{-# LANGUAGE OverloadedStrings, Rank2Types, ScopedTypeVariables,
  GADTs, FlexibleContexts #-}

module Main
  ( main
  , getCredentials
  ) where

import Control.Applicative
import Control.Monad (mzero)
import Control.Monad.IO.Class (MonadIO(liftIO))
import Control.Monad.Trans.Class (lift)
import Data.Function (on)
import Data.Int (Int8, Int16, Int32, Int64)
import Data.Maybe (isJust, isNothing)
import Data.Text (Text)
import Data.Time (parseTime)
import Data.Word (Word, Word8, Word16, Word32, Word64)
import System.Environment (getEnv)
import System.Exit (exitFailure)
import System.IO.Error (isDoesNotExistError)
import Data.List ((\\))
import Data.Monoid ((<>))
import qualified UnliftIO.Exception as E
import qualified Control.Monad.Trans.Resource as R
import qualified Data.Aeson as A
import qualified Data.Aeson.Types as A
import qualified Data.ByteString.Char8 as B
import qualified Data.Conduit as C
import qualified Data.Conduit.List as CL
import qualified Data.Default as D
import qualified Data.Map as Map
import qualified Data.Maybe as M
import qualified Data.Set as S
import qualified Data.Text as T
import qualified Data.Text.Encoding as TE
import qualified Data.Time as TI
import qualified Facebook as FB
import qualified Network.HTTP.Conduit as H
import qualified Test.QuickCheck as QC

import Test.HUnit ((@?=))
import Test.Hspec
import Test.Hspec.QuickCheck

-- | Grab the Facebook credentials from the environment.
getCredentials :: IO FB.Credentials
getCredentials = tryToGet `E.catch` showHelp
  where
    tryToGet = do
      [appName, appId, appSecret] <-
        mapM getEnv ["APP_NAME", "APP_ID", "APP_SECRET"]
      return $ FB.Credentials (T.pack appName) (T.pack appId) (T.pack appSecret)
    showHelp exc
      | not (isDoesNotExistError exc) = E.throwIO exc
    showHelp _ = do
      putStrLn $
        unlines
          [ "In order to run the tests from the 'fb' package, you need"
          , "developer access to a Facebook app.  The tests are designed"
          , "so that your app isn't going to be hurt, but we may not"
          , "create a Facebook app for this purpose and then distribute"
          , "its secret keys in the open."
          , ""
          , "Please give your app's name, id and secret on the enviroment"
          , "variables APP_NAME, APP_ID and APP_SECRET, respectively.  "
          , "For example, before running the test you could run in the shell:"
          , ""
          , "  $ export APP_NAME=\"example\""
          , "  $ export APP_ID=\"458798571203498\""
          , "  $ export APP_SECRET=\"28a9d0fa4272a14a9287f423f90a48f2304\""
          , ""
          , "Of course, these values above aren't valid and you need to"
          , "replace them with your own."
          , ""
          , "(Exiting now with a failure code.)"
          ]
      exitFailure

invalidCredentials :: FB.Credentials
invalidCredentials = FB.Credentials "this" "isn't" "valid"

invalidUserAccessToken :: FB.UserAccessToken
invalidUserAccessToken = FB.UserAccessToken (FB.Id "invalid") "user" farInTheFuture
  where
    Just farInTheFuture = parseTime (error "farInTheFuture") "%Y" "3000"

