defmodule SigmaKit.Components.Forms do
  use Phoenix.LiveComponent
  import SigmaKit.Components.Icons, only: [icon: 1]

  @doc """
  Renders a simple form.

  ## Examples

      <.simple_form for={@form} phx-change="validate" phx-submit="save">
        <.input field={@form[:email]} label="Email"/>
        <.input field={@form[:username]} label="Username" />
        <:actions>
          <.button>Save</.button>
        </:actions>
      </.simple_form>
  """
  attr :for, :any, required: true, doc: "the data structure for the form"
  attr :as, :any, default: nil, doc: "the server side parameter to collect all input under"

  attr :rest, :global,
    include: ~w(autocomplete name rel action enctype method novalidate target multipart),
    doc: "the arbitrary HTML attributes to apply to the form tag"

  slot :inner_block, required: true
  slot :actions, doc: "the slot for form actions, such as a submit button"

  def simple_form(assigns) do
    ~H"""
    <.form :let={f} for={@for} as={@as} {@rest}>
      <div class="space-y-8 bg-white">
        {render_slot(@inner_block, f)}
        <div :for={action <- @actions} class="mt-2 flex items-center justify-between gap-6">
          {render_slot(action, f)}
        </div>
      </div>
    </.form>
    """
  end

  @doc """
  Renders an input with label and error messages.

  A `Phoenix.HTML.FormField` may be passed as argument,
  which is used to retrieve the input name, id, and values.
  Otherwise all attributes may be passed explicitly.

  ## Examples

      <.input field={@form[:email]} type="email" />
      <.input name="my-input" errors={["oh no!"]} />
  """
  attr :id, :any, default: nil, doc: "the id of the input"
  attr :name, :any, doc: "the name of the input"
  attr :label, :string, default: nil, doc: "the label for the input"
  attr :value, :any, doc: "the value of the input"
  attr :dark, :boolean, default: false, doc: "apply dark styling"

  attr :type, :string,
    default: "text",
    values: ~w(checkbox color date datetime-local email file month number password
              range search select tel text textarea time url week),
    doc: "the type of the input"

  attr :field, Phoenix.HTML.FormField,
    doc: "a form field struct retrieved from the form, for example: @form[:email]"

  attr :errors, :list, default: [], doc: "A list of strings to display as field errors"
  attr :checked, :boolean, doc: "the checked flag for checkbox inputs"
  attr :prompt, :string, default: nil, doc: "the prompt for select inputs"
  attr :options, :list, doc: "the options to pass to Phoenix.HTML.Form.options_for_select/2"
  attr :multiple, :boolean, default: false, doc: "the multiple flag for select inputs"

  attr :rest, :global,
    include: ~w(accept autocomplete capture cols disabled form list max maxlength min minlength
                multiple pattern placeholder readonly required rows size step)

  slot :help, doc: "A slot used to display help text under the input"

  def input(%{field: %Phoenix.HTML.FormField{} = field} = assigns) do
    errors = if Phoenix.Component.used_input?(field), do: field.errors, else: []

    assigns
    |> assign(field: nil, id: assigns.id || field.id)
    |> assign(:errors, Enum.map(errors, &translate_error(&1)))
    |> assign_new(:name, fn -> if assigns.multiple, do: field.name <> "[]", else: field.name end)
    |> assign_new(:value, fn -> field.value end)
    |> input()
  end

  def input(%{type: "checkbox"} = assigns) do
    assigns =
      assign_new(assigns, :checked, fn ->
        Phoenix.HTML.Form.normalize_value("checkbox", assigns[:value])
      end)

    ~H"""
    <div>
      <label class="flex items-center gap-4 text-sm leading-6 text-zinc-600">
        <input type="hidden" name={@name} value="false" disabled={@rest[:disabled]} />
        <input
          type="checkbox"
          id={@id}
          name={@name}
          value="true"
          checked={@checked}
          class="rounded border-zinc-300 text-zinc-900 focus:ring-0"
          {@rest}
        />
        {@label}
      </label>
      <.field_error :for={msg <- @errors}>{msg}</.field_error>
    </div>
    """
  end

