defmodule JSONSchemaEditor do
  @moduledoc """
  A Phoenix LiveComponent for visually editing JSON Schemas.

  It provides a rich interface for creating and modifying JSON Schemas (Draft 07), supporting
  nested structures, arrays, validation constraints, and logical composition (oneOf, anyOf, allOf).

  ## Attributes

    * `id` (required) - A unique identifier for the component instance.
    * `schema` (required) - The initial JSON Schema map to edit. Defaults to a basic schema if empty.
    * `on_save` (optional) - A 1-arity callback function invoked when the user clicks "Save".
      It receives the current schema as a map.
    * `class` (optional) - Additional CSS classes to apply to the root container.

  ## Usage

      <.live_component
        module={JSONSchemaEditor}
        id="json-editor"
        schema={@my_schema}
        on_save={fn new_schema -> send(self(), {:save_schema, new_schema}) end}
        class="my-custom-theme"
      />
  """
  use Phoenix.LiveComponent
  alias JSONSchemaEditor.{SchemaUtils, Validator, PrettyPrinter, Components}

  @types ~w(string number integer boolean object array)
  @logic_types ~w(anyOf oneOf allOf)
  @formats ~w(email date-time date time uri uuid ipv4 ipv6 hostname)

  def update(assigns, socket) do
    known_keys = [
      :id,
      :schema,
      :on_save,
      :ui_state,
      :active_tab,
      :myself,
      :class,
      :show_import_modal,
      :import_error
    ]

    {known_assigns, rest} = Map.split(assigns, known_keys)

    socket =
      socket
      |> assign(known_assigns)
      |> assign(:rest, Map.merge(Map.get(socket.assigns, :rest, %{}), rest))
      |> assign_new(:class, fn -> nil end)
      |> assign_new(:ui_state, fn -> %{} end)
      |> assign_new(:schema, fn -> %{} end)
      |> update(:schema, &Map.put_new(&1, "$schema", "https://json-schema.org/draft-07/schema"))
      |> assign(types: @types, formats: @formats, logic_types: @logic_types)
      |> assign_new(:active_tab, fn -> :editor end)
      |> assign_new(:show_import_modal, fn -> false end)
      |> assign_new(:import_error, fn -> nil end)
      |> validate_and_assign_errors()

    {:ok, socket}
  end

  defp validate_and_assign_errors(socket),
    do: assign(socket, :validation_errors, Validator.validate_schema(socket.assigns.schema))

  def handle_event("switch_tab", %{"tab" => tab}, socket),
    do: {:noreply, assign(socket, :active_tab, String.to_existing_atom(tab))}

  def handle_event("open_import_modal", _, socket),
    do: {:noreply, assign(socket, :show_import_modal, true)}

  def handle_event("close_import_modal", _, socket),
    do: {:noreply, assign(socket, :show_import_modal, false) |> assign(:import_error, nil)}

  def handle_event("import_schema", %{"schema_text" => text}, socket) do
    case JSON.decode(text) do
      {:ok, schema} when is_map(schema) ->
        socket =
          socket
          |> assign(:schema, schema)
          |> assign(:show_import_modal, false)
          |> assign(:import_error, nil)
          |> validate_and_assign_errors()

        {:noreply, socket}

      {:ok, _} ->
        {:noreply, assign(socket, :import_error, "Invalid schema: Must be a JSON object")}

      {:error, _} ->
        {:noreply, assign(socket, :import_error, "Invalid JSON")}
    end
  end

  def handle_event("save", _, socket) do
    if Enum.empty?(socket.assigns.validation_errors) and socket.assigns[:on_save],
      do: socket.assigns.on_save.(socket.assigns.schema)

    {:noreply, socket}
  end

  def handle_event("toggle_ui", %{"path" => p, "type" => t}, socket),
    do: {:noreply, update(socket, :ui_state, &Map.update(&1, "#{t}:#{p}", true, fn v -> !v end))}

  def handle_event("change_type", %{"path" => path, "type" => type}, socket) do
    {:noreply,
     update_schema(socket, path, fn node ->
       base = Map.drop(node, ~w(type properties required items anyOf oneOf allOf))

       case type do
         "object" -> Map.merge(base, %{"type" => "object", "properties" => %{}})
         "array" -> Map.merge(base, %{"type" => "array", "items" => %{"type" => "string"}})
         l when l in @logic_types -> Map.put(base, l, [%{"type" => "string"}])
         _ -> Map.put(base, "type", type)
       end
     end)}
  end

  def handle_event("add_property", %{"path" => path}, socket) do
    {:noreply,
     update_schema(socket, path, fn node ->
       props = Map.get(node, "properties", %{})