-- It's actually important to use 'farInTheFuture' since we
-- don't want any tests rejecting this invalid user access
-- token before even giving it to Facebook.
invalidAppAccessToken :: FB.AppAccessToken
invalidAppAccessToken = FB.AppAccessToken "invalid"

main :: IO ()
main = do
  manager <- H.newManager H.tlsManagerSettings
  liftIO $
    do creds <- getCredentials
       hspec $
       -- Run the tests twice, once in Facebook's production tier...
         do facebookTests
              "Production tier: "
              creds
              manager
              (R.runResourceT . FB.runFacebookT creds manager)
              (R.runResourceT . FB.runNoAuthFacebookT manager)
            -- ...and the other in Facebook's beta tier.
            facebookTests
              "Beta tier: "
              creds
              manager
              (R.runResourceT . FB.beta_runFacebookT creds manager)
              (R.runResourceT . FB.beta_runNoAuthFacebookT manager)
            -- Tests that don't depend on which tier is chosen.
            libraryTests manager

facebookTests
  :: String
  -> FB.Credentials
  -> H.Manager
  -> (forall a. FB.FacebookT FB.Auth (R.ResourceT IO) a -> IO a)
  -> (forall a. FB.FacebookT FB.NoAuth (R.ResourceT IO) a -> IO a)
  -> Spec
facebookTests pretitle creds manager runAuth runNoAuth = do
  let describe' = describe . (pretitle ++)
  describe' "getAppAccessToken" $
    do it "works and returns a valid app access token" $
         runAuth $
         do token <- FB.getAppAccessToken
            FB.isValid token #?= True
       it "throws a FacebookException on invalid credentials" $
         R.runResourceT $
         FB.runFacebookT invalidCredentials manager $
         do ret <- E.try $ FB.getAppAccessToken
            case ret of
              Right token -> fail $ show token
              Left (_ :: FB.FacebookException) ->
                lift $ lift (return () :: IO ())
  describe' "isValid" $
    do it "returns False on a clearly invalid user access token" $
         runNoAuth $ FB.isValid invalidUserAccessToken #?= False
       it "returns False on a clearly invalid app access token" $
         runNoAuth $ FB.isValid invalidAppAccessToken #?= False
  describe' "debugToken" $
    do it "works on a test user access token" $
         do runAuth $
              withTestUser D.def $
              \testUser -> do
                Just testUserAccessTokenData <-
                  return (FB.tuAccessToken testUser)
                appToken <- FB.getAppAccessToken
                ret <- FB.debugToken appToken testUserAccessTokenData
                now <- liftIO TI.getCurrentTime
                FB.dtAppId ret &?= Just (FB.appId creds)
                FB.dtAppName ret &?= Just (FB.appName creds)
                case FB.dtExpiresAt ret of
                  Nothing -> fail "dtExpiresAt is Nothing"
                  Just t -> compare t now &?= GT
                FB.dtIsValid ret &?= Just True
                case FB.dtIssuedAt ret of
                  Nothing -> return () -- ok since it's a test user
                  Just t -> compare t now &?= LT
                isJust (FB.dtScopes ret) &?= True
                FB.dtUserId ret &?= Just (FB.tuId testUser)
                case FB.dtAccessToken ret of
                  Nothing -> fail "dtAccessToken is Nothing"
                  Just t -> do
                    let f
                          :: FB.UserAccessToken
                          -> FB.FacebookT FB.Auth (R.ResourceT IO) ()
                        f (FB.UserAccessToken uid dt exps) = do
                          uid &?= FB.tuId testUser
                          dt &?= testUserAccessTokenData
                          Just exps &?= FB.dtExpiresAt ret
                    f t
  describe' "getObject" $
    do it "is able to fetch Facebook's own page" $
         do val <-
              runAuth $ -- Needs permission now: https://developers.facebook.com/docs/graph-api/reference/page#Reading
              do token <- FB.getAppAccessToken
                 A.Object obj <- FB.getObject "/19292868552" [] (Just token)
                 let Just r =
                       flip A.parseMaybe () $
