draft/set.go

package draft

import "math/rand"

// Set is an interface for all game sets/expansions
type Set interface {
	PackSchema() PackSchema
}

// GenericSet is an generalized set of a card game
// Treat this as an example implementation or a starting
type GenericSet struct {
	Cards    []Card
	PackSize int
}

// PackSchema returns the pack schema from a booster containing all possible cards
func (g *GenericSet) PackSchema() PackSchema {
	return PackSchema{
		Slots: []PackSlot{
			{Amount: g.PackSize, Provider: g.RandomProvider()},
		},
	}
}

// RandomProvider returns a provider for random cards from the set
func (g *GenericSet) RandomProvider() CardProvider {
	return func(n int) []Card {
		out := make([]Card, n)
		for n := range out {
			idx := rand.Intn(len(g.Cards))
			out[n] = g.Cards[idx]
		}
		return out
	}
}

// GenericCube is a "consumable" set, meaning cards get taken out of the pool as they are put in packs
type GenericCube struct {
	Cards    []Card
	PackSize int
}

// PackSchema returns the pack schema from a booster containing all possible cards
func (c *GenericCube) PackSchema() PackSchema {
	return PackSchema{
		Slots: []PackSlot{
			{Amount: c.PackSize, Provider: c.RandomProvider()},
		},
	}
}

// RandomProvider returns a provider for random cards from the set
func (c *GenericCube) RandomProvider() CardProvider {
	return func(n int) (out []Card) {
		c.shuffle()
		if len(c.Cards) < n {
			n = len(c.Cards)
		}
		out, c.Cards = c.Cards[:n], c.Cards[n:]
		return
	}
}

func (c *GenericCube) shuffle() {
	rand.Shuffle(len(c.Cards), func(i, j int) {
		c.Cards[i], c.Cards[j] = c.Cards[j], c.Cards[i]
	})
}