{-# LANGUAGE FlexibleContexts    #-}
{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE ScopedTypeVariables #-}
-- | This module defines a test that tries to walk over the
-- CodeGeneratorRequest in `tests/data/schema-codegenreq`,
-- failing if any of the data is not as expected.
module Tests.WalkSchemaCodeGenRequest
    (walkSchemaCodeGenRequestTest)
  where

import Prelude hiding (length)

import Control.Monad  (mapM_, when)
import Test.Framework (Test)
import Test.HUnit     (Assertion, assertEqual)

import qualified Data.ByteString as BS
import qualified Prelude

import Data.Capnp.Untyped hiding (index, length)

import Tests.Util

import Data.Capnp.Basics         (index, length, textBytes)
import Data.Capnp.Classes        (fromStruct)
import Data.Capnp.TraversalLimit (LimitT, execLimitT)

import qualified Capnp.Capnp.Schema as Schema
import qualified Data.Capnp.Message as M


-- | TODO: make this an array; we're doing random access to it below.
-- I(@zenhack) am waiting on this, since at the time of writing @taktoa
-- is working on some array utilities that will get merged soonish, so
-- it probably makes sense to just wait for that.
nodeNames :: [BS.ByteString]
nodeNames =
    [ "Import"
    , "annotation"
    , "Value"
    , "Type"
    ]

-- TODO: This contains a bit of copypasta from some of the untyped tests; should
-- factor that out.
theAssert :: Assertion
theAssert = do
    bytes <- BS.readFile "tests/data/schema-codegenreq"
    msg <- M.decode bytes
    endQuota <- execLimitT 4096 (rootPtr msg >>= reader)
    assertEqual "Correct remaining quota" 2036 endQuota
  where
    reader :: Struct M.ConstMsg -> LimitT IO ()
    reader root = do
        req :: Schema.CodeGeneratorRequest M.ConstMsg <- fromStruct root
        nodes <- Schema.get_CodeGeneratorRequest'nodes req
        requestedFiles <- Schema.get_CodeGeneratorRequest'requestedFiles req
        let 37 = length nodes
        let 1 = length requestedFiles
        mapM_ (walkNode nodes) [0,1..36]
    walkNode nodes i = do
        node <- index i nodes
        -- None of the nodes in the schema have parameters:
        False <- Schema.has_Node'parameters node
        -- And none of them are generic:
        False <- Schema.get_Node'isGeneric node

        nameList <- Schema.get_Node'displayName node
        name <- textBytes nameList
        prefixLen <- Schema.get_Node'displayNamePrefixLength node
        let baseName = BS.drop (fromIntegral prefixLen) name

        when (i < Prelude.length nodeNames && baseName /= (nodeNames !! i)) $
            error "Incorrect name."

        has <- Schema.has_Node'annotations node

        -- there are two annotations in all of the nodes, at these indicies:
        case (has, i `elem` [4, 9]) of
            (False, False) -> return ()
            (True, True) -> do
                1 <- length <$> Schema.get_Node'annotations node
                return ()
            (False, True) ->
                error $ "Node at index " ++ show i ++ " should have had" ++
                        "an annotation."
            (True, False) ->
                error $ "Node at index " ++ show i ++ " should not " ++
                        "have had an annotation."

walkSchemaCodeGenRequestTest :: Test
walkSchemaCodeGenRequestTest =
    assertionsToTest "walk schema CodeGenerationRequest" [theAssert]