                       const $ (,) <$> obj A..:? "id" <*> obj A..:? "name"
                 return r
            val `shouldBe`
              ( Just "19292868552" :: Maybe Text
              , Just "Facebook for Developers" :: Maybe Text)
  describe' "getPage" $
    do it "works for FB Developers" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 page <- FB.getPage_ (FB.Id "19292868552") [] (Just token)
                 FB.pageId page &?= (FB.Id "19292868552")
                 FB.pageName page &?= Just "Facebook for Developers"
                 FB.pageCategory page &?= Nothing
                 FB.pageIsPublished page &?= Nothing
                 FB.pageCanPost page &?= Nothing
                 FB.pagePhone page &?= Nothing
                 FB.pageCheckins page &?= Nothing
                 FB.pageWebsite page &?= Nothing
  describe' "listSubscriptions" $
    do it "returns something" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 val <- FB.listSubscriptions token
                 length val `seq` return ()
  describe' "fetchNextPage" $
    do let fetchNextPageWorks :: FB.Pager A.Value
                              -> FB.FacebookT anyAuth (R.ResourceT IO) ()
           fetchNextPageWorks pager
             | isNothing (FB.pagerNext pager) = return ()
             | otherwise =
               FB.fetchNextPage pager >>= maybe not_ (\_ -> return ())
             where
               not_ =
                 fail "Pager had a next page but fetchNextPage didn't work."
       it "seems to work on a public list of comments" $
         do runAuth $
            -- Postid: https://www.facebook.com/nytimes/posts/10150628170209999
            -- Page id found using this technique: https://www.facebook.com/help/community/question/?id=529591157094317
              do token <- FB.getAppAccessToken
                 fetchNextPageWorks =<<
                   FB.getObject
                     "/5281959998_10150628170209999/comments"
                     []
                     (Just token)
       it "seems to work on a private list of app insights" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 fetchNextPageWorks =<<
                   FB.getObject
                     ("/" <> FB.appId creds <> "/app_insights/api_calls")
                     []
                     (Just token)
  describe' "fetchNextPage/fetchPreviousPage" $
    do let backAndForthWorks :: FB.Pager A.Value
                             -> FB.FacebookT anyAuth (R.ResourceT IO) ()
           backAndForthWorks pager = do
             pager2 <- FB.fetchNextPage pager
             case pager2 of
               Nothing -> True &?= True
               Just pager2' -> do
                 Just pager3 <- FB.fetchPreviousPage pager2'
                 pager3 &?= pager
       it "seems to work on a public list of comments" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 backAndForthWorks =<<
                   FB.getObject
                     "/5281959998_10150628170209999/comments"
                     [("filter", "stream")]
                     (Just token)
       it "seems to work on a private list of app insights" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 backAndForthWorks =<<
                   FB.getObject
                     ("/" <> FB.appId creds <> "/app_insights/api_calls")
                     []
                     (Just token)
  describe' "fetchAllNextPages" $
    do let hasAtLeast :: C.Source IO A.Value -> Int -> IO ()
           src `hasAtLeast` n = src C.$$ go n
             where
               go 0 = return ()
               go m = C.await >>= maybe not_ (\_ -> go (m - 1))
               not_ =
                 fail $
                 "Source does not have at least " ++ show n ++ " elements."
       it "seems to work on a public list of comments" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 pager <-
                   FB.getObject
                     "/63441126719_10154249531391720/comments"
                     []
                     (Just token)
                 src <- FB.fetchAllNextPages pager
                 liftIO $ src `hasAtLeast` 200 -- items
       it "seems to work on a private list of app insights" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 pager <-
