package mlp

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"net/http"
	"strings"

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

// Set is a set/expansion of MLP:CCG
type Set struct {
	ID       SetID
	Name     string
	CardList []draft.Card
	CardData map[string]Card
}

// jsonSet is the set as serialized in the JSON files
type jsonSet struct {
	ID    SetID
	Name  string
	Cards []Card
}

func (j *jsonSet) toSet() (s Set) {
	s.Name = j.Name
	s.CardData = make(map[string]Card)
	s.CardList = make([]draft.Card, len(j.Cards))
	for i, card := range j.Cards {
		s.CardData[card.ID] = card
		s.CardList[i] = draft.Card{ID: card.ID}
	}
	return
}

var loadedSets = make(map[SetID]*Set)

// Errors
var (
	ErrSetNotLoaded = errors.New("set not loaded")
)

// CleanSetCache removes all loaded sets from memory
func CleanSetCache() {
	loadedSets = make(map[SetID]*Set)
}

// LoadSetData loads sets from data
func LoadSetData(sets map[SetID][]byte) error {
	for setid, setdata := range sets {
		_, err := LoadSetBytes(setid, setdata)
		if err != nil {
			return err
		}
	}
	return nil
}

// LoadSetMemory loads a set from memory (must have been previously loaded with LoadSetData or other functions)
func LoadSetMemory(id SetID) (*Set, error) {
	// Check if set is already loaded
	if set, ok := loadedSets[id]; ok {
		return set, nil
	}
	// Not loaded, return error
	return nil, ErrSetNotLoaded
}

// LoadSetBytes loads a set with a specified ID from JSON
func LoadSetBytes(id SetID, setdata []byte) (*Set, error) {
	// Check if set is already loaded
	if set, ok := loadedSets[id]; ok {
		return set, nil
	}

	var jsonset jsonSet
	err := json.Unmarshal(setdata, &jsonset)
	if err != nil {
		return nil, err
	}

	set := jsonset.toSet()
	set.ID = id
	loadedSets[set.ID] = &set
	return &set, err
}

// HTTPClient is the HTTP client used in LoadSetHTTP
var HTTPClient = http.DefaultClient

// HTTPSource is the base URL for fetching sets remotely via HTTP
var HTTPSource = "https://mcg.zyg.ovh/setdata/"

// LoadSetHTTP loads a set using MCG's remote server
func LoadSetHTTP(id SetID) (*Set, error) {
	// Check if set is already loaded
	if set, ok := loadedSets[id]; ok {
		return set, nil
	}

	// Get SetID as string and make it lowercase
	setid := strings.ToLower(string(id))

	resp, err := HTTPClient.Get(HTTPSource + setid + ".json")
	if err != nil || resp.StatusCode != 200 {
		if err == nil {
			err = fmt.Errorf("server returned non-200 response code (%d)", resp.StatusCode)
		}
		return nil, err
	}

	data, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	return LoadSetBytes(id, data)
}