{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes        #-}
{-# LANGUAGE RecordWildCards   #-}
{-# LANGUAGE TupleSections     #-}
{-# LANGUAGE ViewPatterns      #-}

{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}

module OpenTracing.Zipkin.V1.Thrift
    ( toThriftSpan

    , thriftEncodeSpan
    , thriftEncodeSpans
    )
where

import           Control.Lens
import           Data.Bifunctor
import           Data.Bits
import           Data.ByteString.Builder
import           Data.ByteString          (ByteString)
import qualified Data.ByteString.Lazy     as Lazy
import           Data.ByteString.Lens
import           Data.Foldable            (foldl', toList)
import qualified Data.HashMap.Strict      as HashMap
import           Data.Int
import qualified Data.IP                  as IP
import           Data.List.NonEmpty       (NonEmpty (..))
import           Data.Text.Encoding       (decodeUtf8, encodeUtf8)
import qualified Data.Vector              as Vector
import           OpenTracing.Log
import           OpenTracing.Span
import           OpenTracing.Tags
import           OpenTracing.Time
import           OpenTracing.Types
import           OpenTracing.Zipkin.Types (Endpoint (..))
import qualified Pinch
import           Zipkincore.Types
    ( Annotation (..)
    , BinaryAnnotation (..)
    , Span (..)
    , endpoint_ipv4
    , endpoint_ipv6
    , endpoint_port
    , endpoint_service_name
    )
import qualified Zipkincore.Types         as Thrift


toThriftSpan
    :: Endpoint
    -> LogFieldsFormatter
    -> FinishedSpan
    -> Thrift.Span
toThriftSpan (toThriftEndpoint -> loc) logfmt s = Thrift.Span
    { span_trace_id           = view (spanContext . to traceIdLo') s
    , span_trace_id_high      = view (spanContext . to traceIdHi') s
    , span_name               = view spanOperation s
    , span_id                 = view (spanContext . to ctxSpanID') s
    , span_parent_id          = view (spanContext . to ctxParentSpanID') s
    , span_annotations        = annotations
    , span_binary_annotations = binaryAnnotations
    , span_debug              = Nothing
    , span_timestamp          = Just tstart
    , span_duration           = view (spanDuration . to micros . re _Just) s
    }
  where
    tstart = view (spanStart . to micros) s

    (annotations, binaryAnnotations)
        = bimap Vector.fromList Vector.fromList
        . first (<> annFromLogs (view spanLogs s))
        $ annFromTags (view spanTags s)

    annFromTags :: Tags -> ([Thrift.Annotation], [Thrift.BinaryAnnotation])
    annFromTags = perhapsLocal . foldl' go ([],[]) . HashMap.toList . fromTags
      where
        go acc (SpanKind sk) =
            let ann = Thrift.Annotation
                    { annotation_timestamp = tstart
                    , annotation_host      = Just loc
                    , annotation_value     = case sk of
                          RPCClient -> Thrift.cLIENT_SEND
                          RPCServer -> Thrift.sERVER_RECV
                          Producer  -> Thrift.mESSAGE_SEND
                          Consumer  -> Thrift.mESSAGE_RECV
                    }
             in first (ann:) acc

        go acc (k,v) =
            let (anntyp, annval) = toThriftTag v
                ann              = Thrift.BinaryAnnotation
                    { binaryAnnotation_key             = k
                    , binaryAnnotation_value           = annval
                    , binaryAnnotation_annotation_type = anntyp
                    , binaryAnnotation_host            = Just loc
                    }
             in second (ann:) acc

        -- if we don't have a 'SpanKind', we're supposed to tell Zipkin about us
        -- via a 'BinaryAnnotation'
        perhapsLocal ([],bs) = ([],) . (:bs) $ Thrift.BinaryAnnotation
            { binaryAnnotation_key             = Thrift.lOCAL_COMPONENT
            , binaryAnnotation_value           = encodeUtf8 $ endpoint_service_name loc
            , binaryAnnotation_annotation_type = Thrift.STRING
            , binaryAnnotation_host            = Just loc
            }
        perhapsLocal xs = xs

    annFromLogs :: [LogRecord] -> [Thrift.Annotation]
    annFromLogs = foldl' go []
      where
        go acc (LogRecord t fs) = Thrift.Annotation
            { annotation_timestamp = micros t
            , annotation_host      = Just loc
            , annotation_value     = case fs of
                  (Event x :| []) -> x -- proper zipkin annotation
                  fields          -> decodeUtf8 . Lazy.toStrict . toLazyByteString $ logfmt fields
            }
            : acc

thriftEncodeSpan :: Thrift.Span -> ByteString
thriftEncodeSpan = Pinch.encode Pinch.binaryProtocol

thriftEncodeSpans :: Traversable t => t Thrift.Span -> ByteString
thriftEncodeSpans
     = Pinch.encode Pinch.binaryProtocol
     . toList

toThriftTag :: TagVal -> (Thrift.AnnotationType, ByteString)
toThriftTag (BoolT   v) = (Thrift.BOOL, if v then "1" else "0")
toThriftTag (StringT v) = (Thrift.STRING, view (to encodeUtf8) v)
toThriftTag (IntT    v) = (Thrift.I64, Lazy.toStrict . toLazyByteString . int64BE $ v)
toThriftTag (DoubleT v) = (Thrift.DOUBLE, Lazy.toStrict . toLazyByteString . doubleBE $ v)
toThriftTag (BinaryT v) = (Thrift.BYTES, Lazy.toStrict v)

toThriftEndpoint :: Endpoint -> Thrift.Endpoint
toThriftEndpoint Endpoint{..} = Thrift.Endpoint
    { endpoint_ipv4         = packIPv4 $ fromIPv4 ipv4
    , endpoint_port         = maybe 0 (fromIntegral . fromPort) port
    , endpoint_service_name = serviceName
    , endpoint_ipv6         = packIPv6 . fromIPv6 <$> ipv6
    }
  where
    packIPv4 :: IP.IPv4 -> Int32
    packIPv4 ip =
        let [a,b,c,d] = IP.fromIPv4 ip
         in fromIntegral $ a `shiftL` 24 .|. b `shiftL` 16 .|. c `shiftL` 8 .|. d

    packIPv6 :: IP.IPv6 -> ByteString
    packIPv6 = view packedBytes . map fromIntegral . IP.fromIPv6b


traceIdLo' :: SpanContext -> Int64
traceIdLo' = fromIntegral . traceIdLo . ctxTraceID

traceIdHi' :: SpanContext -> Maybe Int64
traceIdHi' = fmap fromIntegral . traceIdHi . ctxTraceID

ctxSpanID' :: SpanContext -> Int64
ctxSpanID' = fromIntegral . ctxSpanID

ctxParentSpanID' :: SpanContext -> Maybe Int64
ctxParentSpanID' = fmap fromIntegral . ctxParentSpanID