                   FB.getObject
                     ("/" <> FB.appId creds <> "/app_insights/api_calls")
                     []
                     (Just token)
                 src <- FB.fetchAllNextPages pager
                 let firstPageElms = length (FB.pagerData pager)
                     hasNextPage = isJust (FB.pagerNext pager)
                 if hasNextPage
                   then liftIO $ src `hasAtLeast` (firstPageElms * 3) -- items
                   else return () -- fail "This isn't an insightful app =(."
  describe' "createTestUser/removeTestUser/getTestUser" $
    do it "creates and removes a new test user" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 -- New test user information
                 let installed =
                       FB.CreateTestUserInstalled
                         ["read_stream", "read_friendlists", "publish_stream"]
                     userInfo =
                       FB.CreateTestUser
                       { FB.ctuInstalled = installed
                       , FB.ctuName = Just "Gabriel"
                       , FB.ctuLocale = Just "en_US"
                       }
                 -- Create the test user
                 newTestUser <- FB.createTestUser userInfo token
                 let newTestUserToken =
                       (M.fromJust $ FB.incompleteTestUserAccessToken newTestUser)
                 -- Get the created user
                 createdUser <-
                   FB.getUser (FB.tuId newTestUser) [] (Just newTestUserToken)
                 -- Remove the test user
                 removed <- FB.removeTestUser newTestUser token
                 -- Check user attributes
                 FB.userId createdUser &?= FB.tuId newTestUser
                 FB.userName createdUser &?= Just "Gabriel"
                 -- FB.userLocale createdUser &?= Just "en_US"   -- fix this test later
                 -- Check if the token is valid
                 FB.isValid newTestUserToken #?= False
                 removed &?= True
  describe' "makeFriendConn" $
    do it "creates two new test users, makes them friends and deletes them" $
         do runAuth $
              withTestUser D.def $
              \testUser1 ->
                 withTestUser D.def $
                 \testUser2 -> do
                   let Just tokenUser1 = FB.incompleteTestUserAccessToken testUser1
                   let Just tokenUser2 = FB.incompleteTestUserAccessToken testUser2
                   -- Check if the new test users' tokens are valid.
                   FB.isValid tokenUser1 #?= True
                   FB.isValid tokenUser2 #?= True
                   -- Create a friend connection between the new test users.
                   FB.makeFriendConn testUser1 testUser2
                   -- Verify that one is a friend of the other.
                   user1 <- FB.getUser (FB.tuId testUser1) [] (Just tokenUser1)
                   user2 <- FB.getUser (FB.tuId testUser2) [] (Just tokenUser2)
                   friends1 <- FB.getUserFriends (FB.tuId testUser1) [] tokenUser1
                   friends2 <- FB.getUserFriends (FB.tuId testUser2) [] tokenUser2
                   FB.pagerData friends1 &?=
                     [ FB.Friend
                         (FB.tuId testUser2)
                         (M.fromJust (FB.userName user2))
                     ]
                   FB.pagerData friends2 &?=
                     [ FB.Friend
                         (FB.tuId testUser1)
                         (M.fromJust (FB.userName user1))
                     ]
  describe' "getTestUsers" $
    do it "gets a list of test users" $
         do runAuth $
              do token <- FB.getAppAccessToken
                 pager <- FB.getTestUsers token
                 src <- FB.fetchAllNextPages pager
                 oldList <- liftIO $ R.runResourceT $ src C.$$ CL.consume
                 withTestUser D.def $
                   \testUser -> do
                     newList <- FB.pagerData <$> FB.getTestUsers token
                     let newList' = map FB.tuId newList
                         oldList' = map FB.tuId oldList
                     ((FB.tuId testUser) `elem` (newList' \\ oldList')) &?= True

