package poker

import (
	"math/rand"
	"time"
)

// Card represents a playing card as a two-character string.
// Ranks: 2-9, T, J, Q, K, A
// Suits: s (spades), h (hearts), d (diamonds), c (clubs)
// Examples: "As", "Kh", "Td", "2c"

var ranks = []string{"2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A"}
var suits = []string{"s", "h", "d", "c"}

// NewDeck returns a freshly shuffled 52-card deck.
func NewDeck() []string {
	deck := make([]string, 0, 52)
	for _, r := range ranks {
		for _, s := range suits {
			deck = append(deck, r+s)
		}
	}
	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
	rng.Shuffle(len(deck), func(i, j int) {
		deck[i], deck[j] = deck[j], deck[i]
	})
	return deck
}

// Deal removes and returns the top n cards from the deck.
func Deal(deck []string, n int) (cards []string, remaining []string) {
	if n > len(deck) {
		n = len(deck)
	}
	return deck[:n], deck[n:]
}