// InfoPanels lists informational views available to the player. The Prompt
// is the InfoPanel shown before the main action menu.
InfoPanels []InfoPanel[C]
Prompt InfoPanel[C]
// Rules are the simulation rules executed every turn after the player has
// run out of remaining actions. See `RuleCollection`'s documentation for
// more information about how rule execution works.
Rules *RuleCollection[C]
// Temporary messages are shown *before* the Prompt. They're cleared just
// before executing rules for the turn, so rules adding to TemporaryMessages
// are creating messages that will show up for the next turn. Temporary
// panels are cleared out at the same time as temporary messages; when
// available, they are listed separately from standard panels (before them).
TemporaryMessages []Message
TemporaryPanels []InfoPanel[C]
// DebugLevel stores how verbose the game should be about errors. If this
// is greater than 0, invisible stats will usually be shown to the player
// (this is up to individual info panels, though). If this is -1 or lower,
// warning messages will not be displayed.
DebugLevel int
}
// GameState represents various states a player's Game can be in.
type GameState int
const (
// The game has not started.
GameUninitialized = GameState(iota)
// The game is ready to play.
GameActive
// The game is over and the player has lost.
GameLost
// The game is over and the player has won.
GameWon
// The game is over because of an error.
GameCrashed
// The game is over because the player cannot take any actions.
GameStalled
)
// InitPlayer returns a mostly-uninitialized Player with the fields
// that require specific initialization already configured and the
// provided StatsCollection (if any) already assigned to its Stats.
// Most fields are not configured and need to be assigned after this.
//
// The Player is initialized with an empty deck, empty rule collection,
// a hand limit of 1, an actions-per-turn limit of 1, and a random
// number generator seeded with the nanosecond component of the current time.
// The Deck shares this random number generator.
func InitPlayer[C StatsCollection](stats C) *Player[C] {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
return &Player[C]{
Stats: stats,
Rand: r,
Deck: &Deck[C]{rand: r},
HandLimit: 1,
ActionsPerTurn: 1,
Rules: NewRuleCollection[C](),
}
}
// Over returns whether this state represents a game that is over.
func (g GameState) Over() bool {
return g == GameLost || g == GameWon || g == GameCrashed || g == GameStalled
}
// ChapterBreak apends a chapter break to p.TemporaryMessages, unless it is
// empty or the most recent non-nil message is already a chapter break.
func (p *Player[C]) ChapterBreak() {
for i := len(p.TemporaryMessages) - 1; i >= 0; i-- {
m := p.TemporaryMessages[i]
if IsSpecialMessage(m, ChapterBreak) {
return
}
if p.TemporaryMessages[i] != nil {
p.TemporaryMessages = append(p.TemporaryMessages, ChapterBreak)
return
}
}
// No non-nil messages -- nothing to do.
}
// SectionBreak apends a section break to p.TemporaryMessages, unless it is
// empty or the most recent non-nil message is already a section/chapter break.
func (p *Player[C]) SectionBreak() {
for i := len(p.TemporaryMessages) - 1; i >= 0; i-- {
m := p.TemporaryMessages[i]
if IsSpecialMessage(m, ChapterBreak) || IsSpecialMessage(m, SectionBreak) {
return
}
if m != nil {
p.TemporaryMessages = append(p.TemporaryMessages, SectionBreak)
return
}
}
// No non-nil messages -- nothing to do.
}
// Simulate executes the simulation up to the start of the next turn. If the
// simulation crashes, the game state becomes GameCrashed. This returns any
// generated errors; if the debugging mode is 0 or greater, they also become
// temporary messages for the next turn.
func (p *Player[C]) Simulate() error {
var errs ErrorCollector
p.TemporaryMessages = nil
p.TemporaryPanels = nil
errs.Add(p.Rules.Run(p))
errs.Add(p.StartNextTurn())
if errs.HasFailure() {
p.State = GameCrashed
}
if p.DebugLevel > 0 && !errs.IsEmpty() {
p.ChapterBreak()
p.TemporaryMessages = append(p.TemporaryMessages, Msgf("%d ERRORS AND WARNINGS:", len(errs.Errs)))
for i, e := range errs.Errs {
yikes := " "
if IsSeriousError(e) {
yikes = "!"