       Map.put(
         node,
         "properties",
         Map.put(props, SchemaUtils.generate_unique_key(props, "new_field"), %{"type" => "string"})
       )
     end)}
  end

  def handle_event("delete_property", %{"path" => path, "key" => key}, socket) do
    {:noreply,
     update_schema(socket, path, fn node ->
       node
       |> Map.update("properties", %{}, &Map.delete(&1, key))
       |> Map.update("required", [], &List.delete(&1, key))
     end)}
  end

  def handle_event("rename_property", %{"path" => path, "old_key" => old, "value" => new}, socket) do
    new = String.trim(new)

    if new == "" or new == old do
      {:noreply, socket}
    else
      {:noreply,
       update_schema(socket, path, fn node ->
         if get_in(node, ["properties", new]) do
           node
         else
           {val, props} = Map.pop(node["properties"], old)

           node
           |> Map.put("properties", Map.put(props, new, val))
           |> Map.update("required", [], fn req ->
             Enum.map(req, &if(&1 == old, do: new, else: &1))
           end)
         end
       end)}
    end
  end

  def handle_event("toggle_required", %{"path" => path, "key" => key}, socket) do
    {:noreply,
     update_schema(socket, path, fn node ->
       Map.update(
         node,
         "required",
         [key],
         &if(key in &1, do: List.delete(&1, key), else: &1 ++ [key])
       )
     end)}
  end

  # Consolidated field updaters
  def handle_event("change_schema", %{"value" => v}, socket),
    do: {:noreply, update_node_field(socket, JSON.encode!([]), "$schema", v)}

  def handle_event("change_format", %{"path" => p, "value" => v}, socket),
    do: {:noreply, update_node_field(socket, p, "format", v)}

  def handle_event("change_title", %{"path" => p, "value" => v}, socket),
    do: {:noreply, update_node_field(socket, p, "title", String.trim(v))}

  def handle_event("change_description", %{"path" => p, "value" => v}, socket),
    do: {:noreply, update_node_field(socket, p, "description", String.trim(v))}

  def handle_event("update_constraint", %{"path" => p, "field" => f, "value" => v}, socket),
    do: {:noreply, update_node_field(socket, p, f, SchemaUtils.cast_value(f, v))}

  def handle_event("update_const", %{"path" => p, "value" => v}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       if v == "",
         do: Map.delete(node, "const"),
         else: Map.put(node, "const", SchemaUtils.cast_value(node["type"] || "string", v))
     end)}
  end

  def handle_event("toggle_additional_properties", %{"path" => p}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       if node["additionalProperties"] == false,
         do: Map.delete(node, "additionalProperties"),
         else: Map.put(node, "additionalProperties", false)
     end)}
  end

  def handle_event("add_enum_value", %{"path" => p}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       def_val =
         case node["type"] do
           "number" -> 0.0
           "integer" -> 0
           "boolean" -> true
           _ -> "new value"
         end

       Map.update(node, "enum", [def_val], &(&1 ++ [def_val]))
     end)}
  end

  def handle_event("remove_enum_value", %{"path" => p, "index" => idx}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       new_enum = List.delete_at(node["enum"] || [], String.to_integer(idx))
       if new_enum == [], do: Map.delete(node, "enum"), else: Map.put(node, "enum", new_enum)
     end)}
  end

  def handle_event("update_enum_value", %{"path" => p, "index" => idx, "value" => v}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       Map.put(
         node,
         "enum",
         List.replace_at(
           node["enum"] || [],
           String.to_integer(idx),
           SchemaUtils.cast_value(node["type"] || "string", v)
         )
       )
     end)}
  end

  def handle_event("add_logic_branch", %{"path" => p, "type" => t}, socket),
    do:
      {:noreply,
       update_schema(socket, p, &Map.update(&1, t, [], fn b -> b ++ [%{"type" => "string"}] end))}

  def handle_event("remove_logic_branch", %{"path" => p, "type" => t, "index" => idx}, socket) do
    {:noreply,
     update_schema(socket, p, fn node ->
       new_branches = List.delete_at(node[t] || [], String.to_integer(idx))

       if new_branches == [],
         do: Map.delete(node, t) |> Map.put("type", "string"),
         else: Map.put(node, t, new_branches)
     end)}
  end

