package api

import (
	"errors"
	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"log/slog"
	"net/http"
	"payment-poc/domain/database"
	"payment-poc/domain/providers"
	"payment-poc/domain/providers/mock"
	stripe2 "payment-poc/domain/providers/stripe"
	"payment-poc/domain/providers/viva"
	wspay2 "payment-poc/domain/providers/wspay"
	"payment-poc/domain/state"
	"strconv"
	"time"
)

func NoMethod() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.JSON(http.StatusNotFound, gin.H{
			"status":  404,
			"created": time.Now(),
			"message": "no handler for method '" + c.Request.Method + "'",
		})
	}
}

func NoRoute() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.JSON(http.StatusNotFound, gin.H{
			"status":  404,
			"created": time.Now(),
			"message": "no handler for " + c.Request.Method + " '" + c.Request.URL.RequestURI() + "'",
		})
	}
}

func RefreshPayment(entryProvider *database.PaymentEntryProvider, paymentGateways map[state.PaymentGateway]providers.PaymentProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := uuid.MustParse(c.Param("id"))
		entry, err := entryProvider.FetchById(id)
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		if paymentGateway, ok := paymentGateways[entry.Gateway]; ok {
			slog.Info("fetching payment info", "entry_id", entry.Id.String(), "state", entry.State)
			entry, err = paymentGateway.UpdatePayment(entry)
			if err == nil {
				entryProvider.UpdateEntry(entry)
				slog.Info("fetched payment info", "entry_id", entry.Id.String(), "state", entry.State)
			}
			c.Redirect(http.StatusSeeOther, "/entries/"+id.String())
		} else {
			if err != nil {
				c.AbortWithError(http.StatusInternalServerError, errors.New("payment gateway not supported: "+string(entry.Gateway)))
				return
			}
		}
	}
}

func CancelPayment(entryProvider *database.PaymentEntryProvider, paymentGateways map[state.PaymentGateway]providers.PaymentProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := uuid.MustParse(c.Param("id"))
		entry, err := entryProvider.FetchById(id)
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		if paymentGateway, ok := paymentGateways[entry.Gateway]; ok {
			slog.Info("canceling payment", "entry_id", id.String(), "state", entry.State)
			entry, err = paymentGateway.CancelTransaction(entry)
			if err == nil {
				entryProvider.UpdateEntry(entry)
				slog.Info("canceled payment", "entry_id", entry.Id.String(), "state", entry.State)
				c.Redirect(http.StatusSeeOther, "/entries/"+id.String())
			} else {
				c.AbortWithError(http.StatusInternalServerError, err)
				return
			}
		} else {
			if err != nil {
				c.AbortWithError(http.StatusInternalServerError, errors.New("payment gateway not supported: "+string(entry.Gateway)))
				return
			}
		}
	}
}

func CompletePayment(entryProvider *database.PaymentEntryProvider, paymentGateways map[state.PaymentGateway]providers.PaymentProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := uuid.MustParse(c.Param("id"))
		entry, err := entryProvider.FetchById(id)
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		if paymentGateway, ok := paymentGateways[entry.Gateway]; ok {
			amount, err := fetchAmount(c.PostForm("amount"))
			if err != nil {
				c.AbortWithError(http.StatusBadRequest, err)
				return
			}
			slog.Info("completing payment with amount", "entry_id", id.String(), "state", entry.State, "amount", float64(amount)/100.0)
			entry, err = paymentGateway.CompleteTransaction(entry, amount)
			if err == nil {
				entryProvider.UpdateEntry(entry)
				slog.Info("completed payment", "entry_id", id.String(), "state", entry.State)
				c.Redirect(http.StatusSeeOther, "/entries/"+id.String())
			} else {
				c.AbortWithError(http.StatusInternalServerError, err)
				return
			}
		} else {
			if err != nil {
				c.AbortWithError(http.StatusInternalServerError, errors.New("payment gateway not supported: "+string(entry.Gateway)))
				return
			}
		}
	}
}

func GetEntry(provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := uuid.MustParse(c.Param("id"))
		entry, err := provider.FetchById(id)
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		c.HTML(200, "info.gohtml", gin.H{"Entry": entry})
	}
}