newtype PageName =
  PageName Text
  deriving (Eq, Show)

instance A.FromJSON PageName where
  parseJSON (A.Object v) = PageName <$> (v A..: "name")
  parseJSON _ = mzero

libraryTests :: H.Manager -> Spec
libraryTests manager = do
  describe "SimpleType" $
    do it "works for Bool" $ (map FB.encodeFbParam [True, False]) @?= ["1", "0"]
       let day = TI.fromGregorian 2012 12 21
           time = TI.TimeOfDay 11 37 22
           diffTime = TI.secondsToDiffTime (11 * 3600 + 37 * 60)
           utcTime = TI.UTCTime day diffTime
           localTime = TI.LocalTime day time
           zonedTime = TI.ZonedTime localTime (TI.minutesToTimeZone 30)
       it "works for Day" $ FB.encodeFbParam day @?= "2012-12-21"
       it "works for UTCTime" $ FB.encodeFbParam utcTime @?= "20121221T1137Z"
       it "works for ZonedTime" $
         FB.encodeFbParam zonedTime @?= "20121221T1107Z"
       let propShowRead
             :: (Show a, Read a, Eq a, FB.SimpleType a)
             => a -> Bool
           propShowRead x = read (B.unpack $ FB.encodeFbParam x) == x
       prop "works for Float" (propShowRead :: Float -> Bool)
       prop "works for Double" (propShowRead :: Double -> Bool)
       prop "works for Int" (propShowRead :: Int -> Bool)
       prop "works for Int8" (propShowRead :: Int8 -> Bool)
       prop "works for Int16" (propShowRead :: Int16 -> Bool)
       prop "works for Int32" (propShowRead :: Int32 -> Bool)
       prop "works for Int64" (propShowRead :: Int64 -> Bool)
       prop "works for Word" (propShowRead :: Word -> Bool)
       prop "works for Word8" (propShowRead :: Word8 -> Bool)
       prop "works for Word16" (propShowRead :: Word16 -> Bool)
       prop "works for Word32" (propShowRead :: Word32 -> Bool)
       prop "works for Word64" (propShowRead :: Word64 -> Bool)
       let propShowReadL
             :: (Show a, Read a, Eq a, FB.SimpleType a)
             => [a] -> Bool
           propShowReadL x =
             read ('[' : B.unpack (FB.encodeFbParam x) ++ "]") == x
       prop "works for [Float]" (propShowReadL :: [Float] -> Bool)
       prop "works for [Double]" (propShowReadL :: [Double] -> Bool)
       prop "works for [Int]" (propShowReadL :: [Int] -> Bool)
       prop "works for [Int8]" (propShowReadL :: [Int8] -> Bool)
       prop "works for [Int16]" (propShowReadL :: [Int16] -> Bool)
       prop "works for [Int32]" (propShowReadL :: [Int32] -> Bool)
       prop "works for [Int64]" (propShowReadL :: [Int64] -> Bool)
       prop "works for [Word]" (propShowReadL :: [Word] -> Bool)
       prop "works for [Word8]" (propShowReadL :: [Word8] -> Bool)
       prop "works for [Word16]" (propShowReadL :: [Word16] -> Bool)
       prop "works for [Word32]" (propShowReadL :: [Word32] -> Bool)
       prop "works for [Word64]" (propShowReadL :: [Word64] -> Bool)
       prop "works for Text" (\t -> FB.encodeFbParam t == TE.encodeUtf8 t)
       prop "works for Id" $
         \i ->
            let toId :: Int -> FB.Id
                toId = FB.Id . T.pack . show
                j = abs i
            in FB.encodeFbParam (toId j) == FB.encodeFbParam j
  describe "parseSignedRequest" $
    do let exampleSig, exampleData :: B.ByteString
           exampleSig = "vlXgu64BQGFSQrY0ZcJBZASMvYvTHu9GQ0YM9rjPSso"
           exampleData =
             "eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsIjAiOiJwYXlsb2FkIn0"
           exampleCreds = FB.Credentials "name" "id" "secret"
           runExampleAuth :: FB.FacebookT FB.Auth (R.ResourceT IO) a -> IO a
           runExampleAuth = R.runResourceT . FB.runFacebookT exampleCreds manager
       it "works for Facebook example" $
         do runExampleAuth $
