#' Generate a Geyser plot.
#'
#' A Geyser plot is a custom plot in which we plot continuous values on the Y axis grouped by a categorical value in the X. This is plotted as a dot plot, jittered so that the dots span
#' all the way to the other groups. On top of this, the mean and .66 and .95 of the data is plotted, depicting the overall distribution of the dots. The cells can, then, be colored by
#' a continuous variable (same as Y axis or different) or a categorical one (same as X axis or different).
#'
#' Special thanks to Christina Blume for coming up with the name of the plot.
#'
#' @inheritParams doc_function
#' @param scale_type \strong{\code{\link[base]{character}}} | Type of color scale to use.  One of:
#' \itemize{
#'   \item \emph{\code{categorical}}: Use a categorical color scale based on the values of "group.by".
#'   \item \emph{\code{continuous}}: Use a continuous color scale based on the values of "feature".
#' }
#' @param order \strong{\code{\link[base]{logical}}} | Whether to order the groups by the median of the data (highest to lowest).
#' @param jitter \strong{\code{\link[base]{numeric}}} | Amount of jitter in the plot along the X axis. The lower the value, the more compacted the dots are.
#' @param colors.use \strong{\code{\link[base]{character}}} | Named vector of colors to use. Has to match the unique values of group.by when scale_type is set to categorical.
#'
#' @return Either a plot of a list of plots, depending on the number of features provided.
#' @export
#' @example /man/examples/examples_do_GeyserPlot.R

do_GeyserPlot <- function(sample,
                          features,
                          assay = NULL,
                          slot = "data",
                          group.by = NULL,
                          split.by = NULL,
                          enforce_symmetry = FALSE,
                          scale_type = "continuous",
                          order = TRUE,
                          plot_cell_borders = TRUE,
                          jitter = 0.45,
                          pt.size = 1,
                          border.size = 2,
                          border.color = "black",
                          legend.position = "bottom",
                          legend.width = 1,
                          legend.length = 20,
                          legend.framewidth = 0.5,
                          legend.tickwidth = 0.5,
                          legend.framecolor = "grey50",
                          legend.tickcolor = "white",
                          legend.type = "colorbar",
                          font.size = 14,
                          font.type = "sans",
                          axis.text.x.angle = 45,
                          viridis.palette = "G",
                          viridis.direction = 1,
                          colors.use = NULL,
                          na.value = "grey75",
                          legend.ncol = NULL,
                          legend.nrow = NULL,
                          legend.icon.size = 4,
                          legend.byrow = FALSE,
                          legend.title = NULL,
                          plot.title = NULL,
                          plot.subtitle = NULL,
                          plot.caption = NULL,
                          xlab = "Groups",
                          ylab = feature,
                          flip = FALSE,
                          min.cutoff = rep(NA, length(features)),
                          max.cutoff = rep(NA, length(features)),
                          number.breaks = 5,
                          diverging.palette = "RdBu",
                          diverging.direction = -1,
                          sequential.palette = "YlGnBu",
                          sequential.direction = -1,
                          use_viridis = TRUE,
                          plot.title.face = "bold",
                          plot.subtitle.face = "plain",
                          plot.caption.face = "italic",
                          axis.title.face = "bold",
                          axis.text.face = "plain",
                          legend.title.face = "bold",
                          legend.text.face = "plain"){
  # Add lengthy error messages.
  withr::local_options(.new = list("warning.length" = 8170))

  check_suggests(function_name = "do_GeyserPlot")
  # Check if the sample provided is a Seurat object.
  check_Seurat(sample = sample)

  # Check logical parameters.
  logical_list <- list("enforce_symmetry" = enforce_symmetry,
                       "order" = order,
                       "plot_cell_borders" = plot_cell_borders,
                       "flip" = flip,
                       "use_viridis" = use_viridis)
  check_type(parameters = logical_list, required_type = "logical", test_function = is.logical)
  # Check numeric parameters.
  numeric_list <- list("pt.size" = pt.size,
                       "jitter" = jitter,
                       "font.size" = font.size,
                       "legend.framewidth" = legend.framewidth,
                       "legend.tickwidth" = legend.tickwidth,
                       "legend.length" = legend.length,
                       "legend.width" = legend.width,
                       "border.size" = border.size,
                       "legend.ncol" = legend.ncol,
                       "legend.nrow" = legend.nrow,
                       "legend.icon.size" = legend.icon.size,
                       "viridis.direction" = viridis.direction,
                       "axis.text.x.angle" = axis.text.x.angle,
                       "number.breaks" = number.breaks,
                       "sequential.direction" = sequential.direction)
  check_type(parameters = numeric_list, required_type = "numeric", test_function = is.numeric)
  # Check character parameters.