}
p.TemporaryMessages = append(p.TemporaryMessages, Msgf("%s[%d]:\t%v", yikes, i, e))
}
}
return errs.Emit()
}
// StartNextTurn increments the turn counter, resets the action counter,
// and draws back up to full. If the player cannot take any actions after
// drawing is complete, the game stalls. (If a drawn card would like to
// force the player to take no actions for a turn, the best approach is to
// make that card Urgent and make it reset ActionsRemaining to 0 after it runs.)
func (p *Player[C]) StartNextTurn() error {
var errs ErrorCollector
p.TurnNumber++
p.ActionsRemaining = p.ActionsPerTurn
errs.Add(p.FillHand())
if len(p.Hand)+len(p.PermanentActions) == 0 {
p.State = GameStalled
errs.Add(Warningf("%w: no cards in hand, no permanent actions", WarningStalemate))
}
if p.ActionsRemaining == 0 {
p.State = GameStalled
errs.Add(Warningf("%w: 0 actions available in the turn", WarningStalemate))
}
return errs.Emit()
}
// FillHand draws up to the hand limit, informing cards that they have been
// drawn. If more than a million cards refuse to enter the hand, this crashes
// with ErrUncooperativeCards. If the deck does not have enough cards, this
// returns WarningTooFewCards.
func (p *Player[C]) FillHand() error {
failureLimit := 1000000
for failureLimit > 0 && p.Deck.Len() > 0 && len(p.Hand) < p.HandLimit {
c := p.Deck.Draw()
if c.Drawn(p) {
p.Hand = append(p.Hand, c)
} else {
failureLimit--
}
}
if len(p.Hand) >= p.HandLimit {
return nil
}
if failureLimit <= 0 {
return ErrUncooperativeCards
}
return WarningTooFewCards
}
// HasUrgentCards returns whether any cards in the Hand think they are Urgent.
func (p *Player[C]) HasUrgentCards() bool {
for _, c := range p.Hand {
if c.Urgent(p) {
return true
}
}
return false
}
// EnactCardUnchecked executes a card choice, removes it from the hand, and
// decrements the ActionsRemaining. It does not check for conflicting Urgent
// cards or already being out of actions. If no such card or card choice
// exists, or the specified choice is not enabled, this returns nil and
// ErrInvalidCard/ErrInvalidChoice without changing anything. Otherwise, this
// returns the result of enacting the card. If enacting the card causes a
// serious error, the State becomes GameCrashed.
func (p *Player[C]) EnactCardUnchecked(cardIdx, choiceIdx int) (Message, error) {
if cardIdx < 0 || cardIdx >= len(p.Hand) {
return nil, fmt.Errorf("%w: no card #%d when %d cards in hand", ErrInvalidCard, cardIdx, len(p.Hand))
}
card := p.Hand[cardIdx]
var errs ErrorCollector
options, err := card.Options(p)
if IsSeriousError(err) {
p.State = GameCrashed
return nil, err
}
errs.Add(err)
if choiceIdx < 0 || choiceIdx > len(options) {
errs.Add(fmt.Errorf("%w: no option #%d on card #%d with %d options", ErrInvalidChoice, choiceIdx, cardIdx, len(options)))
return nil, errs.Emit()
}
chosen := options[choiceIdx]
if !chosen.Enabled(p) {
errs.Add(fmt.Errorf("%w: option %d on card %d was not enabled", ErrInvalidChoice, choiceIdx, cardIdx))
return nil, errs.Emit()
}
p.Hand = DeleteFrom(p.Hand, cardIdx)
p.ActionsRemaining--
ret, err := options[choiceIdx].Enact(p)
errs.Add(err)
if IsSeriousError(err) {
p.State = GameCrashed
return ret, errs.Emit()
}
err = card.Then(p, options[choiceIdx])
errs.Add(err)
if IsSeriousError(err) {
p.State = GameCrashed
}
return ret, errs.Emit()
}
// EnactCard executes a card choice, removes it from the hand, and decrements
// the ActionsRemaining. If the card is not Urgent but urgent cards are
// available, or the player is out of actions, this returns ErrNotUrgent or
// ErrNoActions. Otherwise, this acts like EnactCardUnchecked.
