package draft_test

import (
	"fmt"
	"math/rand"
	"testing"

	"git.fromouter.space/mcg/draft"
)

const PACKSIZE = 5

// Test set that can be used by tests that don't need special features (like alternates)
var testSet = &draft.GenericSet{
	Cards:    []draft.Card{{ID: "a"}, {ID: "b"}, {ID: "c"}},
	PackSize: PACKSIZE,
}

// Test cube that can be used by tests that don't need special features
var testCube = &draft.GenericCube{
	Cards: []draft.Card{
		{ID: "a"}, {ID: "b"}, {ID: "c"}, {ID: "d"}, {ID: "e"},
		{ID: "f"}, {ID: "g"}, {ID: "h"}, {ID: "i"},
	},
	PackSize: PACKSIZE,
}

// TestSetRepeatable makes sure that a set can generate more cards than it contains
func TestSetRepeatable(t *testing.T) {
	// Create a pack
	pack := draft.MakePack(testSet)

	if len(pack) < PACKSIZE {
		t.Fatalf("Pack expected to contain %d cards, contains %d", PACKSIZE, len(pack))
	}

	// Check that all cards have something in it
	for i, card := range pack {
		if card.ID == "" {
			t.Fatalf("Pack contains \"empty\" card")
		}
		if card.ID != "a" && card.ID != "b" && card.ID != "c" {
			t.Fatalf("Pack contains unexpected card %s at index %d, not contained in pool", card.ID, i)
		}
	}
}

// TestAlternateProviders tests alternate providers
func TestAlternateProviders(t *testing.T) {
	customProvider := func(n int) []draft.Card {
		out := make([]draft.Card, n)
		for n := range out {
			out[n] = draft.Card{ID: "x"}
		}
		return out
	}
	s := &draft.GenericSet{
		Cards:    []draft.Card{{ID: "a"}, {ID: "b"}, {ID: "c"}},
		PackSize: 1,
		Alternates: []draft.AlternateProvider{
			{
				Probability: 0.3,
				Provider:    customProvider,
			},
		},
	}
	// Use set seed for getting deterministic results
	rand.Seed(0)

	nonalternates, alternates := 0, 0
	for i := 0; i < 500000; i++ {
		pack := draft.MakePack(s)
		if pack[0].ID == "x" {
			alternates++
		} else {
			nonalternates++
		}
	}

	// Calculate distribution
	distribution := float32(float32(alternates) / (float32(nonalternates) + float32(alternates)))

	// After 500k packs, I'm expecting distribution to be within 2%
	if distribution < 0.29 || distribution > 0.31 {
		t.Fatalf("Distribution is sketchy after 500k packs: %f%%", distribution*100)
	}
}

// TestCubeOverflow makes sure cubes stop providing cards as they are exhausted instead of going out of bound
func TestCubeOverflow(t *testing.T) {
	pack1 := draft.MakePack(testCube)
	pack2 := draft.MakePack(testCube)

	// Pack 2 can only contain 4 cards, as there are not enough cards to fill it
	if len(pack2) >= PACKSIZE {
		t.Fatalf("Pack 2 expected to contain only 4 cards, has %d", len(pack2))
	}

	// Check for duplicates
	allcards := append(pack1, pack2...)
	uniq := sliceUniq(allcards)
	if len(allcards) != len(uniq) {
		t.Fatalf("Duplicate cards found across packs")
	}
}

// ExampleGenericSet is an example usage of the Set APIs to make packs
func ExampleGenericSet() {
	// Create a set with some items
	s := &draft.GenericSet{
		Cards: []draft.Card{
			{ID: "a"},
			{ID: "b"},
			{ID: "c"},
		},
		PackSize: 5,
	}

	// Create a pack
	pack := draft.MakePack(s)

	// Print cards in pack
	for i, card := range pack {
		fmt.Printf("Card #%d: %s\n", i, card.ID)
	}
}

// https://gist.github.com/alioygur/16c66b4249cb42715091fe010eec7e33
func sliceUniq(s []draft.Card) []draft.Card {
	for i := 0; i < len(s); i++ {
		for i2 := i + 1; i2 < len(s); i2++ {
			if s[i].ID == s[i2].ID {
				// delete
				s = append(s[:i2], s[i2+1:]...)
				i2--
			}
		}
	}
	return s
}