package handlers

import (
	"errors"
	"net/http"

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

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

// KYCHandler handles seller identity verification endpoints (v0.13.5 TASK-MKT-001)
type KYCHandler struct {
	kycService *services.KYCService
	logger     *zap.Logger
}

// NewKYCHandler creates a new KYC handler
func NewKYCHandler(kycService *services.KYCService, logger *zap.Logger) *KYCHandler {
	return &KYCHandler{
		kycService: kycService,
		logger:     logger,
	}
}

// CreateVerificationRequest is the request body for starting KYC
type CreateVerificationRequest struct {
	ReturnURL string `json:"return_url"`
}

// StartVerification creates a Stripe Identity verification session
func (h *KYCHandler) StartVerification(c *gin.Context) {
	if h.kycService == nil {
		RespondWithAppError(c, apperrors.NewServiceUnavailableError("KYC verification is not available"))
		return
	}

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

	var req CreateVerificationRequest
	_ = c.ShouldBindJSON(&req)
	returnURL := req.ReturnURL
	if returnURL == "" {
		returnURL = c.Request.URL.Scheme + "://" + c.Request.Host + "/sell?kyc=complete"
	}

	session, err := h.kycService.CreateVerificationSession(c.Request.Context(), userID, returnURL)
	if err != nil {
		if errors.Is(err, services.ErrKYCAlreadyDone) {
			RespondSuccess(c, http.StatusOK, gin.H{"status": "verified", "message": "Already verified"})
			return
		}
		if errors.Is(err, services.ErrKYCNotAvailable) {
			RespondWithAppError(c, apperrors.NewServiceUnavailableError("KYC verification is not available"))
			return
		}
		if errors.Is(err, services.ErrNoStripeAccount) {
			RespondWithAppError(c, apperrors.NewValidationError("Complete Stripe Connect onboarding first"))
			return
		}
		h.logger.Error("StartVerification failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to start verification", err))
		return
	}

	RespondSuccess(c, http.StatusCreated, session)
}

// GetVerificationStatus returns the current KYC status for a seller
func (h *KYCHandler) GetVerificationStatus(c *gin.Context) {
	if h.kycService == nil {
		RespondSuccess(c, http.StatusOK, gin.H{"status": "not_available"})
		return
	}

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

	status, err := h.kycService.GetVerificationStatus(c.Request.Context(), userID)
	if err != nil {
		if errors.Is(err, services.ErrKYCNotAvailable) {
			RespondSuccess(c, http.StatusOK, gin.H{"status": "not_available"})
			return
		}
		h.logger.Error("GetVerificationStatus failed", zap.Error(err), zap.String("user_id", userID.String()))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to get verification status", err))
		return
	}

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