// Package coingecko implements a Service which returns price info on cryptocurrencies from coingecko
package coingecko

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"github.com/matrix-org/go-neb/types"
	mevt "maunium.net/go/mautrix/event"
	"maunium.net/go/mautrix/id"
)

// ServiceType of the coingecko service
const ServiceType = "coingecko"

// Service represents the coingecko service. It has no Config fields.
type Service struct {
	types.DefaultService
}

type CoinList struct {
	Id     string `json:"id"`
	Symbol string `json:"symbol"`
	Name   string `json:"name"`
}

type Market struct {
	Id                           string  `json:"id"`
	Symbol                       string  `json:"symbol"`
	Name                         string  `json:"name"`
	Image                        string  `json:"image"`
	CurrentPrice                 float64 `json:"current_price"`
	MarketCap                    float64 `json:"market_cap"`
	MarketCapRank                int16   `json:"market_cap_rank"`
	FullyDilutedValuation        string  `json:"fully_diluted_valuation"`
	TotalVolume                  float64 `json:"total_volume"`
	High24                       float64 `json:"high_24h"`
	Low24                        float64 `json:"low_24h"`
	PriceChange24h               float64 `json:"price_change_24h"`
	PriceChangePercentage24h     float64 `json:"price_change_percentage_24h"`
	MarketCapChange24h           float64 `json:"market_cap_change_24h"`
	MarketCapChangePercentage24h float64 `json:"market_cap_change_percentage_24h"`
	CirculatingSupply            float64 `json:"circulating_supply"`
	TotalSupply                  float64 `json:"total_supply"`
	MaxSupply                    float64 `json:"max_supply"`
	ATH                          float64 `json:"ath"`
	ATHChangePercentage          float64 `json:"ath_change_percentage"`
	ATHDate                      string  `json:"ath_date"`
	ATL                          float64 `json:"atl"`
	ATLChangePercentage          float64 `json:"atl_change_percentage"`
	ATLDate                      string  `json:"atl_date"`
	LastUpdated                  string  `json:"last_updated"`
}

func getIds(query string) []string {
	req, _ := http.NewRequest("GET", "https://api.coingecko.com/api/v3/coins/list", nil)
	req.Header.Set("Accept", "application/json")
	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()

	var coinList *[]CoinList
	json.NewDecoder(resp.Body).Decode(&coinList)
	var returnList []string
	for _, coin := range *coinList {
		// get the coingecko ids for the requested coin
		if coin.Symbol == query {
			returnList = append(returnList, coin.Id)
		}
	}
	if len(returnList) > 0 {
		return returnList
	} else {
		// fallback to bitcoin
		returnList = append(returnList, "bitcoin")
		return returnList
	}
}

func getData(query []string) string {
	symbol := strings.Join(query, ",")
	url := fmt.Sprintf("https://api.coingecko.com/api/v3/coins/markets?vs_currency=usd&ids=%s&order=market_cap_desc&per_page=1&page=1&sparkline=false", symbol)
	req, _ := http.NewRequest("GET", url, nil)
	req.Header.Set("Accept", "application/json")
	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()

	var coin []*Market
	json.NewDecoder(resp.Body).Decode(&coin)
    c := coin[0]
	const output = `%s (%s)
Current Price: $%.4f
Market Ca: $%.0f
24 Hour Volume: $%.0f
24 Hour High: $%.4f
24 Hour Low: $%.4f
All Time High: $%.4f
All Time Low: $%.4f`
	return fmt.Sprintf(output, c.Id, c.Symbol, c.CurrentPrice, c.MarketCap, c.TotalVolume, c.High24, c.Low24, c.ATH, c.ATL)
}

// Commands supported:
//    !coingecko SYMBOL
// Responds with price data on the currency
func (e *Service) Commands(cli types.MatrixClient) []types.Command {
	return []types.Command{
		{
			Path: []string{"cc"},
			Command: func(roomID id.RoomID, userID id.UserID, args []string) (interface{}, error) {
				coinIds := getIds(strings.Join(args, ""))
				output := getData(coinIds)
				return &mevt.MessageEventContent{
					MsgType: mevt.MsgNotice,
					Body:    output,
				}, nil
			},
		},
	}
}

func init() {
	types.RegisterService(func(serviceID string, serviceUserID id.UserID, webhookEndpointURL string) types.Service {
		return &Service{
			DefaultService: types.NewDefaultService(serviceID, serviceUserID, ServiceType),
		}
	})
}