package handlers

import (
	"net/http"
	"strconv"

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

	"github.com/kms/api-key-service/internal/domain"
	"github.com/kms/api-key-service/internal/services"
)

// ApplicationHandler handles application-related HTTP requests
type ApplicationHandler struct {
	appService  services.ApplicationService
	authService services.AuthenticationService
	logger      *zap.Logger
}

// NewApplicationHandler creates a new application handler
func NewApplicationHandler(
	appService services.ApplicationService,
	authService services.AuthenticationService,
	logger *zap.Logger,
) *ApplicationHandler {
	return &ApplicationHandler{
		appService:  appService,
		authService: authService,
		logger:      logger,
	}
}

// Create handles POST /applications
func (h *ApplicationHandler) Create(c *gin.Context) {
	var req domain.CreateApplicationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("Invalid request body", zap.Error(err))
		c.JSON(http.StatusBadRequest, gin.H{
			"error":   "Bad Request",
			"message": "Invalid request body: " + err.Error(),
		})
		return
	}

	// Get user ID from context
	userID, exists := c.Get("user_id")
	if !exists {
		h.logger.Error("User ID not found in context")
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Authentication context not found",
		})
		return
	}

	app, err := h.appService.Create(c.Request.Context(), &req, userID.(string))
	if err != nil {
		h.logger.Error("Failed to create application", zap.Error(err))
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Failed to create application",
		})
		return
	}

	h.logger.Info("Application created", zap.String("app_id", app.AppID))
	c.JSON(http.StatusCreated, app)
}

// GetByID handles GET /applications/:id
func (h *ApplicationHandler) GetByID(c *gin.Context) {
	appID := c.Param("id")
	if appID == "" {
		c.JSON(http.StatusBadRequest, gin.H{
			"error":   "Bad Request",
			"message": "Application ID is required",
		})
		return
	}

	app, err := h.appService.GetByID(c.Request.Context(), appID)
	if err != nil {
		h.logger.Error("Failed to get application", zap.Error(err), zap.String("app_id", appID))
		c.JSON(http.StatusNotFound, gin.H{
			"error":   "Not Found",
			"message": "Application not found",
		})
		return
	}

	c.JSON(http.StatusOK, app)
}

// List handles GET /applications
func (h *ApplicationHandler) List(c *gin.Context) {
	// Parse pagination parameters
	limit := 50
	offset := 0

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

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

	apps, err := h.appService.List(c.Request.Context(), limit, offset)
	if err != nil {
		h.logger.Error("Failed to list applications", zap.Error(err))
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Failed to list applications",
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"data":   apps,
		"limit":  limit,
		"offset": offset,
		"count":  len(apps),
	})
}

// Update handles PUT /applications/:id
func (h *ApplicationHandler) Update(c *gin.Context) {
	appID := c.Param("id")
	if appID == "" {
		c.JSON(http.StatusBadRequest, gin.H{
			"error":   "Bad Request",
			"message": "Application ID is required",
		})
		return
	}

	var req domain.UpdateApplicationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		h.logger.Warn("Invalid request body", zap.Error(err))
		c.JSON(http.StatusBadRequest, gin.H{
			"error":   "Bad Request",
			"message": "Invalid request body: " + err.Error(),
		})
		return
	}

	// Get user ID from context
	userID, exists := c.Get("user_id")
	if !exists {
		h.logger.Error("User ID not found in context")
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Authentication context not found",
		})
		return
	}

	app, err := h.appService.Update(c.Request.Context(), appID, &req, userID.(string))
	if err != nil {
		h.logger.Error("Failed to update application", zap.Error(err), zap.String("app_id", appID))
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Failed to update application",
		})
		return
	}

	h.logger.Info("Application updated", zap.String("app_id", appID))
	c.JSON(http.StatusOK, app)
}

// Delete handles DELETE /applications/:id
func (h *ApplicationHandler) Delete(c *gin.Context) {
	appID := c.Param("id")
	if appID == "" {
		c.JSON(http.StatusBadRequest, gin.H{
			"error":   "Bad Request",
			"message": "Application ID is required",
		})
		return
	}

	// Get user ID from context
	userID, exists := c.Get("user_id")
	if !exists {
		h.logger.Error("User ID not found in context")
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Authentication context not found",
		})
		return
	}

	err := h.appService.Delete(c.Request.Context(), appID, userID.(string))
	if err != nil {
		h.logger.Error("Failed to delete application", zap.Error(err), zap.String("app_id", appID))
		c.JSON(http.StatusInternalServerError, gin.H{
			"error":   "Internal Server Error",
			"message": "Failed to delete application",
		})
		return
	}

	h.logger.Info("Application deleted", zap.String("app_id", appID))
	c.JSON(http.StatusNoContent, nil)
}