func (p *Player[C]) EnactCard(cardIdx, choiceIdx int) (Message, error) {
if p.ActionsRemaining <= 0 {
return nil, ErrNoActions
}
if cardIdx < 0 || cardIdx >= len(p.Hand) {
return nil, fmt.Errorf("%w: no card #%d when %d cards in hand", ErrInvalidCard, cardIdx, len(p.Hand))
}
if !p.Hand[cardIdx].Urgent(p) && p.HasUrgentCards() {
return nil, ErrNotUrgent
}
return p.EnactCardUnchecked(cardIdx, choiceIdx)
}
// EnactPermanentActionUnchecked executes a permanently-available action and
// decrements the ActionsRemaining. It does not check for conflicting Urgent
// cards or already being out of actions. If no such action or card option
// exists, or the option is not enabled, this returns nil and ErrInvalidCard
// or ErrInvalidChoice without changing anything. Otherwise, this returns the
// result of enacting the permanent action. If enacting the card causes a
// serious error, the State becomes GameCrashed.
func (p *Player[C]) EnactPermanentActionUnchecked(actionIdx, choiceIdx int) (Message, error) {
if actionIdx < 0 || actionIdx >= len(p.PermanentActions) {
return nil, fmt.Errorf("%w: no action #%d when %d permanent actions exist", ErrInvalidCard, actionIdx, len(p.PermanentActions))
}
card := p.PermanentActions[actionIdx]
var errs ErrorCollector
options, err := card.Options(p)
if IsSeriousError(err) {
p.State = GameCrashed
return nil, err
}
errs.Add(err)
if choiceIdx < 0 || choiceIdx > len(options) {
errs.Add(fmt.Errorf("%w: no option #%d on permanent action #%d with %d options", ErrInvalidChoice, choiceIdx, actionIdx, len(options)))
return nil, errs.Emit()
}
chosen := options[choiceIdx]
if !chosen.Enabled(p) {
errs.Add(fmt.Errorf("%w: option #%d on permanent action #%d is not enabled", ErrInvalidChoice, choiceIdx, actionIdx))
return nil, errs.Emit()
}
p.ActionsRemaining--
ret, err := chosen.Enact(p)
errs.Add(err)
if IsSeriousError(err) {
p.State = GameCrashed
return ret, errs.Emit()
}
err = card.Then(p, chosen)
errs.Add(err)
if IsSeriousError(err) {
p.State = GameCrashed
}
return ret, errs.Emit()
}
// EnactPermanentAction executes a permanently-available card and decrements
// the ActionsRemaining. If the action is not Urgent but urgent cards are
// available, or the player is out of actions, this returns ErrNotUrgent or
// ErrNoActions. Otherwise, this acts like EnactPermanentActionUnchecked.
func (p *Player[C]) EnactPermanentAction(actionIdx, choiceIdx int) (Message, error) {
if p.ActionsRemaining <= 0 {
return nil, ErrNoActions
}
if actionIdx < 0 || actionIdx >= len(p.PermanentActions) {
return nil, fmt.Errorf("%w: no action #%d when %d permanent actions available", ErrInvalidCard, actionIdx, len(p.PermanentActions))
}
if !p.PermanentActions[actionIdx].Urgent(p) && p.HasUrgentCards() {
return nil, ErrNotUrgent
}
return p.EnactPermanentActionUnchecked(actionIdx, choiceIdx)
}
// ReportError adds an error to the temporary messages, depending on
// its severity and debug settings:
//
// - If the error is nil, this never does anything.
// - If the error is serious, this emits the error if the debug level is
// -1 or greater.
// - If the error is only a warning, this emits the error if the debug
// level is 0 or greater.
func (p *Player[C]) ReportError(e error) {
if e == nil || p.DebugLevel < -1 {
return
}
if p.DebugLevel < 0 && !IsSeriousError(e) {
return
}
p.ChapterBreak()
severity := "[Warning]"
if IsSeriousError(e) {
severity = "[ERROR]"
}
p.TemporaryMessages = append(p.TemporaryMessages, Msgf("%s: %v", severity, e))
}
// CanAct returns whether the player has actions theoretically available.
func (p *Player[C]) CanAct() bool {
return p.ActionsRemaining > 0 && (len(p.Hand) > 0 || len(p.PermanentActions) > 0)
}