-- | Programming the Arduino with Copilot.
--
-- This module should work on any model of Arduino.
-- See Copilot.Arduino.Uno and Copilot.Arduino.Nano for model-specific code.
--
-- There are also libraries like Copilot.Arduino.Library.Serial to support
-- additional hardware.

{-# LANGUAGE RebindableSyntax #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}

module Copilot.Arduino (
	-- * Arduino sketch generation
	arduino,
	Sketch,
	Input,
	Output,
	-- | A value that varies over time.
	--
	-- The Copilot DSL provides many operations on streams, for example
	-- `Language.Copilot.&&` to combine two streams of Bools.
	-- 
	-- For documentation on using the Copilot DSL, see
	-- <https://copilot-language.github.io/>
	Stream,
	Pin,
	PinCapabilities(..),
	-- * Combinators
	(=:),
	(@:),
	-- * Inputs
	readfrom,
	readfrom',
	pullup,
	Voltage,
	readvoltage,
	readvoltage',
	-- * Outputs
	--
	-- | Only outputs that work on all Arduino boards are included
	-- here. Import a module such as Copilot.Arduino.Uno for
	-- model-specific outputs.
	led,
	writeto,
	DutyCycle,
	pwm,
	MicroSeconds,
	delay,
	-- * Utilities
	blinking,
	firstIteration,
	sketchSpec,
	-- * Copilot DSL
	--
	-- | The Copilot.Language module is re-exported here, including
	-- a version of the Prelude modified for it. You should enable
	-- the RebindableSyntax language extension in your program
	-- to use the Copilot DSL.
	--
	-- > {-# LANGUAGE RebindableSyntax #-}
	--
	-- For documentation on using the Copilot DSL, see
	-- <https://copilot-language.github.io/>
	module X,
) where

import Language.Copilot as X hiding (Stream)
import Language.Copilot (Stream)
import Copilot.Arduino.Internals
import Copilot.Arduino.Main
import Control.Monad.Writer
import qualified Data.Map as M
import qualified Data.Set as S

-- | Connect a `Stream` to an `Output`.
--
-- > led =: blinking
(=:) :: Output t -> Stream t -> Sketch ()
o =: s = tell [(go, toFramework o)]
  where
	go = (outputBehavior o) (outputCond o) s

-- | Use this to make a LED blink on and off.
--
-- On each iteration of the `Sketch`, this changes to the opposite of its
-- previous value.
--
-- This is implemented using Copilot's `clk`, so to get other blinking
-- behaviors, just pick different numbers, or use Copilot `Stream`
-- combinators.
-- 
-- > blinking = clk (period 2) (phase 1)
blinking :: Stream Bool
blinking = clk (period (2 :: Integer)) (phase (1 :: Integer))

-- Same fixity as =<<
infixr 1 =:

-- | By default, an `Output` is written to on each iteration of the `Sketch`.
--
-- For example, this constantly turns on the LED, even though it will
-- already be on after the first iteration.
--
-- > led =: true
--
-- To avoid unnecessary work being done, this combinator can make an
-- `Output` only be written to when the current value of the provided
-- `Stream` is True.
--
-- So to make the LED only be turned on in the first iteration,
-- and allow it to remain on thereafter without doing extra work:
--
-- > led @: firstIteration =: true
(@:) :: Output t -> Stream Bool -> Output t
(@:) o c = o { outputCond = c }

-- | True on the first iteration of the `Sketch`, and False thereafter.
firstIteration :: Stream Bool
firstIteration = [True]++false

-- | Use this to add a delay between each iteration of the `Sketch`.
-- A `Sketch` with no delay will run as fast as the hardware can run it.
--
-- > delay =: constant 100
delay :: Output MicroSeconds
delay = Output
	{ setupOutput = []
	, outputBehavior = \c n -> trigger "delay" c [arg n]
	, outputCond = true
	, outputPinmode = mempty
	}

-- | Reading a Bool from a `Pin`.
--
-- > do
-- > 	buttonpressed <- readfrom pin12
-- > 	led =: buttonpressed
readfrom :: IsDigitalIOPin t => Pin t -> Input Bool
readfrom p = readfrom' p []

-- | The list is used as simulated input when interpreting the program.
readfrom' :: IsDigitalIOPin t => Pin t -> [Bool] -> Input Bool
readfrom' (Pin p@(PinId n)) interpretvalues = mkInput $ InputSource
	{ defineVar = [CLine $ "bool " <> varname <> ";"]
	, setupInput = []
	, inputPinmode = M.singleton p InputMode
	, readInput = [CLine $ varname <> " = digitalRead(" <> show n <> ");"]
	, inputStream = extern varname interpretvalues'
	}
  where
	varname = "arduino_digital_pin_input" <> show n
	interpretvalues'
		| null interpretvalues = Nothing
		| otherwise = Just interpretvalues

-- | Normally when a `Pin` is read with `readfrom`, it is configured
-- without the internal pullup resistor being enabled. Use this to enable
-- the pullup register for all reads from the `Pin`.
--
-- Bear in mind that enabling the pullup resistor inverts the value that
-- will be read from the pin.
--
-- > pullup pin3
pullup :: Pin t -> Sketch ()
pullup (Pin p) = tell [(return (), f)]
  where
	f = mempty
		{ pinmodes = M.singleton p (S.singleton InputPullupMode)
		}

-- | Voltage read from an Arduino's ADC. Ranges from 0-1023.
type Voltage = Int16

-- | Measuring the voltage of a `Pin`.
readvoltage :: IsAnalogInputPin t => Pin t -> Input Voltage
readvoltage p = readvoltage' p []

readvoltage' :: IsAnalogInputPin t => Pin t -> [Int16] -> Input Voltage
readvoltage' (Pin (PinId n)) interpretvalues = mkInput $ InputSource
	{ defineVar = [CLine $ "int " <> varname <> ";"]
	, setupInput = []
	, inputPinmode = mempty
	, readInput = [CLine $ varname <> " = analogRead(" <> show n <> ");"]
	, inputStream = extern varname interpretvalues'
	}
  where
	varname = "arduino_analog_pin_input" <> show n
	interpretvalues'
		| null interpretvalues = Nothing
		| otherwise = Just interpretvalues

-- | Writing to a pin.
--
-- > writeto pin3 =: blinking
writeto :: IsDigitalIOPin t => Pin t -> Output Bool
writeto (Pin p@(PinId n)) = Output
	{ setupOutput = []
	, outputPinmode = M.singleton p OutputMode
	, outputBehavior = 
		\c v -> trigger "digitalWrite" c [arg (constant n), arg v]
	, outputCond = true
	}

-- | PWM output to a pin.
--
-- > pwm pin3 =: constant 128
pwm :: IsPWMPin t => Pin t -> Output DutyCycle
pwm (Pin (PinId n)) = Output
	{ setupOutput = []
	, outputPinmode = mempty -- analogWrite does not need pinMode
	, outputBehavior =
		\c v -> trigger "analogWrite" c [arg (constant n), arg v]
	, outputCond = true
	}

-- | Describes a PWM square wave. Between 0 (always off) and 255 (always on).
type DutyCycle = Word8

-- | The on-board LED.
led :: Output Bool
led = writeto p
  where
	p :: Pin '[ 'DigitalIO ]
	p = Pin (PinId 13)

-- | An 8 bit character.
-- | Extracts a copilot `Spec` from a `Sketch`.
--
-- This can be useful to intergrate with other libraries 
-- such as copilot-theorem.
sketchSpec :: Sketch a -> Spec
sketchSpec (Sketch s) = sequence_ is
  where
	(is, _fs) = unzip (execWriter s)