package api

import (
	"context"
	"log"
	"time"

	"github.com/docker/go-units"
	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/middleware/cors"
	"github.com/gofiber/fiber/v2/middleware/limiter"
	"github.com/gofiber/template/handlebars/v2"

	"gitea.urkob.com/urko/btc-pay-checker/internal/api/handler"
	"gitea.urkob.com/urko/btc-pay-checker/internal/domain"
	"gitea.urkob.com/urko/btc-pay-checker/internal/services"
	"gitea.urkob.com/urko/btc-pay-checker/internal/services/btc"
	"gitea.urkob.com/urko/btc-pay-checker/internal/services/mail"
	"gitea.urkob.com/urko/btc-pay-checker/internal/services/price"
	"gitea.urkob.com/urko/btc-pay-checker/kit/cfg"
)

const (
	MAX_FILE_SIZE     = 25
	MAX_FILE_SIZE_MiB = MAX_FILE_SIZE * units.MiB
)

type RestServer struct {
	app        *fiber.App
	config     *cfg.Config
	btcService *btc.BitcoinService
	orderSrv   *services.Order
	mailSrv    *mail.MailService
	priceSrv   *price.PriceConversor
}

func NewRestServer(
	config *cfg.Config,
	orderSrv *services.Order,
	btcService *btc.BitcoinService,
	priceSrv *price.PriceConversor,
	mailSrv *mail.MailService,
) *RestServer {
	return &RestServer{
		config:     config,
		orderSrv:   orderSrv,
		btcService: btcService,
		priceSrv:   priceSrv,
		mailSrv:    mailSrv,
	}
}

func (s *RestServer) Start(ctx context.Context, apiPort, views string) error {
	engine := handlebars.New(views, ".hbs")
	s.app = fiber.New(fiber.Config{
		Views:     engine,
		BodyLimit: MAX_FILE_SIZE_MiB,
	})

	s.app.Use(limiter.New(limiter.Config{
		Max:               5,
		Expiration:        30 * time.Minute,
		LimiterMiddleware: limiter.SlidingWindow{},
	}))

	s.app.Use(cors.New(cors.Config{
		AllowMethods:  "GET,POST,OPTIONS",
		AllowOrigins:  "*",
		AllowHeaders:  "Origin, Accept, Content-Type, X-CSRF-Token, Authorization",
		ExposeHeaders: "Origin",
	}))

	s.loadViews(views + "/images")

	orderHandler := handler.NewOrderHandler(s.config.WalletAddress, s.orderSrv, s.priceSrv)

	notifChan := make(chan domain.Notification)
	go s.btcService.Notify(ctx, notifChan)
	go s.onNotification(ctx, notifChan)

	s.app.Post("/order", orderHandler.Post)

	if err := s.app.Listen(":" + apiPort); err != nil {
		log.Fatalln("app.Listen:", err)
		return err
	}

	return nil
}

// onNotification Step
// 1- update the block where tx has been forged
// 2- send email to client alerting his block has been forged
// 3- to upload file into arweave
func (s *RestServer) onNotification(ctx context.Context, notifChan chan domain.Notification) {
	for notif := range notifChan {
		order, err := s.orderSrv.FromAmount(ctx, notif.Amount, notif.DoneAt)
		if err != nil {
			log.Println("error while retrieve transaction from forged block: ", err)
			continue
		}

		order.Block = notif.BlockHash
		order.Tx = notif.Tx
		order, err = s.orderSrv.OrderCompleted(ctx, order)
		if err != nil {
			log.Println("OrderCompleted:", err)
			continue
		}

		// notify
		if s.config.WebhookUrl != "" {
			go func() {
				if err := s.orderSrv.Webhook(ctx, s.config.WebhookUrl, order); err != nil {
					log.Println("orderSrv.Webhook:", err)
				}
			}()
		}

		// Send email to client and provider
		if err := s.mailSrv.SendProviderConfirm(mail.SendOK{
			Tx:          order.Tx,
			Block:       order.Block,
			Amount:      order.Amount,
			ExplorerUrl: s.btcService.Explorer(order.Tx),
			CustomerID:  order.ClientID,
			OrderID:     order.OrderID,
			Timestamp:   order.PaidAt,
			To:          order.Email,
		}); err != nil {
			log.Println("error while send confirm email:", err)
			continue
		}
	}
}

func (s *RestServer) loadViews(imagesDir string) {
	s.app.Static("/images", imagesDir)

	s.app.Get("/", func(c *fiber.Ctx) error {
		return c.Render("index", fiber.Map{
			"host": s.config.Host,
		})
	})

	s.app.Get("/error", func(c *fiber.Ctx) error {
		message := c.Query("message")
		return renderError(c, nil, message)
	})
}

func renderError(c *fiber.Ctx, err error, message string) error {
	if err != nil {
		log.Printf("renderError: %s\n", err)
	}
	return c.Render("error", fiber.Map{
		"message": message,
	})
}

func (s *RestServer) Shutdown() error {
	if err := s.app.Server().Shutdown(); err != nil {
		log.Printf("app.Server().Shutdown(): %s\n", err)
		return err
	}
	return nil
}