              do ret <-
                   FB.parseSignedRequest
                     (B.concat [exampleSig, ".", exampleData])
                 ret &?=
                   Just
                     (A.object
                        [ "algorithm" A..= ("HMAC-SHA256" :: Text)
                        , "0" A..= ("payload" :: Text)
                        ])
       it "fails to parse the Facebook example when signature is corrupted" $
         do let corruptedSig = B.cons 'a' (B.tail exampleSig)
            runExampleAuth $
              do ret <-
                   FB.parseSignedRequest
                     (B.concat [corruptedSig, ".", exampleData])
                 ret &?= (Nothing :: Maybe A.Value)
  describe "FQLTime" $
    do it "seems to work" $
         do let input = "[1348678357]"
                output = FB.FQLTime (read "2012-09-26 16:52:37 UTC")
            A.decode input @?= Just [output]
  describe "FbUTCTime" $
    do let output = FB.FbUTCTime (read "2012-09-26 16:52:37 UTC")
       it "seems to work (string)" $
         do let input = "[\"2012-09-26T16:52:37+0000\"]"
            A.decode input @?= Just [output]
       it "seems to work (unix epoch)" $
         do let input = "[1348678357]"
            A.decode input @?= Just [output]
  describe "FQLList" $
    do let j :: [Int] -> Maybe (FB.FQLList Int)
           j = Just . FB.FQLList
       it "parses []" $ do A.decode "[]" @?= j []
       it "parses {}" $ do A.decode "{}" @?= j []
       it "parses [1234]" $ do A.decode "[1234]" @?= j [1234]
       it "parses {\"1234\": 1234}" $
         do A.decode "{\"1234\": 1234}" @?= j [1234]
  describe "FQLObject" $
    do let j :: [(Text, Int)] -> Maybe (FB.FQLObject (Map.Map Text Int))
           j = Just . FB.FQLObject . Map.fromList
       it "parses []" $ do A.decode "[]" @?= j []
       it "parses {}" $ do A.decode "{}" @?= j []
       it "parses {\"abc\": 1234}" $
         do A.decode "{\"abc\": 1234}" @?= j [("abc", 1234)]
       it "does not parse [1234]" $
         do A.decode "[1234]" @?= (Nothing `asTypeOf` j [])
  describe "Id" $
    do it "can be parsed from a string" $
         do A.decode "[\"1234\"]" @?= Just [FB.Id "1234"]
       it "can be parsed from an integer" $
         do A.decode "[1234]" @?= Just [FB.Id "1234"]
       it "can be parsed from an object with a string" $
         do A.decode "{\"id\": \"1234\"}" @?= Just (FB.Id "1234")
       it "can be parsed from an object with an integer" $
         do A.decode "{\"id\": 1234}" @?= Just (FB.Id "1234")
  describe "AccessToken" $
    do it "can be round-tripped with ToJSON/FromJSON (UserKind)" $
         do A.eitherDecode (A.encode invalidUserAccessToken) @?= Right invalidUserAccessToken
       it "can be round-tripped with ToJSON/FromJSON (AppKind)" $
         do A.eitherDecode (A.encode invalidAppAccessToken) @?= Right invalidAppAccessToken

-- Wrappers for HUnit operators using MonadIO
(&?=)
  :: (Eq a, Show a, MonadIO m)
  => a -> a -> m ()
v &?= e = liftIO (v @?= e)

( #?= )
  :: (Eq a, Show a, MonadIO m)
  => m a -> a -> m ()
m #?= e = m >>= (&?= e)

-- | Sad, orphan instance.
instance QC.Arbitrary Text where
  arbitrary = T.pack <$> QC.arbitrary
  shrink = map T.pack . QC.shrink . T.unpack

-- | Perform an action with a new test user. Remove the new test user
-- after the action is performed.
withTestUser
  :: (R.MonadResource m, R.MonadUnliftIO m, R.MonadThrow m)
  => FB.CreateTestUser
  -> (FB.TestUser -> FB.FacebookT FB.Auth m a)
  -> FB.FacebookT FB.Auth m a
withTestUser ctu action = do
  token <- FB.getAppAccessToken
  E.bracket (FB.createTestUser ctu token) (flip FB.removeTestUser token) action