package ln

import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"git.sp4ke.com/sp4ke/bit4sat/btc"
	"git.sp4ke.com/sp4ke/bit4sat/bus"
	"git.sp4ke.com/sp4ke/bit4sat/config"
	"git.sp4ke.com/sp4ke/bit4sat/db"
	"git.sp4ke.com/sp4ke/bit4sat/lndrpc"
	"git.sp4ke.com/sp4ke/bit4sat/utils"
	"github.com/gin-gonic/gin"
	"github.com/mediocregopher/radix/v3"
)

var (
	Client *http.Client
)

func Info() (gin.H, error) {

	result := make(gin.H)
	resp, err := Client.Get(getUrl(InfoEndpoint))
	if err != nil {
		return nil, err
	}

	jsonDec := json.NewDecoder(resp.Body)
	jsonDec.Decode(&result)

	return result, nil
}

// Quick check if invoice was paid
func CheckInvoice(id string) (*Invoice, error) {

	lnInvoice, err := lndrpc.LookupInvoiceRhashStr(id)
	if err != nil {
		return nil, err
	}

	invoice := InvoiceFromLndIn(lnInvoice)

	return invoice, nil
}

// This will watch on the pubsub for paid invoices given an invoice id
func PollPaidInvoice(invoiceId string, invoicePaidChan chan<- *Invoice, errorChan chan<- error) {

	watchPaidChannel := make(chan radix.PubSubMessage)

	busName := fmt.Sprintf("%s_*", bus.InvoicePaidChannelPrefix)

	err := db.DB.RedisPubSub.PSubscribe(watchPaidChannel, busName)
	if err != nil {
		errorChan <- err
		return
	}

	for {
		msg := <-watchPaidChannel

		targetInvoiceId := strings.Split(msg.Channel, "_")[1]
		if targetInvoiceId == invoiceId {

			invoice := Invoice{}

			err := json.Unmarshal(msg.Message, &invoice)
			if err != nil {
				errorChan <- err
				return
			}

			invoicePaidChan <- &invoice
			return

		}

	}
}

func PollPaidInvoiceTMP(invoiceId string, invoiceChan chan<- *Invoice, errorChan chan<- error) {

	invoice := Invoice{}

	reqParams := url.Values{}
	// Timeout in seconds
	reqParams.Set("timeout", strconv.Itoa(60))
	reqURI := fmt.Sprintf("%s/%s/wait?%s",
		getUrl(InvoiceEndpoint),
		invoiceId,
		reqParams.Encode())

	log.Printf("polling to %s", reqURI)

	var err error
	var jsonDec *json.Decoder
	resp := &http.Response{}

	for {
		//log.Println("new poll")
		resp, err = http.Get(reqURI)
		if err != nil {
			log.Printf("Error: ", err)
		}
		jsonDec = json.NewDecoder(resp.Body)

		if resp.StatusCode == http.StatusPaymentRequired {
			log.Printf("invoice %s not yet paid", invoiceId)
			continue
		}

		if resp.StatusCode == http.StatusGone {
			log.Printf("invoice expired %s", invoiceId)
			invoice.Expired = true
			break
		}

		if resp.StatusCode == http.StatusOK {
			log.Printf("Invoice paid %s", invoice)
			break
		} else {
			log.Println("else !")

			// This section handles unknown answer from ln-charge
			log.Printf("InvoicePoll Error: unknown resopnse %s", resp.Status)
			jsonDec.Decode(&invoice)

			close(invoiceChan)
			errorChan <- fmt.Errorf("%s: %s", resp.Status, invoice)

			return
		}

	}

	jsonDec.Decode(&invoice)

	invoiceChan <- &invoice
	log.Printf("quit polling %s", invoiceId)
}

func NewInvoiceForUpload(amount float64, curr Currency, uploadId string) (*Invoice, error) {
	var err error
	var satValue int64

	description := fmt.Sprintf("bit4sat upload: %s", uploadId)

	if curr == CurMSat {
		log.Println("cur is msat")
		// Convert to MSAT, meaning values under 1000 MSAT are ignored
		satValue = int64(amount / 1000)

		// Other supported currecies
	}

	if curr != CurSat {
		log.Println("cur is custom")

		// Get Sat satValue for this invoice
		msatVal, err := btc.ToMsat(CurrencyString[curr], amount)
		if err != nil {
			return nil, err
		}

		satValue = msatVal / 1000
	} else {
		satValue = int64(amount)
	}

	lndInvoice, err := lndrpc.AddInvoiceSat(description, satValue)
	if err != nil {
		return nil, err
	}

	invoice := InvoiceFromLndIn(lndInvoice)
	invoice.QuotedCurrency = CurrencyString[curr]
	invoice.QuotedAmount = amount

	return invoice, nil
}

func NewInvoiceForUploadTMP(amount float32, curr Currency, uploadId string) (*Invoice, error) {

	webhookUrl := fmt.Sprintf("http://%s:%s/%s", config.ApiHost, config.ApiPort,
		config.ChargeCallbackEndpoint)

	reqData := gin.H{
		"description": fmt.Sprintf("bit4sat upload: %s", uploadId),
		"webhook":     webhookUrl,
	}

	// If Satoshi convert to millisat
	if curr == CurSat {
		reqData["msatoshi"] = amount * 1000
	} else {
		reqData["currency"] = CurrencyString[curr]
		reqData["amount"] = amount
	}

	jsonEnc, err := json.Marshal(reqData)
	if err != nil {
		return nil, err
	}

	log.Printf("Asking for invoice with: %s", jsonEnc)

	resp, err := Client.Post(getUrl(InvoiceEndpoint),
		"application/json",
		bytes.NewReader(jsonEnc))

	if err != nil {
		return nil, err
	}

	invoice := Invoice{}
	jsonDec := json.NewDecoder(resp.Body)
	jsonDec.Decode(&invoice)

	return &invoice, nil
}

func getUrl(endpoint string) string {
	url, err := url.Parse(fmt.Sprintf("http://api-token:%s@%s/%s",
		config.LnChargeToken,
		config.LnChargeApi,
		endpoint))
	if err != nil {
		log.Fatal(err)
	}

	return url.String()

}

func init() {
	Client = utils.NewHttpClient()
}