package handler

import (
	"errors"

	"accounting-app/pkg/api"
	"accounting-app/internal/service"

	"github.com/gin-gonic/gin"
)

// DefaultAccountHandler handles HTTP requests for default account settings
// Feature: financial-core-upgrade
// Validates: Requirements 11.1-11.4
type DefaultAccountHandler struct {
	userSettingsService *service.UserSettingsService
}

// NewDefaultAccountHandler creates a new DefaultAccountHandler instance
func NewDefaultAccountHandler(userSettingsService *service.UserSettingsService) *DefaultAccountHandler {
	return &DefaultAccountHandler{
		userSettingsService: userSettingsService,
	}
}

// GetDefaultAccounts handles GET /api/settings/default-accounts
// Returns the current default account settings
// Validates: Requirements 11.1, 11.3
func (h *DefaultAccountHandler) GetDefaultAccounts(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	response, err := h.userSettingsService.GetDefaultAccounts(userId.(uint))
	if err != nil {
		api.InternalError(c, "Failed to get default accounts: "+err.Error())
		return
	}

	api.Success(c, response)
}

// UpdateDefaultAccounts handles PUT /api/settings/default-accounts
// Updates the default account settings
// Validates: Requirements 11.2, 11.4
func (h *DefaultAccountHandler) UpdateDefaultAccounts(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var input service.DefaultAccountsInput
	if err := c.ShouldBindJSON(&input); err != nil {
		api.ValidationError(c, "Invalid request body: "+err.Error())
		return
	}

	response, err := h.userSettingsService.UpdateDefaultAccounts(userId.(uint), input)
	if err != nil {
		if errors.Is(err, service.ErrDefaultAccountNotFound) {
			api.NotFound(c, "Specified account not found")
			return
		}
		if errors.Is(err, service.ErrInvalidDefaultAccount) {
			api.BadRequest(c, "Invalid default account")
			return
		}
		api.InternalError(c, "Failed to update default accounts: "+err.Error())
		return
	}

	api.Success(c, response)
}

// RegisterRoutes registers all default account routes to the given router group
func (h *DefaultAccountHandler) RegisterRoutes(rg *gin.RouterGroup) {
	settings := rg.Group("/settings")
	{
		settings.GET("/default-accounts", h.GetDefaultAccounts)
		settings.PUT("/default-accounts", h.UpdateDefaultAccounts)
	}
}