package handlers

import (
	"errors"
	"net/http"

	apperrors "veza-backend-api/internal/errors"
	"veza-backend-api/internal/core/marketplace"
	"veza-backend-api/internal/services"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gorm.io/gorm"
)

// SellHandler handles Stripe Connect seller payout endpoints
type SellHandler struct {
	db            *gorm.DB
	stripeConnect *services.StripeConnectService
	logger        *zap.Logger
}

// NewSellHandler creates a new SellHandler
func NewSellHandler(db *gorm.DB, stripeConnect *services.StripeConnectService, logger *zap.Logger) *SellHandler {
	return &SellHandler{
		db:            db,
		stripeConnect: stripeConnect,
		logger:        logger,
	}
}

// ConnectOnboardRequest is the request body for onboarding
type ConnectOnboardRequest struct {
	ReturnURL  string `json:"return_url"`
	RefreshURL string `json:"refresh_url"`
}

// ConnectOnboard starts Stripe Connect onboarding and returns the onboarding URL
func (h *SellHandler) ConnectOnboard(c *gin.Context) {
	if h.stripeConnect == nil {
		RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
		return
	}

	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	var req ConnectOnboardRequest
	_ = c.ShouldBindJSON(&req)
	returnURL := req.ReturnURL
	if returnURL == "" {
		returnURL = c.Request.URL.Scheme + "://" + c.Request.Host + "/sell/dashboard?onboarded=success"
	}
	refreshURL := req.RefreshURL
	if refreshURL == "" {
		refreshURL = c.Request.URL.Scheme + "://" + c.Request.Host + "/sell/dashboard?onboarded=refresh"
	}

	url, err := h.stripeConnect.CreateOnboardingLink(c.Request.Context(), userID, returnURL, refreshURL)
	if err != nil {
		if errors.Is(err, services.ErrStripeConnectDisabled) {
			RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
			return
		}
		h.logger.Error("CreateOnboardingLink failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to create onboarding link", err))
		return
	}

	RespondSuccess(c, http.StatusOK, gin.H{"onboarding_url": url})
}

// ConnectCallback syncs account status after Stripe redirect (called by frontend after return)
func (h *SellHandler) ConnectCallback(c *gin.Context) {
	if h.stripeConnect == nil {
		RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
		return
	}

	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	if err := h.stripeConnect.HandleOnboardingCallback(c.Request.Context(), userID); err != nil {
		if errors.Is(err, services.ErrNoStripeAccount) {
			RespondWithAppError(c, apperrors.NewNotFoundError("Stripe account"))
			return
		}
		if errors.Is(err, services.ErrStripeConnectDisabled) {
			RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
			return
		}
		h.logger.Error("HandleOnboardingCallback failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to sync account status", err))
		return
	}

	RespondSuccess(c, http.StatusOK, gin.H{"message": "Account synced"})
}

// GetBalance returns the seller's Stripe Connect balance
func (h *SellHandler) GetBalance(c *gin.Context) {
	if h.stripeConnect == nil {
		RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
		return
	}

	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	bal, err := h.stripeConnect.GetBalance(c.Request.Context(), userID)
	if err != nil {
		if errors.Is(err, services.ErrStripeConnectDisabled) {
			RespondWithAppError(c, apperrors.NewServiceUnavailableError("Stripe Connect is not enabled"))
			return
		}
		h.logger.Error("GetBalance failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to get balance", err))
		return
	}

	RespondSuccess(c, http.StatusOK, gin.H{
		"connected": bal.Connected,
		"available": bal.Available,
		"pending":   bal.Pending,
	})
}

// GetSellerTransfers returns the transfer history for the authenticated seller (v0.603)
func (h *SellHandler) GetSellerTransfers(c *gin.Context) {
	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	var transfers []marketplace.SellerTransfer
	if err := h.db.Where("seller_id = ?", userID).Order("created_at DESC").Find(&transfers).Error; err != nil {
		h.logger.Error("GetSellerTransfers failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to fetch transfers", err))
		return
	}

	RespondSuccess(c, http.StatusOK, transfers)
}