############################################
##  Homogeneity of variance test - 空壳版（照抄 single_mean）
############################################

# Homogeneity of variance tests for radiant.basics
#' @export
homo_variance_test <- function(dataset, var, group, method = "levene",
                               conf_lev = .95, data_filter = "",
                               envir = parent.frame()) {
  df_name <- if (is_string(dataset)) dataset else deparse(substitute(dataset))
  dataset <- get_data(dataset, var, group, filt = data_filter, na.rm = TRUE, envir = envir)
  x <- dataset[[var]]
  g <- dataset[[group]]
  if (!is.numeric(x)) stop(i18n$t("Variable must be numeric"))
  if (length(unique(g)) < 2) stop(i18n$t("Grouping variable must have at least 2 levels"))
  
  ## ---- 空壳结果 ----
  res <- tibble::tribble(
    ~Test, ~Statistic, ~p.value,
    "Levene",       0.42, 0.52,
    "Bartlett",     0.38, 0.54,
    "Fligner",      0.45, 0.50
  )
  
  dat_summary <- dataset %>%
    group_by(!!sym(group)) %>%
    summarise(
      n = n(),
      mean = mean(!!sym(var), na.rm = TRUE),
      sd = sd(!!sym(var), na.rm = TRUE),
      .groups = "drop"
    )
  
  ## 绘图数据
  plot_obj <- list(hist = list(type = "hist", data = dataset, var = var, group = group),
                   density = list(type = "density", data = dataset, var = var, group = group),
                   boxplot = list(type = "boxplot", data = dataset, var = var, group = group))
  
  as.list(environment()) %>% add_class("homo_variance_test")
}

# Summary method
#' @export
summary.homo_variance_test <- function(object, dec = 3, ...) {
  cat("Homogeneity of variance tests\n")
  cat("Data     :", object$df_name, "\n")
  if (!is.empty(object$data_filter)) {
    cat("Filter   :", gsub("\\n", "", object$data_filter), "\n")
  }
  cat("Variable :", object$var, "\n")
  cat("Group    :", object$group, "\n\n")
  
  ## 打印统计量表
  object$res %>%
    as.data.frame(stringsAsFactors = FALSE) %>%
    format_df(dec = dec) %>%
    print(row.names = FALSE)
  cat("\n")
}

# Plot method
#' @export
plot.homo_variance_test <- function(x, plots = c("boxplot", "density"),
                                    shiny = FALSE, custom = FALSE, ...) {
  plot_list <- list()
  if ("boxplot" %in% plots) {
    plot_list[[which("boxplot" == plots)]] <-
      ggplot(x$dat_summary, aes(x = .data[[x$group]], y = .data[[x$var]])) +
      geom_boxplot(fill = "lightblue", alpha = 0.7)
  }
  if ("density" %in% plots) {
    plot_list[[which("density" == plots)]] <-
      ggplot(x$dat_summary, aes(x = .data[[x$var]], fill = .data[[x$group]])) +
      geom_density(alpha = 0.5)
  }
  if ("hist" %in% plots) {
    plot_list[[which("hist" == plots)]] <-
      ggplot(x$dat_summary, aes(x = .data[[x$var]], fill = .data[[x$group]])) +
      geom_histogram(alpha = 0.5, position = "identity", bins = 30)
  }
  
  if (length(plot_list) == 0) return(invisible())
  patchwork::wrap_plots(plot_list, ncol = 1) %>%
    { if (shiny) print(.) else print(.) }
  invisible(x)
}