defmodule ExCogmint do
  @moduledoc """
    Documentation for ExCogmint, the Elixir client library which is a thin wrapper
    around the Cogmint.com API.

    [Cogmint.com](https://www.cogmint.com) is a crowdsourcing / micro task website.


    Example configuration (see `ExCogmint.Config` for more details)

    In your app's config.exs file:
    ```
    config :ex_cogmint,
      cogmint_api_key: System.get_env("COGMINT_API_KEY"),
      callback_url: System.get_env("COGMINT_CALLBACK_URL")
    ```

    cogmint_api_key: required. The API key for your Cogmint account.

    callback_url: optional. Sets the default callback_url on each task created. If your app has a single endpoint for receiving all callbacks from Cogmint it is recommended to set this, or else you
    need to set it individually on every task creation API call.

  """

  @doc """
  Add a new task to an existing project.

  Project_uuid is the project's ID for which you wish to add a new microtask.

  The second argument is a map of substitutions you wish to make to the default project
  task template in order to create the task.

  For example, suppose you have a project asking users
  to determine if a city is a capital city or not. This project likely has a template that looks
  something like:

  "Is [[city]] a capital city?"

  For this project template, we can provide a map replacing the variable `city` with a value
  by passing in a map like

  ```
  %{"city" => "Washington, D.C."}
  ```

  Resulting in a task created for a worker like:

  "Is Washington, D.C. a capital city?"

  ## Examples

  ```
  ExCogmint.add_task!("1234-12345-1234-12345", %{"city" => "Brasilia"})
  ExCogmint.add_task!("abc-123-abc", %{"variable_name_to_replace" => "string inserted"})
  ```

  Potential Responses:
  ```
  {:ok,
    %{
        data: %{
          prompt: "Hotdog or not hotdog?",
          task_uuid: "1234-1234-1234",
          reward: 4,
          callback_url: "https://yoururl.com/callbackyouspecify",
          required_submissions: 3,
          submission_count: 3,
          checked_out_at: <datetime>,
          allowed_completion_time_seconds: 3600,
          external_image_url: "https://www.imagehostingurl.com/maybehotdog.png",
          submissions: []
        }
      }
    }
  ```
  or
  ```
  {:error, "helpful message"}
  ```

  """
  # Substitutions could be a keyword list or a map of kv pairs. project_uuid must be a string.
  def add_task!(nil, _), do: {:error, "project_uuid was nil."}
  def add_task!(_, nil), do: {:error, "substitutions was nil"}
  def add_task!(_, map) when map == %{}, do: {:error, "substitutions map was empty"}

  def add_task!(project_uuid, substitutions)
      when is_map(substitutions) and is_binary(project_uuid) do
    %{"project_uuid" => project_uuid, "substitutions" => substitutions}
    |> ExCogmint.Project.build_add_task_request()
    |> ExCogmint.Client.request!()
  end

  @doc """
  Gets information on a task ("worktask"). Returns the task, including associated submissions as a list of strings.

  Example response:
  ```
  %{
      data: %{
        prompt: "Hotdog or not hotdog?",
        task_uuid: "1234-1234-1234",
        reward: 4,
        callback_url: "https://yoururl.com/callbackyouspecify",
        required_submissions: 3,
        submission_count: 3,
        checked_out_at: <datetime>,
        allowed_completion_time_seconds: 3600,
        external_image_url: "https://www.imagehostingurl.com/maybehotdog.png",
        submissions: ["yes", "yes", "yes"]
      }
    }
  ```

  """
  def get_task!(nil), do: {:error, "get_task! requires a UUID that is not nil"}
  def get_task!(""), do: {:error, "get_task! requires a UUID that is not blank"}
  def get_task!(uuid) when (false == is_binary(uuid)), do: {:error, "UUID should be a string binary"}
  def get_task!(uuid) when byte_size(uuid) < 36, do: {:error, "Invalid UUID: it should be 36 bytes"}

  def get_task!(uuid) when is_binary(uuid) do
    uuid
    |> ExCogmint.Worktask.build_get_task_request()
    |> ExCogmint.Client.request!()
  end


  @doc """
  Retrieve information about a project.

  ## Example

  ```
  ExCogmint.get_project!("39a832c4-6ad0-48ef-9cf3-f251efb124f2")
  ```

  Example response:

  ```
  {:ok,
    %{
      data: %{
        allowed_completion_time_seconds: 3600,
        available_task_count: 89,
        average_outstanding_task_reward_cents: 50,
        default_required_submissions: 3,
        default_reward: 50,
        display_name: "Great Display Name",
        display_short_description: "A short description, visible to workers",
        has_published_tasks: true,
        lifetime_payments_to_workers_cents: 15000,
        name: "Test Project (using test key)",
        uuid: "39a832c4-6ad0-48ef-9cf3-f251efb124f2"
      }
    }
  }
  ```
  """
  def get_project!(nil), do: {:error, "get_project! requires a UUID that is not nil"}
  def get_project!(""), do: {:error, "get_project! requires a UUID that is not blank"}
  def get_project!(uuid) when (false == is_binary(uuid)), do: {:error, "UUID should be a string binary"}
  def get_project!(uuid) when byte_size(uuid) < 36, do: {:error, "Invalid UUID: it should be 36 bytes"}

  def get_project!(uuid) when is_binary(uuid) do
    uuid
    |> ExCogmint.Project.build_get_project_request()
    |> ExCogmint.Client.request!()
  end

  @doc false
  def ping() do
    %{
      path: "/api/v1/ping",
      body: "",
      method: :get
    }
    |> ExCogmint.Client.request!()
  end
end