defmodule ElixirAi.AiProvider do
  alias ElixirAi.Data.DbHelpers
  require Logger
  import ElixirAi.PubsubTopics

  defmodule AiProviderSchema do
    defstruct [:id, :name, :model_name, :api_token, :completions_url]

    def schema do
      Zoi.object(%{
        id: Zoi.optional(Zoi.string()),
        name: Zoi.string(),
        model_name: Zoi.string(),
        api_token: Zoi.nullish(Zoi.string()),
        completions_url: Zoi.nullish(Zoi.string())
      })
    end

    def partial_schema do
      Zoi.object(%{
        id: Zoi.optional(Zoi.string()),
        name: Zoi.string(),
        model_name: Zoi.string()
      })
    end
  end

  def all do
    sql = "SELECT id, name, model_name FROM ai_providers"
    params = %{}

    case DbHelpers.run_sql(sql, params, providers_topic(), AiProviderSchema.partial_schema()) do
      {:error, _} ->
        []

      rows ->
        rows
        |> Enum.map(fn row ->
          row |> convert_uuid_to_string() |> then(&struct(AiProviderSchema, &1))
        end)
        |> tap(&Logger.debug("AiProvider.all() returning: #{inspect(&1)}"))
    end
  end

  defp convert_uuid_to_string(%{id: id} = provider) when is_binary(id) do
    %{provider | id: Ecto.UUID.cast!(id)}
  end

  defp convert_uuid_to_string(provider), do: provider

  def create(attrs) do
    now = DateTime.truncate(DateTime.utc_now(), :second)

    sql = """
    INSERT INTO ai_providers (
      name,
      model_name,
      api_token,
      completions_url,
      inserted_at,
      updated_at
    ) VALUES (
      $(name),
      $(model_name),
      $(api_token),
      $(completions_url),
      $(inserted_at),
      $(updated_at)
    )
    """

    params = %{
      "name" => attrs.name,
      "model_name" => attrs.model_name,
      "api_token" => attrs.api_token,
      "completions_url" => attrs.completions_url,
      "inserted_at" => now,
      "updated_at" => now
    }

    case DbHelpers.run_sql(sql, params, providers_topic()) do
      {:error, :db_error} ->
        {:error, :db_error}

      _result ->
        Logger.info(
          "Provider created, broadcasting :provider_added message to topic #{providers_topic()}"
        )

        Phoenix.PubSub.broadcast(
          ElixirAi.PubSub,
          providers_topic(),
          {:provider_added, attrs}
        )

        :ok
    end
  end

  def find_by_name(name) do
    sql = """
    SELECT id, name, model_name, api_token, completions_url
    FROM ai_providers
    WHERE name = $(name)
    LIMIT 1
    """

    params = %{"name" => name}

    case DbHelpers.run_sql(sql, params, providers_topic(), AiProviderSchema.schema()) do
      {:error, _} -> {:error, :db_error}
      [] -> {:error, :not_found}
      [row | _] -> {:ok, row |> convert_uuid_to_string() |> then(&struct(AiProviderSchema, &1))}
    end
  end

  def find_by_id(id) do
    case Ecto.UUID.dump(id) do
      {:ok, binary_id} ->
        sql = """
        SELECT id, name, model_name, api_token, completions_url
        FROM ai_providers
        WHERE id = $(id)
        LIMIT 1
        """

        params = %{"id" => binary_id}

        case DbHelpers.run_sql(sql, params, providers_topic(), AiProviderSchema.schema()) do
          {:error, _} ->
            {:error, :db_error}

          [] ->
            {:error, :not_found}

          [row | _] ->
            {:ok, row |> convert_uuid_to_string() |> then(&struct(AiProviderSchema, &1))}
        end

      :error ->
        {:error, :invalid_uuid}
    end
  end

  def delete(id) do
    sql = "DELETE FROM ai_providers WHERE id = $(id)::uuid"
    params = %{"id" => id}

    case DbHelpers.run_sql(sql, params, providers_topic()) do
      {:error, :db_error} ->
        {:error, :db_error}

      _result ->
        Logger.info(
          "Provider deleted, broadcasting :provider_deleted message to topic #{providers_topic()}"
        )

        Phoenix.PubSub.broadcast(
          ElixirAi.PubSub,
          providers_topic(),
          {:provider_deleted, id}
        )

        :ok
    end
  end

  def ensure_default_provider do
    endpoint = Application.get_env(:elixir_ai, :ai_endpoint)
    token = Application.get_env(:elixir_ai, :ai_token)
    model = Application.get_env(:elixir_ai, :ai_model)

    if endpoint && token && model do
      case find_by_name("default") do
        {:error, :not_found} ->
          attrs = %{
            name: "default",
            model_name: model,
            api_token: token,
            completions_url: endpoint
          }

          create(attrs)

        {:ok, _} ->
          :ok

        {:error, reason} ->
          {:error, reason}
      end
    else
      Logger.info("AI env vars not configured, skipping default provider creation")
      :ok
    end
  end

  def ensure_providers_from_file do
    case System.get_env("PROVIDERS_CONFIG_PATH") do
      nil ->
        :ok

      path ->
        case YamlElixir.read_from_file(path) do
          {:ok, %{"providers" => providers}} when is_list(providers) ->
            Enum.each(providers, &ensure_provider_from_yaml/1)

          {:ok, _} ->
            Logger.warning("providers.yml: expected a top-level 'providers' list, skipping")

          {:error, reason} ->
            Logger.warning("Could not read providers config from #{path}: #{inspect(reason)}")
        end
    end
  end

  def ensure_configured_providers do
    ensure_default_provider()
    ensure_providers_from_file()
  end

  defp ensure_provider_from_yaml(%{
         "name" => name,
         "model" => model,
         "responses_endpoint" => endpoint,
         "api_key" => api_key
       }) do
    case find_by_name(name) do
      {:error, :not_found} ->
        Logger.info("Creating provider '#{name}' from providers config file")
        create(%{name: name, model_name: model, api_token: api_key, completions_url: endpoint})

      {:ok, _} ->
        Logger.debug("Provider '#{name}' already exists, skipping")

      {:error, reason} ->
        Logger.warning("Could not check existence of provider '#{name}': #{inspect(reason)}")
    end
  end

  defp ensure_provider_from_yaml(entry) do
    Logger.warning(
      "Skipping invalid provider entry in providers config file (must have name, model, responses_endpoint, api_key): #{inspect(entry)}"
    )
  end
end