  character_list <- list("legend.position" = legend.position,
                         "features" = features,
                         "assay" = assay,
                         "group.by" = group.by,
                         "slot" = slot,
                         "split.by" = split.by,
                         "plot.title" = plot.title,
                         "plot.subtitle" = plot.subtitle,
                         "plot.caption" = plot.caption,
                         "scale_type" = scale_type,
                         "viridis.palette" = viridis.palette,
                         "legend.framecolor" = legend.framecolor,
                         "legend.tickcolor" = legend.tickcolor,
                         "legend.type" = legend.type,
                         "font.type" = font.type,
                         "border.color" = border.color,
                         "na.value" = na.value,
                         "diverging.palette" = diverging.palette,
                         "sequential.palette" = sequential.palette,
                         "plot.title.face" = plot.title.face,
                         "plot.subtitle.face" = plot.subtitle.face,
                         "plot.caption.face" = plot.caption.face,
                         "axis.title.face" = axis.title.face,
                         "axis.text.face" = axis.text.face,
                         "legend.title.face" = legend.title.face,
                         "legend.text.face" = legend.text.face)
  # Checks
  check_type(parameters = character_list, required_type = "character", test_function = is.character)

  check_colors(border.color, parameter_name = "border.color")
  check_colors(legend.tickcolor, parameter_name = "legend.tickcolor")
  check_colors(legend.framecolor, parameter_name = "legend.framecolor")
  check_colors(na.value, parameter_name = "na.value")

  check_parameters(parameter = font.type, parameter_name = "font.type")
  check_parameters(parameter = legend.type, parameter_name = "legend.type")
  check_parameters(parameter = legend.position, parameter_name = "legend.position")
  check_parameters(parameter = viridis.palette, parameter_name = "viridis.palette")
  check_parameters(parameter = scale_type, parameter_name = "scale_type")
  check_parameters(parameter = axis.text.x.angle, parameter_name = "axis.text.x.angle")
  check_parameters(parameter = number.breaks, parameter_name = "number.breaks")
  check_parameters(parameter = diverging.palette, parameter_name = "diverging.palette")
  check_parameters(plot.title.face, parameter_name = "plot.title.face")
  check_parameters(plot.subtitle.face, parameter_name = "plot.subtitle.face")
  check_parameters(plot.caption.face, parameter_name = "plot.caption.face")
  check_parameters(axis.title.face, parameter_name = "axis.title.face")
  check_parameters(axis.text.face, parameter_name = "axis.text.face")
  check_parameters(legend.title.face, parameter_name = "legend.title.face")
  check_parameters(legend.text.face, parameter_name = "legend.text.face")
  check_parameters(viridis.direction, parameter_name = "viridis.direction")
  check_parameters(sequential.direction, parameter_name = "sequential.direction")
  check_parameters(diverging.direction, parameter_name = "diverging.direction")

  `%>%` <- magrittr::`%>%`

  # Generate the continuous color palette.
  if (isTRUE(enforce_symmetry)){
    colors.gradient <- compute_continuous_palette(name = diverging.palette,
                                                  use_viridis = FALSE,
                                                  direction = diverging.direction,
                                                  enforce_symmetry = enforce_symmetry)
  } else {
    colors.gradient <- compute_continuous_palette(name = ifelse(isTRUE(use_viridis), viridis.palette, sequential.palette),
                                                  use_viridis = use_viridis,
                                                  direction = ifelse(isTRUE(use_viridis), viridis.direction, sequential.direction),
                                                  enforce_symmetry = enforce_symmetry)
  }

  # Check the assay.
  out <- check_and_set_assay(sample = sample, assay = assay)
  sample <- out[["sample"]]
  assay <- out[["assay"]]
  rm(out)

  # Check that split.by is in metadata variables.
  if (!is.null(split.by)){
    assertthat::assert_that(split.by %in% colnames(sample@meta.data),
                            msg = paste0(add_cross(), crayon_body("The variable for "),
                                         crayon_key("split.by"),
                                         crayon_body(" has to be on the "),
                                         crayon_key("metadata"),
                                         crayon_body(" of the Seurat object.")))
  }


