{-# LANGUAGE DeriveGeneric, DeriveAnyClass #-}
{-# LANGUAGE TypeOperators, DataKinds #-}
{-# LANGUAGE OverloadedStrings #-}

-- | A specification of an API for interacting with a set of printers
module Thermoprint.API
       ( PrinterStatus(..)
       , JobStatus(..)
       , PrintingError(..)
       , DraftTitle
       , ThermoprintAPI
       , thermoprintAPI
       , module Thermoprint.Identifiers
       , module Thermoprint.Printout
       ) where

import Thermoprint.Printout
import Thermoprint.Identifiers

import Servant.API
import Data.Aeson

import Data.Set (Set)
import Data.Map (Map)
import qualified Data.Map as Map (foldMapWithKey, singleton)
import Data.Sequence (Seq)

import Data.IntMap.Strict (IntMap)
import qualified Data.IntMap.Strict as IntMap (foldMapWithKey, singleton)

import Data.Text (Text)

import GHC.Generics (Generic)

import Data.Proxy (Proxy(..))

import Control.Exception (Exception)
import Data.Typeable (Typeable)

instance (Integral k, Ord k, ToJSON v) => ToJSON (Map k v) where
  toJSON = toJSON . Map.foldMapWithKey (IntMap.singleton . castId)

instance (Enum k, Ord k, FromJSON v) => FromJSON (Map k v) where
  parseJSON = fmap (IntMap.foldMapWithKey $ Map.singleton . castId) . parseJSON
       

data PrinterStatus = Busy JobId
                   | Available
                   deriving (Generic, Show, FromJSON, ToJSON)

data JobStatus = Queued PrinterId
               | Printing PrinterId
               | Done
               | Failed PrintingError
               deriving (Generic, Show, FromJSON, ToJSON)

data PrintingError = UnknownError
                   deriving (Typeable, Generic, Show, FromJSON, ToJSON, Exception)

type DraftTitle = Text

type ThermoprintAPI = "printers" :> Get '[JSON] (Map PrinterId PrinterStatus)
                      :<|> "jobs" :> (
                        QueryParam "printer" PrinterId :> QueryParam "min" JobId :> QueryParam "max" JobId :> Get '[JSON] (Seq (JobId, JobStatus))
                        :<|> QueryParam "printer" PrinterId :> ReqBody '[JSON] Printout :> Post '[JSON] JobId
                      )
                      :<|> "job" :> Capture "jobId" JobId :> (
                        Get '[JSON] Printout
                        :<|> "status" :> Get '[JSON] JobStatus
                        :<|> Delete '[] ()
                      )
                      :<|> "drafts" :> (
                        Get '[JSON] (Map DraftId (Maybe DraftTitle))
                        :<|> QueryParam "title" DraftTitle :> ReqBody '[JSON] Printout :> Post '[JSON] DraftId
                      )
                      :<|> "draft" :> Capture "draftId" DraftId :> (
                        QueryParam "title" DraftTitle :> ReqBody '[JSON] Printout :> Put '[] ()
                        :<|> Get '[JSON] (Maybe DraftTitle, Printout)
                        :<|> Delete '[] ()
                        :<|> QueryParam "printer" PrinterId :> Post '[JSON] JobId
                      )

thermoprintAPI :: Proxy ThermoprintAPI
-- ^ Servant occasionally needs an object of this type 
thermoprintAPI = Proxy