defmodule ComponentsElixir.Inventory.Component do
  @moduledoc """
  Schema for electronic components.

  Each component belongs to a category and tracks inventory information
  including count, location, and optional image and datasheet.
  """
  use Ecto.Schema
  import Ecto.Changeset

  alias ComponentsElixir.Inventory.{Category, StorageLocation}

  schema "components" do
    field :name, :string
    field :description, :string
    field :keywords, :string
    field :position, :string
    field :legacy_position, :string
    field :count, :integer, default: 0
    field :datasheet_url, :string
    field :datasheet_filename, :string
    field :image_filename, :string

    belongs_to :category, Category
    belongs_to :storage_location, StorageLocation

    timestamps(type: :naive_datetime_usec)
  end

  @doc false
  def changeset(component, attrs) do
    component
    |> cast(attrs, [:name, :description, :keywords, :position, :count, :datasheet_url, :datasheet_filename, :image_filename, :category_id, :storage_location_id])
    |> validate_required([:name, :category_id])
    |> validate_length(:name, min: 1, max: 255)
    |> validate_length(:description, max: 2000)
    |> validate_length(:keywords, max: 500)
    |> validate_length(:position, max: 100)
    |> validate_number(:count, greater_than_or_equal_to: 0)
    |> validate_url(:datasheet_url)
    |> foreign_key_constraint(:category_id)
    |> foreign_key_constraint(:storage_location_id)
  end

  @doc """
  Changeset for updating component count.
  """
  def count_changeset(component, attrs) do
    component
    |> cast(attrs, [:count])
    |> validate_required([:count])
    |> validate_number(:count, greater_than_or_equal_to: 0)
  end

  @doc """
  Changeset for updating component image.
  """
  def image_changeset(component, attrs) do
    component
    |> cast(attrs, [:image_filename])
  end

  @doc """
  Changeset for updating component datasheet.
  """
  def datasheet_changeset(component, attrs) do
    component
    |> cast(attrs, [:datasheet_filename])
  end

  defp validate_url(changeset, field) do
    validate_change(changeset, field, fn ^field, url ->
      cond do
        is_nil(url) or url == "" -> []
        valid_url?(url) -> []
        true -> [{field, "must be a valid URL"}]
      end
    end)
  end

  defp valid_url?(url) do
    case URI.parse(url) do
      %URI{scheme: scheme} when scheme in ["http", "https"] -> true
      _ -> false
    end
  end

  @doc """
  Returns true if the component has an image.
  """
  def has_image?(%__MODULE__{image_filename: filename}) when is_binary(filename), do: true
  def has_image?(_), do: false

  @doc """
  Returns true if the component has a datasheet file.
  """
  def has_datasheet?(%__MODULE__{datasheet_filename: filename}) when is_binary(filename), do: true
  def has_datasheet?(_), do: false

  @doc """
  Returns the search text for this component.
  """
  def search_text(%__MODULE__{} = component) do
    [component.name, component.description, component.keywords]
    |> Enum.filter(&is_binary/1)
    |> Enum.join(" ")
  end
end