  # Check that group.by is in metadata variables.
  if (!is.null(group.by)){
    assertthat::assert_that(group.by %in% colnames(sample@meta.data),
                            msg = paste0(add_cross(), crayon_body("The variable for "),
                                         crayon_key("group.by"),
                                         crayon_body(" has to be on the "),
                                         crayon_key("metadata"),
                                         crayon_body(" of the Seurat object.")))
  }

  # Check that jitter is in range.
  assertthat::assert_that(jitter > 0 & jitter < 0.5,
                          msg = paste0(add_cross(), crayon_body("The value for "),
                                       crayon_key("jitter"),
                                       crayon_body(" has to be between "),
                                       crayon_key("0"),
                                       crayon_body(" and "),
                                       crayon_key("0.49"),
                                       crayon_body(".")))

  assertthat::assert_that(length(min.cutoff) == length(features),
                          msg = paste0(add_cross(), crayon_body("Please provide "),
                                       crayon_key("as many values"),
                                       crayon_body(" to "),
                                       crayon_key("min.cutoff"),
                                       crayon_body(" than provided "),
                                       crayon_key("features"),
                                       crayon_body(". Use"),
                                       crayon_key("NA"),
                                       crayon_body(" if you want to skip a given feature.")))

  assertthat::assert_that(length(max.cutoff) == length(features),
                          msg = paste0(add_cross(), crayon_body("Please provide "),
                                       crayon_key("as many values"),
                                       crayon_body(" to "),
                                       crayon_key("max.cutoff"),
                                       crayon_body(" than provided "),
                                       crayon_key("features"),
                                       crayon_body(". Use"),
                                       crayon_key("NA"),
                                       crayon_body(" if you want to skip a given feature.")))

  # Will contain the output.
  list.out <- list()

  # Check group.by.
  out <- check_group_by(sample = sample,
                        group.by = group.by,
                        is.heatmap = FALSE)
  sample <- out[["sample"]]
  group.by <- out[["group.by"]]

  if (is.null(colors.use)){
    colors.use <- generate_color_scale(names_use = if (is.factor(sample@meta.data[, group.by])) {
      levels(sample@meta.data[, group.by])
    } else {
      sort(unique(sample@meta.data[, group.by]))
    })
  } else {
    check_colors(colors.use)
    check_consistency_colors_and_names(sample, colors = colors.use, grouping_variable = group.by)
  }

  # Iterate for each feature.
  counter <- 0
  for (feature in features){
    counter <- counter + 1

    max.cutoff.use <- max.cutoff[counter]
    min.cutoff.use <- min.cutoff[counter]

    # Check the feature.
    check_feature(sample = sample,
                  features = feature)


    # Get a vector of all dimensional reduction components.
    dim_colnames <- NULL
    for(red in Seurat::Reductions(object = sample)){
      col.names <- colnames(sample@reductions[[red]][[]])
      dim_colnames <- append(dim_colnames, col.names)
      if (feature %in% col.names){
        # Get the reduction in which the feature is, if this is the case.
        reduction <- red
      }
    }


    # Depending on where the feature is, generate a tibble accordingly.
    if (isTRUE(feature %in% colnames(sample@meta.data))){
      data <- sample@meta.data %>%
              dplyr::select(dplyr::all_of(c(group.by, feature))) %>%
              tibble::rownames_to_column(var = "cell") %>%
              tibble::as_tibble()
    } else if (isTRUE(feature %in% rownames(sample))){
      suppressWarnings({
      data <- SeuratObject::GetAssayData(object = sample,
                                   assay = assay,
                                   slot = slot)[feature, , drop = FALSE] %>%
              as.matrix() %>%
              t() %>%
              as.data.frame() %>%
              tibble::rownames_to_column(var = "cell") %>%
              tibble::tibble() %>%
              dplyr::left_join(y = {sample@meta.data %>%
                                    dplyr::select(dplyr::all_of(c(group.by))) %>%
                                    tibble::rownames_to_column(var = "cell")},
                               by = "cell")
      })
    } else if (isTRUE(feature %in% dim_colnames)){
      data <- sample@reductions[[reduction]][[]][, feature, drop = FALSE] %>%
              as.data.frame() %>%
              tibble::rownames_to_column(var = "cell") %>%
              tibble::tibble() %>%
              dplyr::left_join(y = {sample@meta.data %>%
                                    dplyr::select(dplyr::all_of(c(group.by))) %>%
                                    tibble::rownames_to_column(var = "cell")},
                                    by = "cell")
    }

