-- Implicit CAD. Copyright (C) 2011, Christopher Olah (chris@colah.ca)
-- Copyright (C) 2014-2017, Julia Longtin (julial@turinglace.com)
-- Released under the GNU AGPLV3+, see LICENSE

-- Allow us to use shorter forms of Var and Name.
{-# LANGUAGE PatternSynonyms #-}

-- | Statement related hspec tests.
module ParserSpec.Statement (statementSpec) where

import Prelude (String, Maybe(Just, Nothing), Bool(True), ($))

import Test.Hspec (Spec, Expectation, shouldBe, it, describe)

import ParserSpec.Util (bool, num, minus, plus, mult, index)

import Graphics.Implicit.ExtOpenScad.Definitions (StatementI(StatementI), Symbol(Symbol), Expr(ListE, LamE, (:$)), Statement(NewModule, ModuleCall, If, (:=)), Pattern(ListP), SourcePosition(SourcePosition))

import qualified Graphics.Implicit.ExtOpenScad.Definitions as GIED (Expr(Var), Pattern(Name))

-- Parse an ExtOpenScad program.
import Graphics.Implicit.ExtOpenScad.Parser.Statement (parseProgram)

import Graphics.Implicit.Definitions (Fastℕ)

import Data.Either (Either(Right))

-- Let us use the old syntax when defining Vars and Names.
pattern Var :: String -> Expr
pattern Var  s = GIED.Var  (Symbol s)
pattern Name :: String -> Pattern
pattern Name n = GIED.Name (Symbol n)

-- | an expectation that a string is equivalent to a statement.
infixr 1 -->
(-->) :: String -> [StatementI] -> Expectation
(-->) source stmts =
    parseProgram "noname" source `shouldBe` Right stmts

-- | an expectation that a string generates an error.
-- parsesAsError :: String -> Expectation
-- parsesAsError source = parseProgram "noname" source `shouldSatisfy` isLeft

-- | A single statement.
single :: Statement StatementI -> [StatementI]
single st = [StatementI (SourcePosition 1 1 "noname") st]

-- | A function call.
call :: String -> Fastℕ -> [(Maybe Symbol, Expr)] -> [StatementI] -> StatementI
call name column args stmts = StatementI (SourcePosition 1 column "noname") (ModuleCall (Symbol name) args stmts)

-- | Test assignments.
assignmentSpec :: Spec
assignmentSpec = do
  it "handles assignment" $
    "y = -5 ; " --> single ( Name "y" := num (-5))
  it "handles pattern matching" $
    "[ x , y ] = [ 1 , 2 ] ; " --> single (ListP [Name "x", Name "y"] := ListE [num 1, num 2])
  it "handles the function keyword" $
    "function foo ( x , y ) = x * y ; " --> single fooFunction
  it "handles function with let expression" $
    "function withlet ( b ) = let ( c = 5 ) b + c ; " -->
    single (Name "withlet" := LamE [Name "b"] (LamE [Name "c"] (plus [Var "b", Var "c"]) :$ [num 5]))
  it "handles nested indexing" $
    "x = [ y [ 0 ] - z * 2 ] ; " -->
    single ( Name "x" := ListE [minus [index [Var "y", num 0],
                                           mult [Var "z", num 2]]])
  where
    fooFunction :: Statement st
    fooFunction = Name "foo" := LamE [Name "x", Name "y"]
                                (mult [Var "x", Var "y"])

-- | Test a simple if block.
ifSpec :: Spec
ifSpec = do
  it "parses" $
    "if ( true ) { a ( ) ; }" -->
    single ( If (bool True) [call "a" 15 [] []] [])
  it "parses with else clause" $
    "if ( true ) { a ( ) ; } else {b();}" -->
    single ( If (bool True) [call "a" 15 [] []] [call "b" 31 [] []])

-- | Our entry point. Test all of the statements.
statementSpec :: Spec
statementSpec = do
  describe "empty file" $
    it "returns an empty list" $ "" --> []
  describe "assignment" assignmentSpec
  describe "if" ifSpec
  describe "line comment" $
    it "parses as empty" $ "// foish bar \n " --> []
  describe "multiline comment" $
    it "parses as empty" $ "/* foish bar\n */ " --> []
  describe "module call" $
    it "parses" $ "foo ( ) ; " --> single (ModuleCall (Symbol "foo") [] [])
  describe "disabled module call" $
    it "parses as empty" $ "% foo ( ) ; " --> []
  describe "difference of two cylinders" $
    it "parses correctly" $
      "difference ( ) { cylinder ( r = 5 , h = 20 ) ;cylinder(r=2,h=20); } "
      --> single (
        ModuleCall (Symbol "difference") [] [
           call "cylinder" 18 [(Just (Symbol "r"), num 5.0),
                             (Just (Symbol "h"), num 20.0)]
            [],
           call "cylinder" 47 [(Just (Symbol "r"), num 2.0),
                             (Just (Symbol "h"), num 20.0)]
            []])
  describe "module definition" $ do
    it "parses correctly" $
      "module foo_bar ( ) { }" --> single (NewModule (Symbol "foo_bar") [] [])
    it "accepts argument" $
      "module foo_bar ( x ) { }" --> single (NewModule (Symbol "foo_bar") [(Symbol "x", Nothing)] [])
    it "accepts argument with default" $
      "module foo_bar ( x = 1) { }" --> single (NewModule (Symbol "foo_bar") [(Symbol "x", Just $ num 1)] [])