neiam /gitgud

defmodule GitGud.Languages do
  @moduledoc """
  Filename → language *display name* detection.

  Used by the language-stats walker. Returns the same display strings
  the `LanguageColors` palette is keyed on (e.g. "Elixir", "C++", "Go")
  so the bar + detail page can color segments without an intermediate
  lookup.

  Returns `nil` for filenames we don't recognize, which is also how we
  skip non-source files (images, binaries, LICENSE, …) from the bar.
  """

  @ext %{
    ".ada" => "Ada",
    ".adb" => "Ada",
    ".ads" => "Ada",
    ".asm" => "Assembly",
    ".s" => "Assembly",
    ".bash" => "Bash",
    ".c" => "C",
    ".h" => "C",
    ".cc" => "C++",
    ".cpp" => "C++",
    ".cxx" => "C++",
    ".hpp" => "C++",
    ".hh" => "C++",
    ".hxx" => "C++",
    ".cs" => "C#",
    ".clj" => "Clojure",
    ".cljs" => "Clojure",
    ".cljc" => "Clojure",
    ".coffee" => "CoffeeScript",
    ".cr" => "Crystal",
    ".css" => "CSS",
    ".dart" => "Dart",
    ".eex" => "HTML",
    ".elm" => "Elm",
    ".erl" => "Erlang",
    ".hrl" => "Erlang",
    ".ex" => "Elixir",
    ".exs" => "Elixir",
    ".fs" => "F#",
    ".fsi" => "F#",
    ".fsx" => "F#",
    ".go" => "Go",
    ".graphql" => "GraphQL",
    ".gql" => "GraphQL",
    ".hs" => "Haskell",
    ".hcl" => "HCL",
    ".tf" => "HCL",
    ".tfvars" => "HCL",
    ".heex" => "HTML",
    ".htm" => "HTML",
    ".html" => "HTML",
    ".java" => "Java",
    ".jl" => "Julia",
    ".js" => "JavaScript",
    ".cjs" => "JavaScript",
    ".mjs" => "JavaScript",
    ".jsx" => "JavaScript",
    ".json" => "JSON",
    ".kt" => "Kotlin",
    ".kts" => "Kotlin",
    ".lua" => "Lua",
    ".md" => "Markdown",
    ".markdown" => "Markdown",
    ".ml" => "OCaml",
    ".mli" => "OCaml",
    ".nim" => "Nim",
    ".nix" => "Nix",
    ".php" => "PHP",
    ".pl" => "Perl",
    ".pm" => "Perl",
    ".ps1" => "PowerShell",
    ".py" => "Python",
    ".raku" => "Raku",
    ".r" => "R",
    ".rb" => "Ruby",
    ".rs" => "Rust",
    ".scala" => "Scala",
    ".sc" => "Scala",
    ".scss" => "SCSS",
    ".sass" => "SCSS",
    ".sh" => "Bash",
    ".sol" => "Solidity",
    ".sql" => "SQL",
    ".svelte" => "Svelte",
    ".swift" => "Swift",
    ".tex" => "LaTeX",
    ".toml" => "TOML",
    ".ts" => "TypeScript",
    ".tsx" => "TypeScript",
    ".vim" => "Vim Script",
    ".vue" => "Vue",
    ".wat" => "WebAssembly",
    ".yaml" => "YAML",
    ".yml" => "YAML",
    ".zig" => "Zig",
    ".zsh" => "Bash"
  }

  @basename %{
    "dockerfile" => "Dockerfile",
    "containerfile" => "Dockerfile",
    "makefile" => "Makefile",
    "gnumakefile" => "Makefile",
    "rakefile" => "Ruby",
    "gemfile" => "Ruby",
    "mix.exs" => "Elixir",
    "mix.lock" => "Elixir",
    "rebar.config" => "Erlang"
  }

  @doc """
  Returns the language display name for a filename, or `nil` if we
  don't recognize it. Matches case-insensitively on basename and
  extension.
  """
  @spec detect(String.t() | nil) :: String.t() | nil
  def detect(nil), do: nil

  def detect(name) when is_binary(name) do
    basename = name |> Path.basename() |> String.downcase()

    case Map.get(@basename, basename) do
      nil ->
        ext = basename |> Path.extname()
        Map.get(@ext, ext)

      lang ->
        lang
    end
  end

  @doc false
  def ext_map, do: @ext

  @doc false
  def basename_map, do: @basename
end