func InitializePayment(entryProvider *database.PaymentEntryProvider, paymentGateways map[state.PaymentGateway]providers.PaymentProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		gateway, err := fetchGateway(c.Param("gateway"))
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		if paymentGateway, contains := paymentGateways[gateway]; contains {
			amount, err := fetchAmount(c.Query("amount"))
			if err != nil {
				c.AbortWithError(http.StatusBadRequest, err)
				return
			}
			entry, err := entryProvider.CreateEntry(database.PaymentEntry{
				Gateway:     gateway,
				State:       state.StatePreinitialized,
				TotalAmount: amount,
			})
			slog.Info("creating payment", "entry_id", entry.Id.String(), "state", entry.State, "gateway", gateway, "amount", float64(amount)/100.0)
			if entry, url, err := paymentGateway.CreatePaymentUrl(entry); err == nil {
				slog.Info("created redirect url", "entry_id", entry.Id.String(), "state", entry.State)
				entryProvider.UpdateEntry(entry)
				c.Redirect(http.StatusSeeOther, url)
			} else {
				c.AbortWithError(http.StatusBadRequest, err)
				return
			}
		} else {
			c.AbortWithError(http.StatusBadRequest, errors.New("unsupported payment gateway: "+string(gateway)))
			return
		}
	}
}

func GetGateways(gateways map[state.PaymentGateway]providers.PaymentProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		amount, err := strconv.ParseFloat(c.Query("amount"), 64)
		if err != nil {
			amount = 10.00
		}
		c.HTML(200, "methods.gohtml", gin.H{"Amount": amount, "Gateways": mapGateways(gateways)})
	}
}

func GetIndex(provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		entries, _ := provider.FetchAll()
		c.HTML(200, "index.gohtml", gin.H{"Entries": entries})
	}
}

func VivaOnFailure(vivaService viva.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := vivaService.HandleResponse(c, provider, state.StateError)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func VivaOnSuccess(vivaService viva.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := vivaService.HandleResponse(c, provider, state.StateAccepted)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func StripeOnFailure(stripeService stripe2.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := stripeService.HandleResponse(c, provider, state.StateError)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func StripeOnSuccess(stripeService stripe2.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := stripeService.HandleResponse(c, provider, state.StateAccepted)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func WsPayOnFailure(wspayService wspay2.Service, provider *database.PaymentEntryProvider, finalState state.PaymentState) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := wspayService.HandleErrorResponse(c, provider, finalState)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func WsPayOnSuccess(wspayService wspay2.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := wspayService.HandleSuccessResponse(c, provider)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func MockOnFailure(mockService mock.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := mockService.HandleResponse(c, provider, state.StateError)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func MockOnSuccess(mockService mock.Service, provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		url, err := mockService.HandleResponse(c, provider, state.StateAccepted)
		if err != nil {
			c.AbortWithError(http.StatusInternalServerError, err)
			return
		}
		c.Redirect(http.StatusSeeOther, url)
	}
}

func MockOpenGateway(provider *database.PaymentEntryProvider) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := uuid.MustParse(c.Param("id"))
		entry, err := provider.FetchById(id)
		if err != nil {
			c.AbortWithError(http.StatusBadRequest, err)
			return
		}
		c.HTML(http.StatusOK, "mock_gateway.gohtml", gin.H{"Entry": entry})
	}
}

func mapGateways(gateways map[state.PaymentGateway]providers.PaymentProvider) map[string]string {
	providerMap := map[string]string{}

	for key := range gateways {
		providerMap[string(key)] = mapGatewayName(key)
	}
	return providerMap
}

func mapGatewayName(key state.PaymentGateway) string {
	switch key {
	case state.GatewayStripe:
		return "Stripe"
	case state.GatewayVivaWallet:
		return "Viva wallet"
	case state.GatewayWsPay:
		return "WsPay"
	case state.GatewayMock:
		return "mock"
	}
	return ""
}

func fetchGateway(gateway string) (state.PaymentGateway, error) {
	switch gateway {
	case string(state.GatewayWsPay):
		return state.GatewayWsPay, nil
	case string(state.GatewayStripe):
		return state.GatewayStripe, nil
	case string(state.GatewayVivaWallet):
		return state.GatewayVivaWallet, nil
	case string(state.GatewayMock):
		return state.GatewayMock, nil
	}
	return "", errors.New("unknown gateway: " + gateway)
}

func fetchAmount(amount string) (int64, error) {
	if amount, err := strconv.ParseFloat(amount, 64); err == nil {
		return int64(amount * 100), nil
	} else {
		return 0, err
	}
}