firebird

defmodule Firebird.Phoenix.FormWasm do
  @moduledoc """
  WASM-accelerated HTML form building.

  Provides high-performance form generation using a compiled WASM module.
  Handles HTML escaping, CSRF token injection, method spoofing, and
  Phoenix-compatible form field naming conventions.

  This is the WASM-backed counterpart to `Firebird.Phoenix.Form` which
  is pure Elixir. The WASM version is faster for complex forms with many
  fields due to zero-copy HTML escaping in WASM.

  ## Examples

      {:ok, form} = Firebird.load("fixtures/phoenix_form.wasm")

      # Build a form opening tag
      {:ok, html} = FormWasm.build_form(form, "user", "/users",
        method: :post, csrf_token: "abc123")
      # => ~s(<form action="/users" method="post"><input type="hidden" name="_csrf_token" value="abc123"/>)

      # Build an input field
      {:ok, html} = FormWasm.text_input(form, "user", "name", value: "Alice")
      # => ~s(<input type="text" name="user[name]" id="user_name" value="Alice"/>)
  """

  alias Firebird.Phoenix.WasmHelper

  @doc """
  Build an HTML form opening tag with CSRF token and method spoofing.

  ## Options

  - `:method` - HTTP method (default: :post). :put/:patch/:delete are spoofed
  - `:csrf_token` - CSRF token string
  - `:multipart` - If true, adds multipart/form-data enctype
  - `:class` - CSS class
  - `:id` - HTML id attribute
  """
  @spec build_form(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def build_form(instance, scope, action, opts \\ []) do
    method = Keyword.get(opts, :method, :post) |> to_string()
    csrf = Keyword.get(opts, :csrf_token, "")
    multipart = if Keyword.get(opts, :multipart, false), do: "true", else: "false"
    class = Keyword.get(opts, :class, "")
    id = Keyword.get(opts, :id, "")

    input = Enum.join([scope, action, method, csrf, multipart, class, id], "|")
    WasmHelper.call_string(instance, "build_form", input)
  end

  @doc """
  Build a text input field.

  ## Options

  - `:value` - Current value
  - `:class` - CSS class
  - `:id` - Custom HTML id (default: scope_field)
  - `:placeholder` - Placeholder text
  - `:required` - Whether field is required
  """
  @spec text_input(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def text_input(instance, scope, field, opts \\ []) do
    build_input(instance, "text", scope, field, opts)
  end

  @doc "Build an email input field."
  @spec email_input(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def email_input(instance, scope, field, opts \\ []) do
    build_input(instance, "email", scope, field, opts)
  end

  @doc "Build a password input field."
  @spec password_input(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def password_input(instance, scope, field, opts \\ []) do
    build_input(instance, "password", scope, field, opts)
  end

  @doc "Build a number input field."
  @spec number_input(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def number_input(instance, scope, field, opts \\ []) do
    build_input(instance, "number", scope, field, opts)
  end

  @doc "Build a hidden input field."
  @spec hidden_input(pid(), String.t(), String.t(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def hidden_input(instance, scope, field, opts \\ []) do
    build_input(instance, "hidden", scope, field, opts)
  end

  defp build_input(instance, type, scope, field, opts) do
    value = Keyword.get(opts, :value, "") |> to_string()
    class = Keyword.get(opts, :class, "")
    id = Keyword.get(opts, :id, "")
    placeholder = Keyword.get(opts, :placeholder, "")
    required = if Keyword.get(opts, :required, false), do: "true", else: "false"

    input = Enum.join([type, scope, field, value, class, id, placeholder, required], "|")
    WasmHelper.call_string(instance, "build_input", input)
  end

  @doc """
  Build a textarea element.

  ## Options

  - `:value` - Current content
  - `:rows` - Number of rows
  - `:cols` - Number of columns
  - `:class` - CSS class
  - `:placeholder` - Placeholder text
  - `:required` - Whether field is required
  """
  @spec textarea(pid(), String.t(), String.t(), keyword()) :: {:ok, String.t()} | {:error, term()}
  def textarea(instance, scope, field, opts \\ []) do
    value = Keyword.get(opts, :value, "") |> to_string()
    rows = Keyword.get(opts, :rows, "") |> to_string()
    cols = Keyword.get(opts, :cols, "") |> to_string()
    class = Keyword.get(opts, :class, "")
    placeholder = Keyword.get(opts, :placeholder, "")
    required = if Keyword.get(opts, :required, false), do: "true", else: "false"

    input = Enum.join([scope, field, value, rows, cols, class, placeholder, required], "|")
    WasmHelper.call_string(instance, "build_textarea", input)
  end

  @doc """
  Build a select dropdown element.

  ## Parameters

  - `options` - List of `{value, label}` tuples or list of strings

  ## Options

  - `:selected` - Currently selected value
  """
  @spec select(pid(), String.t(), String.t(), list(), keyword()) ::
          {:ok, String.t()} | {:error, term()}
  def select(instance, scope, field, options, opts \\ []) do
    selected = Keyword.get(opts, :selected, "") |> to_string()

    header = Enum.join([scope, field, selected], "|")

    option_lines =
      Enum.map(options, fn
        {value, label} -> "#{value}|#{label}"
        value -> "#{value}|#{value}"
      end)

    input = Enum.join([header | option_lines], "\n")
    WasmHelper.call_string(instance, "build_select", input)
  end

  @doc """
  Build a checkbox input with hidden field for unchecked state.

  ## Options

  - `:value` - Value when checked (default: "true")
  - `:checked` - Whether checked (default: false)
  - `:label` - Label text
  """
  @spec checkbox(pid(), String.t(), String.t(), keyword()) :: {:ok, String.t()} | {:error, term()}
  def checkbox(instance, scope, field, opts \\ []) do
    value = Keyword.get(opts, :value, "true") |> to_string()
    checked = if Keyword.get(opts, :checked, false), do: "true", else: "false"
    label = Keyword.get(opts, :label, "")

    input = Enum.join([scope, field, value, checked, label], "|")
    WasmHelper.call_string(instance, "build_checkbox", input)
  end

  @doc """
  HTML-escape a string using WASM.
  """
  @spec html_escape(pid(), String.t()) :: {:ok, String.t()} | {:error, term()}
  def html_escape(instance, text) do
    WasmHelper.call_string(instance, "html_escape", text)
  end
end