neiam /gitgud

defmodule GitGud.Themes.Editor do
  @moduledoc """
  Curated subset of Lumis themes exposed in the UI as "editor theme."

  Lumis ships ~250 Neovim-derived themes. Surfacing the entire list in
  a select makes it useless; this module fences the choice to the
  classic palettes most users will recognize. If you want something
  exotic, set the column directly.

  Falls back to a known-good theme if the user's stored choice isn't
  in the curated list (e.g. someone bumped Lumis and a theme got
  renamed).
  """

  # Theme ids match Lumis's `available_themes/0` exactly. Run
  #   `Lumis.available_themes() |> Enum.sort()` in iex to confirm
  # before editing — names like "solarized_dark" or "rose_pine" don't
  # exist; the actual ids are `neosolarized_*` and `rosepine_*`.
  @themes [
    {"OneDark", "onedark"},
    {"Dracula", "dracula"},
    {"Solarized Dark", "neosolarized_dark"},
    {"Solarized Light", "neosolarized_light"},
    {"Monokai", "monokai"},
    {"Monokai Pro", "monokai_pro"},
    {"GitHub Dark", "github_dark"},
    {"GitHub Light", "github_light"},
    {"Gruvbox Dark", "gruvbox_dark"},
    {"Gruvbox Light", "gruvbox_light"},
    {"Nord", "nord"},
    {"Tokyo Night (Storm)", "tokyonight_storm"},
    {"Tokyo Night", "tokyonight_night"},
    {"Tokyo Night (Day)", "tokyonight_day"},
    {"Catppuccin Mocha", "catppuccin_mocha"},
    {"Catppuccin Frappé", "catppuccin_frappe"},
    {"Catppuccin Macchiato", "catppuccin_macchiato"},
    {"Catppuccin Latte", "catppuccin_latte"},
    {"Rose Pine", "rosepine_dark"},
    {"Rose Pine Dawn", "rosepine_dawn"}
  ]

  @default "onedark"

  require Logger

  @doc "List of `{label, value}` tuples suitable for a select input."
  def options, do: @themes

  @doc "All valid theme ids."
  def ids, do: Enum.map(@themes, fn {_, id} -> id end)

  @doc "App default theme used when a user hasn't picked one."
  def default, do: @default

  @doc """
  Resolve a user's theme choice to a valid Lumis id, falling back to
  the default when the stored value is nil or no longer recognized.
  """
  def resolve(nil), do: @default

  def resolve(theme) when is_binary(theme) do
    if theme in ids() do
      theme
    else
      Logger.warning(
        "editor theme #{inspect(theme)} not in curated list; falling back to #{@default}"
      )

      @default
    end
  end

  def resolve(_), do: @default

  @doc "True if `theme` is in the curated list."
  def valid?(theme) when is_binary(theme), do: theme in ids()
  def valid?(_), do: false

  @doc """
  Resolve the editor theme from a LiveView's `current_scope`. Anonymous
  visitors get the app default; authed users get their stored choice
  (falling back to the default if it's nil or no longer valid).
  """
  def for_scope(%{user: %{editor_theme: theme}}), do: resolve(theme)
  def for_scope(_), do: @default
end