  def handle_event("add_contains", %{"path" => p}, socket),
    do: {:noreply, update_schema(socket, p, &Map.put(&1, "contains", %{"type" => "string"}))}

  def handle_event("remove_contains", %{"path" => p}, socket),
    do: {:noreply, update_schema(socket, p, &Map.delete(&1, "contains"))}

  defp update_schema(socket, path_json, update_fn) do
    socket
    |> assign(
      :schema,
      SchemaUtils.update_in_path(socket.assigns.schema, JSON.decode!(path_json), update_fn)
    )
    |> validate_and_assign_errors()
  end

  defp update_node_field(socket, path_json, field, value) do
    update_schema(socket, path_json, fn node ->
      if value in [nil, "", false], do: Map.delete(node, field), else: Map.put(node, field, value)
    end)
  end

  def render(assigns) do
    ~H"""
    <div id={@id} class={["jse-host", @class]} {@rest}>
      <div class="jse-container">
        <div class="jse-header">
          <div class="jse-tabs">
            <button
              class={["jse-tab-btn", @active_tab == :editor && "active"]}
              phx-click="switch_tab"
              phx-value-tab="editor"
              phx-target={@myself}
            >
              Visual Editor
            </button>
            <button
              class={["jse-tab-btn", @active_tab == :preview && "active"]}
              phx-click="switch_tab"
              phx-value-tab="preview"
              phx-target={@myself}
            >
              JSON Preview
            </button>
          </div>
          <div class="jse-schema-selector">
            <label for={"#{@id}-schema-uri"}>$schema</label>
            <input
              type="text"
              id={"#{@id}-schema-uri"}
              value={Map.get(@schema, "$schema")}
              phx-blur="change_schema"
              phx-target={@myself}
              placeholder="Schema URI..."
            />
          </div>
          <button
            class="jse-btn jse-btn-secondary"
            phx-click="open_import_modal"
            phx-target={@myself}
          >
            <span>Import</span> <Components.icon name={:import} />
          </button>
          <button
            class="jse-btn jse-btn-primary"
            phx-click="save"
            phx-target={@myself}
            disabled={not Enum.empty?(@validation_errors)}
          >
            <span>Save</span> <Components.icon name={:save} />
          </button>
        </div>
        <div class="jse-content-area">
          <%= if @active_tab == :editor do %>
            <div class="jse-editor-pane">
              <Components.render_node
                node={@schema}
                path={[]}
                ui_state={@ui_state}
                validation_errors={@validation_errors}
                types={@types}
                logic_types={@logic_types}
                formats={@formats}
                myself={@myself}
              />
            </div>
          <% end %>
          <%= if @active_tab == :preview do %>
            <div class="jse-preview-panel">
              <div class="jse-preview-header">
                <span>Current Schema</span>
                <button
                  class="jse-btn-copy"
                  id={"#{@id}-copy-btn"}
                  phx-hook="JSONSchemaEditorClipboard"
                  data-content={JSON.encode!(@schema)}
                >
                  <span>Copy to Clipboard</span>
                </button>
              </div>
              <div class="jse-preview-content">
                <pre class="jse-code-block"><code><%= PrettyPrinter.format(@schema) %></code></pre>
              </div>
            </div>
          <% end %>
        </div>
      </div>

      <%= if @show_import_modal do %>
        <div class="jse-modal-overlay">
          <div class="jse-modal">
            <div class="jse-modal-header">
              <h3 class="jse-modal-title">Import Schema</h3>
              <button class="jse-btn-icon" phx-click="close_import_modal" phx-target={@myself}>
                <Components.icon name={:close} class="jse-icon-sm" />
              </button>
            </div>
            <form phx-submit="import_schema" phx-target={@myself}>
              <div class="jse-modal-body">
                <%= if @import_error do %>
                  <div class="jse-modal-error">{@import_error}</div>
                <% end %>
                <textarea
                  name="schema_text"
                  class="jse-modal-textarea"
                  placeholder="Paste your JSON Schema here..."
                  autofocus
                ></textarea>
              </div>
              <div class="jse-modal-footer">
                <button
                  type="button"
                  class="jse-btn jse-btn-secondary"
                  phx-click="close_import_modal"
                  phx-target={@myself}
                >
                  Cancel
                </button>
                <button type="submit" class="jse-btn jse-btn-primary">
                  Import
                </button>
              </div>
            </form>
          </div>
        </div>
      <% end %>
    </div>
    """
  end
end