  def input(%{type: "select"} = assigns) do
    ~H"""
    <div>
      <.label dark={@dark} for={@id}>{@label}</.label>
      <select
        id={@id}
        name={@name}
        class={[
          "mt-2 block w-full rounded-lg focus:ring-0 sm:text-sm sm:leading-6",
          @dark && "bg-zinc-900 text-zinc-50 border-zinc-600",
          !@dark && "text-zinc-900",
          @errors == [] && "border-zinc-300 focus:border-zinc-400",
          @errors != [] && "border-rose-400 focus:border-rose-400"
        ]}
        multiple={@multiple}
        {@rest}
      >
        <option :if={@prompt} value="">{@prompt}</option>
        {Phoenix.HTML.Form.options_for_select(@options, @value)}
      </select>
      <.field_error :for={msg <- @errors}>{msg}</.field_error>
    </div>
    """
  end

  def input(%{type: "textarea"} = assigns) do
    ~H"""
    <div>
      <.label for={@id}>{@label}</.label>
      <textarea
        id={@id}
        name={@name}
        class={[
          "mt-2 block w-full rounded-lg text-zinc-900 focus:ring-0 sm:text-sm sm:leading-6 min-h-[6rem]",
          @errors == [] && "border-zinc-300 focus:border-zinc-400",
          @errors != [] && "border-rose-400 focus:border-rose-400"
        ]}
        {@rest}
      >{Phoenix.HTML.Form.normalize_value("textarea", @value)}</textarea>
      <.field_error :for={msg <- @errors}>{msg}</.field_error>
    </div>
    """
  end

  # All other inputs text, datetime-local, url, password, etc. are handled here...
  def input(assigns) do
    ~H"""
    <div>
      <.label for={@id} dark={@dark}>
        {@label}
      </.label>
      <input
        type={@type}
        name={@name}
        id={@id}
        value={Phoenix.HTML.Form.normalize_value(@type, @value)}
        class={[
          "mt-2 block w-full rounded-lg focus:ring-0 sm:text-sm sm:leading-6",
          @dark && "bg-zinc-900 text-zinc-50 border-zinc-600",
          !@dark && "text-zinc-900",
          @errors == [] && "border-zinc-300 focus:border-zinc-400",
          @errors != [] && "border-rose-400 focus:border-rose-400"
        ]}
        {@rest}
      />
      <.field_error :for={msg <- @errors}>{msg}</.field_error>
      <div
        :if={@help != []}
        class={[
          "text-sm mt-1 ml-2 mb-2",
          @dark && "text-zinc-300",
          !@dark && "text-zinc-600"
        ]}
      >
        {render_slot(@help)}
      </div>
    </div>
    """
  end

  @doc """
  Renders a label.
  """
  attr :for, :string, default: nil
  attr :dark, :boolean, default: false
  slot :inner_block, required: true

  def label(assigns) do
    ~H"""
    <label
      for={@for}
      class={[
        "block text-sm font-semibold leading-6",
        !@dark && "text-zinc-800",
        @dark && "text-zinc-50"
      ]}
    >
      {render_slot(@inner_block)}
    </label>
    """
  end

  slot :inner_block, required: true

  def field_error(assigns) do
    ~H"""
    <p class="mt-3 flex gap-3 text-sm leading-6 text-rose-600">
      <.icon name="hero-exclamation-circle-mini" class="mt-0.5 h-5 w-5 flex-none" />
      {render_slot(@inner_block)}
    </p>
    """
  end

  @doc """
  Translates an error message using gettext.
  """
  def translate_error({msg, opts}) do
    # When using gettext, we typically pass the strings we want
    # to translate as a static argument:
    #
    #     # Translate the number of files with plural rules
    #     dngettext("errors", "1 file", "%{count} files", count)
    #
    # However the error messages in our forms and APIs are generated
    # dynamically, so we need to translate them by calling Gettext
    # with our gettext backend as first argument. Translations are
    # available in the errors.po file (as we use the "errors" domain).
    if count = opts[:count] do
      Gettext.dngettext(ReportingWeb.Gettext, "errors", msg, msg, count, opts)
    else
      Gettext.dgettext(ReportingWeb.Gettext, "errors", msg, opts)
    end
  end

  @doc """
  Translates the errors for a field from a keyword list of errors.
  """
  def translate_errors(errors, field) when is_list(errors) do
    for {^field, {msg, opts}} <- errors, do: translate_error({msg, opts})
  end
end