package handlers

import (
	"net/http"
	"strconv"

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

	"veza-backend-api/internal/core/marketplace"
)

// AdminTransferHandler handles admin transfer dashboard endpoints (v0.701).
type AdminTransferHandler struct {
	db     *gorm.DB
	ts     marketplace.TransferService
	logger *zap.Logger
	feeRate float64
}

// NewAdminTransferHandler creates a new AdminTransferHandler.
func NewAdminTransferHandler(db *gorm.DB, ts marketplace.TransferService, feeRate float64, logger *zap.Logger) *AdminTransferHandler {
	return &AdminTransferHandler{
		db:      db,
		ts:      ts,
		logger:  logger,
		feeRate: feeRate,
	}
}

// GetTransfers returns a paginated list of all platform transfers with optional filters.
// Query params: status, seller_id, from, to, limit (default 50), offset (default 0).
func (h *AdminTransferHandler) GetTransfers(c *gin.Context) {
	query := h.db.Model(&marketplace.SellerTransfer{})

	if status := c.Query("status"); status != "" {
		query = query.Where("status = ?", status)
	}
	if sellerIDStr := c.Query("seller_id"); sellerIDStr != "" {
		sellerID, err := uuid.Parse(sellerIDStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid seller_id"})
			return
		}
		query = query.Where("seller_id = ?", sellerID)
	}
	if from := c.Query("from"); from != "" {
		query = query.Where("created_at >= ?", from)
	}
	if to := c.Query("to"); to != "" {
		query = query.Where("created_at <= ?", to)
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		h.logger.Error("GetTransfers count failed", zap.Error(err))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to count transfers"})
		return
	}

	limit := 50
	if l := c.Query("limit"); l != "" {
		if parsed, err := strconv.Atoi(l); err == nil && parsed > 0 && parsed <= 100 {
			limit = parsed
		}
	}
	offset := 0
	if o := c.Query("offset"); o != "" {
		if parsed, err := strconv.Atoi(o); err == nil && parsed >= 0 {
			offset = parsed
		}
	}

	var transfers []marketplace.SellerTransfer
	if err := query.Order("created_at DESC").Limit(limit).Offset(offset).Find(&transfers).Error; err != nil {
		h.logger.Error("GetTransfers find failed", zap.Error(err))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch transfers"})
		return
	}

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

// RetryTransfer manually retries a failed transfer.
func (h *AdminTransferHandler) RetryTransfer(c *gin.Context) {
	if h.ts == nil {
		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "Stripe Connect is not enabled"})
		return
	}

	idStr := c.Param("id")
	if idStr == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "transfer id required"})
		return
	}
	transferID, err := uuid.Parse(idStr)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid transfer id"})
		return
	}

	var t marketplace.SellerTransfer
	if err := h.db.First(&t, transferID).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			c.JSON(http.StatusNotFound, gin.H{"error": "transfer not found"})
			return
		}
		h.logger.Error("RetryTransfer find failed", zap.Error(err), zap.String("transfer_id", idStr))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch transfer"})
		return
	}

	if t.Status != "failed" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "only failed transfers can be retried"})
		return
	}

	err = h.ts.CreateTransfer(c.Request.Context(), t.SellerID, t.AmountCents, t.Currency, t.OrderID.String())
	if err != nil {
		t.RetryCount++
		t.ErrorMessage = err.Error()
		// Could set next_retry_at for worker to pick up later, but for manual retry we just record the failure
		if saveErr := h.db.Save(&t).Error; saveErr != nil {
			h.logger.Error("RetryTransfer save failed", zap.Error(saveErr))
		}
		h.logger.Error("RetryTransfer CreateTransfer failed", zap.Error(err), zap.String("transfer_id", idStr))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Transfer failed: " + err.Error()})
		return
	}

	t.Status = "completed"
	t.ErrorMessage = ""
	if err := h.db.Save(&t).Error; err != nil {
		h.logger.Error("RetryTransfer save failed", zap.Error(err))
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to update transfer"})
		return
	}

	RespondSuccess(c, http.StatusOK, t)
}