defmodule Keenex do
  alias Keenex.HTTP

  @type status :: :ok | :error
  @type response :: {status, map}

  @moduledoc """
  Keenex provides an Elixir interface to the Keen.io HTTP API.

  ## Usage

  Add it to your applications and dependencies in `mix.exs`:

      def application do
        [applications: [:keenex]]
      end

      def deps do
        [{:keenex, "~> 1.0"}]
      end

  Configure it in `config.exs`:

      config :keenex,
        project_id: "xxxxx",  # defaults to System.get_env("KEEN_PROJECT_ID")
        read_key:   "xxxxx",  # defaults to System.get_env("KEEN_READ_KEY")
        write_key:  "xxxxx",  # defaults to System.get_env("KEEN_WRITE_KEY")
        httpoison_opts: [timeout: 5000]  # defaults to []

  And then call functions like:

      {status, response} = Keenex.add_event("dinner.tacos", %{test: "tacos"})

  `status` is either `:ok` or `:error`.

  `response` is a Map converted from the JSON response from Keen.
  Information about the contents of the response can be found
  [here](https://keen.io/docs/api/).
  """

  use Application

  @doc """
  Starts Keenex app.
  """
  def start(_type, _args) do
    Agent.start_link(fn -> [] end, name: __MODULE__)
  end

  @doc """
  Returns schema for a single event collection


  ```
  Keenex.inspect("dinner.tacos")
  ```
  """
  @spec inspect(binary) :: Keenex.response()
  def inspect(event_collection) do
    HTTP.get("/projects/#{project_id()}/events/#{event_collection}")
  end

  @doc """
  Returns schema for all event collections


  ```
  Keenex.inspect_all()
  ```
  """
  @spec inspect_all() :: Keenex.response()
  def inspect_all() do
    HTTP.get("/projects/#{project_id()}/events")
  end

  @doc """
  Publishes an event into the event collection


  ```
  Keenex.add_event("dinner.tacos", %{data: "data"})
  ```
  """
  @spec add_event(binary, map) :: Keenex.response()
  def add_event(event_collection, data) do
    HTTP.post("/projects/#{project_id()}/events/#{event_collection}", data)
  end

  @doc """
  Publishes multiple events to one or more event collections


  ```
  Keenex.add_events(%{event_collection1: [%{data: "data"}], event_collection2: [%{data: "data"}, %{more_data: "data"}]})
  ```
  """
  @spec add_events(map) :: Keenex.response()
  def add_events(events) do
    HTTP.post("/projects/#{project_id()}/events", events)
  end

  @doc """
  Returns the number of events in a collection matching the given criteria
  """
  @spec count(binary, map) :: Keenex.response()
  def count(event_collection, params \\ %{}) do
    params = Map.merge(%{event_collection: event_collection}, params)
    query("count", params)
  end

  @doc """
  Return the number of events with unique values, for a target property in a collection matching given criteria
  """
  @spec count_unique(binary, binary, map) :: Keenex.response()
  def count_unique(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("count_unique", params)
  end

  @doc """
  Return the minimum numeric value for a target property, among all events in a collection matching given criteria.
  """
  @spec minimum(binary, binary, map) :: Keenex.response()
  def minimum(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("minimum", params)
  end

  @doc """
  Return the maximum numeric value for a target property, among all events in a collection matching given criteria.
  """
  @spec maximum(binary, binary, map) :: Keenex.response()
  def maximum(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("maximum", params)
  end

  @doc """
  Calculate the sum of all numeric values for a target property, among all events in a collection matching given criteria.
  """
  @spec sum(binary, binary, map) :: Keenex.response()
  def sum(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("sum", params)
  end

  @doc """
  Calculate the average value for a target property, among all events in a collection matching given criteria.
  """
  @spec average(binary, binary, map) :: Keenex.response()
  def average(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("average", params)
  end

  @doc """
  Calculate the median value for a target property, among all events in a collection matching given criteria.
  """
  @spec median(binary, binary, map) :: Keenex.response()
  def median(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("median", params)
  end

  @doc """
  Calculate a specified percentile value for a target property, among all events in a collection matching given criteria.
  """
  @spec percentile(binary, binary, integer, map) :: Keenex.response()
  def percentile(event_collection, target_property, percentile, params \\ %{}) do
    params =
      Map.merge(
        %{
          event_collection: event_collection,
          target_property: target_property,
          percentile: percentile
        },
        params
      )

    query("percentile", params)
  end

  @doc """
  Return a list of unique property values for a target property, among all events in a collection matching given criteria.
  """
  @spec select_unique(binary, binary, map) :: Keenex.response()
  def select_unique(event_collection, target_property, params \\ %{}) do
    params =
      Map.merge(%{event_collection: event_collection, target_property: target_property}, params)

    query("select_unique", params)
  end

  @doc """
  Runs multiple types of analyses over the same data
  """
  @spec multi_analysis(binary, map, map) :: Keenex.response()
  def multi_analysis(event_collection, analyses, params \\ %{}) do
    params = Map.merge(%{event_collection: event_collection, analyses: analyses}, params)
    query("multi_analysis", params)
  end

  @doc """
  Creates an extraction request for full-form event data with all property values.
  """
  @spec extraction(binary, map) :: Keenex.response()
  def extraction(event_collection, params \\ %{}) do
    params = Map.merge(%{event_collection: event_collection}, params)
    query("extraction", params)
  end

  @doc """
  Returns the number of unique actors that successfully (or unsuccessfully) make it through a series of steps
  """
  @spec funnel(list) :: Keenex.response()
  def funnel(steps, params \\ %{}) do
    params = Map.merge(%{steps: steps}, params)
    query("funnel", params)
  end

  defp query(type, params) do
    HTTP.post("/projects/#{project_id()}/queries/#{type}", params, :read)
  end

  @doc false
  def get_key(key_type) do
    case key_type do
      :write ->
        write_key()

      :read ->
        read_key()
    end
  end

  @doc false
  def project_id do
    config()[:project_id]
  end

  def read_key do
    config()[:read_key]
  end

  def write_key do
    config()[:write_key]
  end

  @doc false
  def httpoison_opts do
    config()[:httpoison_opts]
  end

  defp config do
    [
      project_id: Application.get_env(:keenex, :project_id, System.get_env("KEEN_PROJECT_ID")),
      write_key: Application.get_env(:keenex, :write_key, System.get_env("KEEN_WRITE_KEY")),
      read_key: Application.get_env(:keenex, :read_key, System.get_env("KEEN_READ_KEY")),
      httpoison_opts: Application.get_env(:keenex, :httpoison_opts, [])
    ]
  end
end