defmodule GenDOM.InputEvent do
  @moduledoc """
  Represents events related to user input in editable content.

  The InputEvent interface represents an event notifying the user of editable content changes.
  This includes input in text fields, textareas, contenteditable elements, and any other
  editable content. It provides detailed information about what kind of input occurred.

  ## Specification Compliance

  This module implements the InputEvent interface as defined by:
  - **UI Events Specification**: https://www.w3.org/TR/uievents/#interface-inputevent
  - **Input Events Level 2**: https://www.w3.org/TR/input-events-2/
  - **MDN InputEvent Reference**: https://developer.mozilla.org/en-US/docs/Web/API/InputEvent

  ## Inheritance Chain

  ```
  GenDOM.Event (Base)
  └── GenDOM.UIEvent
      └── GenDOM.InputEvent (extends UIEvent)
  ```

  **Inherits from:** `GenDOM.UIEvent`

  ## Properties

  ### Input Data
  - `data` - String containing the characters inserted (may be null for some input types)
  - `data_transfer` - DataTransfer object for rich text or file input
  - `input_type` - Type of input operation that occurred
  - `is_composing` - Whether the event occurs during IME composition

  ## Input Types

  Common `input_type` values include:
  - `insertText` - Text insertion
  - `deleteContentBackward` - Backspace key
  - `deleteContentForward` - Delete key
  - `insertFromPaste` - Paste operation
  - `insertFromDrop` - Drop operation
  - `formatBold` - Bold formatting
  - `formatItalic` - Italic formatting
  - `insertLineBreak` - Line break insertion
  - `insertParagraph` - Paragraph insertion
  - `undo` - Undo operation
  - `redo` - Redo operation

  ## Event Types

  InputEvent is used for:
  - `beforeinput` - Before input is applied (cancelable)
  - `input` - After input has been applied (not cancelable)

  ## Usage Notes

  - `beforeinput` allows canceling input before it occurs
  - `input` fires after the DOM has been updated
  - Not all input types provide `data` (e.g., deletion operations)
  - Rich text operations may use `data_transfer` instead of `data`

  ## Examples

      # Creating an InputEvent
      event = GenDOM.InputEvent.new("input", %{
        data: "Hello",
        input_type: "insertText",
        is_composing: false,
        bubbles: true,
        cancelable: false
      })

      # Handling input events
      case event.input_type do
        "insertText" ->
          IO.puts("Text inserted: \#{event.data}")
        "deleteContentBackward" ->
          IO.puts("Backspace pressed")
        "insertFromPaste" ->
          handle_paste(event.data_transfer)
        "formatBold" ->
          toggle_bold_formatting()
      end

      # Preventing input in beforeinput event
      if event.type == "beforeinput" do
        if not valid_input?(event.data) do
          Event.prevent_default(event)
        end
      end

      # Checking for IME composition
      if event.is_composing do
        # Wait for composition to complete
        defer_validation()
      end
  """

  use GenDOM.UIEvent, [
    # Input data and type
    data: nil,                    # Characters being inserted (null for non-text operations)
    data_transfer: nil,           # DataTransfer for rich content or files
    input_type: "",               # Type of input operation
    
    # Composition state
    is_composing: false          # True if during IME composition
  ]

  @doc """
  Returns an array of static ranges that will be affected by a change to the DOM.

  This method implements the InputEvent `getTargetRanges()` specification. It returns
  an array of StaticRange objects representing the ranges that will be affected by
  the input operation if it is not canceled.

  ## Parameters
  - `event` - The InputEvent struct

  ## Returns
  An array of StaticRange objects, or an empty array if no ranges are affected
  or if called on an `input` event (only valid for `beforeinput`).

  ## Examples
      ranges = GenDOM.InputEvent.get_target_ranges(event)
      Enum.each(ranges, fn range ->
        IO.puts("Affected range: \#{range.start_offset} to \#{range.end_offset}")
      end)

  ## MDN Reference
  https://developer.mozilla.org/en-US/docs/Web/API/InputEvent/getTargetRanges
  """
  def get_target_ranges(_event) do
    :not_implemented
  end
end
