class Polars::SeriesPlot

def hist
  encoding = {
    x: {field: @series_name, bin: true},
    y: {aggregate: "count"}
  }
  Vega.lite
    .data(@df.rows(named: true))
    .mark(type: "bar", tooltip: true)
    .encoding(encoding)
    .config(axis: {labelFontSize: 12})
end

def initialize(s)
  require "vega"
  name = s.name || "value"
  @df = s.to_frame(name)
  @series_name = name
end

def kde
  if @series_name == "density"
    msg = "cannot use `plot.kde` when Series name is `'density'`"
    raise ArgumentError, msg
  end
  encoding = {
    x: {field: @series_name, type: "quantitative"},
    y: {field: "density", type: "quantitative"}
  }
  Vega.lite
    .data(@df.rows(named: true))
    .transform(density: @series_name, as: [@series_name, "density"])
    .mark(type: "area", tooltip: true)
    .encoding(encoding)
    .config(axis: {labelFontSize: 12})
end

def line
  if @series_name == "index"
    msg = "cannot call `plot.line` when Series name is 'index'"
    raise ArgumentError, msg
  end
  encoding = {
    x: {field: "index", type: "quantitative"},
    y: {field: @series_name, type: "quantitative"}
  }
  Vega.lite
    .data(@df.with_row_index.rows(named: true))
    .mark(type: "line", tooltip: true)
    .encoding(encoding)
    .config(axis: {labelFontSize: 12})
end