package mlp

import (
	"math/rand"

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

// I8PCube is a cube that uses I8Pages' pack schema.
// I8Pages' cube uses different kinds of packs, so a single schema is not possible.
// Therefore, I8PCube itself is not a valid set, but contains two valid sets for
// both types of packs (main deck / problems)
//
// Infos on I8Pages' cube:
// https://docs.google.com/spreadsheets/d/1Ufz4QLwLCZ1vLemAhE6cuAmu2lq_VAN7RhLO9p1opNQ
type I8PCube struct {
	Main     *I8PSet
	Problems *I8PSet
}

// I8PSet is one of the sets of packs contained in a I8PCube
type I8PSet struct {
	Cards  I8PPool
	Schema draft.PackSchema
}

// I8PType is a category of cards to be seeded into packs
type I8PType string

// I8PSchema is a schema to seed a single I8PCube pack
type I8PSchema []I8PSchemaSlot

// I8PSchemaSlot is a single slot of a I8PSchema
type I8PSchemaSlot struct {
	Amount int
	Type   I8PType
}

// All types used for seeding packs
const (
	I8PTypeBlue    I8PType = "blue"
	I8PTypeOrange  I8PType = "orange"
	I8PTypePink    I8PType = "pink"
	I8PTypePurple  I8PType = "purple"
	I8PTypeWhite   I8PType = "white"
	I8PTypeYellow  I8PType = "yellow"
	I8PTypeNone    I8PType = "none"
	I8PTypeMulti   I8PType = "multi"
	I8PTypeEntry   I8PType = "entry"
	I8PTypeProblem I8PType = "problem"

	// Special types
	I8PTypeAll I8PType = "all" // all means "from any other non-problem type"
)

// I8PPool is a pool of card divided into categories
type I8PPool map[I8PType][]Card

// MakeI8PCube takes an organized set of cards and sorts them into a draftable I8PCube
func MakeI8PCube(cards I8PPool, schema I8PSchema) *I8PCube {
	return &I8PCube{
		Main:     makeMainSet(cards, schema),
		Problems: makeProblemSet(cards),
	}
}

func makeMainSet(cards I8PPool, schema I8PSchema) (set *I8PSet) {
	// Create set with the given card pool
	set = &I8PSet{
		Cards: I8PPool{
			I8PTypeBlue:   cards[I8PTypeBlue],
			I8PTypeOrange: cards[I8PTypeOrange],
			I8PTypePink:   cards[I8PTypePink],
			I8PTypePurple: cards[I8PTypePurple],
			I8PTypeWhite:  cards[I8PTypeWhite],
			I8PTypeYellow: cards[I8PTypeYellow],
			I8PTypeNone:   cards[I8PTypeNone],
			I8PTypeMulti:  cards[I8PTypeMulti],
			I8PTypeEntry:  cards[I8PTypeEntry],
		},
	}
	// Build PackSchema from given I8PSchema
	var slots []draft.PackSlot
	for _, slot := range schema {
		// Check for special cases
		var provider draft.CardProvider
		switch slot.Type {
		case I8PTypeAll:
			provider = set.ProviderOther()
		default:
			provider = set.ProviderByType(slot.Type)
		}
		// Add slot
		slots = append(slots, draft.PackSlot{
			Amount:   slot.Amount,
			Provider: provider,
		})
	}
	set.Schema = draft.PackSchema{
		Slots: slots,
	}
	return
}

func makeProblemSet(cards I8PPool) (set *I8PSet) {
	set = &I8PSet{
		Cards: I8PPool{
			I8PTypeProblem: cards[I8PTypeProblem],
		},
	}
	set.Schema = draft.PackSchema{
		Slots: []draft.PackSlot{
			{
				Amount:   12,
				Provider: set.ProviderByType(I8PTypeProblem),
			},
		},
	}
	return
}

// ProviderByType provides cards from a specified category
func (s *I8PSet) ProviderByType(typ I8PType) draft.CardProvider {
	return func(n int) (out []draft.Card) {
		s.shuffle(typ)
		if len(s.Cards[typ]) < n {
			n = len(s.Cards[typ])
		}
		out, s.Cards[typ] = toDraft(s.Cards[typ][:n]), s.Cards[typ][n:]
		return
	}
}

// ProviderOther picks a random card for any available set (except Problems)
func (s *I8PSet) ProviderOther() draft.CardProvider {
	choices := []I8PType{
		I8PTypeBlue,
		I8PTypeOrange,
		I8PTypePink,
		I8PTypePurple,
		I8PTypeWhite,
		I8PTypeYellow,
		I8PTypeNone,
		I8PTypeMulti,
		I8PTypeEntry,
	}
	return func(n int) (out []draft.Card) {
		// Filter types that have enough cards for what we need
		// n is almost always 1, so this should not introduce bias
		available := []I8PType{}
		for _, typ := range choices {
			if len(s.Cards[typ]) >= n {
				available = append(available, typ)
			}
		}

		// Check if there are no pools we can pick stuff from, and exit early
		// THIS IS NOT NORMAL, AND YOU SHOULD FIX YOUR CUBE!
		if len(available) < 1 {
			return
		}

		typ := available[rand.Intn(len(available))]
		return s.ProviderByType(typ)(n)
	}
}

// PackSchema returns the pack schema for building packs from a I8PCube
func (s *I8PSet) PackSchema() draft.PackSchema {
	return s.Schema
}

func (s *I8PSet) shuffle(typ I8PType) {
	rand.Shuffle(len(s.Cards[typ]), func(i, j int) {
		s.Cards[typ][i], s.Cards[typ][j] = s.Cards[typ][j], s.Cards[typ][i]
	})
}

// DefaultI8PSchema returns I8Pages' schema as specified in his docs
func DefaultI8PSchema() I8PSchema {
	return I8PSchema{
		{Amount: 1, Type: I8PTypeBlue},
		{Amount: 1, Type: I8PTypeOrange},
		{Amount: 1, Type: I8PTypePink},
		{Amount: 1, Type: I8PTypePurple},
		{Amount: 1, Type: I8PTypeWhite},
		{Amount: 1, Type: I8PTypeYellow},
		{Amount: 1, Type: I8PTypeNone},
		{Amount: 2, Type: I8PTypeMulti},
		{Amount: 2, Type: I8PTypeEntry},
		{Amount: 1, Type: I8PTypeAll},
	}
}

// PackProvider returns a PackProvider for a given number of main and problem packs
func (c *I8PCube) PackProvider(mainPacks, problemPacks int) draft.PackProvider {
	return func() []draft.Pack {
		packs := make([]draft.Pack, mainPacks+problemPacks)
		for main := 0; main < mainPacks; main++ {
			packs[main] = draft.MakePack(c.Main)
		}
		for problem := 0; problem < problemPacks; problemPacks++ {
			packs[mainPacks+problem] = draft.MakePack(c.Problems)
		}
		return packs
	}
}