# Copyright 2025, Matthias Reik <fledex@reik.org>
#
# SPDX-License-Identifier: Apache-2.0

if Mix.env() in [:test, :dev] do
  defmodule Mix.Tasks.Docs.Fledex.Colors do
    use Mix.Task

    require Fledex
    alias Fledex.Config

    @shortdoc "Generate documentation for all the available Fledex colors from various known color modules"
    @requirements ["compile"]

    @moduledoc """
    Generate documentation for all the available Fledex colors from various known color modules
    See `Fledex.Config.known_color_modules/0` for more details.
    """
    @dir "./pages"
    @name "colors.md"

    @switches [
      path: :string,
      name: :string
    ]
    @aliases [
      o: :path,
      n: :name
    ]

    @doc false
    @spec run([binary()]) :: any()
    def run(args) do
      {cli_opts, _args, _invalid} =
        OptionParser.parse(args, aliases: @aliases, switches: @switches)

      out_dir = cli_opts[:path] || @dir
      out_name = cli_opts[:name] || @name
      file = Path.join(out_dir, out_name)

      Mix.shell().info([:green, "Generating Fledex Colors to #{file}"])
      content = create_content(Config.known_color_modules())
      File.write(file, content, [:utf8, :write])
    end

    defp create_content(modules) do
      Enum.reduce(modules, create_header(modules), fn {module, type, shortcut}, acc ->
        acc <> create_section(module, type, shortcut)
      end)
    end

    defp create_header(modules) do
      header = """
      <!--
      Copyright 2025, Matthias Reik <fledex@reik.org>

      SPDX-License-Identifier: Apache-2.0
      Content autogenerated through the `mix docs.fledex.colors` task
      -->

      # Color Names
      This is a list of all the colors that can be found in Fledex.
      The modules that are marked as `core` are those that will be loaded by default
      if you `use Fledex` or `use Fledex.Config` and nothing else is mentioned.
      Those modules that are marked as `optional` are the ones that get shipped with
      `Fledex` but are not loaded by default.

      You can still load them through `use Fledex` or `use Fledex.Config` by passing
      a `:colors` argument (see `Fledex` and `Fledex.Config`) If you specify your
      own list of color module, you can make use of the alias name (`atom`).

      ```elixir
      use Fledex, colors: [:wiki, :css]
      ```

      Therefore the sections are named with the alias instead of the module name.

      You can also bring your own color name list with your own color modules and
      load them, but in that case you will need to specify the full color module name.
      ```elixir
      use Fledex, colors: [:wiki, MyLibrary.MySuperColors]
      ```

      > #### Info {: .info}
      >
      > The colors get loaded by default in the ordered specified here, so if there
      > is a name conflict the former will win over latter.

      Once you have specified your color lists, you can access those colors through
      their alias names (use them through the `Fledex.Color` protocol or the
      `Fledex.Color.Names` module).

      When using the `Fledex` DSL the names get by default imported, so you can use
      them through their function names too (see `Fledex.__using__/1`)

      This allows to use them in an easy way when defining led sequences like:

      ```elixir
        # load our configuration (only Wiki colors)
        # CAUTION: don't call this several time
        use Fledex.Config, colors: :wiki

        # import the Fledex.Leds module to reduce the typing
        import Fledex.Leds

        # alias some more modules
        alias Fledex.Color
        alias Fledex.Color.Names

        # create our led sequence with the colors: red, green, blue, purple
        leds(10)
          |> light(:red)
          |> green()
          |> light(Color.to_colorint(:blue))
          |> light(Names.info(:purple))
      ```

      ### Table of Content
      """

      Enum.reduce(modules, header, fn module, acc ->
        # long = Atom.to_string(elem(module,0))
        type = Atom.to_string(elem(module, 1))
        short = Atom.to_string(elem(module, 2))

        acc <>
          """
          * [`:#{short}`](##{short}) (#{type})
          """
      end)
    end

    defp create_section(module, type, shortcut) do
      header = """
      ## :#{shortcut}
      (module: `#{module}`, type: `#{type}`, count: `#{length(module.names())}`)

      <table>
      <tr style='border-bottom: 2px solid #000000;'><th>Color</th><th>Name</th></tr>
      """

      module.colors()
      |> Enum.sort_by(& &1, fn left, right -> left.name < right.name end)
      |> Enum.reduce(header, fn color, acc ->
        acc <> create_table_row(color)
      end)
      |> close_table()
    end

    defp close_table(content) do
      content <>
        """
        </table>
        """
    end

    @base16 16
    defp create_table_row(color) do
      hex =
        color.hex
        |> Integer.to_string(@base16)
        |> String.pad_leading(6, "0")

      """
      <tr><td><div style="width: 25px; height: 25px; display: inline-block; background-color: ##{hex}; border: 1px solid black"></div></td><td><code>:#{color.name}</code></td></tr>
      """
    end
  end
end