    # If we also want additional split.by.
    if (!(is.null(split.by))){
      data <- data %>%
              dplyr::left_join(y = {sample@meta.data %>%
                                    dplyr::select(dplyr::all_of(c(split.by))) %>%
                                    tibble::rownames_to_column(var = "cell")},
                               by = "cell") %>%
              dplyr::mutate("split.by" = .data[[split.by]]) %>%
              dplyr::select(-dplyr::all_of(c(split.by)))

    }

    # Proceed with the regular plot.
    if (isTRUE(order)){
      data <- data %>%
              dplyr::mutate("group.by" = factor(.data[[group.by]], levels = {data %>%
                                                                             dplyr::group_by(.data[[group.by]]) %>%
                                                                             dplyr::summarise("mean" = stats::median(.data[[feature]]), na.rm = TRUE) %>%
                                                                             dplyr::arrange(dplyr::desc(.data$mean)) %>%
                                                                             dplyr::pull(.data[[group.by]]) %>%
                                                                             as.character()}),
                            "values" = .data[[feature]])
    } else if (base::isFALSE(order)){
      data <- data %>%
              dplyr::mutate("group.by" = .data[[group.by]],
                            "values" = .data[[feature]])
    }

    # Get the final column names.
    cols.use <- c("values", "group.by")
    if (!(is.null(split.by))){
      cols.use <- append(cols.use, "split.by")
    }

    data <- data %>%
            dplyr::select(dplyr::all_of(cols.use))

    # Define cutoffs.
    range.data <- c(min(data[, "values"], na.rm = TRUE),
                    max(data[, "values"], na.rm = TRUE))

    out <- check_cutoffs(min.cutoff = min.cutoff.use,
                         max.cutoff = max.cutoff.use,
                         feature = feature,
                         limits = range.data)

    range.data <- out$limits


    # Plot.
    if (scale_type == "categorical"){
      p <- ggplot2::ggplot(data = data,
                           mapping = ggplot2::aes(x = .data[["group.by"]],
                                                  y = .data[["values"]],
                                                  color = .data[["group.by"]]))
    } else if (scale_type == "continuous"){
      p <- ggplot2::ggplot(data = data,
                           mapping = ggplot2::aes(x = .data[["group.by"]],
                                                  y = .data[["values"]],
                                                  color = .data[["values"]]))
    }


    if (isTRUE(plot_cell_borders)){
      p <- p +
           ggplot2::geom_point(position = ggplot2::position_jitter(width = jitter,
                                                                   seed = 0),
                               size = pt.size * border.size,
                               color = border.color,
                               na.rm = TRUE)
    }

    scale.setup <- compute_scales(sample = sample,
                                  feature = feature,
                                  assay = assay,
                                  reduction = NULL,
                                  slot = slot,
                                  number.breaks = number.breaks,
                                  min.cutoff = min.cutoff.use,
                                  max.cutoff = max.cutoff.use,
                                  flavor = "Seurat",
                                  enforce_symmetry = enforce_symmetry,
                                  from_data = TRUE,
                                  limits.use = range.data)

    limits <- c(min(data[, "values"], na.rm = TRUE),
                max(data[, "values"], na.rm = TRUE))

    if (limits[1] != range.data[1]){
      limits <- c(range.data[1], limits[2])
    }

    if (limits[2] != range.data[2]){
      limits <- c(limits[1], range.data[2])
    }
    end_value <- max(abs(limits))
    if (isTRUE(scale_type == "continuous")){
      p <- p +
           ggplot2::scale_color_gradientn(colors = colors.gradient,
                                          na.value = na.value,
                                          name = legend.title,
                                          breaks = scale.setup$breaks,
                                          labels = scale.setup$labels,
                                          limits = scale.setup$limits)
    } else if (isTRUE(scale_type == "categorical")){
      p <- p +
           ggplot2::scale_color_manual(values = colors.use,
                                       na.value = na.value)
    }

