defmodule PetalInstaller.ComponentManager do
  alias   PetalInstaller.{FileManager, Constants}

  def copy_all_components(no_rename?) do
    if no_rename? do
      FileManager.get_copy_all_component_paths()
      |> FileManager.recursive_copy()
    else
      web_namespace = FileManager.get_web_namespace()

      FileManager.get_copy_all_component_paths()
      |> copy_and_modify_recursively(web_namespace)
    end
  end

  defp copy_and_modify_recursively({source_dir, dest_dir}, web_namespace) do
    FileManager.mkdir(dest_dir)

    FileManager.ls!(source_dir)
    |> Enum.each(fn item ->
      source_path = Path.join(source_dir, item)
      dest_path =   Path.join(dest_dir, item)

      cond do
        File.dir?(source_path) -> copy_and_modify_recursively({source_path, dest_path}, web_namespace)

        Path.extname(item) == ".ex" ->
          modify_and_write_component(source_path, dest_path, web_namespace)

        true -> FileManager.copy(source_path, dest_path)
      end
    end)
  end

  defp modify_and_write_component(source_path, dest_path, web_namespace) do
    content = File.read!(source_path)
    modified_content = add_web_namespace_to_component(content, web_namespace)
    FileManager.write(dest_path, modified_content)
  end

  defp add_web_namespace_to_component(content, web_namespace) do
    content
    |> String.replace(~r/(\s|^)PetalComponents/, "\\1#{web_namespace}.PetalComponents")
  end

  def fetch_components([], _) do
    IO.puts "Specify component names or use --list to see available components"
    :ok
  end

  def fetch_components(component_names, no_rename?) do
    res = Enum.map(component_names, &fetch_component(&1, no_rename?))

    if Enum.any?(res, &match?({:error, _}, &1)) do
      Enum.each(res, fn
          {:error, reason}  -> IO.puts reason
          _                 -> nil
      end)
    else
      :ok
    end
  end

  ### Will also fetch any dependencies if they don't already exist in users' project
  def copy_specific_component(component_name, no_rename?) do
    {source_path, to_path} = FileManager.get_component_paths(component_name)

    if FileManager.exists?(to_path) do
      IO.puts("The file for #{IO.ANSI.bright()}#{IO.ANSI.yellow()}#{component_name}#{IO.ANSI.reset()} already exists at #{IO.ANSI.bright()}#{IO.ANSI.yellow}#{to_path}#{IO.ANSI.reset()}.")
      response = IO.gets("Overwrite?  (y/n):  ") |> String.trim() |> String.downcase()

      case response do
        "y" -> cont_copy_component(source_path, to_path, no_rename?)
        _   ->
          IO.puts("Skipping #{component_name}")
          :ok
      end

    else
      cont_copy_component(source_path, to_path, no_rename?)
    end
  end

  defp fetch_component(name, no_rename?) do
    cond do
      name == "icon"                   ->
          handle_icon_component(no_rename?)
      Enum.member?(Constants.components(), name)  ->
          copy_specific_component(name, no_rename?)
      true                             ->
          {:error, "Component #{name} not found"}
    end
  end

  defp cont_copy_component(source_path, to_path, no_rename?) do
    if no_rename? do
      extract_and_get_dependencies(source_path)
      FileManager.copy(source_path, to_path)
    else
      web_namespace = FileManager.get_web_namespace()

      extract_and_get_dependencies(source_path, web_namespace)
      modify_and_write_component(source_path, to_path, web_namespace)
    end
  end

  # Trigger when no_rename? is true
  defp extract_and_get_dependencies(source_path) do
    content = FileManager.read!(source_path)

    dependencies = extract_dependencies(content)
    Enum.each(dependencies, fn dep ->
      handle_component_dependency(dep)
    end)
  end

  # Trigger when no_rename? is true
  defp handle_component_dependency(component_name) do
    {source_path, target_path} = FileManager.get_component_paths(component_name)

    if not FileManager.exists?(target_path) do
      extract_and_get_dependencies(source_path)
      FileManager.copy(source_path, target_path, "Error copying component #{component_name}")
    end
  end

  ### Checks for any component dependencies, and installs them if not present
  defp extract_and_get_dependencies(source_path, web_namespace) do
    content = FileManager.read!(source_path)

    dependencies = extract_dependencies(content)
    Enum.each(dependencies, fn dep ->
      handle_component_dependency(dep, web_namespace)
    end)
  end

  ### Similar to copy_specific_component, except doesn't ask the user to overwrite files
  ### if user already has the file, no overwrite occurs
  defp handle_component_dependency(component_name, web_namespace) do
    {source_path, target_path} = FileManager.get_component_paths(component_name)

    if not FileManager.exists?(target_path) do
      extract_and_get_dependencies(source_path, web_namespace)
      modify_and_write_component(source_path, target_path, web_namespace)
    end
  end

  defp extract_dependencies(content) do
    alias_regex   = ~r/alias\s+PetalComponents\.([A-Z][a-zA-Z]+)/
    import_regex  = ~r/import\s+PetalComponents\.([A-Z][a-zA-Z]+)/

    aliases = Regex.scan(alias_regex, content) |> Enum.map(& get_dependency_name/1)
    imports = Regex.scan(import_regex, content) |> Enum.map(& get_dependency_name/1)

    (aliases ++ imports) |> Enum.uniq()
  end

  defp get_dependency_name(scan_result) do
    scan_result
    |> List.last()
    |> Macro.underscore()
  end

  defp handle_icon_component(no_rename?) do
    with  :ok <- copy_specific_component("icon", no_rename?),
          :ok <- copy_icon_folder(no_rename?)
    do
          :ok
    end
  end

  defp copy_icon_folder(no_rename?) do
    {source, dest} = FileManager.get_component_paths("icons")
    if no_rename? do
      FileManager.recursive_copy({source, dest})
    else
      web_namespace = FileManager.get_web_namespace()
      modify_and_write_component(source, dest, web_namespace)
    end
  end
end