    p <- p +
         ggplot2::geom_point(position = ggplot2::position_jitter(width = jitter,
                                                                 seed = 0),
                             size = pt.size,
                             na.rm = TRUE) +
         ggdist::stat_pointinterval(interval_size_range = c(2, 3),
                                    fatten_point = 1.5,
                                    interval_color = "white",
                                    point_color = "white",
                                    position = ggplot2::position_dodge(width = 1),
                                    na.rm = TRUE,
                                    show.legend = FALSE) +
         ggdist::stat_pointinterval(interval_size_range = c(1, 2),
                                    interval_color = "black",
                                    point_color = "black",
                                    position = ggplot2::position_dodge(width = 1),
                                    na.rm = TRUE,
                                    show.legend = FALSE)

    if (!(is.null(split.by))){
      p <- p +
           ggplot2::facet_grid(. ~ split.by)
    }
    p <- p +
         ggplot2::scale_y_continuous(labels = scales::label_number(),
                                     limits = if (isTRUE(enforce_symmetry)) {c(-end_value, end_value)} else {range.data}) +
         ggplot2::labs(title = plot.title,
                       subtitle = plot.subtitle,
                       caption = plot.caption) +
         ggplot2::xlab(xlab) +
         ggplot2::ylab(ylab) +
         ggplot2::theme_minimal(base_size = font.size) +
         ggplot2::theme(axis.title = ggplot2::element_text(color = "black",
                                                           face = axis.title.face),
                        axis.line.x = if (base::isFALSE(flip)) {ggplot2::element_line(color = "black")} else if (isTRUE(flip)) {ggplot2::element_blank()},
                        axis.line.y = if (isTRUE(flip)) {ggplot2::element_line(color = "black")} else if (base::isFALSE(flip)) {ggplot2::element_blank()},
                        axis.text.x = ggplot2::element_text(color = "black",
                                                            face = axis.text.face,
                                                            angle = get_axis_parameters(angle = axis.text.x.angle, flip = flip)[["angle"]],
                                                            hjust = get_axis_parameters(angle = axis.text.x.angle, flip = flip)[["hjust"]],
                                                            vjust = get_axis_parameters(angle = axis.text.x.angle, flip = flip)[["vjust"]]),
                        axis.text.y = ggplot2::element_text(color = "black", face = axis.text.face),
                        axis.ticks = ggplot2::element_line(color = "black"),
                        panel.grid.major = ggplot2::element_blank(),
                        plot.title.position = "plot",
                        plot.title = ggplot2::element_text(face = plot.title.face, hjust = 0),
                        plot.subtitle = ggplot2::element_text(face = plot.subtitle.face, hjust = 0),
                        plot.caption = ggplot2::element_text(face = plot.caption.face, hjust = 1),
                        legend.text = ggplot2::element_text(face = legend.text.face),
                        legend.title = ggplot2::element_text(face = legend.title.face),
                        panel.grid = ggplot2::element_blank(),
                        text = ggplot2::element_text(family = font.type),
                        plot.caption.position = "plot",
                        legend.position = legend.position,
                        legend.justification = "center",
                        plot.margin = ggplot2::margin(t = 10, r = 10, b = 10, l = 10),
                        plot.background = ggplot2::element_rect(fill = "white", color = "white"),
                        panel.background = ggplot2::element_rect(fill = "white", color = "white"),
                        legend.background = ggplot2::element_rect(fill = "white", color = "white"),
                        strip.text =ggplot2::element_text(color = "black", face = "bold"))

    if (isTRUE(scale_type == "continuous")){
      if (is.null(legend.title)){
        legend.title <- feature
      }
      p <- modify_continuous_legend(p = p,
                                    legend.title = legend.title,
                                    legend.aes = "color",
                                    legend.type = legend.type,
                                    legend.position = legend.position,
                                    legend.length = legend.length,
                                    legend.width = legend.width,
                                    legend.framecolor = legend.framecolor,
                                    legend.tickcolor = legend.tickcolor,
                                    legend.framewidth = legend.framewidth,
                                    legend.tickwidth = legend.tickwidth)
    } else if (isTRUE(scale_type == "categorical")){
      if (is.null(legend.title)){
        legend.title <- ""
      }
      p <- p +
           ggplot2::guides(color = ggplot2::guide_legend(title = legend.title,
                                                         ncol = legend.ncol,
                                                         nrow = legend.nrow,
                                                         byrow = legend.byrow,
                                                         override.aes = list(size = legend.icon.size),
                                                         title.position = "top",
                                                         title.hjust = 0.5))
    }

    list.out[[feature]] <- p
  }

  if (isTRUE(flip)){
    p <- p +
         ggplot2::coord_flip()
  }
  return(if (length(features) > 1) {list.out} else {p})
}
